WorldWideScience

Sample records for macrobending single-mode fiber-based

  1. A tunable comb filter using single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop

    Institute of Scientific and Technical Information of China (English)

    Ruan Juan; Zhang Wei-Gang; Zhang Hao; Geng Peng-Cheng; Bai Zhi-Yong

    2013-01-01

    A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated.The filter tunability is achieved by rotating the polarization controller.The spectral shift is dependent on rotation direction and the position of the polarization controller.In addition,the adjustable range achieved by rotating the half-wave-plate polarization controller is twice higher than that of the quarter-wave-plate one.

  2. Few mode fibers based quasi-single mode Raman distributed temperature sensor

    Science.gov (United States)

    Wu, Hao; Wang, Meng; Liu, Tongqing; Yang, Chen; Tong, Weijun; Fu, Songnian; Tang, Ming

    2017-04-01

    We demonstrate a distributed temperature sensor based on quasi-single mode (QSM) Raman scattering in few mode fibers (FMFs). The FMF allows much larger input pump power before the initiate of stimulated Raman scattering compared with the standard single mode fiber (SSMF) and mitigates the detrimental differential mode group delay (DMGD) existing in the conventional multimode fiber (MMF) based Raman distributed temperature sensor (RDTS). Distributed temperature sensing is realized using conventional RDTS hardware over 20km FMFs within 90s, with a spatial resolution of 3m. The temperature resolution is 2.3°C @10km and 6.7°C @20km, respectively.

  3. A new single-mode LMA optical fiber based on an anti-resonance in the cladding

    Science.gov (United States)

    Sharabi, Avidan; Sheintop, Uzziel; Goldin, Shlomo

    2016-03-01

    A novel single-mode large-mode-area (LMA) optical fiber is proposed. The primary part of the cladding is a thin layer with high refractive index. The layer possesses a periodic array of holes (or intrusions) which are either drawn in the propagation direction or drilled in the radial direction. When the holes (or intrusions) are drawn in the propagation direction, the periodicity of their array is in the azimuthal direction. The core may be hollow. The light confinement is achieved via a transmission anti-resonance. Namely, the array of holes allows coupling between an optical mode inside the primary cladding layer and the light both in the core and in the outer space. The light then sees two channels to penetrate the cladding: direct transmission and holes-assisted transmission. A distractive interference between these channels is achieved at an appropriate combination of fiber parameters. The fiber can be designed to hold nearly anyone of TE/TMnm modes. Computer simulations of the fiber were performed using COMSOL. The open boundary was simulated using a perfectly matched layer and the attenuation constants of different modes were determined via the imaginary parts of their propagation constants. As an example, a fiber holding a single TE01 mode inside a core of 100 μm diameter for the vacuum wavelength 1.55 μm was designed. The attenuation constant of the TE01 mode was found to be 5.8 ṡ 10-6 [dB/cm] while the other modes had attenuation of at least 4 orders of magnitude larger. Required fabrication tolerances were calculated and the fabrication of fibers of lengths 10 - 1000 m was found to be feasible. The bandwidth of the fiber was found to be in the range of 5 - 35 nm, depending on its length. Possible applications include high-power CW and pulsed lasers and amplifiers, sensors and others.

  4. Quasi-Rayleigh light scattering by internal elements of a metamaterial in a light-carrying core of a single-mode optical fiber based on the Veselago effect

    Science.gov (United States)

    Malykin, G. B.

    2016-04-01

    At present, single-mode optical fibers composed of metamaterials—so-called "left-handed" optical media—for the far- and mid-IR ranges have already been created. In the near future, left-handed singlemode optical fibers for the visible and near-IR ranges will be created, light-carrying cores of which will be composed by an ordered structure of dielectric elements, the dimensions of which will be much smaller than the light wavelength, while the effective refractive index of the structure will be negative; i.e., the structure will possess the so-called "Veselago effect." We show that, because the dimensions of these dielectric elements many times exceed the dimensions of molecules of optical media, the elements should strongly scatter light, with this scattering considerably exceeding the Rayleigh (molecular) light scattering that occurs in conventional quartz single-mode optical fibers. We propose to term this phenomenon the quasi-Rayleigh light scattering. Numerical estimates of the quasi-Rayleigh light scattering for left-handed single-mode optical fibers at a light wavelength of λ = 1.55 μm have been made.

  5. Single-Mode VCSELs

    Science.gov (United States)

    Larsson, Anders; Gustavsson, Johan S.

    The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.

  6. Macrobend optical sensing for pose measurement in soft robot arms

    Science.gov (United States)

    Sareh, Sina; Noh, Yohan; Li, Min; Ranzani, Tommaso; Liu, Hongbin; Althoefer, Kaspar

    2015-12-01

    This paper introduces a pose-sensing system for soft robot arms integrating a set of macrobend stretch sensors. The macrobend sensory design in this study consists of optical fibres and is based on the notion that bending an optical fibre modulates the intensity of the light transmitted through the fibre. This sensing method is capable of measuring bending, elongation and compression in soft continuum robots and is also applicable to wearable sensing technologies, e.g. pose sensing in the wrist joint of a human hand. In our arrangement, applied to a cylindrical soft robot arm, the optical fibres for macrobend sensing originate from the base, extend to the tip of the arm, and then loop back to the base. The connectors that link the fibres to the necessary opto-electronics are all placed at the base of the arm, resulting in a simplified overall design. The ability of this custom macrobend stretch sensor to flexibly adapt its configuration allows preserving the inherent softness and compliance of the robot which it is installed on. The macrobend sensing system is immune to electrical noise and magnetic fields, is safe (because no electricity is needed at the sensing site), and is suitable for modular implementation in multi-link soft continuum robotic arms. The measurable light outputs of the proposed stretch sensor vary due to bend-induced light attenuation (macrobend loss), which is a function of the fibre bend radius as well as the number of repeated turns. The experimental study conducted as part of this research revealed that the chosen bend radius has a far greater impact on the measured light intensity values than the number of turns (if greater than five). Taking into account that the bend radius is the only significantly influencing design parameter, the macrobend stretch sensors were developed to create a practical solution to the pose sensing in soft continuum robot arms. Henceforward, the proposed sensing design was benchmarked against an electromagnetic

  7. 1Gbps impulse radio ultrawideband multi-hop system employing a single mode fiber repeater

    DEFF Research Database (Denmark)

    Yu, Xianbin; Rodes, Roberto; Jensen, Jesper Bevensee;

    2009-01-01

    We experimentally demonstrate a 1 Gbps impulse radio ultrawideband multi-hop system for wireless-over-fiber applications. The system consists of two 2 m air links and a 23 km single mode fiber based optical repeater......We experimentally demonstrate a 1 Gbps impulse radio ultrawideband multi-hop system for wireless-over-fiber applications. The system consists of two 2 m air links and a 23 km single mode fiber based optical repeater...

  8. Optimize Etching Based Single Mode Fiber Optic Temperature Sensor

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2014-02-01

    Full Text Available This paper presents a description of etching process for fabrication single mode optical fiber sensors. The process of fabrication demonstrates an optimized etching based method to fabricate single mode fiber (SMF optic sensors in specified constant time and temperature. We propose a single mode optical fiber based temperature sensor, where the temperature sensing region is obtained by etching its cladding diameter over small length to a critical value. It is observed that the light transmission through etched fiber at 1550 nm wavelength optical source becomes highly temperature sensitive, compared to the temperature insensitive behavior observed in un-etched fiber for the range on 30ºC to 100ºC at 1550 nm. The sensor response under temperature cycling is repeatable and, proposed to be useful for low frequency analogue signal transmission over optical fiber by means of inline thermal modulation approach.

  9. Single-mode optical fibres

    CERN Document Server

    Cancellieri, G

    1991-01-01

    This book describes signal propagation in single-mode optical fibres for telecommunication applications. Such description is based on the analysis of field propagation, considering waveguide properties and also some of the particular characteristics of the material fibre. The book covers such recent advances as, coherent transmissions; optical amplification; MIR fibres; polarization maintaining; polarization diversity and photon counting.

  10. Experimental Investigation of Macro-Bending Loss in Large Mode Area Photonic Crystal Fibers

    Institute of Scientific and Technical Information of China (English)

    Yinian Zhu; Joo Hin Chong; Ping Shum; Chao Lu

    2003-01-01

    We measured macro-bending losses for two large mode area photonic crystal fibers. Experimental results show that macro-bending loss and loss window are dependent on the parameter d/Λ and number of air-holes ring in the cladding.

  11. Experimental Investigation of Macro-Bending Loss in Large Mode Area Photonic Crystal Fibers

    Institute of Scientific and Technical Information of China (English)

    Joo; Hin; Chong; Ping; Shum

    2003-01-01

    We measured macro-bending losses for two large mode area photonic crystal fibers. Experimental results show that macro-bending loss and loss window are dependent on the parameter d/∧ and number of air-holes ring in the cladding.

  12. Theoretical Design of a Depolarized Interferometric Fiber-Optic Gyroscope (IFOG) on SMF-28 Single-Mode Standard Optical Fiber Based on Closed-Loop Sinusoidal Phase Modulation with Serrodyne Feedback Phase Modulation Using Simulation Tools for Tactical and Industrial Grade Applications.

    Science.gov (United States)

    Pérez, Ramón José; Álvarez, Ignacio; Enguita, José María

    2016-04-27

    This article presents, by means of computational simulation tools, a full analysis and design of an Interferometric Fiber-Optic Gyroscope (IFOG) prototype based on a closed-loop configuration with sinusoidal bias phase- modulation. The complete design of the different blocks, optical and electronic, is presented, including some novelties as the sinusoidal bias phase-modulation and the use of an integrator to generate the serrodyne phase-modulation signal. The paper includes detailed calculation of most parameter values, and the plots of the resulting signals obtained from simulation tools. The design is focused in the use of a standard single-mode optical fiber, allowing a cost competitive implementation compared to commercial IFOG, at the expense of reduced sensitivity. The design contains an IFOG model that accomplishes tactical and industrial grade applications (sensitivity ≤ 0.055 °/h). This design presents two important properties: (1) an optical subsystem with advanced conception: depolarization of the optical wave by means of Lyot depolarizers, which allows to use a sensing coil made by standard optical fiber, instead by polarization maintaining fiber, which supposes consequent cost savings and (2) a novel and simple electronic design that incorporates a linear analog integrator with reset in feedback chain, this integrator generating a serrodyne voltage-wave to apply to Phase-Modulator (PM), so that it will be obtained the interferometric phase cancellation. This particular feedback design with sawtooth-wave generated signal for a closed-loop configuration with sinusoidal bias phase modulation has not been reported till now in the scientific literature and supposes a considerable simplification with regard to previous designs based on similar configurations. The sensing coil consists of an 8 cm average diameter spool that contains 300 m of standard single-mode optical-fiber (SMF-28 type) realized by quadrupolar winding. The working wavelength will be

  13. Theoretical Design of a Depolarized Interferometric Fiber-Optic Gyroscope (IFOG) on SMF-28 Single-Mode Standard Optical Fiber Based on Closed-Loop Sinusoidal Phase Modulation with Serrodyne Feedback Phase Modulation Using Simulation Tools for Tactical and Industrial Grade Applications

    Science.gov (United States)

    Pérez, Ramón José; Álvarez, Ignacio; Enguita, José María

    2016-01-01

    This article presents, by means of computational simulation tools, a full analysis and design of an Interferometric Fiber-Optic Gyroscope (IFOG) prototype based on a closed-loop configuration with sinusoidal bias phase- modulation. The complete design of the different blocks, optical and electronic, is presented, including some novelties as the sinusoidal bias phase-modulation and the use of an integrator to generate the serrodyne phase-modulation signal. The paper includes detailed calculation of most parameter values, and the plots of the resulting signals obtained from simulation tools. The design is focused in the use of a standard single-mode optical fiber, allowing a cost competitive implementation compared to commercial IFOG, at the expense of reduced sensitivity. The design contains an IFOG model that accomplishes tactical and industrial grade applications (sensitivity ≤ 0.055 °/h). This design presents two important properties: (1) an optical subsystem with advanced conception: depolarization of the optical wave by means of Lyot depolarizers, which allows to use a sensing coil made by standard optical fiber, instead by polarization maintaining fiber, which supposes consequent cost savings and (2) a novel and simple electronic design that incorporates a linear analog integrator with reset in feedback chain, this integrator generating a serrodyne voltage-wave to apply to Phase-Modulator (PM), so that it will be obtained the interferometric phase cancellation. This particular feedback design with sawtooth-wave generated signal for a closed-loop configuration with sinusoidal bias phase modulation has not been reported till now in the scientific literature and supposes a considerable simplification with regard to previous designs based on similar configurations. The sensing coil consists of an 8 cm average diameter spool that contains 300 m of standard single-mode optical-fiber (SMF-28 type) realized by quadrupolar winding. The working wavelength will be

  14. Theoretical Design of a Depolarized Interferometric Fiber-Optic Gyroscope (IFOG on SMF-28 Single-Mode Standard Optical Fiber Based on Closed-Loop Sinusoidal Phase Modulation with Serrodyne Feedback Phase Modulation Using Simulation Tools for Tactical and Industrial Grade Applications

    Directory of Open Access Journals (Sweden)

    Ramón José Pérez

    2016-04-01

    Full Text Available This article presents, by means of computational simulation tools, a full analysis and design of an Interferometric Fiber-Optic Gyroscope (IFOG prototype based on a closed-loop configuration with sinusoidal bias phase- modulation. The complete design of the different blocks, optical and electronic, is presented, including some novelties as the sinusoidal bias phase-modulation and the use of an integrator to generate the serrodyne phase-modulation signal. The paper includes detailed calculation of most parameter values, and the plots of the resulting signals obtained from simulation tools. The design is focused in the use of a standard single-mode optical fiber, allowing a cost competitive implementation compared to commercial IFOG, at the expense of reduced sensitivity. The design contains an IFOG model that accomplishes tactical and industrial grade applications (sensitivity ≤ 0.055 °/h. This design presents two important properties: (1 an optical subsystem with advanced conception: depolarization of the optical wave by means of Lyot depolarizers, which allows to use a sensing coil made by standard optical fiber, instead by polarization maintaining fiber, which supposes consequent cost savings and (2 a novel and simple electronic design that incorporates a linear analog integrator with reset in feedback chain, this integrator generating a serrodyne voltage-wave to apply to Phase-Modulator (PM, so that it will be obtained the interferometric phase cancellation. This particular feedback design with sawtooth-wave generated signal for a closed-loop configuration with sinusoidal bias phase modulation has not been reported till now in the scientific literature and supposes a considerable simplification with regard to previous designs based on similar configurations. The sensing coil consists of an 8 cm average diameter spool that contains 300 m of standard single-mode optical-fiber (SMF-28 type realized by quadrupolar winding. The working

  15. Performance study of macro-bending EDFA/Raman hybrid optical fiber amplifiers

    Science.gov (United States)

    Mahran, O.

    2015-10-01

    In this paper, we present an analytical study of a (macro-bending EDFA)/Raman hybrid optical amplifier. The bending radius is 4 mm with EDFA length 10 m with forward pump power in the range (100-500 mW) and Raman amplifier length (12-55 km) with backward pump power variations (80-200 mW) is considered in our model. Due to bending loss in EDFA, the gain of hybrid amplifier is increased to ~7 dB more than the normal EDFA/Raman hybrid amplifier and the noise figure is decreased by ~2 dB rather than without macro-bending EDFA/Raman hybrid amplifier. The signal to noise ratio (OSNR) calculations shows a better performance of macro-bending EDFA/Raman hybrid amplifier than without macro-bending one. A flat gain is obtained in the signal wavelength region (1560-1600 nm), which is the L-band. The calculated results for macro-bending case are compared with experimental results of normal case by Lee et al., in the L-band showing an increase in the gain, reduction in the noise figure and more gain flatness at the input signal -20 dBm for macro-bending EDFA/Raman hybrid amplifier.

  16. A Temperature Sensor Based on a Polymer Optical Fiber Macro-Bend

    Science.gov (United States)

    Moraleda, Alberto Tapetado; García, Carmen Vázquez; Zaballa, Joseba Zubia; Arrue, Jon

    2013-01-01

    The design and development of a plastic optical fiber (POF) macrobend temperature sensor is presented. The sensor has a linear response versus temperature at a fixed bend radius, with a sensitivity of 1.92·10−3 (°C)−1. The sensor system used a dummy fiber-optic sensor for reference purposes having a resolution below 0.3 °C. A comprehensive experimental analysis was carried out to provide insight into the effect of different surrounding media on practical macro-bend POF sensor implementation. Experimental results are successfully compared with bend loss calculations. PMID:24077323

  17. A Temperature Sensor Based on a Polymer Optical Fiber Macro-Bend

    Directory of Open Access Journals (Sweden)

    Joseba Zubia Zaballa

    2013-09-01

    Full Text Available The design and development of a plastic optical fiber (POF macrobend temperature sensor is presented. The sensor has a linear response versus temperature at a fixed bend radius, with a sensitivity of . The sensor system used a dummy fiber-optic sensor for reference purposes having a resolution below 0.3 °C. A comprehensive experimental analysis was carried out to provide insight into the effect of different surrounding media on practical macro-bend POF sensor implementation. Experimental results are successfully compared with bend loss calculations.

  18. Highly birefringent single mode spiral shape photonic crystal fiber based sensor for gas sensing applications

    Directory of Open Access Journals (Sweden)

    Md. Ibadul Islam

    2017-06-01

    Full Text Available This article represents a gas sensor based on spiral photonic crystal fiber (S-PCF for detecting harmful or colorless gasses and monitoring air pollution by metering gas condensate elements in production facilities. The proposed micro-structured S-PCF contains two layers porous core encircled by a spiral shape cladding. The geometrical parameters are tuned to fix the optimized S-PCF structure. The numerical analysis of the proposed S-PCF is performed by utilizing finite element method (FEM with circular perfectly match layer (C-PML. The relative sensitivity and birefringence of the recommended structure are 57.61% and 7.53 × 10−3 respectively at 1.33 μm wavelength on the absorption line of toxic gasses (methane and hydrogen fluoride. The exhibited beam divergence is about 4.1° at the same wavelength. Besides, beat length, nonlinear coefficient, effective area and V parameters are also described briefly for optimized S-PCF structure over broader wavelength range from 1 μm to 1.8 μm.

  19. Single-mode biological distributed feedback laser

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Maier-Flaig, Florian; Lemmer, Uli

    2013-01-01

    Single-mode second order distributed feedback (DFB) lasers of riboflavin (vitamin B2) doped gelatine films on nanostructured low refractive index material are demonstrated. Manufacturing is based on a simple UV nanoimprint and spin-coating. Emission wavelengths of 543 nm and 562 nm for two...

  20. Properties of Single Mode Polymer Optical Fiber

    Institute of Scientific and Technical Information of China (English)

    YANG Dong-xiao

    2003-01-01

    The density,dynamic modulus,Young's modulus,tensile strength,extension properties,Fourier transform infrared spectrum and differential scanning calorimetry have been measured and discussed for single mode polymethyl-methacrylate optical fiber.The results show that the fiber can provide large strain range for polymeric optical fiber Bragg gratings.

  1. Single-mode glass waveguide technology for optical interchip communication on board level

    Science.gov (United States)

    Brusberg, Lars; Neitz, Marcel; Schröder, Henning

    2012-01-01

    The large bandwidth demand in long-distance telecom networks lead to single-mode fiber interconnects as result of low dispersion, low loss and dense wavelength multiplexing possibilities. In contrast, multi-mode interconnects are suitable for much shorter lengths up to 300 meters and are promising for optical links between racks and on board level. Active optical cables based on multi-mode fiber links are at the market and research in multi-mode waveguide integration on board level is still going on. Compared to multi-mode, a single-mode waveguide has much more integration potential because of core diameters of around 20% of a multi-mode waveguide by a much larger bandwidth. But light coupling in single-mode waveguides is much more challenging because of lower coupling tolerances. Together with the silicon photonics technology, a single-mode waveguide technology on board-level will be the straight forward development goal for chip-to-chip optical interconnects integration. Such a hybrid packaging platform providing 3D optical single-mode links bridges the gap between novel photonic integrated circuits and the glass fiber based long-distance telecom networks. Following we introduce our 3D photonic packaging approach based on thin glass substrates with planar integrated optical single-mode waveguides for fiber-to-chip and chip-to-chip interconnects. This novel packaging approach merges micro-system packaging and glass integrated optics. It consists of a thin glass substrate with planar integrated singlemode waveguide circuits, optical mirrors and lenses providing an integration platform for photonic IC assembly and optical fiber interconnect. Thin glass is commercially available in panel and wafer formats and characterizes excellent optical and high-frequency properties. That makes it perfect for microsystem packaging. The paper presents recent results in single-mode waveguide technology on wafer level and waveguide characterization. Furthermore the integration in a

  2. Investigation of load effect on macro-bend losses for an SMS fiber structure with a small bend radius

    Science.gov (United States)

    Rahmah, Fitri; Sekartedjo, Sekartedjo; Hatta, Agus Muhamad

    2016-11-01

    Modelling of load effect on macro-bend losses for a singlemode-multimode-singlemode (SMS) fiber structure with small bend radius is presented. Load effect on macro-bend losses for the SMS fiber structure placed between two high-density polyethylene (HDPE) boards are investigated theoretically and experimentally. A model on macro-bend losses for SMS fiber structure is constructed by using the light transmission formula in a straight SMS fiber structure and taking into account the effective number of guided modes due to the macrobending. In the experimental, a mandrel with a diameter of 0.8 mm is used to induce the bend. When the loads are applied on the system, the mandrel will affect the bend losses for the SMS fiber structure. It is shown numerically and experimentally that the bend-loss of SMS fiber structure strongly depends on the applied loads and the multimode fiber (MMF) lengths.

  3. Macrobending Loss Measurements of G.657 Fiber with Suppression of Ripple Effect Induced by Whispering Gallery Modes

    Science.gov (United States)

    Li, Chunsheng; Wang, Tao; Li, Linyin; Zhang, Xiaoguang

    2016-02-01

    During the macrobending loss performance tests of ITU-T G.657 fiber under small bending radius, the test results show big differencesin many tests for the same test samples and conditions. Research shows that the main reason for the difference is Whispering gallery modes phenomenon in small bending radius [1]. The inappropriate test conditions can affect the accuracy of macrobending loss test results. In the test of product validation and field application, single wavelength light source and optical power meter were often used. How to judge whether there is effect existing and how to remove the Whispering gallery modes influence in the testing process has become the key to correctly test macrobending loss by light source and optical power meter. This paper introduces the method of eliminating Whispering gallery modes effect during the macrobending test under small bending radius by single wavelength light source and optical power meter.

  4. Endlessly single-mode photonic crystal fiber as a high resolution probe.

    Science.gov (United States)

    Valtna-Lukner, Heli; Repän, Jaagup; Valdma, Sandhra-Mirella; Piksarv, Peeter

    2016-11-20

    We sample ultra-broadband light, focused onto a diffraction-limited spot, to an endlessly single-mode photonic crystal fiber (ESM) and detect both the field amplitude and phase using a SEA TADPOLE interferometer. We resolve spatial features up to 2.5 times finer than the fiber mode size while sampling the periodic features of the bipolar oscillating field in the transverse section. The resolution enhancement is expected also in other types of single-mode fibers in intensity measurements and leads to an inexpensive method for characterizing the point-spread function of such optical fields, e.g., diffraction-limited spots from microscope objectives. In addition, we demonstrate the guidance of a high-NA light field in the fine structure of an ESM fiber mode. The results are especially valuable for devices where a fiber tip acts as an input slit and defines the spatial resolution, e.g., fiber-based interferometers, spectrometers, and sensors.

  5. Single-mode fiber, velocity interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Krauter, K. G.; Jacobson, G. F.; Patterson, J. R.; Nguyen, J. H.; Ambrose, W. P. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore California 94551 (United States)

    2011-04-15

    In this paper, we describe a velocity interferometer system based entirely on single-mode fiber optics. This paper includes a description of principles used in developing the single-mode velocity interferometry system (SMV). The SMV design is based on polarization-insensitive components. Polarization adjusters are included to eliminate the effects of residual birefringence and polarization dependent losses in the interferometers. Characterization measurements and calibration methods needed for data analysis and a method of data analysis are described. Calibration is performed directly using tunable lasers. During development, we demonstrated its operation using exploding-foil bridge-wire fliers up to 200 m/s. In a final test, we demonstrated the SMV in a gas gun experiment up to 1.2 km/sec. As a basis for comparison in the gas gun experiment, we used another velocimetry technique that is also based on single-mode fiber optics: photonic Doppler velocimetry (PDV). For the gas gun experiment, we split the light returned from a single target spot and performed a direct comparison of the homodyne (SMV) and heterodyne (PDV) techniques concurrently. The two techniques had a negligible mean difference and a 1.5% standard deviation in the one-dimensional shock zone. Within one interferometer delay time after a sudden Doppler shift, a SMV unencumbered by multimode-fiber dispersion exhibits two color beats. These beats have the same period as PDV beats--this interference occurs between the ''recently'' shifted and ''formerly unshifted'' paths within the interferometer. We believe that recognizing this identity between homodyne and heterodyne beats is novel in the shock-physics field. SMV includes the conveniences of optical fiber, while removing the time resolution limitations associated with the multimode delivery fiber.

  6. Alcohol sensor based on single-mode-multimode-single-mode fiber structure

    Science.gov (United States)

    Mefina Yulias, R.; Hatta, A. M.; Sekartedjo, Sekartedjo

    2016-11-01

    Alcohol sensor based on Single-mode -Multimode-Single-mode (SMS) fiber structure is being proposed to sense alcohol concentration in alcohol-water mixtures. This proposed sensor uses refractive index sensing as its sensing principle. Fabricated SMS fiber structure had 40 m of multimode length. With power input -6 dBm and wavelength 1550 nm, the proposed sensor showed good response with sensitivity 1,983 dB per % v/v with measurement range 05 % v/v and measurement span 0,5% v/v.

  7. A novel periodic macrobending hetero-core fiber optic sensor embedded in textile for respiratory movements' analysis

    Science.gov (United States)

    Alemdar, Kubra; Likoglu, Sumeyra; Fidanboylu, Kemal; Toker, Onur

    2014-03-01

    This paper presents the design of a novel periodic macrobending hetero-core fiber optic sensor embedded in textile for respiratory movements' analysis. We report on several different designs based on textiles which have different loop periodicity and configuration of optical fiber types. In all experiments, the changes of textile elongation are measured during breathing movements. In order to demonstrate the superiority of the proposed sensor, experiments were done on a macrobending sensor constructed from 62.5-50-62.5 hetero-core fiber and a macrobending sensor constructed from 62.5/125 μm multi-mode fiber having different loops. Experimental results show that the sensitivity of the proposed macrobending sensor constructed using hetero-core optical fiber is much higher than the sensor constructed from plain multi-mode optical fiber. It is also shown that, the sensitivity of the sensor increases as the number of loops is increased. On the other hand, several experiments were performed for periodic macrobending sensors having different bending radius by changing the lengths of loops amplitude and period. We demonstrate that the sensors tested on different patients' morphology can successfully sense respiratory movements.

  8. Single-Mode Soft Glass Fibres

    Science.gov (United States)

    Jedrzejewski, Kazimierz

    1990-01-01

    The technology of single-mode optical soft glass fibres is developed. The well-known rod in tube technique with multiple sleeving was taken to achieve proper dimensions. The ultrasonic mill-drill was used to prepare different structures: high ▵ , high birefringent, D-shaped, multicore, metal wire/glass compound and doped. The temperature processes were carried out very carefully to avoid glass decomposition. The geometry, refractive index profiles, mode near field patterns and λc agreed with the predicted and material data. The losses were reasonably low, better then 370 dB/km (800 nm). The enhanced Verdet constants and nonlinear coefficients values, high dopants levels and other special properties including low process temperatures are very attractive for fibre short range applications, sensors and devices e.g. polarizers, couplers, lasers, filters.

  9. Pulse distortion in single-mode fibers.

    Science.gov (United States)

    Marcuse, D

    1980-05-15

    A theory is presented of the propagation of Gaussian pulses in single-mode optical fibers by expanding the propagation constant in a Taylor series that includes the third derivative with respect to frequency. The light source is assumed to have a Gaussian spectral distribution whose width relative to the width of the Gaussian signal pulse is arbitrary. Formulas are derived for the spectrum of the ensemble average of the optical pulse, from which the shape of the average pulse itself is obtained by the fast Fourier transform. Also derived is an expression for the rms pulse width. The theory is applicable at all wavelengths including the vicinity of the zero first-order dispersion point.

  10. Single mode, extreme precision Doppler spectrographs

    CERN Document Server

    Schwab, Christian; Betters, Christopher H; Bland-Hawthorn, Joss; Mahadevan, Suvrath

    2012-01-01

    The 'holy grail' of exoplanet research today is the detection of an earth-like planet: a rocky planet in the habitable zone around a main-sequence star. Extremely precise Doppler spectroscopy is an indispensable tool to find and characterize earth-like planets; however, to find these planets around solar-type stars, we need nearly one order of magnitude better radial velocity (RV) precision than the best current spectrographs provide. Recent developments in astrophotonics (Bland-Hawthorn & Horton 2006, Bland-Hawthorn et al. 2010) and adaptive optics (AO) enable single mode fiber (SMF) fed, high resolution spectrographs, which can realize the next step in precision. SMF feeds have intrinsic advantages over multimode fiber or slit coupled spectrographs: The intensity distribution at the fiber exit is extremely stable, and as a result the line spread function of a well-designed spectrograph is fully decoupled from input coupling conditions, like guiding or seeing variations (Ihle et al. 2010). Modal noise, a...

  11. Single Mode, Extreme Precision Doppler Spectrographs

    Science.gov (United States)

    Schwab, Christian; Leon-Saval, Sergio G.; Betters, Christopher H.; Bland-Hawthorn, Joss; Mahadevan, Suvrath

    2014-04-01

    The `holy grail' of exoplanet research today is the detection of an earth-like planet: a rocky planet in the habitable zone around a main-sequence star. Extremely precise Doppler spectroscopy is an indispensable tool to find and characterize earth-like planets; however, to find these planets around solar-type stars, we need nearly one order of magnitude better radial velocity (RV) precision than the best current spectrographs provide. Recent developments in astrophotonics (Bland-Hawthorn & Horton 2006, Bland-Hawthorn et al. 2010) and adaptive optics (AO) enable single mode fiber (SMF) fed, high resolution spectrographs, which can realize the next step in precision. SMF feeds have intrinsic advantages over multimode fiber or slit coupled spectrographs: The intensity distribution at the fiber exit is extremely stable, and as a result the line spread function of a well-designed spectrograph is fully decoupled from input coupling conditions, like guiding or seeing variations (Ihle et al. 2010). Modal noise, a limiting factor in current multimode fiber fed instruments (Baudrand & Walker 2001), can be eliminated by proper design, and the diffraction limited input to the spectrograph allows for very compact instrument designs, which provide excellent optomechanical stability. A SMF is the ideal interface for new, very precise wavelength calibrators, like laser frequency combs (Steinmetz et al. 2008, Osterman et al. 2012), or SMF based Fabry-Perot Etalons (Halverson et al. 2013). At near infrared wavelengths, these technologies are ready to be implemented in on-sky instruments, or already in use. We discuss a novel concept for such a spectrograph.

  12. Crosstalk-Managed Heterogeneous Single-Mode 32-Core Fibre

    DEFF Research Database (Denmark)

    Sasaki, Y.; Fukumoto, Ryohei; Takenaga, Katsuhiro

    2016-01-01

    A heterogeneous single-mode 32-core fibre with a cladding diameter of 243 micrometer is designed and fabricated. The highest core count in single-mode multi-core fibres and low worst-case crosstalk of less than -24 dB/1000 km in C-band are achieved simultaneously.......A heterogeneous single-mode 32-core fibre with a cladding diameter of 243 micrometer is designed and fabricated. The highest core count in single-mode multi-core fibres and low worst-case crosstalk of less than -24 dB/1000 km in C-band are achieved simultaneously....

  13. Single-mode fiber systems for deep space communication network

    Science.gov (United States)

    Lutes, G.

    1982-01-01

    The present investigation is concerned with the development of single-mode optical fiber distribution systems. It is pointed out that single-mode fibers represent potentially a superior medium for the distribution of frequency and timing reference signals and wideband (400 MHz) IF signals. In this connection, single-mode fibers have the potential to improve the capability and precision of NASA's Deep Space Network (DSN). Attention is given to problems related to precise time synchronization throughout the DSN, questions regarding the selection of a transmission medium, and the function of the distribution systems, taking into account specific improvements possible by an employment of single-mode fibers.

  14. Transmission loss between single-mode Gaussian antennas.

    Science.gov (United States)

    Perlot, Nicolas; Rohde, Michael

    2016-08-22

    We analytically derive a set of formulas for the transmission loss in vacuum between antennas that send and receive single-mode Gaussian beams. We relate our results to standard far-field link budget parameters.

  15. Design and characterization of a wearable macrobending fiber optic sensor for human joint angle determination

    Science.gov (United States)

    Silva, Ana S.; Catarino, André; Correia, Miguel V.; Frazão, Orlando

    2013-12-01

    The work presented here describes the development and characterization of intensity fiber optic sensor integrated in a specifically designed piece of garment to measure elbow flexion. The sensing head is based on macrobending incorporated in the garment, and the increase of curvature number was studied in order to investigate which scheme provided a good result in terms of sensitivity and repeatability. Results showed the configuration that assured a higher sensitivity (0.644 dBm/deg) and better repeatability was the one with four loops. Ultimately, this sensor can be used for rehabilitation purposes to monitor human joint angles, namely, elbow flexion on stroke survivors while performing the reach functional task, which is the most common upper-limb human gesture.

  16. Fiber optic macro-bend based sensor for detection of metal loss

    Science.gov (United States)

    Li, Weijie; Ho, Siu Chun Michael; Luo, Mingzhang; Huynh, Quyen; Song, Gangbing

    2017-04-01

    Metal loss in metallic structures, often as a result of corrosion, is a severe problem across multiple industries. Catastrophic consequence of structural failure due to such loss of structural metal requires an accurate determination and assessment of corrosion. Widely used electrochemical methods can only suggest the likelihood of the metal loss due to corrosion while failing to provide a quantitative measure of the accumulated amount of corrosion. Due to its unique advantages such as small size, light weight, resistance to electromagnetic interference and corrosion, fiber optic sensing technique has been emerging as a promising alternative for most sensing applications. In this paper, a novel type of ferromagnetic distance-based metal loss sensor is proposed based on the principle of fiber optic macro-bend loss. The proposed sensor is composed of the bended optical fiber, the magnet and a spring. The magnet is connected to the spring and the fiber bend is attached to the spring in such a way that the movement of the magnet will induce a change in bending radius of the optical fiber. Metal loss in the monitored sample increases the distance between the magnet and the metal surface and thereby reducing the magnetic force. A change in magnetic force will lead to the variation in light intensity loss of the fiber optic macro-bend, thus metal loss, such as in the form of corrosion pits, can be detected by the proposed metal loss sensor. The practicality of the proposed distance sensor for metal loss measurement is validated through scanning the fabricated corrosion samples.

  17. General model of signal propagation in a Raman amplified single-mode fiber based coherent optical communication system

    Science.gov (United States)

    Cheng, Jingchi; Tang, Ming; Fu, Songnian; Shum, Perry Ping; Liu, Deming

    2016-12-01

    The distributed Raman amplifier (DRA) has been widely utilized in state-of-the-art coherent optical communication systems using multi-level modulation formatted signals in order to improve transmission performance. A general model based on Jones vector notation governing the signal propagation under Raman amplified link is proposed. Primary physics including both linear and nonlinear effects have been taken into account. The numerical approach for solving the equations is illustrated in detail. Using the model, system characterization and optimization can be easily performed. We also compare our model with the commonly used coarse-step method. It is found that the coarse-step method will exaggerate the cross-polarization modulation induced impairments by over 6 dB and will become unusable when the pump power is as high as several Watts. The proposed model provides a guideline for the simulation of Raman amplified coherent transmission systems.

  18. Spectrally tailored supercontinuum generation from single-mode-fiber amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Qiang; Guo, Zhengru; Zhang, Qingshan [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); Liu, Yang; Li, Wenxue [State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 Zhongshan North Road, Shanghai 200062 (China); Zeng, Heping, E-mail: hpzeng@phy.ecnu.edu.cn [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 Zhongshan North Road, Shanghai 200062 (China)

    2014-05-19

    Spectral filtering of an all-normal-dispersion Yb-doped fiber laser was demonstrated effective for broadband supercontinuum generation in the picosecond time region. The picosecond pump pulses were tailored in spectrum with 1 nm band-pass filter installed between two single-mode fiber amplifiers. By tuning the spectral filter around 1028 nm, four-wave mixing was initiated in a photonic crystal fiber spliced with single-mode fiber, as manifested by the simultaneous generation of Stokes wave at 1076 nm and anti-Stokes wave at 984 nm. Four-wave mixing took place in cascade with the influence of stimulated Raman scattering and eventually extended the output spectrum more than 900 nm of 10 dB bandwidth. This technique allows smooth octave supercontinuum generation by using simple single-mode fiber amplifiers rather than complicated multistage large-mode-area fiber amplifiers.

  19. Compact Single-Mode Distributed Bragg Reflector Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    XUE Yi-Yuan; AN Hong-Lin; FU Li-Bin; LIN Xiang-Zhi; LIU Hong-Du

    2000-01-01

    A compact single-mode distributed Bragg reflector (DBR) fiber laser with narrow spectral linewidth is investigated. Firstly, based on our theoretical analysis the single longitudinal mode operation domain is obtained. Then, a single-mode DBR fiber laser of 7.9cm long with master oscillator power amplifier (MOPA) configuration is designed and constructed to operate in the single-mode domain. The fiber laser is pumped by a semiconductor laser at 975.5nm. The master oscillator operates at 1556.91 nm with a cw output power of 1.43mW for a pump power of 55.35 mW. Its slope efficiency is 2.7% and the spectral linewidth is less than 1.2MHz (instrument resolution limited). With the MOPA configuration the laser output power and slope efficiency are increased to 7.8mW and 16.9%, respectively.

  20. Quasi-single-mode homogeneous 31-core fibre

    DEFF Research Database (Denmark)

    Sasaki, Y.; Saitoh, S.; Amma, Y.

    2015-01-01

    A homogeneous 31-core fibre with a cladding diameter of 230 μm for quasi-single-mode transmission is designed and fabricated. LP01-crosstalk of -38.4 dB/11 km at 1550 nm is achieved by using few-mode trench-assisted cores.......A homogeneous 31-core fibre with a cladding diameter of 230 μm for quasi-single-mode transmission is designed and fabricated. LP01-crosstalk of -38.4 dB/11 km at 1550 nm is achieved by using few-mode trench-assisted cores....

  1. Equalization of dispersion in single-mode fibers.

    Science.gov (United States)

    Marcuse, D

    1981-02-15

    Optical pulse equalization in single-mode fibers using positive and negative chromatic dispersion has been demonstrated by Lin et al. [Opt. Lett. 5, 476 (1980)]. In this paper, an earlier theory of pulse propagation in single-mode fibers is extended to the case of a tandem arrangement of N fibers with different dispersive properties. The theory includes first- and second-order dispersion. It is shown that, by using fibers with positive and negative chromatic dispersion, the first-order dispersion term cancels out on average.

  2. Chirped Optical Solitons in Single-mode Birefringent Fibers.

    Science.gov (United States)

    Mahmood, M F

    1996-12-01

    The trapping behavior of two chirped solitons forming a bound state in a single-mode birefringent fiber is investigated on the basis of a model of coupled nonlinear Schroedinger equations. The positive initial chirp plays an important role in controlling the threshold amplitude for soliton trapping without causing excessive pulse broadening.

  3. Single-mode nonclassicality criteria via Holstein-Primakoff transformation

    CERN Document Server

    Tasgin, Mehmet Emre

    2015-01-01

    Recently, two quantifications for nonclassicality of a single-mode field are shown to be equivalent; (i) the rank of entanglement it can generate by a beam-splitter and (ii) the number of terms needed to expand it as superposition of coherent states. We show that nonclassicality criteria can be obtained with an alternative approach. The rank of two-mode entanglement among 2-level identical particles converges to the rank of single-mode nonclassicality within the Holstein-Primakoff transformation, at the large particle number limit. In particular, we show that the entanglement criterion of Hillery & Zubairy converges to the Mandel's $Q$-parameter which is used to reveal nonclassicality, and spin-squeezing criterion of S{\\o}rensen et al. converges to single-mode squeezing condition. We obtain additional nonclassicality criteria not existing in the literature. We also discuss if single-mode nonclassicality can be visualized as the entanglement of space generating the photons. Moreover, in a forthcoming study...

  4. A Wide-Range Displacement Sensor Based on Plastic Fiber Macro-Bend Coupling.

    Science.gov (United States)

    Liu, Jia; Hou, Yulong; Zhang, Huixin; Jia, Pinggang; Su, Shan; Fang, Guocheng; Liu, Wenyi; Xiong, Jijun

    2017-01-20

    This paper proposes the strategy of fabricating an all fiber wide-range displacement sensor based on the macro-bend coupling effect which causes power transmission between two twisted bending plastic optical fibers (POF), where the coupling power changes with the bending radius of the fibers. For the sensor, a structure of two twisted plastic fibers is designed with the experimental platform that we constructed. The influence of external temperature and displacement speed shifts are reported. The displacement sensor performance is the sensor test at different temperatures and speeds. The sensor was found to be satisfactory at both room temperature and 70 °C when the displacement is up to 140 mm. The output power is approximately linear to a displacement of 110 mm-140 mm under room temperature and 2 mm/s speed at 19.805 nW/mm sensitivity and 0.12 mm resolution. The simple structure of the sensor makes it reliable for other applications and further utilizations, promising a bright future.

  5. A Wide-Range Displacement Sensor Based on Plastic Fiber Macro-Bend Coupling

    Directory of Open Access Journals (Sweden)

    Jia Liu

    2017-01-01

    Full Text Available This paper proposes the strategy of fabricating an all fiber wide-range displacement sensor based on the macro-bend coupling effect which causes power transmission between two twisted bending plastic optical fibers (POF, where the coupling power changes with the bending radius of the fibers. For the sensor, a structure of two twisted plastic fibers is designed with the experimental platform that we constructed. The influence of external temperature and displacement speed shifts are reported. The displacement sensor performance is the sensor test at different temperatures and speeds. The sensor was found to be satisfactory at both room temperature and 70 °C when the displacement is up to 140 mm. The output power is approximately linear to a displacement of 110 mm–140 mm under room temperature and 2 mm/s speed at 19.805 nW/mm sensitivity and 0.12 mm resolution. The simple structure of the sensor makes it reliable for other applications and further utilizations, promising a bright future.

  6. Research on high-temperature sensing characteristics based on modular interference of single-mode multimode single-mode fiber

    Science.gov (United States)

    Peng, Zhaozhuang; Wang, Li; Yan, Huanhuan

    2016-11-01

    Application of high temperature fiber sensing system is very extensive. It can be mainly used in high temperature test aerospace, such as, materials, chemicals, and energy. In recent years, various on-line optical fiber interferometric sensors based on modular interference of single-mode-multimode-single-mode(SMS) fiber have been largely explored in high temperature fiber sensor. In this paper we use the special fiber of a polyimide coating, its sensor head is composed of a section of multimode fiber spliced in the middle of Single-mode fiber. When the light is launched into the multimode fiber(MMF) through the lead-in single-mode fiber(SMF), the core mode and cladding modes are excited and propagate in the MMF respectively. Then, at the MMF-SMF spliced point, the excited cladding modes coupled back into the core of lead-out SMF interfere with SMF core mode. And the wavelength of the interference dip would shift differently with the variation of the temperature. By this mean, we can achieve the measurement of temperature. The experimental results also show that the fiber sensor based on SMS structure has a highly temperature sensitivity. From 30° to 300°, with the temperature increasing, the interference dip slightly shifts toward longer wavelength and the temperature sensitivity coefficient is 0.0115nm/°. With high sensitivity, simple structure, immunity to electromagnetic interferences and a good linearity of the experimental results, the structure has an excellent application prospect in engineering field.

  7. The influence of temperature to a refractive index sensor based on a macro-bending tapered plastic optical fiber

    Science.gov (United States)

    Teng, Chuan-xin; Yu, Fang-da; Jing, Ning; Zheng, Jie

    2016-09-01

    The temperature influence to a refractive index (RI) sensor based on a macro-bending tapered plastic optical fiber (POF) was investigated experimentally. The total temperature dependence loss (TDLtotal) and total temperature dependence RI deviation (TDRtotal) were measured at different temperature (10-60 °C) over an RI range of 1.33-1.41. The temperature dependence RI deviation of the sensor itself was obtained by subtracting the temperature dependence RI of measured liquid from TDRtotal. Therefore, the influence of temperature variation to the sensor was characterized and corrected.

  8. Spectropolarimetric interferometer based on single-mode glass waveguides.

    Science.gov (United States)

    Qi, Zhi-Mei; Xia, Shanhong; Matsuda, Naoki

    2008-02-04

    A novel simple spectropolarimetric interferometer was developed based on single-mode potassium ion-exchanged (PIE) glass waveguides that generally have a large birefringence due to the compressive stress induced in the ion-exchanged layers. By using the spectropolarimetric interferometry, wavelength dependence of the modal birefringence of single-mode PIE waveguides was accurately obtained in a broad bandwidth, without need to measure individual modal indices. The modal birefringence decreases with increasing wavelength. The spectropolarimetric interferometer was demonstrated to be responsive to changes occurring within the penetration depth of the evanescent field. A refractive-index change of Deltan = 0.002 was easily detected in the case of a 2-cm-long interaction path length.

  9. Single-mode squeezing in arbitrary spatial modes

    CERN Document Server

    Semmler, Marion; Chille, Vanessa; Gabriel, Christian; Banzer, Peter; Aiello, Andrea; Marquardt, Christoph; Leuchs, Gerd

    2016-01-01

    As the generation of squeezed states of light has become a standard technique in laboratories, attention is increasingly directed towards adapting the optical parameters of squeezed beams to the specific requirements of individual applications. It is known that imaging, metrology, and quantum information may benefit from using squeezed light with a tailored transverse spatial mode. However, experiments have so far been limited to generating only a few squeezed spatial modes within a given setup. Here, we present the generation of single-mode squeezing in Laguerre-Gauss and Bessel-Gauss modes, as well as an arbitrary intensity pattern, all from a single setup using a spatial light modulator (SLM). The degree of squeezing obtained is limited mainly by the initial squeezing and diffractive losses introduced by the SLM, while no excess noise from the SLM is detectable at the measured sideband. The experiment illustrates the single-mode concept in quantum optics and demonstrates the viability of current SLMs as fl...

  10. Single mode variable-sensitivity fiber optic sensors

    Science.gov (United States)

    Murphy, K. A.; Fogg, B. R.; Gunther, M. F.; Claus, R. O.

    1992-01-01

    We review spatially-weighted optical fiber sensors that filter specific vibration modes from one dimensional beams placed in clamped-free and clamped-clamped configurations. The sensitivity of the sensor is varied along the length of the fiber by tapering circular-core, dual-mode optical fibers. Selective vibration mode suppression on the order of 10 dB was obtained. We describe experimental results and propose future extensions to single mode sensor applications.

  11. High-power single-mode trench-assisted EDFA

    Science.gov (United States)

    Gaur, Ankita; Rastogi, Vipul

    2015-06-01

    A trench assisted, 0.15-NA, effective single mode leaky Erbium Doped Fiber Amplifier is proposed for high power applications. The segmented-core of the fiber enables to achieve 783 μm2 mode area which reduces nonlinearity and increases power handling capacity of the fiber. The leakage loss of the modes is controlled by annular core segments and low index trench in the cladding. The leakage loss of the LP11 mode is 10.49 dB/m and that of the fundamental mode is 0.017 dB/m at 1530 nm wavelength. We have injected 20 mW power into each mode and have calculated the gain for 26 m length of the fiber using 250 W pump at 980 nm wavelength. The signal power in the LP01 mode is amplified to 122 W and that in the LP11 mode drops down to 5.78×10-27 W. The low output signal power in LP11 mode ensures selective single mode amplification of fundamental mode. Selective single mode amplification confirms good beam quality at the output end.

  12. Liquid level sensor based on fiber ring laser with single-mode-offset coreless-single-mode fiber structure

    Science.gov (United States)

    Wang, Zixiao; Tan, Zhongwei; Xing, Rui; Liang, Linjun; Qi, Yanhui; Jian, Shuisheng

    2016-10-01

    A novel reflective liquid level sensor based on single-mode-offset coreless-single-mode (SOCS) fiber structure is proposed and experimentally demonstrated. Theory analyses and experimental results indicate that offset fusion can remarkably enhance the sensitivity of sensor. Ending-reflecting structure makes the sensor compact and easy to deploy. Meanwhile, we propose a laser sensing system, and the SOCS structure is used as sensing head and laser filter simultaneously. Experimental results show that laser spectra with high optical signal-to-noise ratio (-30 dB) and narrow 3-dB bandwidth (<0.15 nm) are achieved. Various liquids with different indices are used for liquid level sensing, besides, the refractive index sensitivity is also investigated. In measurement range, the sensing system presents steady laser output.

  13. Multi-Beam Interference Transmission Spectrum Observed from an Eccentric Core Single-Mode Fiber

    Institute of Scientific and Technical Information of China (English)

    FAN Un-Yong; JIANG Wei-Wei; ZHAO Rui-Feng; PEI Li; JIAN Shui-Sheng

    2011-01-01

    @@ An eccentric core single-mode fiber, whose core is away from the axis of the fiber, is fabricated by using the fiber preform goniometric-groove method and the stack-and-draw method.An eccentric core single-mode fiber without coating is spliced between two single-mode fibers.Fundamental mode and cladding modes are excited at one splicing point between the eccentric core single-mode fiber and the single-mode fiber, and propagate in the eccentric core single-mode fiber, then interfere with each other at the other splicing point.Multi-beam interference transmission spectrum is observed.An in-line fiber interferometric strain sensor based on the eccentric core single-mode fiber is realized.%An eccentric core single-mode fiber, whose core is away from the axis of the fiber, is fabricated by using the fiber preform goniometric-groove method and the stack-and-draw method. An eccentric core single-mode fiber without coating is spliced between two single-mode fibers. Fundamental mode and cladding modes are excited at one splicing point between the eccentric core single-mode fiber and the single-mode fiber, and propagate in the eccentric core single-mode fiber, then interfere with each other at the other splicing point. Multi-beam interference transmission spectrum is observed. An in-line fiber interferometric strain sensor based on the eccentric core single-mode fiber is realized.

  14. Single mode dye-doped polymer photonic crystal lasers

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Buss, Thomas; Smith, Cameron

    2010-01-01

    Dye-doped polymer photonic crystal (PhC) lasers fabricated by combined nanoimprint and photolithography are studied for their reproducibility and stability characteristics. We introduce a phase shift in the PhC lattice that substantially improves the yield of single wavelength emission. Single mode...... emission and reproducibility of laser characteristics are important if the lasers are to be mass produced in, e. g., optofluidic sensor chips. The fabrication yield is above 85% with highly reproducible wavelengths (within 0.5%), and the temperature dependence on the wavelength is found to be -0.045 or -0...

  15. Stochastic Resonance in Linear Regime of a Single- Mode Laser

    Institute of Scientific and Technical Information of China (English)

    ZHANG Liang-Ying; CAO Li; WU Da-Jin; WANG Jun

    2003-01-01

    We present an analytic investigation of the signal-to-noise ratio by studying the linear model of a single-mode laser driven by coloured pump noise (TI) and coloured quantum noise (TZ) with coloured cross-correlation (TS), and obtain an exact analytic expression of the signal-to-noise ratio. We detect that the stochastic resonance occurs when the noise correlation coefficient A < 0. Furthermore, we analyse the effect of TI , T2 and Ta on the signal-to-noise ratio, and derive the condition under which the stochastic resonance occurs.

  16. Pulse distortion in single-mode fibers. Part 2.

    Science.gov (United States)

    Marcuse, D

    1981-09-01

    The theory of pulse distortion in single-mode fibers is extended to include laser sources such as injection lasers operating simultaneously at several distinct wavelengths. The transmitted pulse is expressed as a Fourier integral whose spectral function is given by an analytical expression in closed form. The rms width of the transmitted pulse is also expressed in closed form. Numerical examples illustrate the influence of the spectral width of the source and of its asymmetry on the shape and rms width of the pulse.

  17. Single-mode fiber linearly tapered planar waveguide tunable coupler

    Science.gov (United States)

    Das, Alok K.; Hussain, Anwar

    1997-09-01

    We developed a simple system of tunable fiber film coupler using a linearly tapered thin-film planar waveguide (PWG) evanescently coupled by a single-mode distributed fiber half-coupler. We investigate the characteristics of the coupler theoretically and experimentally taking into consideration the refractive index ( n f ) of nonuniform films, the magnitude of nonuniformity ( m ) of the films, and the source wavelength ( ). The thickness variation of the nonuniform film is along the direction of propagation of optical power. Tapered and plano concave thin films of a mix of oils as well as a plano concave poly(methyl methacrylate) film were fabricated to serve as nonuniform PWG s. Similar to single-mode fiber with a uniform thickness PWG coupler, such a coupler also provides light modulation with a change of n f . However, position shifting of a half-coupler in a tapered PWG structure along the direction of propagation exhibits the variation of fiber throughput power. This action serves as a simple system for a tunable fiber film coupler. Wavelength-dependent throughput fiber power for such a coupler also behaves as a filter. The center wavelength can be controlled by shifting the position of the half-coupler. A coupling fiber as a half-coupler can be used for efficient coupling. We performed a theoretical analysis of the structure using Marcuse s model and observed good agreement with the experimental results.

  18. Design of SMS (Single mode-Multi mode coreless-Single mode) optical fiber as corrosion sensor

    Science.gov (United States)

    Aisyah, Putri Yeni; Hatta, Agus M.; Pratama, Detak Yan

    2016-11-01

    Conventional corrosion sensors such as ultrasonic guided waves, eddy current and thermography have been widely applied, however, these sensors have disadvantage of suffering from additional damage, as these sensors are placed in corrosive environment, often hidden and could not be directly observed, therefore corrosion inspection using conventional sensor is much more expensive and time consuming. Usage of optical fiber as corrosion sensor, based on changes in light intensity due to corrosion effect, is an alternative to overcome the disadvantage of conventional sensors. We proposed to use Single mode - Multimode Coreless - Single mode structured optical fiber as sensor. Multimode section of the optical fiber is coated with aluminium as the corrosion object. Experiment result shows that the corrosion process have an effect of decreasing the output sensor power as the corrosion rate increasing. Experimental test is conducted on the sensor, in which time interval of corrosion treatment is 9 hours. It is obtained from the test result that the highest value of output power is 13.19 dBm. Furthermore when the weight loss range of aluminium layer is 0 - 140 mg after corrosion treatment and the length of multimode fiber is 10 mm, the highest sensitivity of the sensor is 0.094 dBm/mg.

  19. Single-Mode WGM Resonators Fabricated by Diamond Turning

    Science.gov (United States)

    Grudinin, Ivan; Maleki, Lute; Savchenkov, Anatoliy; Matsko, Andrewy; Strekalov, Dmitry; Iltchenko, Vladimir

    2008-01-01

    A diamond turning process has made possible a significant advance in the art of whispering-gallery-mode (WGM) optical resonators. By use of this process, it is possible to fashion crystalline materials into WGM resonators that have ultrahigh resonance quality factors (high Q values), are compact (ranging in size from millimeters down to tens of microns), and support single electromagnetic modes. This development combines and extends the developments reported in "Few- Mode Whispering-Gallery-Mode Resonators" (NPO-41256), NASA Tech Briefs, Vol. 30, No. 1 (January 2006), page 16a and "Fabrication of Submillimeter Axisymmetric Optical Components" (NPO-42056), NASA Tech Briefs, Vol. 31, No. 5 (May 2007), page 10a. To recapitulate from the first cited prior article: A WGM resonator of this special type consists of a rod, made of a suitable transparent material, from which protrudes a thin circumferential belt of the same material. The belt is integral with the rest of the rod and acts as a circumferential waveguide. If the depth and width of the belt are made appropriately small, then the belt acts as though it were the core of a single-mode optical fiber: the belt and the rod material adjacent to it support a single, circumferentially propagating mode or family of modes. To recapitulate from the second cited prior article: A major step in the fabrication of a WGM resonator of this special type is diamond turning or computer numerically controlled machining of a rod of a suitable transparent crystalline material on an ultrahigh-precision lathe. During the rotation of a spindle in which the rod is mounted, a diamond tool is used to cut the rod. A computer program is used to control stepping motors that move the diamond tool, thereby controlling the shape cut by the tool. Because the shape can be controlled via software, it is possible to choose a shape designed to optimize a resonator spectrum, including, if desired, to limit the resonator to supporting a single mode

  20. Single-Mode, Distributed Feedback Interband Cascade Lasers

    Science.gov (United States)

    Frez, Clifford F. (Inventor); Borgentun, Carl E. (Inventor); Briggs, Ryan M. (Inventor); Bagheri, Mahmood (Inventor); Forouhar, Siamak (Inventor)

    2016-01-01

    Single-mode, distributed feedback interband cascade lasers (ICLs) using distributed-feedback gratings (e.g., lateral Bragg gratings) and methods of fabricating such ICLs are provided. The ICLs incorporate distributed-feedback gratings that are formed above the laser active region and adjacent the ridge waveguide (RWG) of the ICL. The ICLs may incorporate a double-ridge system comprising an optical confinement structure (e.g., a RWG) disposed above the laser active region that comprises the first ridge of the double ridge system, a DFB grating (e.g., lateral Bragg grating) disposed above the laser active region and adjacent the optical confinement structure, and an electric confinement structure that passes at least partially through the laser active region and that defines the boundary of the second ridge comprises and the termination of the DFB grating.

  1. Measurement of Spatial Filtering Capabilities of Single Mode Infrared Fibers

    Science.gov (United States)

    Ksendzov, Alexander; Bloemhof, E.; White, V.; Wallace, J. K.; Gappinger, R. O.; Sanghera, J. S.; Busse, L. E.; Kim, W. J.; Pureza, P. C.; Nguyen, V. Q.; hide

    2006-01-01

    Spatial filtering is necessary to achieve deep nulls in optical interferometer and single mode infrared fibers can serve as spatial filters. The filtering function is based on the ability of these devices to perform the mode-cleaning function: only the component of the input field that is coupled to the single bound (fundamental) mode of the device propagates to the output without substantial loss. In practical fiber devices, there are leakage channels that cause light not coupled into the fundamental mode to propagate to the output. These include propagation through the fiber cladding and by means of a leaky mode. We propose a technique for measuring the magnitude of this leakage and apply it to infrared fibers made at the Naval Research Laboratory and at Tel Aviv University.

  2. Single-mode fibre coupler as refractometer sensor

    Indian Academy of Sciences (India)

    Pabitra Nath; Mridul Buragohain

    2012-12-01

    We report a simple, non-intrusive fibre-optic refractometer sensor for measuring the refractive index of liquid and optically transparent solid medium. Sensing principle of the proposed sensor is based on monitoring the back-reflected light signal through the second input port of a 2 × 1 single-mode fibre coupler when light signal from the output port is focussed at the interface of air and a liquid or solid medium and back-reflected exactly along the same path. Depending on the refractive index of the medium, the amount of back-reflected intensity would vary and in the present work we exploit this principle to measure the refractive index of an optically transparent medium. Variation of refractive index as small as 0.001 RIU can be measured with our proposed sensor.

  3. Pulse distortion in single-mode fibers. 3: Chirped pulses.

    Science.gov (United States)

    Marcuse, D

    1981-10-15

    The theory of pulse distortion in single-mode fibers is extended to include laser sources that suffer a linear wavelength sweep (chirp) during the duration of the pulse. The transmitted pulse is expressed as a Fourier integral whose spectral function is given by an analytical expression in closed form. The rms width of the transmitted pulse is also expressed in closed form. Numerical examples illustrate the influence of the chirp on the shape and rms width of the pulse. A somewhat paradoxical situation exists. A given input pulse can be made arbitrarily short by a sufficiently large amount of chirping, and, after a given fiber length, this chirped pulse returns to its original width. But at this particular distance an unchirped pulse would be only [equiation] times longer. Thus chirping can improve the rate of data transmission by only 40%.

  4. New amplitude equation of single-mode laser

    Institute of Scientific and Technical Information of China (English)

    张莉; 曹力; 吴大进

    2003-01-01

    The white-gain model and the white-loss model of a single-mode laser are investigated in the presence of crosscorrelations between the real and imaginary parts of quantum noise as well as pump noise. It was found that, like the white cubic model (2001 Chin. Phys. Lett. 18 370), the amplitude equations are all decoupled from the phase equations for the two models, and the same novel term appears in the amplitude equations of the two models. So we can put the amplitude equations of all the models into a general form, that is, the new amplitude equation. We further use this new amplitude equation to study specifically the stationary properties of the laser intensity for the white-gain model.

  5. Single-mode dispersive waves and soliton microcomb dynamics

    CERN Document Server

    Yi, Xu; Zhang, Xueyue; Yang, Ki Youl; Vahala, Kerry

    2016-01-01

    Dissipative Kerr solitons are self-sustaining optical wavepackets in resonators. They use the Kerr nonlinearity to both compensate dispersion and to offset optical loss. Besides providing insights into nonlinear resonator physics, they can be applied in frequency metrology, precision clocks, and spectroscopy. Like other optical solitons, the dissipative Kerr soliton can radiate power in the form of a dispersive wave through a process that is the optical analogue of Cherenkov radiation. Dispersive waves typically consist of an ensemble of optical modes. A limiting case is demonstrated in which the dispersive wave is concentrated into a single cavity mode. In this limit, its interaction with the soliton is shown to induce bistable behavior in the spectral and temporal properties of the soliton. Also, an operating point of enhanced repetition-rate stability is predicted and observed. The single-mode dispersive wave can therefore provide quiet states of soliton comb operation useful in many applications.

  6. Monolithic single mode interband cascade lasers with wide wavelength tunability

    Science.gov (United States)

    von Edlinger, M.; Weih, R.; Scheuermann, J.; Nähle, L.; Fischer, M.; Koeth, J.; Kamp, M.; Höfling, S.

    2016-11-01

    Monolithic two-section interband cascade lasers offering a wide wavelength tunability in the wavelength range around 3.7 μm are presented. Stable single mode emission in several wavelength channels was realized using the concept of binary superimposed gratings and two-segment Vernier-tuning. The wavelength selective elements in the two segments were based on specially designed lateral metal grating structures defined by electron beam lithography. A dual-step dry etch process provided electrical separation between the segments. Individual current control of the segments allowed wavelength channel selection as well as continuous wavelength tuning within channels. A discontinuous tuning range extending over 158 nm in up to six discrete wavelength channels was achieved. Mode hop free wavelength tuning up to 14 nm was observed within one channel. The devices can be operated in continuous wave mode up to 30 °C with the output powers of 3.5 mW around room temperature.

  7. Single-mode dispersive waves and soliton microcomb dynamics

    Science.gov (United States)

    Yi, Xu; Yang, Qi-Fan; Zhang, Xueyue; Yang, Ki Youl; Li, Xinbai; Vahala, Kerry

    2017-03-01

    Dissipative Kerr solitons are self-sustaining optical wavepackets in resonators. They use the Kerr nonlinearity to both compensate dispersion and offset optical loss. Besides providing insights into nonlinear resonator physics, they can be applied in frequency metrology, precision clocks, and spectroscopy. Like other optical solitons, the dissipative Kerr soliton can radiate power as a dispersive wave through a process that is the optical analogue of Cherenkov radiation. Dispersive waves typically consist of an ensemble of optical modes. Here, a limiting case is studied in which the dispersive wave is concentrated into a single cavity mode. In this limit, its interaction with the soliton induces hysteresis behaviour in the soliton's spectral and temporal properties. Also, an operating point of enhanced repetition-rate stability occurs through balance of dispersive-wave recoil and Raman-induced soliton-self-frequency shift. The single-mode dispersive wave can therefore provide quiet states of soliton comb operation useful in many applications.

  8. Sensitive acoustic vibration sensor using single-mode fiber tapers.

    Science.gov (United States)

    Li, Yi; Wang, Xiaozhen; Bao, Xiaoyi

    2011-05-01

    Optical fiber sensors are a good alternative to piezoelectric devices in electromagnetic sensitive environments. In this study, we reported a fiber acoustic sensor based on single-mode fiber (SMF) tapers. The fiber taper is used as the sensing arm in a Mach-Zehnder interferometer. Benefiting from their micrometer dimensions, fiber tapers have shown higher sensitivities to the acoustic vibrations than SMFs. Under the same conditions, the thinnest fiber taper in this report, with a diameter of 1.7 µm, shows a 20 dB improvement in the signal to noise ratio as compared to that of an SMF. This acoustic vibration sensor can detect the acoustic waves over the frequencies of 30 Hz-40 kHz, which is limited by the acoustic wave generator in experiments. We also discussed the phase changes of fiber tapers with different diameters under acoustic vibrations.

  9. Macro-Bending Influence on Radiation Induced Attenuation Measurement in Optical Fibres

    CERN Document Server

    Guillermain, E; Ricci, D; Weinand, U

    2014-01-01

    Influence of the bending radius on the measurement of radiation induced attenuation in glass optical fibres is discussed in this paper. Radiation induced attenuation measured in two single-mode fibre types shows discrepancies when coiled around a low bending radius spool: the observed attenuation is lower than expected. A series of dedicated tests reveals that this invalid measurement is related to the displacement of the mode field towards the cladding when the fibre is bent with a low radius, and to the different radiation resistances of the core and cladding glasses. For irradiation tests of optical fibres, the spool radius should therefore be carefully chosen.

  10. Propagation of pulse fluctuations in single-mode fibers.

    Science.gov (United States)

    Marcuse, D

    1980-06-01

    An earlier paper [Applied Optics 19, 1653 (1980)] dealt with the ensemble averages of pulses propagating in single-mode fibers. In this paper we discuss pulse fluctuations. The light pulses are generated by modulation of the power of a continuously operating light source consisting of N discrete sinusoidal frequencies randomly phased relative to each other. The fixed amplitudes of the sinusoidal frequency components of the source are adjusted to fit into a Gaussian envelope, and the modulating pulse has a Gaussian distribution in time. This mathematical model approximates a laser light source operating in several free-running longitudinal modes. We find that the fluctuations of the modulated light pulses can die out if the pulses travel a long distance in a dispersive fiber, provided the spacings between the sinusoidal frequency components of the light source are larger than the spectral width of the modulating signal. If the source frequency components are spaced more closely than the spectral width of the modulating pulse, fluctuations persist indefinitely independent of fiber length. However, in a practical system, whose input pulse is only about half as short as the output pulse, fluctuations are practically unaffected by transmission through a fiber.

  11. Dynamic single-mode semiconductor lasers with a distributed reflector

    Energy Technology Data Exchange (ETDEWEB)

    Suematsu, Y.; Arai, S.; Kishino, K.

    1983-03-01

    Recent progress in dynamic single-mode (DSM) semiconductor lasers in the wavelength of 1.5-1.6 microns are reviewed, and the basic principle of DSM operation is given. Study of the DSM laser is originated for application to wide-band optical-fiber communication in the lowest loss wavelength region of 1.5 to 1.65 microns. A DSM laser consists of a mode-selective resonator and a transverse-mode-controller waveguide, as in the narrow-striped distributed-Bragg-reflector (DBR) laser, so as to maintain a fixed axial mode under rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some DSM lasers. Structures, static and dynamic characteristics of lasing wavelength, output power, and reliability of state-of-the-art DSM lasers are reviewed. Dynamic spectral width of 0.3 nm, output power of a few milliwatts, and reliability over a few thousand hours are reported for experimental DSM lasers. 120 references.

  12. Dynamic single-mode semiconductor lasers with a distributed reflector

    Science.gov (United States)

    Suematsu, Y.; Arai, S.; Kishino, K.

    1983-03-01

    Recent progress in dynamic single-mode (DSM) semiconductor lasers in the wavelength of 1.5-1.6 microns are reviewed, and the basic principle of DSM operation is given. Study of the DSM laser is originated for application to wide-band optical-fiber communication in the lowest loss wavelength region of 1.5 to 1.65 microns. A DSM laser consists of a mode-selective resonator and a transverse-mode-controller waveguide, as in the narrow-striped distributed-Bragg-reflector (DBR) laser, so as to maintain a fixed axial mode under rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some DSM lasers. Structures, static and dynamic characteristics of lasing wavelength, output power, and reliability of state-of-the-art DSM lasers are reviewed. Dynamic spectral width of 0.3 nm, output power of a few milliwatts, and reliability over a few thousand hours are reported for experimental DSM lasers.

  13. Intensity based sensor based on single mode optical fiber patchcords

    Science.gov (United States)

    Bayuwati, Dwi; Waluyo, Tomi Budi; Mulyanto, Imam

    2016-11-01

    This paper describes the use of several single mode (SM) fiber patchcords available commercially in the market for intensity based sensor by taking the benefit of bending loss phenomenon. Firtsly, the full transmission spectrum of all fiber patchcords were measured and analyzed to examine its bending properties at a series of wavelength using white light source and optical spectrum analyzer. Bending spectral at various bending diameter using single wavelength light sources were then measured for demonstration.Three good candidates for the intensity based sensor are SM600 fiber patchcord with 970 nm LED, SMF28 fiber patchcord with 1050 nm LED and 780HP fiber patchcord with 1310 nm LED which have noticeable bending sensitive area. Experiments show that the combination of the SMF28with 1050 nm LED has 30 mm measurement range which is the widest; with sensitivity 0.107 dB/mm and resolution 0.5 mm compared with combination of SM600 patchcord and LED 970 nm which has the best sensitivity (0.891 dB/mm) and resolution (0.06 mm) but smaller range measurement (10 mm). Some suitable applications for each fiber patchcord - light source pair have also been discussed.

  14. Pump combiner for air-clad fiber with PM single-mode signal feed-through

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Nielsen, Martin D.; Skovgaard, Peter M.W.;

    2009-01-01

    A pump combiner with single-mode PM signal feed-through designed for an air-clad photonic crystal fiber is demonstrated. Signal coupling is realized by a novel taper element allowing single-mode guidance at a taper ratio of 3.7.......A pump combiner with single-mode PM signal feed-through designed for an air-clad photonic crystal fiber is demonstrated. Signal coupling is realized by a novel taper element allowing single-mode guidance at a taper ratio of 3.7....

  15. Study on single-mode photonic crystal fibers in wide wavelength range

    Institute of Scientific and Technical Information of China (English)

    Wei Chen; Jinyan Li; Shiyu Li; Haiqing Li; Zuowen Jiang; Jinggang Peng

    2007-01-01

    @@ The comparatively large mode field single-mode photonic crystal fibers (PCFs) were fabricated, the lightwave from 600- to 1600-nm wavelength along this PCF could be transmitted in single mode. The manufacturing process technologies of the PCFs were exploited, and the drawing parameters of PCFs were also presented. The structure parameters on the single-mode performance of PCFs were theoretically studied,and in practice the design was proved. The measurements of cut-off wavelength and light intensity distribution showed that the PCF had comparatively wide single-mode operating wavelength range.

  16. Stable CW Single-Mode Photonic Crystal Fiber DFB Ring Laser

    Institute of Scientific and Technical Information of China (English)

    Kevin Cook; John Canning; John Holdsworth; Chris Dewhurst

    2008-01-01

    We demonstrate stable single-mode CW operation of a DFB ring laser based on Er3+ doped photonics crystal fiber (PCF). The incorporation of a ring cavity allows one single mode to lase and also suppresses the unwanted effect of self-pulsing. Such a narrow linewidth source in PCF has great potential in spectroscopy.

  17. Interesting effect of aspect ratio on Kerr nonlinear optical processes in subwavelength diameter single-mode trapezoidal index fiber using Marcuse-type spot-size formulations

    Science.gov (United States)

    Sadhu, Arunangshu; Sarkar, Somenath

    2016-08-01

    We investigate the Kerr nonlinear optical processes (NOPs) in the case of a single-mode trapezoidal index fiber based on recently formulated and appropriate Marcuse-type relations for spot size in terms of normalized frequency corresponding to such fiber having various aspect ratios. With the help of these relations, we have analyzed the maximum NOP in these fibers having prospective the merits of tight light confinement in the subwavelength diameter waveguiding region. The comparative investigation reveals that the aspect ratio having a value of 0.7 is the most promising candidate for maximum optical nonlinearity, constructional convenience, and less diffraction. The analysis should be attractive for system users as a ready reference.

  18. Tripartite entanglement of bosonic systems in a noninertial frame beyond the single- mode approximation

    Directory of Open Access Journals (Sweden)

    M Soltani

    2015-12-01

    Full Text Available In this work, we generalize the entanglement of three-qbit Bosonic systems beyond the single-mode approximation when one of the observers is accelerated. For this purpose, we review the effects of acceleration on field modes and quantum states. The single-mode approximation and beyond the single-mode approximation methods are introduced. After this brief introduction, the main problem of this paper, tripartite entanglement of bosonic systems in a noninertial frame beyond the single- mode approximation is investigated. The tripartite entangled states have different classes with GHZ and W states being most important. Here, we choose &pi-tangle as a measure of tripartite entanglement. If the three parties share GHZ state, the corresponding &pi-tangle will increase by increasing acceleration for some Unruh modes. This phenomenon, increasing entanglement, has never been observed in the single-mode approximation for bosonic case. Moreover, the &pi-tangle dose not exhibit a monotonic behavior with increasing acceleration. In the infinite acceleration limit, the &pi-tangle goes to different nonzero values for distinct Unruh modes. Unlike GHZ state, the entanglement of the W state shows only monotonically increasing and decreasing behaviors with increasing acceleration. Also, the entanglement for all possible choices of Unruh modes approaches only 0.176 in the high acceleration limit. Therefore, according to the quantum entanglement, there is no distinction between the single-mode approximation and beyond the single-mode approximation methods in this limit.

  19. Fiber-Based Polarization Diversity Detection for Polarization-Sensitive Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Hamid Pahlevaninezhad

    2014-09-01

    Full Text Available We present a new fiber-based polarization diversity detection (PDD scheme for polarization sensitive optical coherence tomography (PSOCT. This implementation uses a new custom miniaturized polarization-maintaining fiber coupler with single mode (SM fiber inputs and polarization maintaining (PM fiber outputs. The SM fiber inputs obviate matching the optical lengths of the two orthogonal OCT polarization channels prior to interference while the PM fiber outputs ensure defined orthogonal axes after interference. Advantages of this detection scheme over those with bulk optics PDD include lower cost, easier miniaturization, and more relaxed alignment and handling issues. We incorporate this PDD scheme into a galvanometer-scanned OCT system to demonstrate system calibration and PSOCT imaging of an achromatic quarter-wave plate, fingernail in vivo, and chicken breast, salmon, cow leg, and basa fish muscle samples ex vivo.

  20. A novel fiber-based adsorbent technology

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, T.A. [Chemica Technologies, Inc., Bend, OR (United States)

    1997-10-01

    In this Phase I Small Business Innovation Research program, Chemica Technologies, Inc. is developing an economical, robust, fiber-based adsorbent technology for removal of heavy metals from contaminated water. The key innovation is the development of regenerable adsorbent fibers and adsorbent fiber cloths that have high capacity and selectivity for heavy metals and are chemically robust. The process has the potential for widespread use at DOE facilities, mining operations, and the chemical process industry.

  1. An optimal algorithm for single-mode close-loop excitation in shallow water

    Institute of Scientific and Technical Information of China (English)

    PENG Dayong; ZENG Juan; LI Haifeng; LIU Haijun; ZHAO Wenyao; GAO Tianfu

    2011-01-01

    An optimal algorithm for single-mode close-loop excitation in shallow water is presented. By analyzing the covariance of estimation value of Green's function matrix, an optimal source array weights matrix is presented to estimate Green's function matrix. The weights matrix is a unitary matrix, and absolute values of the matrix elements are equal. Algorithm based on the weights matrix makes single-mode excitation converge at maximum speed and be steady. Advantages of the algorithm are confirmed by numerical simulations. Finally, results of shallow water experiment are presented, and the energy ratio of single mode is higher than 97 percent.

  2. Efficient coupling of starlight into single mode photonics using Adaptive Injection (AI)

    Science.gov (United States)

    Norris, Barnaby; Cvetojevic, Nick; Gross, Simon; Arriola, Alexander; Tuthill, Peter; Lawrence, Jon; Richards, Samuel; Goodwin, Michael; Zheng, Jessica

    2016-08-01

    Using single-mode fibres in astronomy enables revolutionary techniques including single-mode interferometry and spectroscopy. However, injection of seeing-limited starlight into single mode photonics is extremely difficult. One solution is Adaptive Injection (AI). The telescope pupil is segmented into a number of smaller subapertures each with size r0, such that seeing can be approximated as a single tip / tilt / piston term for each subaperture, and then injected into a separate fibre via a facet of a segmented MEMS deformable mirror. The injection problem is then reduced to a set of individual tip tilt loops, resulting in high overall coupling efficiency.

  3. Inversed Vernier effect based single-mode laser emission in coupled microdisks

    CERN Document Server

    Li, Meng; Wang, Kaiyang; Li, Jiankai; Xiao, Shumin; Song, Qinghai

    2015-01-01

    Recently, on-chip single-mode laser emission has attracted considerable research attention due to its wide applications. While most of single-mode lasers in coupled microdisks or microrings have been qualitatively explained by either Vernier effect or inversed Vernier effect, none of them have been experimentally confirmed. Here, we studied the mechanism for single-mode operation in coupled microdisks. We found that the mode numbers had been significantly reduced to nearly single-mode within a large pumping power range from threshold to gain saturation. The detail laser spectra showed that the largest gain and the first lasing peak were mainly generated by one disk and the laser intensity was proportional to the frequency detuning. The corresponding theoretical analysis showed that the experimental observations were dominated by internal coupling within one cavity, which was similar to the recently explored inversed Vernier effect in two coupled microrings. We believe our finding will be important for underst...

  4. Mode coupling in hybrid square-rectangular lasers for single mode operation

    Science.gov (United States)

    Ma, Xiu-Wen; Huang, Yong-Zhen; Yang, Yue-De; Xiao, Jin-Long; Weng, Hai-Zhong; Xiao, Zhi-Xiong

    2016-08-01

    Mode coupling between a square microcavity and a Fabry-Pérot (FP) cavity is proposed and demonstrated for realizing single mode lasers. The modulations of the mode Q factor as simulation results are observed and single mode operation is obtained with a side mode suppression ratio of 46 dB and a single mode fiber coupling loss of 3.2 dB for an AlGaInAs/InP hybrid laser as a 300-μm-length and 1.5-μm-wide FP cavity connected to a vertex of a 10-μm-side square microcavity. Furthermore, tunable single mode operation is demonstrated with a continuous wavelength tuning range over 10 nm. The simple hybrid structure may shed light on practical applications of whispering-gallery mode microcavities in large-scale photonic integrated circuits and optical communication and interconnection.

  5. Single-mode GaAs/AlGaAs quantum cascade microlasers

    Institute of Scientific and Technical Information of China (English)

    Gao Yu; Liu Junqi; Liu Fengqi; Zhang Wei; Zhang Quande; Liu Wanfeng; Li Lu; Wang Lijun; Wang Zhanguo

    2009-01-01

    Single-mode edge emitting GaAs/A1GaAs quantum cascade microlasers at a wavelength of about 11.4 μm were realized by shortening the Fabry-P6rot cavity length. The spacing of the longitudinal resonator modes is inversely proportional to the cavity length. Stable single-mode emission with a side mode suppression ratio of about 19 dB at 85 K for a 150-μm-long device was demonstrated.

  6. Refractive index sensor based on an abrupt taper Michelson interferometer in a single-mode fiber.

    Science.gov (United States)

    Tian, Zhaobing; Yam, Scott S-H; Loock, Hans-Peter

    2008-05-15

    A simple refractive index sensor based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a single symmetrically abrupt taper region in a short piece of single-mode fiber that is terminated by approximately 500 nm thick gold coating. The sensitivity of the new sensor is similar to that of a long-period-grating-type sensor, and its ease of fabrication offers a low-cost alternative to current sensing applications.

  7. Realization of Arbitrary Inverse Unitary Transformation of Single Mode Fibre by Using Three Wave Plates

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-Kai; REN Ji-Gang; PENG Cheng-Zhi; JIANG Shuo; WANG Xiang-Bin

    2007-01-01

    We report a method to realize the arbitrary inverse unitary transformation imposed by a single-mode fibre on photon's polarization by the succession of two quarter-wave plates and a half-wave plate. The process of realization by polarization state vector. The method is meaningful in quantum communication experiment such as quantum teleportation, in which an unknown arbitrary quantum state should be kept to be unchanged in the case of using a single-mode fibre for time delay.

  8. Refractometric sensors based on multimode interference in a thin-film coated single-mode-multimode-single-mode structure with reflection configuration.

    Science.gov (United States)

    Del Villar, Ignacio; Socorro, Abian B; Corres, Jesus M; Arregui, Francisco J; Matias, Ignacio R

    2014-06-20

    Thin-film coated single-mode-multimode-single-mode (SMS) structures have been analyzed both theoretically and experimentally with the aim of detecting different refractive indices. By adequate selection of the thickness of the thin film and of the diameter of the multimode segment in the SMS structure, a seven-fold improvement can be obtained in the sensitivity of the device to the surrounding medium refractive index, achieving a maximum sensitivity of 1199.18  nm/refractive index unit for the range of refractive indices from 1.321 to 1.382. Using layer-by-layer self-assembly for deposition, both on the cladding and on the tip of the multimode segment, allows the reflected power to increase, which avoids the application of a mirror on the tip of the multimode segment.

  9. Optic Fiber-Based Dynamic Pressure Sensor

    Institute of Scientific and Technical Information of China (English)

    Jiu-Lin Gan; Hai-Wen Cai; Jian-Xin Geng; Zheng-Qing Pan; Rong-Hui Qu; Zu-Jie Fang

    2008-01-01

    Weigh-in-Motion(WIM) technique is the process of measuring the dynamic tire forces of a moving vehicle and estimating the corresponding tire loads of the static vehicle. Compared with the static weigh station, WIM station is an efficient and cost effective choice that will minimize unneccessary stops and delay for truckers. The way to turn birefringence of single-mode fiber into a prime quality for a powerful and reliable sensor is shown. Preliminary results for the development of a weigh-in-motion (WIM) technique based on sagnac-loop sensor are presented. After a brief description of the sensor and its principle of operation, the theoretical model is developed. Then, a full characterization made in static conditions is presented.

  10. Kagome fiber based industrial laser beam delivery

    Science.gov (United States)

    Maurel, M.; Gorse, A.; Beaudou, B.; Lekiefs, Q.; Chafer, M.; Debord, B.; Gérôme, F.; Benabid, F.

    2017-02-01

    We report on a Hollow Core-Photonic Crystal Fiber (HC-PCF) based high power ultra-short pulse laser beam delivery system (GLO-BDS) that combines ease-of-use, high laser-coupling efficiency, robustness and industrial compatible cabling. The GLO-BDS comprises a pre-aligned laser-injection head, a sheath cable protected HC-PCF and a modular fiber-output head. It enables fiber-core gas loading and evacuation in a hermetic fashion. 5 m long GLO-BDS were demonstrated for Yb USP laser, Ti:Sapphire laser and frequency-doubled Yb USP laser. They all exhibit a transmission coefficient larger than 80%, and a laser output profile close to single mode (M2 <1.3).

  11. Multiplexed single-mode wavelength-to-time mapping of multimode light

    Science.gov (United States)

    Chandrasekharan, Harikumar K.; Izdebski, Frauke; Gris-Sánchez, Itandehui; Krstajić, Nikola; Walker, Richard; Bridle, Helen L.; Dalgarno, Paul A.; MacPherson, William N.; Henderson, Robert K.; Birks, Tim A.; Thomson, Robert R.

    2017-01-01

    When an optical pulse propagates along an optical fibre, different wavelengths travel at different group velocities. As a result, wavelength information is converted into arrival-time information, a process known as wavelength-to-time mapping. This phenomenon is most cleanly observed using a single-mode fibre transmission line, where spatial mode dispersion is not present, but the use of such fibres restricts possible applications. Here we demonstrate that photonic lanterns based on tapered single-mode multicore fibres provide an efficient way to couple multimode light to an array of single-photon avalanche detectors, each of which has its own time-to-digital converter for time-correlated single-photon counting. Exploiting this capability, we demonstrate the multiplexed single-mode wavelength-to-time mapping of multimode light using a multicore fibre photonic lantern with 121 single-mode cores, coupled to 121 detectors on a 32 × 32 detector array. This work paves the way to efficient multimode wavelength-to-time mapping systems with the spectral performance of single-mode systems.

  12. Inversed Vernier effect based single-mode laser emission in coupled microdisks

    Science.gov (United States)

    Li, Meng; Zhang, Nan; Wang, Kaiyang; Li, Jiankai; Xiao, Shumin; Song, Qinghai

    2015-09-01

    Recently, on-chip single-mode laser emissions in coupled microdisks have attracted considerable research attention due to their wide applications. While most of single-mode lasers in coupled microdisks or microrings have been qualitatively explained by either Vernier effect or inversed Vernier effect, none of them have been experimentally confirmed. Here, we studied the mechanism of single-mode laser operation in coupled microdisks. We found that the mode numbers had been significantly reduced to nearly single-mode within a large pumping power range from threshold to gain saturation. The detail laser spectra showed that the largest gain and the first lasing peak were mainly generated by one disk and the laser intensity was proportional to the wavelength detuning of two set of modes. The corresponding theoretical analysis showed that the experimental observations were dominated by internal coupling within one cavity, which was similar to the recently explored inversed Vernier effect in two coupled microrings. We believe our finding will be important for understanding the previous experimental findings and the development of on-chip single-mode laser.

  13. Comparison of Numerical Modelling of Degradation Mechanisms in Single Mode Optical Fibre Using MATLAB and VPIphotonics

    Directory of Open Access Journals (Sweden)

    Jana Sajgalikova

    2015-01-01

    Full Text Available Mathematical models for description of physical phenomena often use the statistical description of the individual phenomena and solve those using suitable methods. If we want to develop numerical model of optical communication system based on transmission through single mode optical fibres, we need to consider whole series of phenomena that affect various parts of the system. In the single-mode optical fibre we often encounter influence of chromatic dispersion and nonlinear Kerr effects. By observing various different degradation mechanisms, every numerical model should have its own limits, which fulfil more detailed specification. It is inevitable to consider them in evaluation. In this paper, we focus on numerical modelling of degradation mechanisms in single-mode optical fibre. Numerical solution of non-linear Schroedinger equation is performed by finite difference method applied in MATLAB environment and split-step Fourier method, which is implemented by VPIphotonics software.

  14. Selection of lasing direction in single mode semiconductor square ring cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin-Woong; Kim, Kyoung-Youm; Moon, Hee-Jong; Hyun, Kyung-Sook, E-mail: kshyun@sejong.ac.kr [Department of Optical Engineering, Sejong University, 98 Kunja-Dong, Kwangjin-K, Seoul 143-747 (Korea, Republic of)

    2016-02-07

    We propose and demonstrate a selection scheme of lasing direction by imposing a loss imbalance structure into the single mode square ring cavity. The control of the traveling direction is realized by introducing a taper-step section in one of the straight waveguides of the square ring cavity. It was shown by semi-analytic calculation that the taper-step section in the cavity provides effective loss imbalance between two travelling directions as the round trip repeats. Various kinds of square cavities were fabricated using InGaAsP/InGaAs multiple quantum well semiconductor materials in order to test the direction selectivity while maintaining the single mode. We also measured the pump power dependent lasing spectra to investigate the maintenance property of the lasing direction. The experimental results demonstrated that the proposed scheme is an efficient means for a unidirectional lasing in a single mode laser.

  15. Efficient single-mode photon-coupling device utilizing a nanofiber tip.

    Science.gov (United States)

    Chonan, Sho; Kato, Shinya; Aoki, Takao

    2014-04-24

    Single-photon sources are important elements in quantum optics and quantum information science. It is crucial that such sources be able to couple photons emitted from a single quantum emitter to a single propagating mode, preferably to the guided mode of a single-mode optical fiber, with high efficiency. Various photonic devices have been successfully demonstrated to efficiently couple photons from an emitter to a single mode of a cavity or a waveguide. However, efficient coupling of these devices to optical fibers is sometimes challenging. Here we show that up to 38% of photons from an emitter can be directly coupled to a single-mode optical fiber by utilizing the flat tip of a silica nanofiber. With the aid of a metallic mirror, the efficiency can be increased to 76%. The use of a silicon waveguide further increases the efficiency to 87%. This simple device can be applied to various quantum emitters.

  16. A fiber micro-vibration sensor based on single-mode fiber ring laser

    Institute of Scientific and Technical Information of China (English)

    Shenglai Zhen; Renzhu Liu; Benli Yu; Jing Zhang; Baogang Han

    2009-01-01

    A new micro-vibration sensor based on single-mode fiber ring laser is put forward. The Mach-Zehnder interferometric (MZI) detection technique is presented for interrogating laser frequency shift due to the measurand (piezoelectric transducer (PZT) is used to simulate the micro-vibration) induced laser cavity strain from both single- and multi-mode lasers. In the experiment, compared with multi-mode laser sensors, the single-mode laser sensor is proved to be a sensor with high resolution. When the PZT is driven by the analog signal (0.03 rad near 2 kHz), the signal-to-noise ratio (SNR) of output signal from the single-mode laser sensor is close to 55 dB and the sensitivity of the sensor is about 5 x 10-5 rad/Hz1/2.

  17. Highly efficient generation of single-mode photon pairs using a crystalline whispering gallery mode resonator

    CERN Document Server

    Förtsch, Michael; Fürst, Josef U; Strekalov, Dmitry; Gerrits, Thomas; Stevens, Martin J; Sedlmeir, Florian; Schwefel, Harald G L; Nam, Sae Woo; Leuchs, Gerd; Marquardt, Christoph

    2014-01-01

    We report a highly efficient source of narrow-band photon pairs based on parametric down-conversion in a crystalline whispering gallery mode resonator. Remarkably, each photon of a pair is strictly emitted into a single spatial and temporal mode, as witnessed by Glaubers autocorrelation function. We explore the phase-matching conditions in spherical geometries, and determine the requirements of the single-mode operation. Understanding these conditions has allowed us to experimentally demonstrate a single-mode pair-detection rate of $0.97 \\cdot 10^6$ pairs/s per mW pump power per 20 MHz bandwidth without the need of additional filter cavities.

  18. Broadband amplified spontaneous emission from Er3+-doped single-mode tellurite fibre

    Institute of Scientific and Technical Information of China (English)

    Chen Dong-Dan; Zhang Qin-Yuan; Liu Yue-Hui; Xu Shan-Hui; Yang Zhong-Min; Deng Zai-De; Jiang Zhong-Hong

    2006-01-01

    This paper reports on the fabrication and characterization of a newly erbium-doped single-mode tellurite glass-fibre applicable for 1.5-μm optical amplifiers. A very broad erbium amplified spontaneous emission in the range 1450-1650 nm from erbium-doped single-mode tclluritc glass-fibre is obtained upon excitation of a 980-nm laser diode. The effects of the length of glass-fibre and the pumping power of laser diode on the amplified spontaneous emission are discussed.The result indicates that the tellurite glass-fibre is a promising candidate for designing fibre-optic amplifiers and lasers.

  19. Design and characterization of single-mode holey fibers with low bending losses

    OpenAIRE

    Tsuchida, Yukihiro; Saitoh, Kunimasa; KOSHIBA, Masanori

    2005-01-01

    As the fiber-to-the-home network construction increased, optical fiber cables are demanded to be easier to handle and require less space. Under this situation, a single mode fiber (SMF) permitting small bending radius is strongly requested. In this paper, we propose and demonstrate a novel type of bending-insensitive single-mode holey fiber which has a doped core and two layers of holes with different air-hole diameters. The fiber has a mode field diameter of 9.3 μm at 1.55 ...

  20. Frequency Stabilization of a Single Mode Terahertz Quantum Cascade Laser to the Kilohertz Level

    Science.gov (United States)

    2009-04-27

    Frequency stabilization of a single mode terahertz quantum cascade laser to the kilohertz level 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...primarily in a single-longitudinal mode (SLM) up to a bias voltage of 3.7 V and a multi-lodgitudinal mode ( MLM ) at higher voltages. It was mounted in a

  1. Evolution of a Thermo Vacuum State in a Single-Mode Amplitude Dissipative Channel

    Institute of Scientific and Technical Information of China (English)

    WANG Chang-Chun; FAN Hong-Yi

    2010-01-01

    @@ We investigate how an initial thermo vacuum state, in the context of thermo field dynamics, evolves in a single-mode amplitude dissipative channel, and find that in this process the thermo squeezing effect decreases while the fictitious-mode vacuum becomes chaotic.

  2. 870nm Bragg grating in single mode TOPAS microstructured polymer optical fibre

    DEFF Research Database (Denmark)

    Yuan, Wu; Webb, David J.; Kalli, Kyriacos

    2011-01-01

    We report the fabrication and characterization of a fiber Bragg grating (FBG) with 870 nm resonance wavelength in a single-mode TOPAS microstructured polymer optical fiber (mPOF). The grating has been UV-written with the phase-mask technique using a 325 nm HeCd laser. The static tensile strain...

  3. Extremely low-loss single-mode photonic crystal fiber in the terahertz regime

    DEFF Research Database (Denmark)

    Islam, Raonaqul; Hasanuzzaman, G. K M; Sadath, Md Anwar;

    2015-01-01

    This paper presents an updated design and numerical characterization of a rotated porous-core hexagonal photonic crystal fiber (PCF) for single-mode terahertz (THz) wave guidance. The simulation results are found using an efficient finite element method (FEM) which show a better and ultra-low eff...

  4. A novel high-efficiency single-mode quantum dot single photon source

    DEFF Research Database (Denmark)

    Gerard, J.M.; Gregersen, Niels; Nielsen, Torben Roland

    2008-01-01

    We present a novel single-mode single photon source exploiting the emission of a semiconductor quantum dot (QD) located inside a photonic wire. Besides an excellent coupling (>95%) of QD spontaneous emission to the fundamental guided mode [1], we show that a single photon collection efficiency...

  5. Single mode cavities for parametric oscillatory instability suppression in laser gravitational wave detectors

    Science.gov (United States)

    Poplavskiy, Mikhail V.

    Parametric oscillatory instability will be a serious problem restricting the power circulating in laser gravitation wave detectors (aLIGO). For parametric oscillatory instability suppression we suggest to use practically "single mode" Fabry-Perot (FP) cavity with little changed mirror's specular surface.

  6. 870nm Bragg grating in single mode TOPAS microstructured polymer optical fibre

    DEFF Research Database (Denmark)

    Yuan, Wu; Webb, David J.; Kalli, Kyriacos;

    2011-01-01

    We report the fabrication and characterization of a fiber Bragg grating (FBG) with 870 nm resonance wavelength in a single-mode TOPAS microstructured polymer optical fiber (mPOF). The grating has been UV-written with the phase-mask technique using a 325 nm HeCd laser. The static tensile strain se...

  7. Dynamical Properties of a Single-Mode Laser with Both Colored Noise and Injected Signal

    Institute of Scientific and Technical Information of China (English)

    LENG Feng; LUO Xiao-Qin; ZHU Shi-Qun

    2001-01-01

    The colored noise in a single-mode laser with injected signal is investigated by the method of two-dimensional unified colored noise approximation. The normalized correlation function λ2(0), the intensity correlation time Tc and effective eigenvalue λeff are calculated. The effects of the injected signal Io, colored noise strength P' and the noise

  8. Single-mode hole-assisted fiber as a bending-loss insensitive fiber

    Science.gov (United States)

    Nakajima, Kazuhide; Shimizu, Tomoya; Matsui, Takashi; Fukai, Chisato; Kurashima, Toshio

    2010-12-01

    We investigate the design and characteristics of a single-mode and low bending loss HAF both numerically and experimentally. An air filling fraction S is introduced to enable us to design a HAF with desired characteristics more easily. We show that we can expect to realize a single-mode and low bending loss HAF by considering the S dependence of the bending loss α b and cutoff wavelength λ c as well as their relative index difference Δ dependence. We also show that the mode-field diameter (MFD) and chromatic dispersion characteristics of the single-mode and low bending loss HAF can be tailored by optimizing the distance between the core and the air holes. We also investigate the usefulness of the fabricated HAFs taking the directly modulated transmission and multipath interference (MPI) characteristics into consideration. We show that the designed HAF has sufficient applicability to both analog and digital transmission systems. Our results reveal that the single-mode and low bending loss HAF is beneficial in terms of developing a future fiber to the home (FTTH) network as well as for realizing flexible optical wiring.

  9. Conditional generation of arbitrary single-mode quantum states of light by repeated photon subtractions

    CERN Document Server

    Fiurasek, J; Cerf, N J; Fiurasek, Jaromir; Garcia-Patron, Raul; Cerf, Nicolas J.

    2005-01-01

    We propose a scheme for the conditional generation of arbitrary finite superpositions of (squeezed) Fock states in a single mode of a traveling optical field. The suggested setup requires only a source of squeezed states, beam splitters, strong coherent beams, and photodetectors with single-photon sensitivity. The method does not require photodetectors with a high efficiency nor with a single-photon resolution.

  10. Optically controllable dual-mode switching in single-mode Fabry-Pérot laser diode subject to one side-mode feedback and external single mode injection

    Science.gov (United States)

    Wu, Jian-Wei; Won, Yong Hyub

    2017-06-01

    In this paper, broadly tunable dual-mode lasing system is presented and demonstrated based on single-mode Fabry-Pérot laser diode subject to the feedback of one side mode amplified by an erbium-doped fiber amplifier in the external feedback cavity. The spacing between two resonance modes in output lasing spectrum is broadly tuned by introducing differently amplified side mode into the single-mode laser via the external cavity consisted of amplifier, filter, and polarization controller so that two difference frequencies of 1 THz and 0.6 THz are given to display the tunable behavior of dual-mode emission in this work. Therefore, under an external injection mode into the laser condition, the power dependent injection locking and optical bistability of generated dual-mode emission are discussed in detail. At different wavelength detunings, the emitted two resonance modes including the dominant and feedback modes are switched to on- or off-state by selecting proper high-low power level of the external injection mode. As a consequence, the maximum value of achieved dual-mode on-off ratio is as high as up to 45 dB.

  11. Convection-driven kinematic dynamos at low Rossby and magnetic Prandtl numbers: single mode solutions

    CERN Document Server

    Calkins, Michael A; Tobias, Steven M; Aurnou, Jonathan M; Marti, Philippe

    2015-01-01

    The onset of dynamo action is investigated within the context of a newly developed low Rossby, low magnetic Prandtl number, convection-driven dynamo model. The model represents an asymptotically exact form of an $\\alpha^2$ mean field dynamo model in which the small-scale convection is represented explicitly by the finite amplitude, single mode convective solutions first investigated by Bassom and Zhang (Geophys.~Astrophys.~Fluid Dyn., \\textbf{76}, p.223, 1994). Both steady and oscillatory convection are considered for a variety of horizontal planforms. The kinematic helicity is observed to be a monotonically increasing function of the Rayleigh number; as a result, very small magnetic Prandtl number dynamos can be found for a sufficiently large Rayleigh number. All dynamos are found to be oscillatory with an oscillation frequency that increases as the strength of the convection is increased and the magnetic Prandtl number is reduced. Single mode solutions which exhibit boundary layer behavior in the kinematic ...

  12. Multimode filter composed of single-mode surface acoustic wave/bulk acoustic wave resonators

    Science.gov (United States)

    Huang, Yulin; Bao, Jingfu; Tang, Gongbin; Wang, Yiling; Omori, Tatsuya; Hashimoto, Ken-ya

    2017-07-01

    This paper discusses the possibility of realizing multimode filters composed of multiple single-mode resonators by using radio frequency surface and bulk acoustic wave (SAW/BAW) technologies. First, the filter operation and design principle are given. It is shown that excellent filter characteristics are achievable by combining multiple single-mode resonators with identical capacitance ratios provided that their resonance frequencies and clamped capacitances are set properly. Next, the effect of balun performance is investigated. It is shown that the total filter performance is significantly degraded by balun imperfections such as the common-mode rejection. Then, two circuits are proposed to improve the common-mode rejection, and their effectiveness is demonstrated.

  13. Surface enhanced Raman spectroscopy using a single mode nanophotonic-plasmonic platform

    CERN Document Server

    Peyskens, Frédéric; Van Dorpe, Pol; Thomas, Nicolas Le; Baets, Roel

    2015-01-01

    Surface Enhanced Raman Spectroscopy (SERS) is a well-established technique for enhancing Raman signals. Recently photonic integrated circuits have been used, as an alternative to microscopy based excitation and collection, to probe SERS signals from external metallic nanoparticles. However, in order to develop quantitative on-chip SERS sensors, integration of dedicated nanoplasmonic antennas and waveguides is desirable. Here we bridge this gap by demonstrating for the first time the generation of SERS signals from integrated bowtie nanoantennas, excited and collected by a single mode waveguide, and rigorously quantify the enhancement process. The guided Raman power generated by a 4-Nitrothiophenol coated bowtie antenna shows an 8 x 10^6 enhancement compared to the free-space Raman scattering. An excellent correspondence is obtained between the theoretically predicted and observed absolute Raman power. This work paves the way towards fully integrated lab-on-a-chip systems where the single mode SERS-probe can b...

  14. In-Line Fiber Optic Interferometric Sensors in Single-Mode Fibers

    Directory of Open Access Journals (Sweden)

    De-Wen Duan

    2012-08-01

    Full Text Available In-line fiber optic interferometers have attracted intensive attention for their potential sensing applications in refractive index, temperature, pressure and strain measurement, etc. Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers. It’s known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, we review two kinds of typical in-line fiber optic interferometers formed in single-mode fibers fabricated with different post-processing techniques. Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented.

  15. Multiplexed Single-Mode Wavelength-to-Time Mapping of Multimode Light

    CERN Document Server

    Chandrasekharan, Harikumar K; Gris-Sánchez, Itandehui; Krstajić, Nikola; Walker, Richard; Bridle, Helen L; Dalgarno, Paul A; MacPherson, William N; Henderson, Robert K; Birks, Tim A; Thomson, Robert R

    2016-01-01

    We demonstrate that photonic lanterns based on tapered multicore fibres provide an efficient way to couple multimode states of light to a two-dimensional array of Single-Photon Avalanche Detectors (SPADs), each of which has its own Time-to-Digital Converter (TDC) for Time-Correlated Single-Photon-Counting (TCSPC). Exploiting this capability, we demonstrate multiplexed single-mode wavelength-to-time conversion of multimode states of light using a multicore-fibre photonic lantern with 121 single-mode cores, coupled in a one-to-one fashion to 121 SPADS on a 32 $\\times$ 32 pixel CMOS SPAD array. The application of photonic lanterns for coupling multimode light to SPAD arrays in this manner may find wide-ranging applications in areas such as Raman spectroscopy, coherent LIDAR and quantum optics.

  16. Transmission behaviors of single mode hollow metallic waveguides dedicated to mid-infrared nulling interferometry

    CERN Document Server

    Abel-Tiberini, Laetitia; Arezki, Brahim; Kern, Pierre; Grille, Romain; Labeye, Pierre; Broquin, Jean-Emmanuel

    2008-01-01

    This paper reports the characterization of hollow metallic waveguides (HMW) to be used as single-mode wavefront filters for nulling interferometry in the 6-20 microns range. The measurements presented here were performed using both single-mode and multimode conductive waveguides at 10.6 microns. We found propagation losses of about 16dB/mm, which are mainly due to the theoretical skin effect absorption in addition to the roughness of the waveguide metallic walls. The input and output coupling efficiency of our samples has been improved by adding tapers to minimize the impedance mismatch. A proper distinction between propagation losses and coupling losses is presented. Despite their elevate propagation losses, HMW show excellent spatial filtering capabilities in a spectral range where photonics technologies are only emerging.

  17. Single-mode hollow-core photonic crystal fiber made from soft glass

    Science.gov (United States)

    Jiang, X.; Euser, T. G.; Abdolvand, A.; Babic, F.; Tani, F.; Joly, N. Y.; Travers, J. C.; St. J. Russell, P.

    2011-08-01

    We demonstrate the first soft-glass hollow core photonic crystal fiber. The fiber is made from a high-index lead-silicate glass (Schott SF6, refractive index 1.82 at 500 nm). Fabricated by the stack-and-draw technique, the fiber incorporates a 7-cell hollow core embedded in a highly uniform 6-layer cladding structure that resembles a kagomé-like lattice. Effective single mode guidance of light is observed from 750 to 1050 nm in a large mode area (core diameter ~30 μm) with a low loss of 0.74 dB/m. The underlying guidance mechanism of the fiber is investigated using finite element modeling. The fiber is promising for applications requiring single mode guidance in a large mode area, such as particle guidance, fluid and gas filled devices.

  18. Capacity of coherent-state adaptive decoders with interferometry and single-mode detectors

    Science.gov (United States)

    Rosati, Matteo; Mari, Andrea; Giovannetti, Vittorio

    2017-07-01

    A class of adaptive decoders (ADs) for coherent-state sequences is studied, including in particular the most common technology for optical-signal processing, e.g., interferometers, coherent displacements, and photon-counting detectors. More generally we consider ADs comprising adaptive procedures based on passive multimode Gaussian unitaries and arbitrary single-mode destructive measurements. For classical communication on quantum phase-insensitive Gaussian channels with a coherent-state encoding, we show that the AD's optimal information transmission rate is not greater than that of a single-mode decoder. Our result also implies that the ultimate classical capacity of quantum phase-insensitive Gaussian channels is unlikely to be achieved with the considered class of ADs.

  19. Arc-discharge effects on residual stress and refractive index in single-mode optical fibers.

    Science.gov (United States)

    Wang, Pengfei; Jenkins, Micah H; Gaylord, Thomas K

    2016-03-20

    Arc-discharge effects on the residual stress and refractive index in single-mode optical fibers are investigated using a previously developed three-dimensional concurrent stress-index measurement method. Using commercial optical fibers and a commercial fusion splicer, the residual stress and refractive index perturbations caused by weak electrical arc discharges in single-mode fibers were measured. Refractive index changes greater than 10-4 and longitudinal perturbation lengths of less than 500 μm were shown to be possible. The subsequent prospects for arc-induced long-period fiber gratings are analyzed, and a typical transmission resonance is predicted to have a depth of 56 dB and a bandwidth of 0.08 nm at a wavelength of 1585 nm. The results of this investigation will be useful in modeling device performance and optimization of arc-induced long-period fiber grating fabrication.

  20. Quantum Otto engine of a two-level atom with single-mode fields.

    Science.gov (United States)

    Wang, Jianhui; Wu, Zhaoqi; He, Jizhou

    2012-04-01

    We establish a quantum Otto engine (QOE) of a two-level atom, which is confined in a one-dimensional (1D) harmonic trap and is coupled to single-mode radiation fields. Besides two adiabatic processes, the QOE cycle consists of two isochoric processes, along one of which the two-level atom as the working substance interacts with a single-mode radiation field. Based on the semigroup approach, we derive the time for completing any adiabatic process and then present a performance analysis of the heat engine model. Furthermore, we generalize the results to the performance optimization for a QOE of a single two-level atom trapped in a 1D power-law potential. Our result shows that the efficiency at maximum power output is dependent on the trap exponent θ but is independent of the energy spectrum index σ.

  1. The second-order interference of two independent single-mode He-Ne lasers

    CERN Document Server

    Liu, Jianbin; Bai, Bin; Wang, Wentao; Chen, Hui; Zhou, Yu; Li, Fu-Li; Xu, Zhuo

    2014-01-01

    The second-order spatial and temporal interference patterns with two independent single-mode He-Ne lasers are observed in a Hong-Ou-Mandel interferometer. Two-photon interference in Feynman's path integral theory is employed to interpret the experimental results. The conditions to observe the second-order interference pattern with two independent single-mode continuous wave lasers are discussed. It is concluded that two-photon interference exists for not only identical photons, but also photons with different spectrums if the detection system can not distinguish them in principle. The second-order temporal beating with two independent lasers can be employed to measure the coherence time and frequency of one laser if the properties of the other laser were known.

  2. Photo-structurable polymer for interlayer single-mode waveguide fabrication by femtosecond laser writing

    Science.gov (United States)

    Nguyen, Ho Hoai Duc; Hollenbach, Uwe; Pfirrmann, Stefan; Ostrzinski, Ute; Pfeiffer, Karl; Hengsbach, Stefan; Mohr, Juergen

    2017-04-01

    We present the fabrication and characterization of inter-layer single-mode light-guiding structures in a newly developed photo-structurable polymer via femtosecond laser writing. A host-guest polymer system utilizing external diffusion induces permanent and high refractive index modulation. Analyzing the complete curing and the impact of external diffusion on refractive index profile helps optimize the fabrication process. The fabrications of 4 × 2 array interconnect and 3-waveguide core fan-out device involve only a single layer, and need no stacking or alignment effort. The resulting pitch size and crosstalk between single-mode waveguides are 25 μm and -34 dB, respectively. Adding sensitizer into the photopolymer to increase its sensitivity in two-photon polymerization at a writing wavelength of 390 nm reduces the surface roughness of written structures by a factor of seven.

  3. Single-mode vertically integrated waveguide photodetectors for WDM data receiver applications

    Science.gov (United States)

    Densmore, Adam S.; Pimenov, Kirill; Tolstikhin, Valery I.

    2004-12-01

    The advantages of monolithic integration of passive and active optoelectronic components into multifunctional PICs (photonic integrated circuits) are numerous and well known. In WDM transmission systems, where up to hundreds of wavelength channels may be present and must be manipulated on a per wavelength basis, the advantages of PICs containing wavelength (de)multiplexers and arrays of active components rapidly multiply. This has been exploited in our earlier reported SurePath family of InP-based PICs for optical channel monitoring / equalization, which contain an echelle grating demultiplexer and single-mode vertically integrated waveguide photodetectors / electroabsorption attenuators inserted into each of its output channels. Now, the same design principles and fabrication techniques have been utilized for the development of a dense WDM data receiver. This paper concentrates on the key building block of such a component, the single-mode vertically integrated waveguide photodetector. A detailed characterization and analysis of the device performance are presented.

  4. Quantum Otto engine of a two-level atom with single-mode fields

    Science.gov (United States)

    Wang, Jianhui; Wu, Zhaoqi; He, Jizhou

    2012-04-01

    We establish a quantum Otto engine (QOE) of a two-level atom, which is confined in a one-dimensional (1D) harmonic trap and is coupled to single-mode radiation fields. Besides two adiabatic processes, the QOE cycle consists of two isochoric processes, along one of which the two-level atom as the working substance interacts with a single-mode radiation field. Based on the semigroup approach, we derive the time for completing any adiabatic process and then present a performance analysis of the heat engine model. Furthermore, we generalize the results to the performance optimization for a QOE of a single two-level atom trapped in a 1D power-law potential. Our result shows that the efficiency at maximum power output is dependent on the trap exponent θ but is independent of the energy spectrum index σ.

  5. Design and characterization of single-mode holey fibers with low bending losses.

    Science.gov (United States)

    Tsuchida, Yukihiro; Saitoh, Kunimasa; Koshiba, Masanori

    2005-06-13

    As the fiber-to-the-home network construction increased, optical fiber cables are demanded to be easier to handle and require less space. Under this situation, a single mode fiber (SMF) permitting small bending radius is strongly requested. In this paper, we propose and demonstrate a novel type of bending-insensitive single-mode holey fiber that has a doped core and two layers of holes with different air-hole diameters. The fiber has a mode field diameter of 9.3 microm at 1.55 microm and a cutoff wavelength below 1.1 microm, and shows a bending loss of 0.011 dB/turn at 1.55 microm for a bending radius of 5 mm and a low splice loss of 0.08 dB per fusion-splicing to a conventional SMF.

  6. Design of large-core single-mode Yb3+-doped photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xing-tao; ZHENG Yi; LIU Xiao-xu; ZHOU Gui-yao; LIU Zhao-lun; HOU Lan-tian

    2012-01-01

    The effective index of the cladding fundamental space-filing mode in photonic crystal fiber (PCF) is simulated by the effective index method.The variation of the effective index with the structure parameters of the fiber is achieved.For thefirst thne,the relations of the V parameter ofYb3+-doped PCF with the refractive index of core and the structure parameters of the fiber are provided.The single-mode characteristics of large-core yb3+-doped photonic crystal fibers with 7 and 19 missing air holes in the core are analyzed.The large-core single-mode Yb3+-doped photonic crystal fibers with core diameters of 50 μm,100 μm and 150 μm are designed.The results provide theory instruction for the design and fabrication of fiber.

  7. A surface plasmon resonance sensor based on a single mode D-shape polymer optical fiber

    Science.gov (United States)

    Gasior, Katarzyna; Martynkien, Tadeusz; Napiorkowski, Maciej; Zolnacz, Kinga; Mergo, Pawel; Urbanczyk, Waclaw

    2017-02-01

    For the first time to our knowledge, we report a successful fabrication of surface plasmon resonance (SPR) sensors in a specially developed single-mode birefringent polymer D-shape fiber with a core made of PMMA/PS copolymer. A small distance between the core and the cladding boundary allows to deposit a gold layer directly onto the flat fiber surface, which significantly simplifies the sensors fabrication process. The developed SPR sensor exhibits a sensitivity of 2765 nm RIU-1 for the refractive index of external medium equal to 1.410, which is similar to the sensitivity of the SPR sensors based on conventional side-polished single-mode silica fibers. Using the finite element method, we also numerically studied the sensor performance. The sensor characteristics obtained in the simulations are in a relatively good agreement with the experimental results.

  8. Modeling and optimization of single-mode vertical cavity surface emitting lasers

    Science.gov (United States)

    Dahiya, Sandeep; Kumar, Suresh; Kaushik, Brajesh Kumar

    2016-10-01

    Vertical cavity surface emitting laser (VCSEL) plays a vital role in optical network. The present investigation reports the performance comparison of the modeling of single-mode VCSELs at room temperature for continuous wave operation. VCSEL for the study consists of InGaAsP-based cavity or active region sandwiched between GaAs/AlGaAs top mirror and GaAs/AlAs bottom mirrors with the aim of increasing the power conversion efficiency (PCE), lasing power, and decreasing the threshold current. It is observed that VCSELs with lower diameter are most suitable to achieve energy-efficient operation. The PCE obtained is ˜50% for the proposed single-mode VCSELs. The proposed VCSELs are suitable for short-reach optical interconnects such as chip-to-chip and board-to-board communication in high-performance computers.

  9. Combined single-mode/multimode fiber link supporting simplified in-building 60-GHz gigabit wireless access

    DEFF Research Database (Denmark)

    Pham, Tien Thang; Lebedev, Alexander; Beltrán, Marta

    2012-01-01

    -conversion, combined single mode/multimode fiber transmission and envelope detection. Error-free transmission of 2-Gbps data in 60-GHz band over a composite channel including 10-km standard single-mode fiber (SSMF)/1-km multimode fiber (MMF) and 6.5-m air transmission was successfully achieved....

  10. On limitation of quality factor of single mode resonators with finite size

    CERN Document Server

    Ferdous, Fahmida; Vyatchanin, Sergey P; Matsko, Andrey B; Maleki, Lute

    2014-01-01

    Using realistic numerical models we analyze radiative loss of bound and unbound modes of specially designed high-Q whispering gallery and Fabry-Perot cavities of similar size and shape, and find a set of parameters when they can be treated as single mode structures. We show that these cavities have similar properties in spite of their different loss mechanisms. The cavity morphology engineering does not lead to reduction of the resonator quality factor.

  11. Thermal Effects on the Single-Mode Regime of Distributed Modal Filtering Rod Fiber

    DEFF Research Database (Denmark)

    Coscelli, Enrico; Poli, Federica; Alkeskjold, Thomas Tanggaard;

    2012-01-01

    Power scaling of fiber laser systems requires the development of innovative active fibers, capable of providing high pump absorption, ultralarge effective area, high-order mode suppression, and resilience to thermal effects. Thermally induced refractive index change has been recently appointed as...... with the same effective area. In fact, as the pump power is increased, their single-mode regime is preserved, being only blue-shifted in wavelength....

  12. Stochastic Multiresonance for Periodically Modulated Noise in a Single-Mode Laser

    Institute of Scientific and Technical Information of China (English)

    王俊; 曹力; 吴大进

    2003-01-01

    Multiplicatively introducing the noise and the signal into the gain-noise model of a single-mode laser system, we detect the two forms of stochastic resonance (the single-peak form stochastic resonance and stochastic multiresonance) in the curve of the dependence of signal-to-noise ratio upon the noise correlation time. Moreover, when the correlation coefficient and the intensities of both noises are changed, the two forms of stochastic resonance alternate.

  13. Electro-optical circuit board with single-mode glass waveguide optical interconnects

    Science.gov (United States)

    Brusberg, Lars; Neitz, Marcel; Pernthaler, Dominik; Weber, Daniel; Sirbu, Bogdan; Herbst, Christian; Frey, Christopher; Queisser, Marco; Wöhrmann, Markus; Manessis, Dionysios; Schild, Beatrice; Oppermann, Hermann; Eichhammer, Yann; Schröder, Henning; Hâkansson, Andreas; Tekin, Tolga

    2016-03-01

    A glass optical waveguide process has been developed for fabrication of electro-optical circuit boards (EOCB). Very thin glass panels with planar integrated single-mode waveguides can be embedded as a core layer in printed circuit boards for high-speed board-level chip-to-chip and board-to-board optical interconnects over an optical backplane. Such singlemode EOCBs will be needed in upcoming high performance computers and data storage network environments in case single-mode operating silicon photonic ICs generate high-bandwidth signals [1]. The paper will describe some project results of the ongoing PhoxTroT project, in which a development of glass based single-mode on-board and board-to-board interconnection platform is successfully in progress. The optical design comprises a 500 μm thin glass panel (Schott D263Teco) with purely optical layers for single-mode glass waveguides. The board size is accommodated to the mask size limitations of the fabrication (200 mm wafer level process, being later transferred also to larger panel size). Our concept consists of directly assembling of silicon photonic ICs on cut-out areas in glass-based optical waveguide panels. A part of the electrical wiring is patterned by thin film technology directly on the glass wafer surface. A coupling element will be assembled on bottom side of the glass-based waveguide panel for 3D coupling between board-level glass waveguides and chip-level silicon waveguides. The laminate has a defined window for direct glass access for assembling of the photonic integrated circuit chip and optical coupling element. The paper describes the design, fabrication and characterization of glass-based electro-optical circuit board with format of (228 x 305) mm2.

  14. Wave turbulence in integrable systems: nonlinear propagation of incoherent optical waves in single-mode fibers

    OpenAIRE

    2011-01-01

    International audience; We study theoretically, numerically and experimentally the nonlinear propagation of partially incoherent optical waves in single mode optical fibers. We revisit the traditional treatment of the wave turbulence theory to provide a statistical kinetic description of the integrable scalar NLS equation. In spite of the formal reversibility and of the integrability of the NLS equation, the weakly nonlinear dynamics reveals the existence of an irreversible evolution toward a...

  15. Bandwidth comparison of photonic crystal fibers and conventional single mode fibers

    DEFF Research Database (Denmark)

    Nielsen, Martin Dybendal; Folkenberg, Jacob Riis; Mortensen, Niels Asger;

    2004-01-01

    We experimentally compare the optical bandwidth of a conventional single-mode fiber (SMF) with 3 different photonic crystal fibers (PCF) all optimized for visible applications. The spectral attenuation, single-turn bend loss, and mode-field diameters (MFD) are measured and the PCF is found to have...... a significantly larger bandwidth than the SMF for an identical MFD. It is shown how this advantage can be utilized for realizing a larger MFD for the PCF while maintaining a bending resistant fiber....

  16. Optimization of Output Properties for Bias Signal-Modulated in a Single-Mode Laser

    Institute of Scientific and Technical Information of China (English)

    LI Tai-Quan; DONG Ping; YANG Hong-Quan; HAN Li-Bo

    2005-01-01

    Defining the quantity K as the signal-to-noise ratio (SNR) and the normalized intensity fluctuation C(0) of a single-mode laser for bias signal modulation driven by color noises with colored correlation, the whole output properties of the laser system is described by K. It is found that there is a maximum in the curves of K versus D, Q, and io. The optimization parameters are gained.

  17. High-power monolithic single-mode diode lasers employing active photonic lattices

    Science.gov (United States)

    Botez, Dan

    2003-06-01

    Photonic-lattice structures with modulated gain, that is active photonic lattices (APLs), of large index steps and gain preferentially enhanced on the low-index lattice sites have been used, as early as 1988, for effective lateral-mode control range in large-aperture (100-200 microns) high-power coherent devices. Photonic-bandpass (PBP) structures relying on long-range resonant leaky-wave coupling, so called ROW arrays, have allowed stable, near-diffraction-limited beam operation to powers as high as 1.6W CW and 10W peak pulsed. Photonic-bandgap (PBG) structures with a built-in lattice defect, so called ARROW lasers, have provided up to 0.5W peak-pulsed stable, single-mode power and hold the potential for 1W CW reliable single-mode operation from apertures 8-10 microns wide. The solution for high-efficiency surface emission, from 2nd-order DFB/DBR lasers, in an orthonormal, single-lobe beam pattern was found in 2000. Recently, single-lobe and single-mode operation in a diffraction-limited beam orthonormal to the chip surface was demonstrated from 1.5mm-long DFB/DBR ridge-guide lasers. That opens the way for the realization of 2-D surface-emitting,2nd-order APLs for the stable generation of watts of CW single-lobe, single-mode power from large 2-D apertures, as well as scalability of such devices at the wafer level.

  18. Optimal coupling of entangled photons into single-mode optical fibers

    CERN Document Server

    Andrews, R; Sarkar, S; Sarkar, Sarben

    2004-01-01

    We present a consistent multimode theory that describes the coupling of single photons generated by collinear Type-I parametric down-conversion into single-mode optical fibers. We have calculated an analytic expression for the fiber diameter which maximizes the pair photon count rate. For a given focal length and wavelength, a lower limit of the fiber diameter for satisfactory coupling is obtained.

  19. Late-time quadratic growth in single-mode Rayleigh-Taylor instability.

    Science.gov (United States)

    Wei, Tie; Livescu, Daniel

    2012-10-01

    The growth of the two-dimensional single-mode Rayleigh-Taylor instability (RTI) at low Atwood number (A=0.04) is investigated using Direct Numerical Simulations. The main result of the paper is that, at long times and sufficiently high Reynolds numbers, the bubble acceleration becomes stationary, indicating mean quadratic growth. This is contrary to the general belief that single-mode Rayleigh-Taylor instability reaches a constant bubble velocity at long times. At unity Schmidt number, the development of the instability is strongly influenced by the perturbation Reynolds number, defined as Rep≡λsqrt[Agλ/(1+A)]/ν. Thus, the instability undergoes different growth stages at low and high Rep. A new stage, chaotic development, was found at sufficiently high Rep values, after the reacceleration stage. During the chaotic stage, the instability experiences seemingly random acceleration and deceleration phases, as a result of complex vortical motions, with strong dependence on the initial perturbation shape (i.e., wavelength, amplitude, and diffusion thickness). Nevertheless, our results show that the mean acceleration of the bubble front becomes constant at late times, with little influence from the initial shape of the interface. As Rep is lowered to small values, the later instability stages, chaotic development, reacceleration, potential flow growth, and even the exponential growth described by linear stability theory, are subsequently no longer reached. Therefore, the results suggest a minimum Reynolds number and a minimum development time necessary to achieve all stages of single-mode RTI development, requirements which were not satisfied in the previous studies of single-mode RTI.

  20. Tellurite suspended nanowire surrounded with large holes for single-mode SC and THG generations

    Science.gov (United States)

    Liao, Meisong; Qin, Guanshi; Yan, Xin; Chaudhari, Chitrarekha; Suzuki, Takenobu; Ohishi, Yasutake

    2011-05-01

    For a suspended nanowire, the holes surrounding the core are expected to be as large as possible to propagate the light at wavelengths as long as possible. However, the fabrication of nanowire surrounded with large holes is still a challenge so far. In this paper, a method which involves pumping positive pressure of nitrogen gas in both the cane fabrication and fiber-drawing processes, is proposed. A suspended nanowire, with a core diameter of 480 nm and an unprecedented large diameter ratio of holey region to core (DRHC) of at least 62, is fabricated in the length of several hundred meters. Owing to the large holes, the confinement loss of the suspended nanowire is insignificant when the wavelength of light propagated in it is 1700 nm. Additionally, the tube-shaped glass cladding of the suspended nanowire shifts the singlemode cutoff wavelength to 810 nm, which is much shorter than the cutoff wavelength, 1070 nm, of a naked nanowire with the same diameter. A single-mode supercontinuum (SC) generation covering a wavelength range of 900-1600 nm is obtained under 1064 nm pump pulse with the peak power as low as 24 W. A single-mode third harmonic generation (THG) is observed by this nanowire under the pump of a 1557 nm femtosecond fiber laser. This work indicates that the suspended nanowire with large holes can provide high nonlinearity together with single-mode propagation, which leads to interesting applications in compact nonlinear devices.

  1. On the Relative Advantage of Mixed-Mode versus Single-Mode Surveys

    Directory of Open Access Journals (Sweden)

    Jorre Vannieuwenhuyze

    2013-12-01

    Full Text Available Survey researchers increasingly use mixed-mode surveys for general population data collection because mixed-mode surveys are argued to provide lower selection error at constant budgets or lower variable costs at constant selection error. Nevertheless, the advantage of lower selection error and variable costs might be counteracted by higher measurement error and by higher fixed costs. This trade-off between selection error, measurement error, variable costs and fixed costs has hardly been studied within the existing literature about mixed-mode surveys. This paper discusses a possible procedure for evaluating this trade-off by comparing the performance (mean squared error of mixed-mode survey designs against single-mode survey designs. The procedure is further illustrated by real example data stemming from a mixed-mode mail---face-to-face survey. This illustration yields smaller errors for single-mode designs under low budgets but smaller errors for mixed-mode designs under large budgets or, alternatively, a budgetary advantage of single-mode designs when the allowed error is relatively high but a budgetary advantage of mixed-mode designs when the allowed error is relatively small. However, the validity of these results depend on several modelling assumptions which may be topics for future research.

  2. Single-mode low threshold current multi-hole vertical-cavity surface-emitting lasers

    Institute of Scientific and Technical Information of China (English)

    Zhao Zhen-Bo; Xu Chen; Xie Yi-Yang; Zhou Kang; Liu Fa; Shen Guang-Di

    2012-01-01

    A multi-hole vertical-cavity surface-emitting laser (VCSEL) operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-reflector of an oxidationconfined 850 nm VCSEL.The single-mode output power of 2.6 mW,threshold current of 0.6 mA,full width of half maximum lasing spectrum of less than 0.1 nm,side mode suppression ratio of 28.4 dB,and far-field divergence angle of about 10° are obtained.The effects of different hole depths on the optical characteristics are simulated and analysed,including far-field divergence,spectrum and lateral cavity mode.The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter-hole spacing and the scattering loss at the bottom of the holes,particularly for higher order modes.

  3. Single-mode planar optics for 4-20um wavelengths astronomical interferometry

    Science.gov (United States)

    Laurent, E.; Kern, P.; Schanen, I.; Rousselet-Perraut, K.

    2002-06-01

    Single-mode planar optics for 4-20 micrometers wavelengths astronomical interferometry. Spatial filtering is a critical issue to achieve nulling interferometry in the framework of spatial missions aimed at the detection of exoplanets. Several working interferometric instruments take benefits of guided optics for spatial filtering in the near IR wavelengths and thus provide accurate visibility measurements. Futhermore planar optics would also provides beam combining functions within a single compact and stable device. Existing telecom technology allows beam combiner realizations for 0.8 to 1.6 micrometers wavelengths. Last works allow us to valid these technologies up to 2.4 micrometers for stellar interferometry in the H and K bands. Technological developments are required to meet the scientific domain of the spatial missions like IRSI/DARWIN and TPF dedicated to thermal infrared wavelengths [4-20 micrometers]. We present the most promising materials with their technologies to manufacture single-mode planar optics for this wavelength range. First set of solutions involved chalcogenide glasses. Channel waveguides could be manufactured by photo-exposition method or thin layer etching process. Another solution is using porous silicon obtained from an acid dissolution of a silicon substrate which allows refractive index modulation. The last set of solution is based on thin films etching of semiconductor materials like silicon, germanium, zinc sulfide and zinc selenide.Test benches for the single-mode behavior are also presented. For each solutions, we present some manufactured waveguides with their optical characterizations.

  4. Distributed Bragg reflector ring oscillators: A large aperture source of high single-mode optical power

    Energy Technology Data Exchange (ETDEWEB)

    Dzurko, K.M.; Hardy, A.; Scifres, D.R.; Welch, D.F.; Waarts, R.G.; Lang, R.J. (Spectra Diode Labs., San Jose, CA (United States))

    1993-06-01

    Distributed Bragg reflector (DBR) ring oscillators are the first monolithic semiconductor lasers containing broad-area active regions which operate in a single mode to several times their threshold current. Orthogonally oriented diffraction gratings surrounding an unpatterned active region select a single spatial and temporal mode of oscillation. This paper presents both analytic and experimental verification of single mode operation for active dimensions up to 368 [times] 1000 [mu]m. Threshold current densities under 200 A/cm[sup 2] and total differential efficiencies greater than 60% have been measured. DBR ring oscillators have demonstrated over 1 W of single frequency output power, 460 mW of spatially coherent, single frequency output power, and nearly circular diffraction limited output to 4 [times] I[sub th]. The performance potential of these devices is enormous, considering that the output apertures are nearly two orders of magnitude wider than conventional single mode sources which generate up to 0.2 W of coherent output.

  5. Multimode to single-mode converters: new results on 1-to-61 photonic lanterns

    Science.gov (United States)

    Olaya, J.-C.; Ehrlich, K.; Haynes, D. M.; Haynes, R.; Leon-Saval, S. G.; Schirdewahn, D.

    2012-09-01

    Photonic Lanterns are a fibre-based component performing the adiabatic conversion from a multimode fibre to a series of single-mode fibres. This conversion is required for combining fibre-based instruments used in astronomy with complex photonic functions. As any fibre-based system, the optical properties of the Photonic Lanterns need to be fully evaluated. In this paper, we present results on the performance of a 1-to-61 Photonic Lantern in terms of spectral transmission and modal noise characteristics. Firstly, we compare the spectra obtained at the output of two photonic lanterns spliced together in multimode-to-multimode configuration with spectra obtained when transmitting light through step-index single-mode and multimode fibres. We then show that the photonic lantern is generating less modal noise than a step-index multimode fibre of same core diameter, when it is submitted to bending and stretching, and we propose an interpretation of this result based on static mode scrambling performance and single-mode behavior.

  6. Precision single mode fibre integral field spectroscopy with the RHEA spectrograph

    Science.gov (United States)

    Rains, Adam D.; Ireland, Michael J.; Jovanovic, Nemanja; Feger, Tobias; Bento, Joao; Schwab, Christian; Coutts, David W.; Guyon, Olivier; Arriola, Alexander; Gross, Simon

    2016-08-01

    The RHEA Spectrograph is a single-mode echelle spectrograph designed to be a replicable and cost effective method of undertaking precision radial velocity measurements. Two versions of RHEA currently exist, one located at the Australian National University in Canberra, Australia (450 - 600nm wavelength range), and another located at the Subaru Telescope in Hawaii, USA (600 - 800 nm wavelength range). Both instruments have a novel fibre feed consisting of an integral field unit injecting light into a 2D grid of single mode fibres. This grid of fibres is then reformatted into a 1D array at the input of the spectrograph (consisting of the science fibres and a reference fibre capable of receiving a white-light or xenon reference source for simultaneous calibration). The use of single mode fibres frees RHEA from the issue of modal noise and significantly reduces the size of the optics used. In addition to increasing the overall light throughput of the system, the integral field unit allows for cutting edge science goals to be achieved when operating behind the 8.2m Subaru Telescope and the SCExAO adaptive optics system. These include, but are not limited to: resolved stellar photospheres; resolved protoplanetary disk structures; resolved Mira shocks, dust and winds; and sub-arcsecond companions. We present details and results of early tests of RHEA@Subaru and progress towards the stated science goals.

  7. Femtosecond laser fabrication of fiber based optofluidic platform for flow cytometry applications

    Science.gov (United States)

    Serhatlioglu, Murat; Elbuken, Caglar; Ortac, Bulend; Solmaz, Mehmet E.

    2017-02-01

    Miniaturized optofluidic platforms play an important role in bio-analysis, detection and diagnostic applications. The advantages of such miniaturized devices are extremely low sample requirement, low cost development and rapid analysis capabilities. Fused silica is advantageous for optofluidic systems due to properties such as being chemically inert, mechanically stable, and optically transparent to a wide spectrum of light. As a three dimensional manufacturing method, femtosecond laser scanning followed by chemical etching shows great potential to fabricate glass based optofluidic chips. In this study, we demonstrate fabrication of all-fiber based, optofluidic flow cytometer in fused silica glass by femtosecond laser machining. 3D particle focusing was achieved through a straightforward planar chip design with two separately fabricated fused silica glass slides thermally bonded together. Bioparticles in a fluid stream encounter with optical interrogation region specifically designed to allocate 405nm single mode fiber laser source and two multi-mode collection fibers for forward scattering (FSC) and side scattering (SSC) signals detection. Detected signal data collected with oscilloscope and post processed with MATLAB script file. We were able to count number of events over 4000events/sec, and achieve size distribution for 5.95μm monodisperse polystyrene beads using FSC and SSC signals. Our platform shows promise for optical and fluidic miniaturization of flow cytometry systems.

  8. Very low zero-dispersion wavelength predicted for single-mode modified-total-internal-reflection crystal fibre

    DEFF Research Database (Denmark)

    Jacobsen, Rune Shim; Lægsgaard, Jesper; Bjarklev, Anders Overgaard

    2004-01-01

    A zero-dispersion wavelength (lgr/sub ZD/) below 600 nm has been predicted for a pure silica modified-total-internal-reflection (M-TIR) single-mode crystal fibre with a 1 mm pitch. The fibre is single mode from at least 250 nm, i.e., from well below lgr/sub ZD/. Both a method for designing single......-mode crystal fibres using an anti-guiding structure and a fast calculation scheme for investigating the structure for different pitch sizes are proposed....

  9. GaSb-based single-mode distributed feedback lasers for sensing (Conference Presentation)

    Science.gov (United States)

    Gupta, James A.; Bezinger, Andrew; Lapointe, Jean; Poitras, Daniel; Aers, Geof C.

    2017-02-01

    GaSb-based tunable single-mode diode lasers can enable rapid, highly-selective and highly-sensitive absorption spectroscopy systems for gas sensing. In this work, single-mode distributed feedback (DFB) laser diodes were developed for the detection of various trace gases in the 2-3.3um range, including CO2, CO, HF, H2S, H2O and CH4. The lasers were fabricated using an index-coupled grating process without epitaxial regrowth, making the process significantly less expensive than conventional DFB fabrication. The devices are based on InGaAsSb/AlGaAsSb separate confinement heterostructures grown on GaSb by molecular beam epitaxy. DFB lasers were produced using a two step etch process. Narrow ridge waveguides were first defined by optical lithography and etched into the semiconductor. Lateral gratings were then defined on both sides of the ridge using electron-beam lithography and etched to produce the index-grating. Effective index modeling was used to optimize the ridge width, etch depths and the grating pitch to ensure single-lateral-mode operation and adequate coupling strength. The effective index method was further used to simulate the DFB laser emission spectrum, based on a transfer matrix model for light transmission through the periodic structure. The fabricated lasers exhibit single-mode operation which is tunable through the absorption features of the various target gases by adjustment of the drive current. In addition to the established open-path sensing applications, these devices have great potential for optoelectronic integrated gas sensors, making use of integrated photodetectors and possibly on-chip Si photonics waveguide structures.

  10. Efficient multi-mode to single-mode conversion in a 61 port photonic lantern

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Skovgaard, Peter M. W.; Dybendahl Maack, Martin

    2010-01-01

    (MMF) cladding. Our fabricated Photonic Lanterns are solid all-glass versions, with the MMF defined by a low-index tube surrounding the single-mode fibers (SMFs). We show experimentally that these devices can be used to achieve efficient and reversible coupling between a MMF and 61 SMFs, when perfectly...... matched launch conditions into the MMF are ensured. The total coupling loss from a 100 µm core diameter MM section to the ensemble of 61 SMFs and back to another 100 µm core MM section is measured to be as low as 0.76 dB. This demonstrates the feasibility of using the Photonic Lanterns within the field...

  11. Enhanced Sensitivity in a Superluminal Single Mode DPAL Cavity at Room Temperature

    Science.gov (United States)

    Abi-Salloum, Tony; Yablon, Joshua; Tseng, Shih; Shahriar, Selim

    2012-06-01

    The note beat between two counter-propagating beams in a cavity is used to measure the effective change of the length of the cavity or interferometer for applications such as optical gyroscopes, vibrometers, and gravitational wave detectors. We show in this talk how a superluminal single mode laser cavity can enhance the measured note beat dramatically. We consider the inhomogeneous broadening case and study the dependence of the enhancement factor on few key parameters. We also show how Diode Pump Alkali Lasers (DPAL) are excellent candidates for such devices. Using a Rubidium based DPAL, we study the characteristics of these lasers and their effect on the proposed enhanced sensitivity.

  12. Optical absorption in commercial single mode optical fibres for the LHC machine

    CERN Document Server

    Wijnands, T J; Kuhnhenn, J; Hoeffgen, S K; Weinand, U; TS

    2007-01-01

    The optical absorption of light at 1310 nm and 1550 nm in various commercially available Single Mode (SM) fibres samples has been studied. The absorption was measured as a function of dose, dose rate, temperature and light power. The samples were irradiated with gamma rays from a 60Co source and exposed to a complex radiation field from high energy physics. One fibre sample with an F-doped core exhibits extreme low absorption of light at 1310 nm during irradiation up to doses of at least 100 kGy.

  13. Supercontinuum generation and carrier envelope offset frequency measurement in a tapered single-mode fiber

    CERN Document Server

    Zhang, Long; Zhao, Yanying; Hou, Lei; Yu, Zijiao; Wei, Zhiyi

    2014-01-01

    We report supercontinuum generation by launching femtosecond Yb fiber laser pulses into a tapered single-mode fiber of 3 um core diameter. A spectrum of more than one octave, from 550 to 1400 nm, has been obtained with an output power of 1.3 W at a repetition rate of 250 MHz, corresponding to a coupling efficiency of up to 60%. By using a typical f-2f interferometer, the carrier envelope offset frequency was measured and found to have a signal-to-noise ratio of nearly 30 dB.

  14. Low-NA single-mode LMA photonic crystal fiber amplifier

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Scolari, Lara; Broeng, Jes

    2011-01-01

    Enabling Single-Mode (SM) operation in Large-Mode-Area (LMA) fiber amplifiers and lasers is critical, since a SM output ensures high beam quality and excellent pointing stability. In this paper, we demonstrate and test a new design approach for achieving ultra-low NA SM rod fibers by using...... a spatially Distributed Mode Filter (DMF). This approach achieves SM performance in a short and straight rod fiber and allows preform tolerances to be compensated during draw. A low-NA SM rod fiber amplifier having a mode field diameter of ~60μm at 1064nm and a pump absorption of 27dB/m at 976nm...

  15. Low-loss single-mode integrated waveguides in soda-lime glass

    Science.gov (United States)

    Dyakonov, I. V.; Kalinkin, A. A.; Saygin, M. Yu.; Abroskin, A. G.; Radchenko, I. V.; Straupe, S. S.; Kulik, S. P.

    2016-09-01

    Low-loss single-mode optical waveguide fabrication process in extra-white soda-lime glass is demonstrated. Waveguiding structures are formed in bulk substrates employing femtosecond laser writing technology. The combination of a slit beam shaping method and a multiscan fabrication process enables writing of waveguides with a well-defined symmetric cross-sectional profile. Fabricated waveguides exhibit 0.86 dB/cm propagation loss for 800-nm wavelength. Bending loss in the waveguides is addressed experimentally and compared with a model for radiation loss.

  16. Influence of net gain on the statistical fluctuation in a single-mode laser system

    Institute of Scientific and Technical Information of China (English)

    Qinghua Cheng; Dahai Xu; Li Cao; Dajin Wu

    2006-01-01

    @@ Using linear approximation method, we calculate the intensity correlation time of a single-mode laser driven by both colored pump noise with signal modulation and the quantum noise with cross-correlation between its real and imaginary parts, and analyze the influence of the net gain coefficient a0 on the statistical fluctuation of the laser system. It is found that for the case that the colored pump noise is long time correlated, the main factor influencing the statistical fluctuation of the laser system is a0, and the frequency of the modulation signal has negligible effect on the statistical fluctuation of the laser system.

  17. Frequency noise suppression of a single mode laser with an unbalanced fiber interferometer for subnanometer interferometry.

    Science.gov (United States)

    Šmíd, Radek; Čížek, Martin; Mikel, Břetislav; Číp, Ondřej

    2015-01-12

    We present a method of noise suppression of laser diodes by an unbalanced Michelson fiber interferometer. The unstabilized laser source is represented by compact planar waveguide external cavity laser module, ORIONTM (Redfern Integrated Optics, Inc.), working at 1540.57 nm with a 1.5-kHz linewidth. We built up the unbalanced Michelson interferometer with a 2.09 km-long arm based on the standard telecommunication single-mode fiber (SMF-28) spool to suppress the frequency noise by the servo-loop control by 20 dB to 40 dB within the Fourier frequency range, remaining the tuning range of the laser frequency.

  18. Frequency Noise Suppression of a Single Mode Laser with an Unbalanced Fiber Interferometer for Subnanometer Interferometry

    OpenAIRE

    Radek Šmíd; Martin Čížek; Břetislav Mikel; Ondřej Číp

    2015-01-01

    We present a method of noise suppression of laser diodes by an unbalanced Michelson fiber interferometer. The unstabilized laser source is represented by compact planar waveguide external cavity laser module, ORIONTM (Redfern Integrated Optics, Inc.), working at 1540.57 nm with a 1.5-kHz linewidth. We built up the unbalanced Michelson interferometer with a 2.09 km-long arm based on the standard telecommunication single-mode fiber (SMF-28) spool to suppress the frequency noise by the servo-loo...

  19. Low-loss single-mode integrated waveguides in soda-lime glass

    CERN Document Server

    Kalinkin, Alexander; Abroskin, Andrey; Radchenko, Igor; Straupe, Stanislav; Kulik, Sergei

    2016-01-01

    Low-loss single-mode optical waveguide fabrication process in extra-white soda-lime glass is demonstrated. Waveguiding structures are formed in bulk substrates employing femtosecond laser writing technology. The combination of a slit beam-shaping method and a multiscan fabrication process enables printing of waveguides with a well-defined symmetric cross-section profile. Fabricated waveguides exhibit 0.86 dB/cm propagation loss for 800~nm wavelength. Bending loss in the waveguides are addressed experimentally and compared with a model for radiation loss.

  20. Stochastic resonance in a single-mode laser driven by frequency modulated signal and coloured noises

    Institute of Scientific and Technical Information of China (English)

    Jin Guo-Xiang; Zhang Liang-Ying; Cao Li

    2009-01-01

    By adding frequency modulated signals to the intensity equation of gain-noise model of the single-mode laser driven by two coloured noises which are correlated, this paper uses the linear approximation method to calculate the power spectrum and signal-to-noise ratio (SNR) of the laser intensity. The results show that the SNR appears typical stochastic resonance with the variation of intensity of the pump noise and quantum noise. As the amplitude of a modulated signal has effects on the SNR, it shows suppression, monotone increasing, stochastic resonance, and multiple stochastic resonance with the variation of the frequency of a carrier signal and modulated signal.

  1. In-line single-mode fiber variable optical attenuator based on electrically addressable microdroplets

    Science.gov (United States)

    Duduś, A.; Blue, R.; Zagnoni, M.; Stewart, G.; Uttamchandani, D.

    2014-07-01

    We report an in-line, fiber optic, broadband variable optical attenuator employing a side-polished, single-mode optical fiber integrated on a digital microfluidics platform. The system is designed to electrically translate a liquid droplet along the polished surface of an optical fiber using electrowetting forces. This fiber optic device has the advantage of no moving mechanical parts and lends itself to miniaturization. A maximum attenuation of 25 dB has been obtained in the wavelength range between 1520 nm and 1560 nm.

  2. Time-Delayed Feedback Control in a Single-Mode Laser System

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of time-delayed feedback control in a single-mode laser system is investigated. Using the small time delay approximation, the analytic expression of the stationary probability distribution function of the laser field is obtaincd. The mean, normalized variance and skewness of the steady-state laser intensity are calculated. It is found that the time-delayed feedback control can suppress the intensity fluctuation of the laser system. The numerical simulations are in good agreement with the approximate analytic results.

  3. A new automatic alignment technology for single mode fiber-waveguide based on improved genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yu; CHEN Zhuang-zhuang; LI Ya-juan; DUAN Jian

    2009-01-01

    A novel automatic alignment algorithm of single mode fiber-waveguide based on improved genetic algorithm is proposed. The genetic searching is based on the dynamic crossover operator and the adaptive mutation operator to solve the premature convergence of simple genetic algorithm The improved genetic algorithm combines with hill-climbing method and pattern searching algorithm, to solve low precision of simple genetic algorithm in later searching. The simulation results indicate that the improved genetic algorithm can rise the alignment precision and reach the coupling loss of 0.01 dB when platform moves near 207 space points averagely.

  4. Narrow linewidth single-mode semiconductor laser development for coherent detection lidar

    Science.gov (United States)

    Mansour, Kamjou; Ksendzov, Alexander; Menzies, Robert T.; Maker, Paul D.; Muller, Richard E.; Manfra, M. J.; Turner, George W.

    2003-01-01

    High power, tunable, single mode, narrow linewidth semiconductor lasers in the 2.05-(micro)m wavelength region are needed to develop semiconductor laser reference oscillators for optical remote sensing from Earth orbit. 2.05-I1/4m narrow linewidth monolithic distributed feedback (DFB) and distributed Bragg reflector (DBR) with the external grating ridge waveguide lasers fabricated from epitaxially grown InGaAs/InGaAsP/InP and in InGaAsSb/AlGaAsSb/GaSb heterostructures are reported.

  5. Operational condition of direct single-mode-fiber coupled FSO terminal under strong atmospheric turbulence

    Science.gov (United States)

    Arimoto, Yoshinori

    2011-03-01

    This paper discusses the operational condition for direct single-mode-fiber-coupling FSO terminals under the various adverse weather conditions, such as strong atmospheric turbulences and rain falls. A good correlation between the scintillation index of the intensities of beacon receiving power and the signal fading depth has been observed, which allows us to predict the signal link quality based on the beacon scintillation index provided by the classical scintillation theory and concludes that the scintillation index for the beacon beam should be less than 0.1. This paper also reports the effect of performance enhancements provided by the new adaptive controller for the stable and robust terminal operation.

  6. Response of two-band systems to a single-mode quantized field

    Science.gov (United States)

    Shi, Z. C.; Shen, H. Z.; Wang, W.; Yi, X. X.

    2016-03-01

    The response of topological insulators (TIs) to an external weakly classical field can be expressed in terms of Kubo formula, which predicts quantized Hall conductivity of the quantum Hall family. The response of TIs to a single-mode quantized field, however, remains unexplored. In this work, we take the quantum nature of the external field into account and define a Hall conductance to characterize the linear response of a two-band system to the quantized field. The theory is then applied to topological insulators. Comparisons with the traditional Hall conductance are presented and discussed.

  7. Cladding waveguide gratings in standard single-mode fiber for 3D shape sensing.

    Science.gov (United States)

    Waltermann, Christian; Doering, Alexander; Köhring, Michael; Angelmahr, Martin; Schade, Wolfgang

    2015-07-01

    Femtosecond laser pulses were used for the direct point-by-point inscription of waveguides into the cladding of standard single-mode fibers. Homogeneous S-shaped waveguides have been processed as a bundle of overlapping lines without damaging the surrounding material. Within these structures, FBGs have been successfully inscribed and characterized. A sensor device to measure the bending direction of a fiber was created by two perpendicular inscribed cladding waveguides with FBG. Finally, a complete 3D shape sensor consisting of several bending sensor planes, capable of detecting bending radii even below 2.5 cm is demonstrated.

  8. Narrow linewidth single-mode semiconductor laser development for coherent detection lidar

    Science.gov (United States)

    Mansour, Kamjou; Ksendzov, Alexander; Menzies, Robert T.; Maker, Paul D.; Muller, Richard E.; Manfra, M. J.; Turner, George W.

    2003-01-01

    High power, tunable, single mode, narrow linewidth semiconductor lasers in the 2.05-(micro)m wavelength region are needed to develop semiconductor laser reference oscillators for optical remote sensing from Earth orbit. 2.05-I1/4m narrow linewidth monolithic distributed feedback (DFB) and distributed Bragg reflector (DBR) with the external grating ridge waveguide lasers fabricated from epitaxially grown InGaAs/InGaAsP/InP and in InGaAsSb/AlGaAsSb/GaSb heterostructures are reported.

  9. Static and Dynamic Regimes of Arbitrary Gain Compensation Single-Mode Laser Diodes

    CERN Document Server

    Tannous, C

    2001-01-01

    We report on a methodology for the evaluation of the DC characteristics, small-signal frequency response and large-signal dynamic response of carrier and photon density responses in semiconductor laser diodes. A single mode laser is considered and described with a pair of rate equations containing a novel non-linear gain compensation term depending on a single parameter that can be chosen arbitrarily. This approach can be applied to any type of solid-state laser as long as it is described by a set of rate equations.

  10. Flat Supercontinuum Generated in a Single-Mode Optical Fibre with a New Chromatic Dispersion Profile

    Institute of Scientific and Technical Information of China (English)

    XU Yong-Zhao; REN Xiao-Min; ZHANG Xia; HUANG Yong-Qing; XU Wen-Cheng

    2005-01-01

    @@ A new chromatic dispersion profile of a single-mode opticalfibre is proposed for generating a supercontinuum with a flatly broadened spectrum. The chromatic dispersion D( λ, z) is a convex function of wavelengths and has no zero-dispersion wavelengths over the whole part of thefibre as D(λ, z) is negative. It is shown that the flat supercontinuum spectrum is obtained when the pump wavelength is set in the vicinity of the wavelength at which the peak chromatic dispersion is near zero and the strong residual pump component is eliminated.

  11. Observation of Single-Mode, Kelvin-Helmholtz Instability in a Supersonic Flow.

    Science.gov (United States)

    Wan, W C; Malamud, G; Shimony, A; Di Stefano, C A; Trantham, M R; Klein, S R; Shvarts, D; Kuranz, C C; Drake, R P

    2015-10-02

    We report the first observation, in a supersonic flow, of the evolution of the Kelvin-Helmholtz instability from a single-mode initial condition. To obtain these data, we used a novel experimental system to produce a steady shock wave of unprecedented duration in a laser-driven experiment. The shocked, flowing material creates a shear layer between two plasmas at high energy density. We measured the resulting interface structure using radiography. Hydrodynamic simulations reproduce the large-scale structures very well and the medium-scale structures fairly well, and imply that we observed the expected reduction in growth rate for supersonic shear flow.

  12. Stochastic resonance of bias signal-modulated noise in a single-mode laser

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Cao Li; Wu Da-Jin

    2004-01-01

    Stochastic resonance (SR) for bias signal modulation is studied in a single-mode laser system. By investigating a gain-noise model driven by correlated pump noise and quantum noir, we find that, whether the correlation coefficient between both the noises is positive or negative, SR always appears in the dependence of signal-to-noise ratio (SNR) upon the noise correlation time and the frequency of the modulation signal. However, only when the correlation coefficient between both noises is negative can SR occur in the dependence of SNR upon the quantum noise intensity and pump noise intensity, while when the correlation coefficient between both noises is positive, it shows monotonically.

  13. Effects of underwater turbulence on laser beam propagation and coupling into single-mode optical fiber.

    Science.gov (United States)

    Hanson, Frank; Lasher, Mark

    2010-06-01

    We characterize and compare the effects of turbulence on underwater laser propagation with theory. Measurements of the coupling efficiency of the focused beam into a single-mode fiber are reported. A simple tip-tilt control system, based on the position of the image centroid in the focal plane, was shown to maintain good coupling efficiency for a beam radius equal to the transverse coherence length, r(0). These results are relevant to high bandwidth communication technology that requires good spatial mode quality.

  14. Efficient multi-mode to single-mode coupling in a photonic lantern

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Skovgaard, Peter M.; Nielsen, Martin D.;

    2009-01-01

    We demonstrate the fabrication of a high performance multi-mode (MM) to single-mode (SM) splitter or “photonic lantern”, first described by Leon-Saval et al. (2005). Our photonic lantern is a solid all-glass version, and we show experimentally that this device can be used to achieve efficient...... and reversible coupling between a MM fiber and a number of SM fibers, when perfectly matched launch conditions into the MM fiber are ensured. The fabricated photonic lantern has a coupling loss for a MM to SM tapered transition of only 0.32 dB which proves the feasibility of the technology...

  15. Fast random number generation with spontaneous emission noise of a single-mode semiconductor laser

    Science.gov (United States)

    Zhang, Jianzhong; Zhang, Mingjiang; Liu, Yi; Li, Pu; Yi, Xiaogang; Zhang, Mingtao; Wang, Yuncai

    2016-11-01

    We experimentally demonstrate a 12.5 Gb s-1 random number generator based on measuring the spontaneous emission noise of a single-mode semiconductor laser. The spontaneous emission of light is quantum mechanical in nature and is an inborn physical entropy source of true randomness. By combining a high-speed analog-to-digital converter and off-line processing, random numbers are extracted from the spontaneous emission with the verified randomness. The generator is simple, robust, and with no need of accurately tuning the comparison threshold. The use of semiconductor lasers makes it particularly compatible with the delivery of random numbers in optical networks.

  16. Stability of the single-mode output of a laser diode array with phase conjugate feedback

    DEFF Research Database (Denmark)

    Juul Jensen, S.; Løbel, M.; Petersen, P.M.

    2000-01-01

    The stability of the output of a single-mode laser diode array with frequency selective phase conjugate feedback has been investigated experimentally. Both the long-term stability of the laser output and the sensitivity to feedback generated by external reflection of the output beam are examined....... The output power and the center wavelength are found to be extremely stable in a 100 h stability measurement. External feedback of the output beam into the laser is seen to decrease both the spatial and the temporal coherence of the output significantly. We outline an approach to obtain a stable single...

  17. Efficient multi-mode to single-mode conversion in a 61 port photonic lantern

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Skovgaard, Peter M. W.; Dybendahl Maack, Martin

    2010-01-01

    (MMF) cladding. Our fabricated Photonic Lanterns are solid all-glass versions, with the MMF defined by a low-index tube surrounding the single-mode fibers (SMFs). We show experimentally that these devices can be used to achieve efficient and reversible coupling between a MMF and 61 SMFs, when perfectly...... matched launch conditions into the MMF are ensured. The total coupling loss from a 100 µm core diameter MM section to the ensemble of 61 SMFs and back to another 100 µm core MM section is measured to be as low as 0.76 dB. This demonstrates the feasibility of using the Photonic Lanterns within the field...

  18. Supercontinuum generation by noise-like pulses transmitted through normally dispersive standard single-mode fibers.

    Science.gov (United States)

    Zaytsev, Alexey; Lin, Chih-Hsuan; You, Yi-Jing; Chung, Chia-Chun; Wang, Chi-Luen; Pan, Ci-Ling

    2013-07-01

    We report generation of broadband supercontinuum (SC) by noise-like pulses (NLPs) with a central wavelength of 1070 nm propagating through a long piece of standard single-mode fibers (~100 meters) in normal dispersion region far from the zero-dispersion point. Theoretical simulations indicate that the physical mechanism of SC generation is due to nonlinear effects in fibers. The cascaded Raman scattering is responsible for significant spectral broadening in the longer wavelength regions whereas the Kerr effect results in smoothing of SC generated spectrum. The SC exhibits low threshold (43 nJ) and a flat spectrum over 1050-1250 nm.

  19. Seamless Transmission between Single-Mode Optical Fibers Using Free Space Optics System

    Science.gov (United States)

    Yoshida, Koichi; Tsujimura, Takeshi

    This paper presents a free space optics system installed between two single-mode optical fibers (SMFs). The result looks as if the two SMFs were seamlessly connected without the need for any photoelectric devices. Misalignments between the two SMFs caused by disturbances are actively compensated for by introducing a laser beam controller that incorporates an opto-mechatronic mechanism with four degrees of freedom. Experiments using a prototype are conducted to verify the effectiveness of the proposed FSO system for initial beam acquisition and beam tracking when there is a vibration disturbance.

  20. Supercontinuum Spectra generation in the single-mode optical fibre with Concave dispersion profile

    Institute of Scientific and Technical Information of China (English)

    Xu Wen-Cheng; Gao Jie-Li; Liang Zhan-Qiang; Chen Qiao-Hong; Liu Song-Hao

    2006-01-01

    In this paper,a new method is proposed to generate broad supercontinuum (SC) spectra in the single-mode optical fibre with concave dispersion profile.We numerically simulate pulse evolutions and discuss physics mechanism in detail for SC spectrum generation in the optical fibre with concave dispersion profile.Furthermore,general criteria are presented for specifying the shape of SC spectrum by introducing normalized parameters,which are related to the fibres and the initial pump pulses.The results show that the flat and broad SC spectra are indeed generated in our proposed optical fibre.

  1. Theoretical Design of Single-Polarization Single- Mode Microstructured Polymer Optical Fibres

    Institute of Scientific and Technical Information of China (English)

    REN Li-Yong; WANG Han-Yi; ZHANG Ya-Ni; YAO Bao-Li; ZHAO Wei

    2007-01-01

    Using the full-vector plane-wave expansion method, a kind of PMMA-based polarization-maintaining microstructured optical fibre (PM-mPOF) is theoretically studied. Dependence of the cutoff wavelengths of the two orthogonal polarization states (polarized along the two principal axes of PM-mPOF) on the structure parameters of the fibre is investigated in detail. A single-polarization single-mode (SPSM) PM-mPOF working in the visible region is designed and optimized with the result of the maximum SPSM bandwidth of 140 nm.

  2. A novel high-efficiency single-mode quantum dot single photon source

    DEFF Research Database (Denmark)

    Gerard, J.M.; Gregersen, Niels; Nielsen, Torben Roland

    2008-01-01

    We present a novel single-mode single photon source exploiting the emission of a semiconductor quantum dot (QD) located inside a photonic wire. Besides an excellent coupling (>95%) of QD spontaneous emission to the fundamental guided mode [1], we show that a single photon collection efficiency...... above 80% within a 0.5 numerical aperture can be achieved using a bottom Bragg mirror and a tapering of the nanowire tip. Because this photon collection strategy does not exploit the Purcell effect, it could also be efficiently applied to broadband single photon emitters such as F-centers in diamond....

  3. Quantum entanglement in the system of two two-level atoms interacting with a single-mode vacuum field

    Institute of Scientific and Technical Information of China (English)

    Zeng Ke; Fang Mao-Fa

    2005-01-01

    The entanglement properties of the system of two two-level atoms interacting with a single-mode vacuum field are explored. The quantum entanglement between two two-level atoms and a single-mode vacuum field is investigated by using the quantum reduced entropy; the quantum entanglement between two two-level atoms, and that between a single two-level atom and a single-mode vacuum field are studied in terms of the quantum relative entropy. The influences of the atomic dipole-dipole interaction on the quantum entanglement of the system are also discussed. Our results show that three entangled states of two atoms-field, atom-atom, and atom-field can be prepared via two two-level atoms interacting with a single-mode vacuum field.

  4. Investigation on a compact in-line multimode-single-mode-multimode fiber structure

    Science.gov (United States)

    Yin, Bin; Li, Yang; Liu, Zhi-bo; Feng, Suchun; Bai, Yunlong; Xu, Yao; Jian, Shuisheng

    2016-06-01

    We carried out a detailed investigation on a compact in-line multimode single-mode multimode (MSM) fiber structure. Both theoretical modal and experimental setup were established to demonstrate the transmission characteristics and the corresponding responses of the applied strain and temperature. The proposed structure simply involves a section of the single-mode fiber (SMF) spliced to two sections of multimode fiber (MMF) and lead-in and lead-out SMFs. The excited environment-sensitive cladding modes together with the fundamental mode in the central SMF form a typical Mach-Zehnder interferometer (MZI). We analyzed the transmission characteristics of the different length of the middle SMF and the MMF in detail. In the experiment, we obtained the extinction ratio of the MSM fiber structure based MZI comb spectrum which was up to 20 dB, and sensitivities of 0.7096 pm/με (0-2000 με) and 44.12 pm/°C (10-70 °C), which proved the potential sensing applications of the proposed fiber structure.

  5. Single-mode tunable laser emission in the single-exciton regime from colloidal nanocrystals.

    Science.gov (United States)

    Grivas, Christos; Li, Chunyong; Andreakou, Peristera; Wang, Pengfei; Ding, Ming; Brambilla, Gilberto; Manna, Liberato; Lagoudakis, Pavlos

    2013-01-01

    Whispering-gallery-mode resonators have been extensively used in conjunction with different materials for the development of a variety of photonic devices. Among the latter, hybrid structures, consisting of dielectric microspheres and colloidal core/shell semiconductor nanocrystals as gain media, have attracted interest for the development of microlasers and studies of cavity quantum electrodynamic effects. Here we demonstrate single-exciton, single-mode, spectrally tuned lasing from ensembles of optical antenna-designed, colloidal core/shell CdSe/CdS quantum rods deposited on silica microspheres. We obtain single-exciton emission by capitalizing on the band structure of the specific core/shell architecture that strongly localizes holes in the core, and the two-dimensional quantum confinement of electrons across the elongated shell. This creates a type-II conduction band alignment driven by coulombic repulsion that eliminates non-radiative multi-exciton Auger recombination processes, thereby inducing a large exciton-bi-exciton energy shift. Their ultra-low thresholds and single-mode, single-exciton emission make these hybrid lasers appealing for various applications, including quantum information processing.

  6. Lithographic VCSEL array multimode and single mode sources for sensing and 3D imaging

    Science.gov (United States)

    Leshin, J.; Li, M.; Beadsworth, J.; Yang, X.; Zhang, Y.; Tucker, F.; Eifert, L.; Deppe, D. G.

    2016-05-01

    Sensing applications along with free space data links can benefit from advanced laser sources that produce novel radiation patterns and tight spectral control for optical filtering. Vertical-cavity surface-emitting lasers (VCSELs) are being developed for these applications. While oxide VCSELs are being produced by most companies, a new type of oxide-free VCSEL is demonstrating many advantages in beam pattern, spectral control, and reliability. These lithographic VCSELs offer increased power density from a given aperture size, and enable dense integration of high efficiency and single mode elements that improve beam pattern. In this paper we present results for lithographic VCSELs and describes integration into military systems for very low cost pulsed applications, as well as continuouswave applications in novel sensing applications. The VCSELs are being developed for U.S. Army for soldier weapon engagement simulation training to improve beam pattern and spectral control. Wavelengths in the 904 nm to 990 nm ranges are being developed with the spectral control designed to eliminate unwanted water absorption bands from the data links. Multiple beams and radiation patterns based on highly compact packages are being investigated for improved target sensing and transmission fidelity in free space data links. These novel features based on the new VCSEL sources are also expected to find applications in 3-D imaging, proximity sensing and motion control, as well as single mode sensors such as atomic clocks and high speed data transmission.

  7. Study of the atmospheric refraction in a single mode instrument - Application to AMBER/VLTI

    CERN Document Server

    Robbe-Dubois, Sylvie; Bresson, Yves; Petrov, Romain G; Carbillet, Marcel; Lecoarer, Etienne; Rantakyrö, Frederik; Tallon-Bosc, Isabelle; Vannier, Martin; Antonelli, Pierre; Martinot-Lagarde, Gregoire; Roussel, Alain; Tasso, Daniel

    2009-01-01

    This paper presents a study of the atmospheric refraction and its effect on the light coupling efficiency in an instrument using single-mode optical fibers. We show the analytical approach which allowed us to assess the need to correct the refraction in J- and H-bands while observing with an 8-m Unit Telescope. We then developed numerical simulations to go further in calculations. The hypotheses on the instrumental characteristics are those of AMBER (Astronomical Multi BEam combineR), the near infrared focal beam combiner of the Very Large Telescope Interferometric mode (VLTI), but most of the conclusions can be generalized to other single-mode instruments. We used the software package caos (Code for Adaptive Optics Systems) to take into account the atmospheric turbulence effect after correction by the ESO system MACAO (Multi-Application Curvature Adaptive Optics). The opto-mechanical study and design of the system correcting the atmospheric refraction on AMBER is then detailed. We showed that the atmospheric...

  8. Experimental verification of a model describing the intensity distribution from a single mode optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    Moro, Erik A [Los Alamos National Laboratory; Puckett, Anthony D [Los Alamos National Laboratory; Todd, Michael D [UCSD

    2011-01-24

    The intensity distribution of a transmission from a single mode optical fiber is often approximated using a Gaussian-shaped curve. While this approximation is useful for some applications such as fiber alignment, it does not accurately describe transmission behavior off the axis of propagation. In this paper, another model is presented, which describes the intensity distribution of the transmission from a single mode optical fiber. A simple experimental setup is used to verify the model's accuracy, and agreement between model and experiment is established both on and off the axis of propagation. Displacement sensor designs based on the extrinsic optical lever architecture are presented. The behavior of the transmission off the axis of propagation dictates the performance of sensor architectures where large lateral offsets (25-1500 {micro}m) exist between transmitting and receiving fibers. The practical implications of modeling accuracy over this lateral offset region are discussed as they relate to the development of high-performance intensity modulated optical displacement sensors. In particular, the sensitivity, linearity, resolution, and displacement range of a sensor are functions of the relative positioning of the sensor's transmitting and receiving fibers. Sensor architectures with high combinations of sensitivity and displacement range are discussed. It is concluded that the utility of the accurate model is in its predicative capability and that this research could lead to an improved methodology for high-performance sensor design.

  9. Efficient multi-mode to single-mode conversion in a 61 port photonic lantern

    Science.gov (United States)

    Noordegraaf, D.; Skovgaard, P. M. W.; Maack, M. D.; Bland-Hawthorn, J.; Haynes, R.; Lægsgaard, J.

    2010-02-01

    We demonstrate the fabrication of a multi-mode (MM) to 61 port single-mode (SM) splitter or "Photonic Lantern". Low port count Photonic Lanterns were first described by Leon-Saval et al. (2005). These are based on a photonic crystal fiber type design, with air-holes defining the multi-mode fiber (MMF) cladding. Our fabricated Photonic Lanterns are solid all-glass versions, with the MMF defined by a low-index tube surrounding the single-mode fibers (SMFs). We show experimentally that these devices can be used to achieve efficient and reversible coupling between a MMF and 61 SMFs, when perfectly matched launch conditions into the MMF are ensured. The total coupling loss from a 100 μm core diameter MM section to the ensemble of 61 SMFs and back to another 100 μm core MM section is measured to be as low as 0.76 dB. This demonstrates the feasibility of using the Photonic Lanterns within the field of astrophotonics for coupling MM star-light to an ensemble of SM fibers in order to perform fiber Bragg grating based spectral filtering.

  10. Multi-mode to single-mode conversion in a 61 port photonic lantern

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Skovgaard, Peter M.W.; Maack, Martin D.;

    2010-01-01

    Efficient multi-mode (MM) to single-mode (SM) conversion in a 61 port splitter or “Photonic Lantern” is demonstrated. The coupling loss from a 100 µm core diameter MM section to an ensemble of 61 SM fibers and back to another 100 µm core MM section is measured to be as low as 0.76 dB. This demons......Efficient multi-mode (MM) to single-mode (SM) conversion in a 61 port splitter or “Photonic Lantern” is demonstrated. The coupling loss from a 100 µm core diameter MM section to an ensemble of 61 SM fibers and back to another 100 µm core MM section is measured to be as low as 0.76 d......B. This demonstration shows the feasibility of using the Photonic Lanterns within the field of astrophotonics for coupling MM star-light to an ensemble of SM fibers in order to perform fiber Bragg grating based spectral filtering."...

  11. Bend-insensitive single-mode photonic crystal fiber with ultralarge effective area for dual applications

    Science.gov (United States)

    Islam, Md. Asiful; Alam, M. Shah

    2013-05-01

    A novel photonic crystal fiber (PCF) having circular arrangement of cladding air holes has been designed and numerically optimized to obtain a bend insensitive single mode fiber with large mode area for both wavelength division multiplexing (WDM) communication and fiber-to-the-home (FTTH) application. The bending loss of the proposed bent PCF lies in the range of 10-3 to 10-4 dB/turn or lower over 1300 to 1700 nm, and 2 × 10-4 dB/turn at the wavelength of 1550 nm for a 30-mm bend radius with a higher order mode (HOM) cut-off frequency below 1200 nm for WDM application. When the whole structure of the PCF is scaled down, a bending loss of 6.78×10-4 dB/turn at 1550 nm for a 4-mm bend radius is obtained, and the loss remains in the order of 10-4 dB/turn over the same range of wavelength with an HOM cut-off frequency below 700 nm, and makes the fiber useful for FTTH applications. Furthermore, this structure is also optimized to show a splice loss near zero for fusion-splicing to a conventional single-mode fiber (SMF).

  12. High-Power Single-Mode 2.65-micron InGaAsSb/AlInGaAsSb Diode Lasers

    Science.gov (United States)

    Frez, Clifford F.; Briggs, Ryan M.; Forouhar, Siamak; Borgentun, Carl E.; Gupta, James

    2013-01-01

    Central to the advancement of both satellite and in-situ science are improvements in continuous-wave and pulsed infrared laser systems coupled with integrated miniaturized optics and electronics, allowing for the use of powerful, single-mode light sources aboard both satellite and unmanned aerial vehicle platforms. There is a technological gap in supplying adequate laser sources to address the mid-infrared spectral window for spectroscopic characterization of important atmospheric gases. For high-power applications between 2 to 3 micron, commercial laser technologies are unsuitable because of limitations in output power. For instance, existing InP-based laser systems developed for fiber-based telecommunications cannot be extended to wavelengths longer than 2 micron. For emission wavelengths shorter than 3 micron, intersubband devices, such as infrared quantum cascade lasers, become inefficient due to band-offset limitations. To date, successfully demonstrated singlemode GaSb-based laser diodes emitting between 2 and 3 micron have employed lossy metal Bragg gratings for distributed- feedback coupling, which limits output power due to optical absorption. By optimizing both the quantum well design and the grating fabrication process, index-coupled distributed-feedback 2.65-micron lasers capable of emitting in excess of 25 mW at room temperature have been demonstrated. Specifically, lasers at 3,777/cm (2.65 micron) have been realized to interact with strong absorption lines of HDO and other isotopologues of H2O. With minor modifications of the optical cavity and quantum well designs, lasers can be fabricated at any wavelength within the 2-to-3-micron spectral window with similar performance. At the time of this reporting, lasers with this output power and wavelength accuracy are not commercially available. Monolithic ridge-waveguide GaSb lasers were fabricated that utilize secondorder lateral Bragg gratings to generate single-mode emission from InGaAsSb/ Al

  13. High-power single-mode vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Samal, Nigamananda

    High-power single-mode vertical-cavity surface-emitting lasers (VCSEL) have a great potential to replace the distributed feedback (DFB) and Fabry-Perot (FP) edge emitting lasers that are currently used in optical communication. VCSELs also have tremendous potential in many niche applications such as "optical read and write," laser printing, bar code scanning and sensing. Despite many of their inherent advantages over its rivals, VCSELs still suffer from some outstanding issues. Most prominent are "limited power" and "multi-mode behavior" at higher injection. This work aims at a few solutions for these fundamental issues. Using strain-compensated GaAsSb as an active material and a standard single-aperture design, 1.3 mum VCSELs are demonstrated and characterized. These devices face basic issues such as "limited output power" and "multi-mode behavior." These VCSELs achieved room temperature CW operation with power outputs from 50--200 muW for wavelengths ranging from 1245 to 1290 nm. To resolve the issue of limited power, several on-wafer thermal-management schemes are proposed. One of the schemes is pursued in this work. To resolve the issue of multi-mode behavior, a novel device design using asymmetric double oxide-apertures is proposed, theoretically modeled, and implemented in this work. The optical mode behavior of this novel design is compared with a traditional single-aperture design using fabricated devices and theoretical modeling. A clear trend of spectral purity in the modal behavior of the devices, under both continuous wave (CW) and pulsed conditions, is demonstrated and is in good agreement with theoretical predictions. One of the novel designs tested on an InGaAs VCSEL has shown a multi-mode power more than 23 mW with maximum wall plug efficiency of 32%, threshold current of 2.5 mA, threshold voltage of 1.2 V, and a slope efficiency of 0.83 W/A. The best design demonstrated a room temperature CW single-mode output power of more than 7 mW with a side

  14. Dynamical Properties of a Single-Mode Laser Driven by Quadratic Pump Noise

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; CAO Li

    2007-01-01

    We propose a single-mode laser model driven by quadratic pump noise with cross correlation between the real and imaginary parts of the pump noise. The effect of the cross-correlation coefficient λp between the real and imaginary parts of the pump noise on dynamical properties is studied by using of the linear approximation. The theoretical expressions of intensity correlation function λ(t), normalized intensity fluctuation λ(0) are calculated.It is found that the most conspicuous effects of λp on both the intensity correlation function and the normalized intensity fluctuation appear at |λp| = √0.5, but not at |λp| = 1.

  15. Note: Improving distributed strain sensing sensitivity in OFDR by reduced-cladding single mode fiber

    Science.gov (United States)

    Ding, Zhenyang; Yang, Di; Du, Yang; Zhou, Yonghan; Xu, Zhexi; Liu, Kun; Jiang, Junfeng; Liu, Tiegen

    2016-12-01

    We present a method to improve distributed strain sensing sensitivity by a reduced-cladding single mode fiber (RC SMF) using a Rayleigh backscattering spectra shift in optical frequency domain reflectometry. Comparing with a standard SMF with 250 μm diameter, a commercial low attenuation RC SMF with 165 μm diameter is shown to enhance the strain sensing sensitivity by about four-fold. Using this property, the system using the RC SMF can achieve smaller minimal measurable strain (MMS) in the same sensing spatial resolution (SSR) or smaller SSR in the same MMS than using the standard SMF. In our experiment, the system using RC SMF can achieve the MMS of 15 μstrain with a SSR of 4.5 cm or the MMS of 3 μstrain with a SSR of 18 cm.

  16. Single-mode and single-polarization photonics with anchored-membrane waveguides.

    Science.gov (United States)

    Chiles, Jeff; Fathpour, Sasan

    2016-08-22

    An integrated photonic platform with "anchored-membrane" structures, the T-Guide, is proposed, numerically investigated, fabricated and characterized. These compact air-clad structures have high index contrast and are much more stable than prior membrane-type structures. Their semi-infinite geometry enables single-mode and single-polarization (SMSP) operation over unprecedented bandwidths. Modal simulations quantify this behavior, showing that an SMSP window of 2.75 octaves (1.2-8.1 μm) is feasible for silicon T-Guides, spanning almost the entire transparency range of silicon. Dispersion engineering for T-Guides yields broad regions of anomalous group velocity dispersion, rendering them a promising platform for nonlinear applications such as wideband frequency conversion. Cut-back measurements of fabricated silicon T-guides at λ = 3.64 μm show low propagation losses of 1.75 ± 0.3 dB/cm.

  17. Single-mode all-fiber structured modal interference for temperature and refractive index sensing

    Science.gov (United States)

    Xian, Pei; Feng, Guoying; Ju, Yao; Zhang, Wei; Zhou, Shouhuan

    2017-08-01

    A new type of optical fiber sensor based on an asymmetric structured microfiber modal interferometer is proposed and demonstrated. The sensor head is simply made of single-mode fiber using the electrical arc discharge technique. Owing to the reflection spectrum dips formed by the interference between the cladding modes and the core mode, measurements of temperature and the refractive index (RI) can be obtained by monitoring the wavelength shifts of the interference spectrum. Experiments show that the sensor exhibits a good response to temperature and the ambient RI variation, with maximum sensitivities of 0.079 nm °C-1 and  -49.957 nm/RIU, respectively. The merits of its cost-effective and simple fabrication makes this sensor a promising device for sensing applications.

  18. Intensity Tuning in Single Mode Microchip Nd:YAG Laser with External Cavity

    Institute of Scientific and Technical Information of China (English)

    TAN Yi-Dong; ZHANG Shu-Lian

    2006-01-01

    We investigate the characteristics of intensity tuning in a single mode microchip Nd:YAG laser with an external cavity. The undulation of laser intensity in a period of λ/2 change of the internal cavity length is observed.Two different optical feedback cases are performed. One is an external cavity reflector perfectly aligned and the other is an external cavity reflector tilted. However, the fluctuation frequency of laser intensity in a period of λ/2 change of the internal cavity length in these two cases is found to be determined by the ratio of external cavity length to internal cavity length. Meanwhile, for the tilted external cavity, the fluctuation frequency is also related to multiple feedbacks in the tilted external cavity.

  19. Frequency Noise Suppression of a Single Mode Laser with an Unbalanced Fiber Interferometer for Subnanometer Interferometry

    Directory of Open Access Journals (Sweden)

    Radek Šmíd

    2015-01-01

    Full Text Available We present a method of noise suppression of laser diodes by an unbalanced Michelson fiber interferometer. The unstabilized laser source is represented by compact planar waveguide external cavity laser module, ORIONTM (Redfern Integrated Optics, Inc., working at 1540.57 nm with a 1.5-kHz linewidth. We built up the unbalanced Michelson interferometer with a 2.09 km-long arm based on the standard telecommunication single-mode fiber (SMF-28 spool to suppress the frequency noise by the servo-loop control by 20 dB to 40 dB within the Fourier frequency range, remaining the tuning range of the laser frequency.

  20. Influence of Temperature on Stimulated Raman Scattering in Single-Mode Silica Fibre

    Institute of Scientific and Technical Information of China (English)

    MEN Zhi-Wei; FANG Wen-Hui; SUN Xiu-Ping; LI Zuo-Wei; YI Han-Wei; WANG Zhao-Min; GAO Shu-Qin; LU Guo-Hui

    2008-01-01

    One piece of single-mode silica fibre is used to study of temperature characteristics of stimulated Raman scattering(SRS), additional peaks (double-humped) are observed at both sides of pump light and 1st-order Stokes light in the experiment. The frequency shift of the double-humped is calculated by stimulated Four-Photon mixing (SFPM)phase matching theory, the result is consistent with the frequency shift of this experiment. Simultaneously, the experimental conditions accord with the theoretical calculation of effective coherence length. We indicate that the double-humped phenomenon is caused by SFPM. The intensity of double-humped is first increased, then decreased and finally disappeared as the temperature increases. This phenomenon has been explained theoretically.

  1. Analyses of Valid Range for the Linear Approximation in a Single-Mode Laser

    Institute of Scientific and Technical Information of China (English)

    CHENGQing-Hua; CAOLi; WANGJun; WUDa-Jin

    2004-01-01

    Using the linear approximation method, we calculated the steady-state mean normalized intensity fluctuation for a loss-noise model of a single-mode laser driven by a pump noise and a quantum noise, whose real part and imaginary part are cross-correlated. We analyzed the valid range for the linear approximation method by studying the influences on the steady-state mean normalized intensity fluctuation by the cross-correlation coefficient, the intensities of the quantum and pump noise, the net gain, and the amplitude and frequency of the input signal, and we found that the valid range becomes wider when the cross-correlation between the real and imaginary part of quantum noise is weaker, the noise intensities of quantum and pump are weaker, the laser system is far from the threshold and the signal has smaller amplitude and higher frequency.

  2. Single-Mode Optical Waveguides on Native High-Refractive-Index Substrates

    CERN Document Server

    Grote, Richard R

    2016-01-01

    High-refractive-index semiconductor optical waveguides form the basis for modern photonic integrated circuits (PICs) , but the conventional methods of achieving optical confinement require a thick lower-refractive-index support layer that impedes large-scale co-integration with electronics. To address this challenge, we present a general architecture for single-mode waveguides that confine light in a high-refractive-index material on a native substrate. Our waveguide consists of a high-aspect-ratio fin of the guiding material surrounded by lower-refractive-index dielectrics and is compatible with standard top-down fabrication techniques. The proposed waveguide geometry removes the need for a buried-oxide-layer in silicon photonics, as well as the InGaAsP layer in InP-based PICs and will allow for photonic integration on emerging material platforms such as diamond and SiC.

  3. Estimation of cut-off wavelength of rare earth doped single-mode fibers

    Science.gov (United States)

    Kaur, Jagneet; Thyagarajan, K.; Pal, B. P.

    1999-11-01

    A new empirical relation is proposed describing spectral variation of mode-field radius (MFR) as inferred from measurements in the far-field of the fiber. It is shown that using this relation, it is possible to estimate the cut-off wavelength ( λc) of the fiber. The proposed technique is successfully tested through measurements made on two standard step index single-mode fibers, as well as on an erbium doped fiber (EDF) having λc falling within its strong absorption band around 980 nm. This empirical formula is more accurate than the widely used Marcuse's formula to describe spectral dependence of MFR determined through measurements made in the fiber's far-field. The proposed technique is especially suited for estimation of λc of doped fibers in which λc falls within an absorption band.

  4. Micro-lensed single-mode optical fiber with high numerical aperture

    CERN Document Server

    Kato, Shinya; Aoki, Takao

    2013-01-01

    We show that the output mode of a single-mode optical fiber can be directly focused to a sub-wavelength waist with a finite working distance by tapering the fiber to a diameter of the order of the wavelength and terminating it with a spherically/hemispherically shaped tip. Numerical simulations show that a beam waist with a width of as small as 0.62\\lambda can be formed. We fabricate micro-lensed fibers and construct a probe-scanning confocal reflection microscope. Measurements on gold nano-particles show a spatial profile with a width of 0.29\\lambda for \\lambda = 850 nm, which is in good agreement with the numerical simulations. Due to their monolithic structures, these micro-lensed fibers will be flexible substitutes for conventional compound lenses in various experimental conditions such as cryogenic temperature and ultra-high vacuum.

  5. Low-loss single-mode negatively curved square-core hollow fibers.

    Science.gov (United States)

    Chen, Yang; Saleh, Mohammed F; Joly, Nicolas Y; Biancalana, Fabio

    2017-04-01

    We introduce a novel design of anti-resonant fibers with negative-curvature square cores to be employed in 1.55 and 2.94 μm transmission bands. The fibers have low losses and single-mode operation via optimizing the negative curvature of the guiding walls. The first proposed fiber shows a broadband transmission window spanning 0.9-1.7 μm, with losses of 0.025 and 0.056 dB/m at 1.064 and 1.55 μm, respectively. The second proposed fiber has approximately a 0.023 dB/m guiding loss at 2.94 μm with a small cross-sectional area, useful for laser micromachining applications.

  6. Investigation of bending loss in a single-mode optical fibre

    Indian Academy of Sciences (India)

    A Zendehnam; M Mirzaei; A Farashiani; L Horabadi Farahani

    2010-04-01

    Loss of optical power in a single-mode optical fibre due to bending has been investigated for a wavelength of 1550 nm. In this experiment, the effects of bending radius (4–15 mm, with steps of 1 mm), and wrapping turns (up to 40 turns) on loss have been studied. Twisting the optical fibre and its influence on power loss also have been investigated. Variations of bending loss with these two parameters have been measured, loss with number of turns and radius of curvature have been measured, and with the help of computer curve fitting method, semi-empirical relationships between bending loss and these two parameters have been found, which show good agreement with the obtained experimental results.

  7. Design of distributed Raman temperature sensing system based on single-mode optical fiber

    Institute of Scientific and Technical Information of China (English)

    Ziheng XU; Deming LIU; Hairong LIU; Qizhen SUN; Zhifeng SUN; Xu ZHANG; Wengang WANG

    2009-01-01

    The distributed optical fiber temperature sensor system based on Raman scattering has developed rapidly since it was invented in 1970s. The optical wavelengths used in most of the distributed temperature optical fiber sensor system based on the Raman scattering are around from 840 to 1330 nm, and the system operates with multimode optical fibers. However, this wavelength range is not suitable for long-distance transmission due to the high attenuation and dispersion of the transmission optical fiber. A novel distributed optical fiber Raman temperature sensor system based on standard single-mode optical fiber is proposed. The system employs the wavelength of 1550 nm as the probe light and the standard communication optical fiber as the sensing medium to increase the sensing distance. This system mainly includes three modules: the probe light transmitting module, the light magnifying and transmission module, and the signal acquisition module.

  8. Intensity modulation in single-mode microchip Nd:YAG lasers with asymmetric external cavity

    Institute of Scientific and Technical Information of China (English)

    Tan Yi-Dong; Zhang Shu-Lian; Liu Wei-Xin; Mao Wei

    2007-01-01

    Intensity modulation induced by the asymmetric external cavity in single-mode microchip Nd:YAG lasers is presented. Two kinds of experimental results are discussed based on multiple feedback effects. In one case, the intensity modulation curve is a normal sine wave, whose fringe frequency is four times higher than that of a conventional optical feedback system, caused by multiple feedback effects. In the other case, the intensity modulation curve is the overlapping of the above quadruple-frequency signal and conventional optical feedback signal, which is determined by the additional phase difference induced by the asymmetric external cavity. The theoretical analyses are in good agreement with the experimental results. The quadruple-frequency modulation of the laser output intensity can greatly increase the resolution of displacement measurement of an optical feedback system.

  9. Dispersion flattened, low-loss porous fiber for single-mode terahertz wave guidance

    Science.gov (United States)

    Islam, Raonaqul; Rana, Sohel

    2015-05-01

    A porous-core circular photonic crystal fiber is designed for low-loss terahertz (THz) wave propagation. The circular arrangement of air holes, both in the periodic cladding and the porous core, makes it possible to guide most of the optical power through low-loss air, which is confirmed by the rigorous analysis of modal properties of the fiber while maintaining the single-mode propagation condition. The simulation results, found by using an efficient finite element method, show that a flattened dispersion of ±0.09 ps/THz/cm within 0.9 to 1.3 THz and an ultra-low material loss of 0.053 cm-1 at f=1 THz is obtained for the reported design at optimal parameters. This kind of structure can be fabricated using capillary stacking or a sol-gel technique and is expected to be useful for wideband imaging and telecom applications.

  10. General Laser Intensity Langevin Equation in a Single-Mode Laser Model

    Institute of Scientific and Technical Information of China (English)

    KE Sheng-Zhi; CAO Li; WU Da-Jin; YAO Kai-Lun

    2001-01-01

    A two-dimensional single-mode laser model is investigated, with cross-correlations between the real and imaginary parts of the quantum noise as well as the pump noise. The general closed form of the laser intensity Langevin equation (GILE) is obtained under a stable locked phase resulting from the cross-correlation λq between the real and imaginary parts of the quantum noise. Because of the presence of a new term containing λq, we can unify the two opposite intensity Langevin equations which correspond to the two special cases for |λq| → 0 and |λq| → 1 in the GILE. It is expected that the transient and stationary properties of the laser model can be changed qualitatively when λq varies.

  11. A Novel Acoustic Emission Fiber Optic Sensor Based on a Single Mode Optical Fiber Coupler

    Institute of Scientific and Technical Information of China (English)

    CHEN Rongsheng; LIAO Yanbiao; ZHENG Gangtie; LIU Tongyu; Gerard Franklyn Fernando

    2001-01-01

    This paper reports, for the first time, on the use of a fused-taper single mode optical fiber coupler as a sensing element for the detection of acoustic emission (AE) and ultrasound. When an acoustic wave impinges on the mode-coupling region of a coupler, the coupling coefficient is modulated via the photo-elastic effect. Therefore, the transfer function of the coupler is modulated by an acoustic wave. The sensitivity of the sensor at 140 kHz was approximately 5.2 mV/Pa and the noise floor was 1 Pa. The bandwidth of the sensor was up to several hundred kHz. This AE sensor exhibits significant advantage compared with interferometer-based AE sensors.

  12. Quantum phases and dynamics of bosonic atoms trapped in a single-mode optical cavity

    Science.gov (United States)

    Sundar, Bhuvanesh; Mueller, Erich

    2016-05-01

    Motivated by experiments performed by R. Landig et al. (arXiv:1511.00007), we theoretically explore the behavior of bosonic atoms trapped in a single-mode cavity in the presence of a two-dimensional optical lattice. As explained by arXiv:1511.00007, Rayleigh scattering of light from the lattice-inducing beams into the cavity produces infinite-range cavity-mediated interactions between the atoms, leading to competition between superfluid, supersolid, Mott insulating and charge density wave phases. We calculate the phase diagram for a uniform trap using a variation of the Gutzwiller Ansatz. We also calculate the spatial distribution of the different phases in the gas in the presence of a harmonic trap. We explore hysteretic behavior when parameters of the system are changed.

  13. Single-mode tapered optical fiber loop immunosensor II: assay of anti-cholera toxin immunoglobulins

    Science.gov (United States)

    Marks, Robert S.; Hale, Zoe M.; Levine, Myron M.; Lowe, C. R.; Payne, Frank P.

    1994-07-01

    An evanescent wave immunoassay for cholera antitoxin immunoglobulins was performed using a single mode tapered optical fiber loop sensor. The transducer was silanized with 3- glycidoxypropyltrimethoxysilane and chemically modified to link covalently either cholera toxin B subunit or a synthetic peptide derived from it, CTP3. The sensor was exposed to seral fluids, obtained from human volunteers having been exposed to live virulent Vibrio cholerae 01 and shown to produce rice-water stools. Other toxins of interest, such as Clostridium botulinum toxin A, have been tested on similar systems. The bound unlabelled immunoglobulins were then exposed to a mixture of FITC-anti-IgG and TRITC-anti-IgA, without requirement for a separation step. The emanating fluorescent emissions of fluorescein and rhodamine, excited by the input laser light, were coupled back into the guided mode of the tapered fiber, and used to determine the concentrations of the complementary antigens.

  14. Single mode waveguide platform for spontaneous and surface-enhanced on-chip Raman spectroscopy.

    Science.gov (United States)

    Dhakal, Ashim; Peyskens, Frédéric; Clemmen, Stéphane; Raza, Ali; Wuytens, Pieter; Zhao, Haolan; Le Thomas, Nicolas; Baets, Roel

    2016-08-01

    We review an on-chip approach for spontaneous Raman spectroscopy and surface-enhanced Raman spectroscopy based on evanescent excitation of the analyte as well as evanescent collection of the Raman signal using complementary metal oxide semiconductor (CMOS)-compatible single mode waveguides. The signal is either directly collected from the analyte molecules or via plasmonic nanoantennas integrated on top of the waveguides. Flexibility in the design of the geometry of the waveguide, and/or the geometry of the antennas, enables optimization of the collection efficiency. Furthermore, the sensor can be integrated with additional functionality (sources, detectors, spectrometers) on the same chip. In this paper, the basic theoretical concepts are introduced to identify the key design parameters, and some proof-of-concept experimental results are reviewed.

  15. Versatile chromatic dispersion measurement of a single mode fiber using spectral white light interferometry.

    Science.gov (United States)

    Lee, Ji Yong; Kim, Dug Young

    2006-11-27

    We present a versatile and accurate chromatic dispersion measurement method for single mode optical fibers over a wide spectral range (200 nm) using a spectral domain white light interferometer. This technique is based on spectral interferometry with a Mach-Zehnder interferometer setup and a broad band light source. It takes less than a second to obtain a spectral interferogram for a few tens of centimeter length fiber sample. We have demonstrated that the relative group velocity, the chromatic dispersion and the dispersion slope of a sample fiber can be obtained very accurately regardless of the zero-dispersion wavelength (ZDW) of a sample after frequency dependent optical phase was directly retrieved from a spectral interferogram. The measured results with our proposed method were compared with those obtained with a conventional time-domain dispersion measurement method. A good agreement between those results indicates that our proposed method can measure the chromatic dispersion of a short length optical fiber with very high accuracy.

  16. Influence of Temperature and Pressure on Dispersion Properties of Nonlinear Single Mode Optical Fibers

    Directory of Open Access Journals (Sweden)

    Mostafa H. Ali, Ahmed E. Elsamahy, Maher A. Farhoud and Taymour A. Hamdalla

    2012-10-01

    Full Text Available Near field distribution, propagation constant and dispersion characteristics of nonlinear single-mode optical fibers have been investigated. Shooting-method technique is used and implemented into a computer code for both profiles of step-index and graded-index fibers. An error function is defined to estimate the discrepancy between the expected electric-field radial derivative at the core-cladding interface and that obtained by numerically integrating the wave equation through the use of Runge-Kutta method. All of the above calculations done under the ocean depth in which the depth will affect the refractive index that have a direct effect on all the optical fiber parameters.KeyWords: Nonlinear refractive index, Normalized propagation constant, Mode delay factor, Material dispersion, Waveguide dispersion.

  17. Formation of Single-mode Laser in Perovskite Nanowire via Nano-manipulation

    CERN Document Server

    Wang, Kaiyang; Liu, Shuai; Li, Jiankai; Xiao, Shumin; Song, Qinghai

    2015-01-01

    Perovskite based micro- and nano- lasers have attracted considerable research attention in past two years. However, the properties of perovskite devices are mostly fixed once they are synthesized. Here we demonstrate the tailoring of lasing properties of perovskite nanowire lasers via nano-manipulation. By utilizing a tungsten probe, one nanowire has been lifted from the wafer and re-positioned its two ends on two nearby perovskite blocks. Consequently, the conventional Fabry-Perot lasers are completely suppressed and a single laser peak has been observed. The corresponding numerical model reveals that the single-mode lasing operation is formed by the whispering gallery mode in the transverse plane of perovskite nanowire. Our research provides a simple way to tailor the properties of nanowire and it will be essential for the applications of perovskite optoelectronics.

  18. Space-efficient fiber ribbon composed of reduced-cladding single-mode fibers

    Science.gov (United States)

    Chang, J. H.; Bae, S. H.; Kim, Hoon; Ouh, C. H.; Jung, C. H.; Cho, H. S.; Chung, Y. C.

    2016-09-01

    We develop a space-efficient single-mode fiber (SMF) having a cladding diameter of only 82 μm. This SMF has the depressed-cladding index profile and its mode-field diameter, cutoff wavelength, and macro bending loss are designed to be similar to those of the conventional step-index SMF. We fabricate this reduced-cladding SMF and measure its optical and mechanical characteristics. The results show that this fiber satisfies major specifications of the ITU-T G.654 recommendations. We also fabricate a fiber ribbon by using twelve of these reduced-cladding SMFs. Compared to a commercial fiber ribbon made of twelve standard SMFs having 125-μm cladding diameter, this fiber ribbon can improve the spatial efficiency by ∼75%.

  19. Comb-calibrated solar spectroscopy through a multiplexed single-mode fiber channel

    CERN Document Server

    Probst, R A; Doerr, H-P; Steinmetz, T; Kentischer, T J; Zhao, G; Hänsch, T W; Udem, Th; Holzwarth, R; Schmidt, W

    2015-01-01

    We investigate a new scheme for astronomical spectrograph calibration using the laser frequency comb at the Solar Vacuum Tower Telescope on Tenerife. Our concept is based upon a single-mode fiber channel, that simultaneously feeds the spectrograph with comb light and sunlight. This yields nearly perfect spatial mode matching between the two sources. In combination with the absolute calibration provided by the frequency comb, this method enables extremely robust and accurate spectroscopic measurements. The performance of this scheme is compared to a sequence of alternating comb and sunlight, and to absorption lines from Earth's atmosphere. We also show how the method can be used for radial-velocity detection by measuring the well-explored 5-minute oscillations averaged over the full solar disk. Our method is currently restricted to solar spectroscopy, but with further evolving fiber-injection techniques it could become an option even for faint astronomical targets.

  20. Comparison of Fourier and model-based estimators in single mode multiaxial interferometry

    CERN Document Server

    Tatulli, E

    2006-01-01

    There are several solutions to code the signal arising from optical long baseline multi-aperture interferometers. In this paper,we focus on the {\\bf non homothetic spatial coding scheme} (multiaxial) with the fringe pattern coded along one dimension on one detector(all-in-one). After describing the physical principles governing single mode interferometers using that sort of recombination scheme, we analyze two different existing methods that measure the source visibility. The first technique, so-called Fourier estimator, consists in integrating the high frequency peak of the power spectral density of the interferogram. The second method, so-called model-based estimator, has been specifically developed for the AMBER instrument of the VLTI and deals with directly modelling the interferogram recorded on the detector. Performances of both estimators are computed in terms of Signal to Noise Ratio (SNR) of the visibility, assuming that the interferograms are perturbed by photon and detector noises. Theoretical expr...

  1. Printed Large-Area Single-Mode Photonic Crystal Bandedge Surface-Emitting Lasers on Silicon.

    Science.gov (United States)

    Zhao, Deyin; Liu, Shihchia; Yang, Hongjun; Ma, Zhenqiang; Reuterskiöld-Hedlund, Carl; Hammar, Mattias; Zhou, Weidong

    2016-01-04

    We report here an optically pumped hybrid III-V/Si photoic crystal surface emitting laser (PCSEL), consisting of a heterogeneously integrated III-V InGaAsP quantum well heterostructure gain medium, printed on a patterned defect-free Si photonic crystal (PC) bandedge cavity. Single mode lasing was achieved for a large area laser, with a side-mode suppression ratio of 28 dB, for lasing operation temperature ~ 200 K. Two types of lasers were demonstrated operating at different temperatures. Detailed modal analysis reveals the lasing mode matches with the estimated lasing gain threshold conditions. Our demonstration promises a hybrid laser sources on Si towards three-dimensional (3D) integrated Si photonics for on-chip wavelength-division multiplex (3D WDM) systems for a wide range of volume photonic/electronic applications in computing, communication, sensing, imaging, etc.

  2. Fluctuations of Single-Mode Laser Driven by Two Different Kinds of Colored Noise

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A single-mode laser with coupling between additive and multiplicative noise terms is investigated when the multiplicative noise and the coupling between two noise terms are colored fluctuations with finite correlation times T1 and τ2. Combining the unified colored noise approximation (UCNA) and the functional analysis, the stationary probability distribution (SPD) and the variance of the laser intensity is derived. It is found that the colored nature of multiplicative noise and the coupling strength between two noise terms can affect both the structure and the height of the SPD, while the colored nature of the coupling between two noise terms can only affect the height of the SPD. The multiplicative noise can enhance the intensity fluctuations while the additive noise can reduce the fluctuations in a laser system. Numerical simulations are presented and consistent to the analytical results.

  3. Stochastic resonance for signal-modulated pump noise in a single-mode laser

    Institute of Scientific and Technical Information of China (English)

    Liangying Zhang; Li Cao; Fahui Zhu

    2006-01-01

    By adopting the gain-noise model of the single-mode laser in which with bias and periodical signals serve as inputs, combining with the effect of coloured pump noise, we use the linear approximation method to calculate the power spectrum and signal-to-noise ratio (SNR) of the laser intensity under the condition of pump noise and quantum noise cross-related in the form of δ function. It is found that with the change of pump noise correlation time, both SNR and the output power will occur stochastic resonance (SR). If the bias signal α is very small, changing the intensities of pump noise and quantum noise respectively does not lead to the appearance of SR in the SNR; while α increases to a certain number, SR appears.

  4. Single-mode and single-polarization photonics with anchored-membrane waveguides

    CERN Document Server

    Chiles, Jeff

    2016-01-01

    An integrated photonic platform with anchored-membrane structures, the T-Guide, is proposed and numerically investigated. These compact air-clad structures have high index contrast and are much more stable than prior membrane-type structures. Their semi-infinite geometry enables single-mode and single-polarization (SMSP) operation over unprecedented bandwidths. Modal simulations quantify this behavior, showing that an SMSP window of 2.75 octaves (1.2 - 8.1 {\\mu}m) is feasible for silicon T-Guides, spanning almost the entire transparency range of silicon. Dispersion engineering for T-Guides yields broad regions of anomalous group velocity dispersion, rendering them a promising platform for nonlinear applications, such as wideband frequency conversion.

  5. Single mode waveguide platform for spontaneous and surface-enhanced on-chip Raman spectroscopy

    CERN Document Server

    Dhakal, Ashim; Clemmen, Stéphane; Raza, Ali; Wuytens, Pieter; Zhao, Haolan; Thomas, Nicolas Le; Baets, Roel

    2016-01-01

    We review an on-chip approach for spontaneous Raman spectroscopy and Surface Enhanced Raman Spectroscopy (SERS) based on evanescent excitation of the analyte as well as evanescent collection of the Raman signal using Complementary Metal Oxide Semiconductor (CMOS) compatible single mode waveguides. The signal is either directly collected from the analyte molecules or via plasmonic nanoantennas integrated on top of the waveguides. Flexibility in the design of the geometry of the waveguide, and/or the geometry of the antennas, enables optimization of the collection efficiency. Furthermore the sensor can be integrated with additional functionality (sources, detectors, spectrometers) on the same chip. In this paper, the basic theoretical concepts are introduced to identify the key design parameters and some proof-of-concept experimental results are reviewed.

  6. Report on first masing and single mode locking in a prebunched beam FEM oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, M.; Eichenbaum, A.; Kleinman, H. [Tel-Aviv Univ., Ramat-Aviv (Israel)] [and others

    1995-12-31

    Radiation characteristics of a table-top free electron maser (FEM) are described in this paper. The FEM employs a prebunched electron beam and is operated as an oscillator in the low-gain collective (Raman) regime. Using electron beam prebunching single mode locking at any one of the possible oscillation modes was obtained. The electron beam is prebunched by a microwave tube section before it is injected into the wiggler. By tuning the electron beam bunching frequency, the FEM oscillation frequency can be locked to any eigen frequency of the resonant waveguide cavity which is within the frequency band of net gain of the FEM. The oscillation build up process is sped up, when the FEM operates with a prebunched electron beam, and the build-up time of radiation is shortened significantly. First measurements of masing with and without prebunching and characterization of the emitted radiation are reported.

  7. Single-mode and tunable VCSELs in the near- to mid-infraredInvited Paper

    Institute of Scientific and Technical Information of China (English)

    Markus-Christian Amann; Werner Hofmann

    2008-01-01

    @@ Single-mode, long-wavelength vertical-cavity surface-emitting lasers (VCSELs) in the near- to mid-infrared covering the wavelength range from 1.3 to 2.3μm are presented. This wide spectral emission range opens applications in gas sensing and optical interconnects. All these lasers are monolithically grown in the InGaA1As-InP material system utilizing a buried tunnel junction (BTJ) as current aperture. Fabricated with a novel high-speed design with reduced parasitics, bandwidths in excess of 10 GHz at 1.3 and 1.55 μm have been achieved. Therefore, the coarse wavelength division multiplexing (CWDM) wavelength range of 1.3 to 1.6 μm at 10 Gb/s can be accomplished with one technology. Error-free data-transmission at 10 Gb/s over a fiber link of 20 km is demonstrated. One-dimensional arrays have been fabricated with emission wavelengths addressable by current tuning. Micro-electro-mechanical system (MEMS) tunable devices provide an extended tuning range in excess of 50 nm with high spectral purity. All these devices feature continuous-wave (CW) operation with typical single-mode output powers exceeding 1 mW. The operation voltage is around 1 - 1.5 V and power consumption is as low as 10 - 20 mW. Furthermore, we have also developed VCSELs based on GaSb, targeting at the wavelength range from 2.3 to 3.0 μm. The functionality of tunable diode laser spectroscopy (TDLS) systems is shown by presenting a laser hygrometer applying a 1.84-μm VCSEL.

  8. High-efficiency multipass Ti:sapphire amplifiers for a continuous-wave single-mode laser.

    Science.gov (United States)

    Georges, P; Estable, F; Salin, F; Poizat, J P; Grangier, P; Brun, A

    1991-02-01

    We present the amplification of a continuous-wave single-mode ring dye laser in Ti:sapphire. A peak gain of 2 x 10(6) has been obtained in a passive multipass amplifier, which yielded 20-nsec pulses of 0.7-mJ energy at 780 nm. We discuss the advantages of this passive multipass amplifier in comparison with a regenerative amplifier that we have also developed. By second-harmonic generation we obtained high-peak-power UV pulses from the amplified single-mode laser.

  9. Single-mode solid-state polymer dye laser fabricated with standard I-line UV lithography

    DEFF Research Database (Denmark)

    Balslev, Søren; Mironov, Andrej; Nilsson, Daniel

    2005-01-01

    We present single-mode solid-state polymer dye lasers fabricated with standard UV lithography. The lasers use a high-order Bragg grating and rely on index-tuning of a photosensitive polymer for waveguiding. The gain medium is Rhodamine 6G.......We present single-mode solid-state polymer dye lasers fabricated with standard UV lithography. The lasers use a high-order Bragg grating and rely on index-tuning of a photosensitive polymer for waveguiding. The gain medium is Rhodamine 6G....

  10. Application of Single-Mode Fiber-Coupled Receivers in Optical Satellite to High-Altitude Platform Communications

    Directory of Open Access Journals (Sweden)

    Oswald Wallner

    2008-05-01

    Full Text Available In a free-space optical communication system employing fiber-optic components, the phasefront distortions induced by atmospheric turbulence limit the efficiency with which the laser beam is coupled into a single-mode fiber. We analyze different link scenarios including a geostationary (GEO satellite, a high-altitude platform (HAP, and an optical ground station (OGS. Single-mode coupled optically preamplified receivers allow for efficient suppression of background noise and highly sensitive detection. While GEO-to-OGS communication suffers from atmospheric turbulence, we demonstrate that GEO-to-HAP communication allows for close to diffraction-limited performance when applying tip-tilt correction.

  11. Collapse and revival of a single-Cooper-pair box in a single-mode quantized field

    Institute of Scientific and Technical Information of China (English)

    姚延荪; 邹健; 邵彬

    2003-01-01

    We study the quantum dynamics of a single-Cooper-pair box biased by a classical voltage and also irradiated by a single-mode quantized field.We demonstrate that under weak damping of the quantized field,the collapse-revival phenomena can exist in this system,and the oscillations of the collapse and revival depend sensitively on the initial state of the single-mode quantized field and the damping rate κ.We also demonstrate that this system can show the beats phenomena.

  12. Application of Single-Mode Fiber-Coupled Receivers in Optical Satellite to High-Altitude Platform Communications

    Directory of Open Access Journals (Sweden)

    Fidler Franz

    2008-01-01

    Full Text Available Abstract In a free-space optical communication system employing fiber-optic components, the phasefront distortions induced by atmospheric turbulence limit the efficiency with which the laser beam is coupled into a single-mode fiber. We analyze different link scenarios including a geostationary (GEO satellite, a high-altitude platform (HAP, and an optical ground station (OGS. Single-mode coupled optically preamplified receivers allow for efficient suppression of background noise and highly sensitive detection. While GEO-to-OGS communication suffers from atmospheric turbulence, we demonstrate that GEO-to-HAP communication allows for close to diffraction-limited performance when applying tip-tilt correction.

  13. Effects of cross-correlated noises on the intensity fluctuation of the single-mode laser system

    Institute of Scientific and Technical Information of China (English)

    Bing Wang; Shuwen Dai; Shuping Ge

    2006-01-01

    @@ A single-mode laser model with cross-correlated additive and multiplicative noise terms is considered, and the effects of correlation between noises on the relaxation time and the intensity correlation function are studied. Using the projection operator method and taking into account the effects of the memory kernels of the intensity correlation function, the analytic expressions for the relaxation time and the correlation function are derived. Based on numerical computations, it is found that the self-correlation time and the cross-correlation time have the same effects on the single-mode laser system.

  14. Comparison of high power large mode area and single mode 1908nm Tm-doped fiber lasers

    Science.gov (United States)

    Johnson, Benjamin R.; Creeden, Daniel; Limongelli, Julia; Pretorius, Herman; Blanchard, Jon; Setzler, Scott D.

    2016-03-01

    We compare large mode area (LMA) and single-mode (SM) double-clad fiber geometries for use in high power 1908nm fiber lasers. With a simple end-pumped architecture, we have generated 100W of 1908nm power with LMA fiber at 40% optical efficiency and 117W at 52.2% optical efficiency with single-mode fiber. We show the LMA fiber is capable of generating >200W and the SM fiber is capable of >300W at 1908nm. In all cases, the fiber lasers are monolithic power-oscillators with no free-space coupling.

  15. Polarimetry noise in fiber-based optical coherence tomography instrumentation

    Science.gov (United States)

    Zhang, Ellen Ziyi; Vakoc, Benjamin J.

    2011-01-01

    High noise levels in fiber-based polarization-sensitive optical coherence tomography (PS-OCT) have broadly limited its clinical utility. In this study we investigate contribution of polarization mode dispersion (PMD) to the polarimetry noise. We develop numerical models of the PS-OCT system including PMD and validate these models with empirical data. Using these models, we provide a framework for predicting noise levels, for processing signals to reduce noise, and for designing an optimized system. PMID:21935044

  16. Three-Colour Single-Mode Electroluminescence from Alq3 Tuned by Microcavities

    Institute of Scientific and Technical Information of China (English)

    赵家民; 马凤英; 刘星元; 刘云; 初国强; 宁永强; 王立军

    2002-01-01

    Organic metal microcavities were fabricated by using full-reflectivity aluminium film and semi-transparent silverfilm as cavity mirrors. Unlike conventional organic microcavities, such as the typical structure of glass/DBR/ITO/-organic layers/metal mirror, a microcavity with a shorter cavity length was obtained by using two metal mirrors,where DBR is the distributed Bragg reflector consisting of alternate quarter-wave layers of high and low refractiveindex materials. It is realized that red, green and blue single-mode electroluminescence (EL) from the micro-cavities with the structure, glass/Ag/TPD/Alqa/A1, are electrically-driven when the thickness of the Alqa layerchanges. Compared to a non-cavity reference sample whose EL spectrum peak is located at 520nm with a fullwidth at half maximum (FWHM) of 93 nm, the microcavity devices show apparent cavity effects. The EL spectraof red, green and blue microcavities are peaked at 604nm, 540nm and 491 nm, with FWHM of 43 nm, 38nm and47nm, respectively.

  17. Intrinsic pressure response of a single mode cyclo olefin polymer fiber bragg grating

    DEFF Research Database (Denmark)

    Pedersen, Jens Kristian Mølgaard; Woyessa, Getinet; Nielsen, Kristian

    2016-01-01

    and relative humidity the pressure calibration is performed in a gas free environment with the FBG submerged in water. As a result of the incompressible nature of water no temperature effects due to rapid pressure changes are observed. We find a highly linear, hysteresis-free response with a sensitivity of 2......The intrinsic pressure response of a Fibre Bragg Grating (FBG) inscribed in a single-mode cyclo olefin polymer (COP) microstructured polymer optical fibre (mPOF) in the range 0-200 bar is investigated for the first time. In order to efficiently suppress the effects from changes in temperature.......982 ± 0.002 pm/bar. The corresponding fractional sensitivity is found to be 34.5·10-6 MPa-1 which is of the same order of magnitude as the results obtained for a multimode PMMA mPOF-FBG at 1562 nm previously reported in the literature. The resulting pressure resolution of our sensor is estimated to be 2...

  18. Design and experiments of a linear piezoelectric motor driven by a single mode

    Science.gov (United States)

    Liu, Zhen; Yao, Zhiyuan; Li, Xiang; Fu, Qianwei

    2016-11-01

    In this contribution, we propose a novel linear piezoelectric motor with a compact stator that is driven by a single mode. The linear piezoelectric motor can realize bidirectional motion by changing the vibration modes of the stator. Finite element analysis is performed to determine the required vibration mode of the stator and obtain the optimal stator structure and dimensions. Furthermore, the trajectories of the driving foot are analyzed with and without consideration of the mechanical contact with the slider. It is shown that the trajectory of the driving foot is an oblique line when disregarding the contact, and the trajectory becomes an oblique ellipse while taking into account the contact. Finally, a prototype of the motor is fabricated based on the results of finite element analysis. The optimization results show that the motor reaches its maximum thrust force of 4.0 kg, maximum thrust-weight ratio of 33.3, maximum unloaded velocity of 385 mm/s under the excitation of Mode-B, and maximum unloaded velocity of 315 mm/s under the excitation of Mode-L.

  19. Influence of photo- and thermal bleaching on pre-irradiation low water peak single mode fibers

    Science.gov (United States)

    Yin, Jianchong; Wen, Jianxiang; Luo, Wenyun; Xiao, Zhongyin; Chen, Zhenyi; Wang, Tingyun

    2011-12-01

    Reducing the radiation-induced transmission loss in low water peak single mode fiber (LWP SMF) has been investigated by using photo-bleaching method with 980nm pump light source and using thermal-bleaching method with temperature control system. The results show that the radiation-induced loss of pre-irradiation optical fiber can be reduced effectively with the help of photo-bleaching or thermal-bleaching. Although the effort of photo-bleaching is not as significant as thermal-bleaching, by using photo-bleaching method, the loss of fiber caused by radiation-induced defects can be reduced best up to 49% at 1310nm and 28% at 1550nm in low pre-irradiation condition, the coating of the fiber are not destroyed, and the rehabilitating time is just several hours, while self-annealing usually costs months' time. What's more, the typical high power LASER for photo-bleaching can be 980nm pump Laser Diode, which is very accessible.

  20. Characterization of Mid-Infrared Single Mode Fibers as Modal Filters

    Science.gov (United States)

    Ksendzov, A.; Lay, O.; Martin, S.; Sanghera, J. S.; Busse, L. E.; Kim, W. H.; Pureza, P. C.; Nguyen, V. Q.; Aggarwal, I. D.

    2007-01-01

    We present a technique for measuring the modal filtering ability of single mode fibers. The ideal modal filter rejects all input field components that have no overlap with the fundamental mode of the filter and does not attenuate the fundamental mode. We define the quality of a nonideal modal filter Q(sub f) as the ratio of transmittance for the fundamental mode to the transmittance for an input field that has no overlap with the fundamental mode. We demonstrate the technique on a 20 cm long mid-infrared fiber that was produced by the U.S. Naval Research Laboratory. The filter quality Q(sub f) for this fiber at 10.5 micron wavelength is 1000 +/- 300. The absorption and scattering losses in the fundamental mode are approximately 8 dB/m. The total transmittance for the fundamental mode, including Fresnel reflections, is 0.428 +/- 0.002. The application of interest is the search for extrasolar Earthlike planets using nulling interferometry. It requires high rejection ratios to suppress the light of a bright star, so that the faint planet becomes visible. The use of modal filters increases the rejection ratio (or, equivalently, relaxes requirements on the wavefront quality) by reducing the sensitivity to small wavefront errors. We show theoretically that, exclusive of coupling losses, the use of a modal filter leads to the improvement of the rejection ratio in a two-beam interferometer by a factor of Q(sub f).

  1. Mid-infrared laser light nulling experiment using single-mode conductive waveguides

    CERN Document Server

    Labadie, L; Maurand, R; Labeye, P; Kern, P; Arezki, B; Broquin, J -E

    2007-01-01

    Aims: In the context of space interferometry missions devoted to the search of exo-Earths, this paper investigates the capabilities of new single mode conductive waveguides at providing modal filtering in an infrared and monochromatic nulling experiment; Methods: A Michelson laser interferometer with a co-axial beam combination scheme at 10.6 microns is used. After introducing a Pi phase shift using a translating mirror, dynamic and static measurements of the nulling ratio are performed in the two cases where modal filtering is implemented and suppressed. No additional active control of the wavefront errors is involved. Results: We achieve on average a statistical nulling ratio of 2.5e-4 with a 1-sigma upper limit of 6e-4, while a best null of 5.6e-5 is obtained in static mode. At the moment, the impact of external vibrations limits our ability to maintain the null to 10 to 20 seconds.; Conclusions: A positive effect of SM conductive waveguide on modal filtering has been observed in this study. Further improv...

  2. Single-mode optical waveguides on native high-refractive-index substrates

    Science.gov (United States)

    Grote, Richard R.; Bassett, Lee C.

    2016-10-01

    High-refractive-index semiconductor optical waveguides form the basis for modern photonic integrated circuits (PICs). However, conventional methods for achieving optical confinement require a thick lower-refractive-index support layer that impedes large-scale co-integration with electronics and limits the materials on which PICs can be fabricated. To address this challenge, we present a general architecture for single-mode waveguides that confine light in a high-refractive-index material on a native substrate. The waveguide consists of a high-aspect-ratio fin of the guiding material surrounded by lower-refractive-index dielectrics and is compatible with standard top-down fabrication techniques. This letter describes a physically intuitive, semi-analytical, effective index model for designing fin waveguides, which is confirmed with fully vectorial numerical simulations. Design examples are presented for diamond and silicon at visible and telecommunications wavelengths, respectively, along with calculations of propagation loss due to bending, scattering, and substrate leakage. Potential methods of fabrication are also discussed. The proposed waveguide geometry allows PICs to be fabricated alongside silicon CMOS electronics on the same wafer, removes the need for heteroepitaxy in III-V PICs, and will enable wafer-scale photonic integration on emerging material platforms such as diamond and SiC.

  3. Piezoelectric transducer parameter selection for exciting a single mode from multiple modes of Lamb waves

    Institute of Scientific and Technical Information of China (English)

    Rang Hai-Yan; Yu Jian-Bo

    2011-01-01

    Excitation and propagation of Lamb waves by using rectangular and circular piezoelectric transducers surfacebonded to an isotropic plate are investigated in this work. Analytical stain wave solutions are derived for the two transducer shapes,giving the responses of these transducers in Lamb wave fields. The analytical study is supported by a numerical simulation using the finite element method. Symmetric and antisymmetric components in the wave propagation responses are inspected in detail with respect to test parameters such as the transducer geometry,the length and the excitation frequency. By placing only one piezoelectric transducer on the top or the bottom surface of the plate and weakening the strength of one mode while enhancing the strength of the other modes to find the centre frequency,with which the peak wave amplitude ratio between the S0 and A0 modes is maximum,a single mode excitation from the multiple modes of the Lamb waves can be achieved approximately. Experimental data are presented to show the validity of the analyses. The results are used to optimize the Lamb wave detection system.

  4. Mapping out spin and particle conductances of a single-mode channel with tunable interactions

    Science.gov (United States)

    Lebrat, Martin; Krinner, Sebastian; Grenier, Charles; Husmann, Dominik; Häusler, Samuel; Nakajima, Shuta; Brantut, Jean-Philippe; Esslinger, Tilman

    2016-05-01

    We study particle and spin transport in a single-mode quantum point contact, shaped by light potentials onto a charge neutral, quantum degenerate gas of 6 Li fermions with tunable interactions. The spin and particle conductances are measured as a function of chemical potential or confinement, covering weak attraction, where quantized conductance is observed, to the strongly interacting superfluid regime. Spin conductance exhibits a broad maximum when varying the chemical potential at moderate interactions, which signals the emergence of superfluidity. In contrast, the particle conductance is unexpectedly enhanced even before the gas is expected to turn into a superfluid: it shows conductance plateaus at non-universal values continuously increasing from 1/h to 4/h, as the interaction strength is increased from weak to intermediate. For strong interactions, the particle conductance plateaus disappear and the spin conductance gets suppressed, confirming the spin-insulating character of a superfluid. Our observations document the breakdown of universal conductance quantization as many-body correlations appear. This anomalous quantization is incompatible with a Fermi liquid description, shedding new light on the nature of the strongly attractive Fermi gas in the normal phase.

  5. Numerical Simulations of the Single-mode, Reacting Richtmyer-Meshkov Instability Using Detailed Chemistry

    Science.gov (United States)

    Attal, Nitesh; Ramaprabhu, Praveen

    2013-11-01

    The interaction of a shock wave with a chemically reacting front is of importance to the design of supersonic combustors and scramjets where mixing from the Richtmyer-Meshkov Instability (RMI) could be tapped to increase combustion efficiency. We will describe results of shock-driven, reacting RMI of a sinusoidally perturbed, single-mode interface separating Hydrogen (fuel) and Oxygen at 300 K and 1625 K respectively. The non-premixed interface was accelerated by a Mach 1.2 shock traversing from the light (H2) to heavy (O2) fluid (Atwood number = 0.5) in a numerical shock tube of aspect ratio 12. The 2D simulations were performed using the compressible flow code FLASH, with modifications to handle detailed chemistry and temperature-dependent material properties. The initial thickness of the material interface was systematically varied to study the effect of the diffusion thickness on the flame and instability dynamics. Product formation and heat release as a result of chemical reactions were described according to the 9-species, 19-steps detailed reaction mechanism.

  6. Superlinear growth of Rayleigh scattering-induced intensity noise in single-mode fibers

    CERN Document Server

    Cahill, James P; Zhou, Weimin; Menyuk, Curtis R; Carter, Gary M

    2015-01-01

    Rayleigh scattering generates intensity noise close to an optical carrier that propagates in a single-mode optical fiber. This noise degrades the performance of optoelectronic oscillators and RF-photonic links. When using a broad linewidth laser, we previously found that the intensity noise power scales linearly with optical power and fiber length, which is consistent with guided entropy mode Rayleigh scattering (GEMRS), a third order nonlinear scattering process, in the spontaneous limit. In this work, we show that this behavior changes significantly with the use of a narrow linewidth laser. Using a narrow linewidth laser, we measured the bandwidth of the intensity noise plateau to be 10 kHz. We found that the scattered noise power scales superlinearly with fiber length up to lengths of 10 km in the frequency range of 500 Hz to 10 kHz, while it scales linearly in the frequency range of 10 Hz to 100 Hz. These results suggest that the Rayleigh-scattering-induced intensity noise cannot be explained by third-ord...

  7. Refractive beam shapers for material processing with high power single mode and multimode lasers

    Science.gov (United States)

    Laskin, Alexander; Laskin, Vadim

    2013-02-01

    The high power multimode fiber-coupled laser sources, like solid state lasers or laser diodes as well as single mode and multimode fiber lasers, are now widely used in various industrial laser material processing technologies like metal or plastics welding, cladding, hardening, brazing, annealing. Performance of these technologies can be essentially improved by varying the irradiance profile of a laser beam with using beam shaping optics, for example, the field mapping refractive beam shapers like piShaper. Operational principle of these devices presumes transformation of laser beam irradiance distribution from Gaussian to flattop, super-Gauss, or inverse-Gauss profile with high flatness of output wave front, conserving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field. Important feature of piShaper is in capability to operate with TEM00 and multimode lasers, the beam shapers can be implemented not only as telescopic optics but also as collimating systems, which can be connected directly to fiber-coupled lasers or fiber lasers, thus combining functions of beam collimation and irradiance transformation. This paper will describe some features of beam shaping of high-power laser sources, including multimode fiber coupled lasers, and ways of adaptation of beam shaping optical systems design to meet requirements of modern laser technologies. Examples of real implementations will be presented as well.

  8. Numerical Experiments with a Turbulent Single-Mode Rayleigh-Taylor Instability

    Energy Technology Data Exchange (ETDEWEB)

    Cloutman, L.D.

    2000-04-01

    Direct numerical simulation is a powerful tool for studying turbulent flows. Unfortunately, it is also computationally expensive and often beyond the reach of the largest, fastest computers. Consequently, a variety of turbulence models have been devised to allow tractable and affordable simulations of averaged flow fields. Unfortunately, these present a variety of practical difficulties, including the incorporation of varying degrees of empiricism and phenomenology, which leads to a lack of universality. This unsatisfactory state of affairs has led to the speculation that one can avoid the expense and bother of using a turbulence model by relying on the grid and numerical diffusion of the computational fluid dynamics algorithm to introduce a spectral cutoff on the flow field and to provide dissipation at the grid scale, thereby mimicking two main effects of a large eddy simulation model. This paper shows numerical examples of a single-mode Rayleigh-Taylor instability in which this procedure produces questionable results. We then show a dramatic improvement when two simple subgrid-scale models are employed. This study also illustrates the extreme sensitivity to initial conditions that is a common feature of turbulent flows.

  9. On-sky single-mode fiber coupling measurements at the Large Binocular Telescope

    CERN Document Server

    Bechter, Andrew; Ketterer, Ryan; Crepp, Justin R; Reynolds, Robert O; Bechter, Eric; Hinz, Philip; Pedichini, Fernando; Foley, Michael; Runburg, Elliott; Onuma, Eleanya; Gaudi, Scott; Micela, Giuseppina; Pagano, Isabella; Woodward, Charles E

    2016-01-01

    The demonstration of efficient single-mode fiber (SMF) coupling is a key requirement for the development of a compact, ultra-precise radial velocity (RV) spectrograph. iLocater is a next generation instrument for the Large Binocular Telescope (LBT) that uses adaptive optics (AO) to inject starlight into a SMF. In preparation for commissioning iLocater, a prototype SMF injection system was installed and tested at the LBT in the Y-band (0.970-1.065 $\\mu$m). This system was designed to verify the capability of the LBT AO system as well as characterize on-sky SMF coupling efficiencies. SMF coupling was measured on stars with variable airmasses, apparent magnitudes, and seeing conditions for six half-nights using the Large Binocular Telescope Interferometer. We present the overall optical and mechanical performance of the SMF injection system, including details of the installation and alignment procedure. A particular emphasis is placed on analyzing the instrument's performance as a function of telescope elevation...

  10. End Face Damage and Fiber Fuse Phenomena in Single-Mode Fiber-Optic Connectors

    Directory of Open Access Journals (Sweden)

    Yoshito Shuto

    2016-01-01

    Full Text Available The evolution of both the core melting and fiber fuse phenomena in a single-mode fiber-optic connector was studied theoretically. Carbon black was chosen as a light-absorbent material. A thin absorbent layer with a thickness of 1 μm order was assumed to be formed between the fiber end faces in the connector. When a high-power laser operating at 1.48 or 1.55 μm was input into the connector, the temperature on the fiber core surface increased owing to heat conduction from the light-absorbent material. The heat flow process of the core, which caused the core to melt or the fiber fuse phenomenon, was theoretically calculated with the explicit finite-difference method. The results indicated that initial attenuation of less than 0.5 dB was desirable to prevent core fusion in the connectors when the input 1.48 μm laser power was 1 W. It was found that a core temperature of more than 4000 K was necessary to generate and maintain a fiber fuse.

  11. Experimental demonstration of single-mode fiber coupling over relatively strong turbulence with adaptive optics.

    Science.gov (United States)

    Chen, Mo; Liu, Chao; Xian, Hao

    2015-10-10

    High-speed free-space optical communication systems using fiber-optic components can greatly improve the stability of the system and simplify the structure. However, propagation through atmospheric turbulence degrades the spatial coherence of the signal beam and limits the single-mode fiber (SMF) coupling efficiency. In this paper, we analyze the influence of the atmospheric turbulence on the SMF coupling efficiency over various turbulences. The results show that the SMF coupling efficiency drops from 81% without phase distortion to 10% when phase root mean square value equals 0.3λ. The simulations of SMF coupling with adaptive optics (AO) indicate that it is inevitable to compensate the high-order aberrations for SMF coupling over relatively strong turbulence. The SMF coupling efficiency experiments, using an AO system with a 137-element deformable mirror and a Hartmann-Shack wavefront sensor, obtain average coupling efficiency increasing from 1.3% in open loop to 46.1% in closed loop under a relatively strong turbulence, D/r0=15.1.

  12. Superlinear growth of Rayleigh scattering-induced intensity noise in single-mode fibers.

    Science.gov (United States)

    Cahill, James P; Okusaga, Olukayode; Zhou, Weimin; Menyuk, Curtis R; Carter, Gary M

    2015-03-09

    Rayleigh scattering generates intensity noise close to an optical carrier that propagates in a single-mode optical fiber. This noise degrades the performance of optoelectronic oscillators and RF-photonic links. When using a broad linewidth laser, we previously found that the intensity noise power scales linearly with optical power and fiber length, which is consistent with guided entropy mode Rayleigh scattering (GEMRS), a third order nonlinear scattering process, in the spontaneous limit. In this work, we show that this behavior changes significantly with the use of a narrow linewidth laser. Using a narrow linewidth laser, we measured the bandwidth of the intensity noise plateau to be 10 kHz. We found that the scattered noise power scales superlinearly with fiber length up to lengths of 10 km in the frequency range of 500 Hz to 10 kHz, while it scales linearly in the frequency range of 10 Hz to 100 Hz. These results suggest that the Rayleigh-scattering-induced intensity noise cannot be explained by third-order nonlinear scattering in the spontaneous limit, as previously hypothesized.

  13. Asymptotically single-mode small-core terahertz Bragg fibre with low loss and low dispersion

    Science.gov (United States)

    Hong, B.; Swithenbank, M.; Somjit, N.; Cunningham, J.; Robertson, I.

    2017-02-01

    This paper presents a novel design concept, which is verified by analytical and simulation results, of a single-mode small-core terahertz Bragg fibre exhibiting the properties of low loss and low dispersion. Conventionally, a single-TE01-mode Bragg fibre requires a large core and many cladding layer periods to achieve a significant propagation loss discrimination between the desired mode and other unwanted competing modes. The use of a second-order bandgap in this paper completely eliminates this requirement, and enhances propagation loss discrimination using just a small core with a diameter at least 50% smaller than the conventional design and only four cladding layer periods. Furthermore, a generalized half-wavelength condition is proposed, promoting the manipulation of photonic bandgap for Bragg fibre. The TE01 mode has a null point in the electric field close to the boundary interface between the core and the cladding, and this phenomenon has been exploited to minimize the impact of support bridges, which mechanically maintain the air gaps, on the propagation loss of the fibre. Finally, we propose a novel design of a tightly confined single-TE01-mode small-air-core Bragg fibre with propagation loss and group velocity dispersion less than 1.2 dB m-1 and  -0.6 ps/THz/cm, respectively, between frequencies of 0.85 THz and 1.15 THz.

  14. Graphene surface plasmon waveguides incorporating high-index dielectric ridges for single mode transmission

    Science.gov (United States)

    Sun, Yu; Zheng, Zheng; Cheng, Jiangtao; Liu, Jianwei

    2014-10-01

    We report a novel plasmonic waveguide by incorporating a uniformly-biased graphene sheet over a high-index ridge. The fundamental mode in the proposed waveguide concentrates in the low-index low-loss gap, which is easier to excite and leads to longer propagation length than that of graphene ribbon waveguides', where the field is mostly confined at the high-loss graphene edges. The single mode transmission can be achieved at far-infrared regime without the hard-to-fabricate, ultra-narrow ribbon that results in extra material loss. Instead of the reflection mechanism at the ribbon edges, the optical field is laterally confined by the effective index difference of graphene plasmons due to the ridge. The results based on the effective index method (EIM) have been validated by finite-element simulations at each stage. Rapid design and optimization is carried out by EIM without requiring further extensive numerical computations. The presented waveguide might be employed in integrated wafer-scale photonic systems to enable high performance graphene-based devices.

  15. Performance and future developments of the RHEA single-mode spectrograph

    Science.gov (United States)

    Bento, Joao; Feger, Tobias; Ireland, Michael J.; Rains, Adam; Jovanovic, Nemanja; Coutts, David W.; Schwab, Christian; Arriola, Alexander; Gross, Simon

    2016-08-01

    The Replicable High-resolution Exoplanet and Asteroseismology (RHEA) spectrograph is being developed to serve as a basis for multiple copies across a network of small robotic telescopes. The spectrograph operates at the diffraction-limit by using a single-mode fiber input, resulting in a compact and modal-noise-free unit. The optical design is mainly based on off-the-shelf available components and comprises a near-Littrow configuration with prism cross-disperser. The échelle format covers a wavelength range of 430-650 nm at R=75,000 resolving power. In this paper we briefly summarize the current status of the instrument and present preliminary results from the first on-sky demonstration of the prototype using a fully automated 16" telescope, where we observe stable and semi-variable stars up to V=3.5 magnitude. Future steps to enhance the efficiency and passive stability of RHEA are discussed in detail. For example, we show the concept of using a multi-fiber injection unit, akin to a photonic lantern, which not only enables increased throughput but also offers simultaneous wavelength calibration.

  16. BEND-INDUCED LOSSES IN A SINGLE-MODE MICROSTRUCTURED FIBER WITH A LARGE CORE

    Directory of Open Access Journals (Sweden)

    Y. A. Gatchin

    2015-03-01

    Full Text Available A study of bend-induced losses in a silica-based single-mode microstructured fiber with a core diameter ranging from 20 to 35 microns and increased relative air content in the holey cladding has been conducted. With the use of the equivalent step-index profile method in approximation of waveguide parameters of microstructured fiber (normalized frequency and normalized transverse attenuation constant the effect of bending on the spectral position of the fundamentalmode short-wavelength leakage boundary has been analyzed. Upon measurement of spectral characteristics of attenuation in the considered fibers good accordance of numerical and experimental data has been found out. It is shown that increase of the air content in the holey cladding leads to expansion of the mentioned boundary to lower wavelengths for the value from 150 to 800 nm depending on the core size and bending conditions. A single-transverse-mode propagation is achieved on fiber length of 5-10 meters due to a substantial difference in losses of fundamental and higher-order guided modes attained by bending. Optical losses in all studied samples are less than 10 dB/km at the wavelength λ = 1550 nm. The results of the study can be applied in the design of high-power laser systems having such basic requirements as a relatively large mode spot and high beam quality.

  17. Toward single-mode active crystal fibers for next-generation high-power fiber devices.

    Science.gov (United States)

    Lai, Chien-Chih; Gao, Wan-Ting; Nguyen, Duc Huy; Ma, Yuan-Ron; Cheng, Nai-Chia; Wang, Shih-Chang; Tjiu, Jeng-Wei; Huang, Chun-Ming

    2014-08-27

    We report what we believe to be the first demonstration of a facile approach with controlled geometry for the production of crystal-core ceramic-clad hybrid fibers for scaling fiber devices to high average powers. The process consists of dip coating a solution of polycrystalline alumina onto a high-crystallinity 40-μm-diameter Ti:sapphire single-crystalline core followed by thermal treatments. Comparison of the measured refractive index with high-resolution transmission electron microscopy reveals that a Ca/Si-rich intragranular layer is precipitated at grain boundaries by impurity segregation and liquid-phase formation due to the relief of misfit strain energy in the Al2O3 matrix, slightly perturbing the refractive index and hence the optical properties. Additionally, electron backscatter diffractions supply further evidence that the Ti:sapphire single-crystalline core provides the template for growth into a sacrificial polycrystalline cladding, bringing the core and cladding into a direct bond. The thus-prepared doped crystal core with the undoped crystal cladding was achieved through the abnormal grain-growth process. The presented results provide a general guideline both for controlling crystal growth and for the performance of hybrid materials and provides insights into how one might design single-mode high-power crystal fiber devices.

  18. Single-mode interface states in heterostructure waveguides with Bragg and non-Bragg gaps

    Science.gov (United States)

    Fan, Ya-Xian; Sang, Tang-Qing; Liu, Ting; Xu, Lan-Lan; Tao, Zhi-Yong

    2017-01-01

    Interface states can always arise in heterostructures that consist of two or more (artificial) materials with topologically different energy bands. The gapped band structure can be classified by the Chern number (a topological invariant) generally or the Zak phase in one-dimensional periodic systems. Recently, topological properties have been employed to investigate the interface states occurring at the connecting regions of the heterostructures of mechanical isostatic lattices and acoustical waveguides. Here, we study this heterostructure phenomenon by carefully connecting two corrugated stainless steel waveguides with Bragg and non-Bragg gaps at approximately the same frequency. These two waveguide structures can be achieved by continuously varying their geometry parameters when a topological transition exists in the forbidden bands, in which the reflection impedance changes the sign. Furthermore, a localized single high-order mode has been observed at the interface because of the transverse mode interactions, which relate to the non-Bragg gaps created by the different transverse mode resonances. Such a localized acoustic single mode with very large enhanced intensity could find its applications in sound detection, biomedical imaging, and underwater sound control, and could also enrich our means of wave front manipulations in various engineering fields. PMID:28287173

  19. Fidelity of Quantum Teleportation for Single-Mode Squeezed State Light

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-Xiang; XIE Chang-De; PENG Kun-Chi

    2005-01-01

    @@ The fidelity of quantum teleportation of a single-mode squeezed state of light is calculated based on the general theory of quantum-mechanical measurement in the Schrodinger picture. It is shown that the criterion for the nonclassical state teleportation is different from that for coherent state. F = 1/2 is no longer the rigorous boundary between classical and quantum teleportation for a squeezed state of light. When the quantum entanglement of an Einstein-Podolsky-Rosen (EPR) beam used for teleportation and the parameters of the system are given,the fidelity depends on the squeezing of the input squeezed state. The higher the squeezing is, the smaller the fidelity is, and the lower the classical limitation of fidelity is. The dependence of the optimum gain for teleporting a squeezed vacuum state upon the EPR entanglement is also calculated. The results obtained provide important references for designing experimental systems of teleporting a non-classical state and judging the quality of the teleported quantum state.

  20. Highly efficient high power single-mode fiber amplifier utilizing the distributed mode filtering bandgap rod fiber

    DEFF Research Database (Denmark)

    Laurila, Marko; Alkeskjold, Thomas T.; Jørgensen, Mette Marie

    2012-01-01

    We report on an ytterbium doped single mode distributed mode filtering rod fiber in an amplifier configuration delivering high average output power, up to 292 watts, using a mode-locked 30ps source at 1032nm with good power conversion efficiency. We study the modal stability of the output beam...

  1. Normalized intensity correlation function of single-mode laser system driven by colored cross-correlation noises

    Institute of Scientific and Technical Information of China (English)

    Bing Wang; Xiuqing Wu

    2008-01-01

    @@ Considering a single-mode laser system with cross-correlated additive colored noise and multiplicative colored noise, we study the effects of correlation among noises on the normalized intensity correlation function C(s).C(s) is derived by means of the projection operator method.

  2. Modal Filtering for Nulling Interferometry-First Single-Mode Conductive Waveguides in the Mid-Infrared

    CERN Document Server

    Labadie, L; Kern, P; Schanen, I; Arezki, B; Broquin, J E

    2005-01-01

    This paper presents the work achieved for the manufacturing and characterization of first single-mode waveguides to be used as modal filters for nulling interferometry in the mid-infrared range [4-20 um]. As very high dynamic range is mandatory for detection of Earth-like planets, modal filtering is one of the most stringent instrumental aspects. The hollow metallic waveguides (HMW) presented here are manufactured using micro-machining techniques. Single-mode behavior has been investigated in laboratory through a technique of polarization analysis while transmission features have been measured using flux relative comparison. The single-mode behavior have been assessed at lambda=10.6 um for rectangular waveguides with dimensions a=10 um and b<5.3 um with an accuracy of ~2.5 %. The tests have shown that a single-polarization state can be maintained in the waveguide. A comparison with results on multi-mode HMW is proposed. Excess losses of 2.4 dB (~ 58 % transmission) have been measured for a single-mode wave...

  3. Single-mode regime in large-mode-area rare-earth-doped rod-type PCFs

    DEFF Research Database (Denmark)

    Poli, F.; Cucinotta, A.; Passaro, D.

    2009-01-01

    In this paper, large-mode-area, double-cladding, rare-earth-doped photonic crystal fibers are investigated in order to understand how the refractive index distribution and the mode competition given by the amplification can assure single-mode propagation. Fibers with different core diameters, i...

  4. Lasing mode regulation and single-mode realization in ZnO whispering gallery microcavities by the Vernier effect.

    Science.gov (United States)

    Wang, Y Y; Xu, C X; Jiang, M M; Li, J T; Dai, J; Lu, J F; Li, P L

    2016-10-07

    The wide direct bandgap and strong exciton binding energy of ZnO have inspired examinations of ultraviolet lasing over the previous decades. However, regulation of the lasing mode, especially the realization of single mode lasing, is still a challenge. In this study, a ZnO comb-like structure with an array of microrods was selected to design coupled whispering-gallery-mode cavities, wherein the naturally varied air-gap between the adjacent microrods created a flexible condition for optical field coupling without any complicated micromanipulation. Spectral behaviour of lasing and coupling interaction between coupled ZnO microrods were systematically investigated. By regulating the nano-scale inter-space of dual coupled microrods, stable single-mode lasing with a higher Q factor and lower threshold was obtained successfully based on the Vernier effect. The formation conditions and the mechanism of single-mode lasing derived from the coupled ZnO microrods were discussed in detail. It also demonstrated an approach to construct high quality single-mode lasing by tuning the diameters of the coupled ZnO microrods.

  5. Selective mode coupling in microring resonators for single mode semiconductor lasers

    Science.gov (United States)

    Arbabi, Amir

    Single mode semiconductor laser diodes have many applications in optical communications, metrology and sensing. Edge-emitting single mode lasers commonly use distributed feedback structures, or narrowband reflectors such as distributed Bragg reflectors (DBRs) and sampled grating distributed Bragg reflectors (SGDBRs). Compact, narrowband reflectors with high reflectivities are of interest to replace the commonly used DBRs and SGDBRs. This thesis presents our work on the simulation, design, fabrication, and characterization of devices operating based on the coupling of degenerate modes of a microring resonator, and investigation of the possibility of using them for improving the performance of laser diodes. In particular, we demonstrate a new type of compact, narrowband, on-chip reflector realized by selectively coupling degenerate modes of a microring resonator. For the simulation and design of reflective microring resonators, a fast and accurate analysis method is required. Conventional numerical methods for solving Maxwell's equations such as the finite difference time domain and the finite element method (FEM) provide accurate results but are computationally intense and are not suitable for the design of large 3D structures. We formulated a set of coupled mode equations that, combined with 2D FEM simulations, can provide a fast and accurate tool for the modeling and design of reflective microrings. We developed fabrication processing recipes and fabricated passive reflective microrings on silicon substrates with a silicon nitride core and silicon dioxide cladding. Narrowband single wavelength reflectors were realized which are 70 times smaller than a conventional DBR with the same bandwidth. Compared to the conventional DBR, they have faster roll-off, and no side modes. The smaller footprint saves real estate, reduces tuning power and makes these devices attractive as in-line mirrors for low threshold narrow linewidth laser diodes. Self-heating caused by material

  6. Sintered silicon carbide: a new ceramic vessel material for microwave chemistry in single-mode reactors.

    Science.gov (United States)

    Gutmann, Bernhard; Obermayer, David; Reichart, Benedikt; Prekodravac, Bojana; Irfan, Muhammad; Kremsner, Jennifer M; Kappe, C Oliver

    2010-10-25

    Silicon carbide (SiC) is a strongly microwave absorbing chemically inert ceramic material that can be utilized at extremely high temperatures due to its high melting point and very low thermal expansion coefficient. Microwave irradiation induces a flow of electrons in the semiconducting ceramic that heats the material very efficiently through resistance heating mechanisms. The use of SiC carbide reaction vessels in combination with a single-mode microwave reactor provides an almost complete shielding of the contents inside from the electromagnetic field. Therefore, such experiments do not involve electromagnetic field effects on the chemistry, since the semiconducting ceramic vial effectively prevents microwave irradiation from penetrating the reaction mixture. The involvement of electromagnetic field effects (specific/nonthermal microwave effects) on 21 selected chemical transformations was evaluated by comparing the results obtained in microwave-transparent Pyrex vials with experiments performed in SiC vials at the same reaction temperature. For most of the 21 reactions, the outcome in terms of conversion/purity/product yields using the two different vial types was virtually identical, indicating that the electromagnetic field had no direct influence on the reaction pathway. Due to the high chemical resistance of SiC, reactions involving corrosive reagents can be performed without degradation of the vessel material. Examples include high-temperature fluorine-chlorine exchange reactions using triethylamine trihydrofluoride, and the hydrolysis of nitriles with aqueous potassium hydroxide. The unique combination of high microwave absorptivity, thermal conductivity, and effusivity on the one hand, and excellent temperature, pressure and corrosion resistance on the other hand, makes this material ideal for the fabrication of reaction vessels for use in microwave reactors.

  7. Toward photostable multiplex analyte detection on a single mode planar optical waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Mukundan, Harshini [Los Alamos National Laboratory; Xei, Hongshi [Los Alamos National Laboratory; Anderson, Aaron S [Los Alamos National Laboratory; Grace, Wynne K [Los Alamos National Laboratory; Martinez, Jennifer S [NON LANL; Swanson, Basil [Los Alamos National Laboratory

    2009-01-01

    We have developed a waveguide-based optical biosensor for the sensitive and specific detection of biomarkers associated with disease. Our technology combines the superior optical properties of single-mode planar waveguides, the robust nature of functionalized self-assembled monolayer sensing films and the specificity of fluorescence sandwich immunoassays to detect biomarkers in complex biological samples such as serum, urine and sputum. We have previously reported the adaptation of our technology to the detection of biomarkers associated with breast cancer and anthrax. However, these approaches primarily used phospholipid bilayers as the functional film and organic dyes (ex: AlexaFluors) as the fluorescence reporter. Organic dyes are easily photodegraded and are not amenable to multiplexing because of their narrow Stokes' shift. Here we have developed strategies for conjugation of the detector antibodies with quantum dots for use in a multiplex detection platform. We have previously evaluated dihydroxylipoic acid quantum dots for the detection of a breast cancer biomarker. In this manuscript, we investigate the detection of the Bacillus anthracis protective antigen using antibodies conjugated with polymer-coated quantum dots. Kinetics of binding on the waveguide-based biosensor is reported. We compare the sensitivity of quantum dot labeled antibodies to those labeled with AlexaFluor and demonstrate the photostability of the former in our assay platform. In addition, we compare sulfydryl labeling of the antibody in the hinge region to that of nonspecific amine labeling. This is but the first step in developing a multiplex assay for such biomarkers on our waveguide platform.

  8. Analysis of multi-mode to single-mode conversion at 635 nm and 1550 nm

    Science.gov (United States)

    Zamora, Vanessa; Bogatzki, Angelina; Arndt-Staufenbiel, Norbert; Hofmann, Jens; Schröder, Henning

    2016-03-01

    We propose two low-cost and robust optical fiber systems based on the photonic lantern (PL) technology for operating at 635 nm and 1550 nm. The PL is an emerging technology that couples light from a multi-mode (MM) fiber to several single-mode (SM) fibers via a low-loss adiabatic transition. This bundle of SM fibers is observed as a MM fiber system whose spatial modes are the degenerate supermodes of the bundle. The adiabatic transition allows that those supermodes evolve into the modes of the MM fiber. Simulations of the MM fiber end structure and its taper transition have been performed via functional mode solver tools in order to understand the modal evolution in PLs. The modelled design consists of 7 SM fibers inserted into a low-index capillary. The material and geometry of the PLs are chosen such that the supermodes match to the spatial modes of the desired step-index MM fiber in a moderate loss transmission. The dispersion of materials is also considered. These parameters are studied in two PL systems in order to reach a spectral transmission from 450 nm to 1600 nm. Additionally, an analysis of the geometry and losses due to the mismatching of modes is presented. PLs are typically used in the fields of astrophotonics and space photonics. Recently, they are demonstrated as mode converters in telecommunications, especially focusing on spatial division multiplexing. In this study, we show the use of PLs as a promising interconnecting tool for the development of miniaturized spectrometers operating in a broad wavelength range.

  9. Diffractive Combiner of Single-Mode Pump Laser-Diode Beams

    Science.gov (United States)

    Liu, Duncan; Wilson, Daniel; Qiu, Yueming; Forouhar, Siamak

    2007-01-01

    An optical beam combiner now under development would make it possible to use the outputs of multiple single-mode laser diodes to pump a neodymium: yttrium aluminum garnet (Nd:YAG) nonplanar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired frequency. Heretofore, an Nd:YAG NPRO like the present one has been pumped by a single multimode laser-diode beam delivered via an optical fiber. It would be desirable to use multiple pump laser diodes to increase reliability beyond that obtainable from a single pump laser diode. However, as explained below, simplistically coupling multiple multimode laser-diode beams through a fiber-optic combiner would entail a significant reduction in coupling efficiency, and lasing would occur at one or more other frequencies in addition to the single desired frequency. Figure 1 schematically illustrates the principle of operation of a laser-diode-pumped Nd:YAG NPRO. The laser beam path is confined in a Nd:YAG crystal by means of total internal reflections on the three back facets and a partial-reflection coating on the front facet. The wavelength of the pump beam - 808 nm - is the wavelength most strongly absorbed by the Nd:YAG crystal. The crystal can lase at a wavelength of either 1,064 nm or 1,319 nm - which one depending on the optical coating on the front facet. A thermal lens effect induced by the pump beam enables stable lasing in the lowest-order transverse electromagnetic mode (the TEM00 mode). The frequency of this laser is very stable because of the mechanical stability of the laser crystal and the unidirectional nature of the lasing. The unidirectionality is a result of the combined effects of (1) a Faraday rotation induced by an externally applied magnetic field and (2) polarization associated with non-normal incidence and reflection on the front facet.

  10. Model of a single mode energy harvester and properties for optimal power generation

    Science.gov (United States)

    Liao, Yabin; Sodano, Henry A.

    2008-12-01

    The process of acquiring the energy surrounding a system and converting it into usable electrical energy is termed power harvesting. In the last few years, the field of power harvesting has experienced significant growth due to the ever increasing desire to produce portable and wireless electronics with extended life. Current portable and wireless devices must be designed to include electrochemical batteries as the power source. The use of batteries can be troublesome due to their finite energy supply, which necessitates their periodic replacement. In the case of wireless sensors that are to be placed in remote locations, the sensor must be easily accessible or of disposable nature to allow the device to function over extended periods of time. Energy scavenging devices are designed to capture the ambient energy surrounding the electronics and covert it into usable electrical energy. The concept of power harvesting works towards developing self-powered devices that do not require replaceable power supplies. The development of energy harvesting systems is greatly facilitated by an accurate model to assist in the design of the system. This paper will describe a theoretical model of a piezoelectric based energy harvesting system that is simple to apply yet provides an accurate prediction of the power generated around a single mode of vibration. Furthermore, this model will allow optimization of system parameters to be studied such that maximal performance can be achieved. Using this model an expression for the optimal resistance and a parameter describing the energy harvesting efficiency will be presented and evaluated through numerical simulations. The second part of this paper will present an experimental validation of the model and optimal parameters.

  11. Fiber-based swept-source terahertz radar.

    Science.gov (United States)

    Huang, Yu-Wei; Tseng, Tzu-Fang; Kuo, Chung-Chiu; Hwang, Yuh-Jing; Sun, Chi-Kuang

    2010-05-01

    We demonstrate an all-terahertz swept-source imaging radar operated at room temperature by using terahertz fibers for radiation delivery and with a terahertz-fiber directional coupler acting as a Michelson interferometer. By taking advantage of the high water reflection contrast in the low terahertz regime and by electrically sweeping at a high speed a terahertz source combined with a fast rotating mirror, we obtained the living object's distance information with a high image frame rate. Our experiment showed that this fiber-based swept-source terahertz radar could be used in real time to locate concealed moving live objects with high stability.

  12. Fiber based polarization filter for radially and azimuthally polarized light.

    Science.gov (United States)

    Jocher, Christoph; Jauregui, Cesar; Voigtländer, Christian; Stutzki, Fabian; Nolte, Stefan; Limpert, Jens; Tünnermann, Andreas

    2011-09-26

    We demonstrate a new fiber based concept to filter azimuthally or radially polarized light. This concept is based on the lifting of the modal degeneracy that takes place in high numerical aperture fibers. In such fibers, the radially and azimuthally polarized modes can be spectrally separated using a fiber Bragg grating. As a proof of principle, we filter azimuthally polarized light in a commercially available fiber in which a fiber Bragg grating has been written by a femtosecond pulsed laser. © 2011 Optical Society of America

  13. A stable fiber-based Fabry-Perot cavity

    CERN Document Server

    Steinmetz, T; Colombe, Y; Hunger, D; Hänsch, T W; Warburton, R J; Reichel, J

    2006-01-01

    We report the development of a fiber-based, tunable optical cavity with open access. The cavity is of the Fabry-Perot type and is formed with miniature spherical mirrors positioned on the end of single- or multi-mode optical fibers by a transfer technique which involves lifting a high-quality mirror from a smooth convex substrate, either a ball lens or micro-lens. The cavities typically have a finesse of $\\sim 1,000$ and a mode volume of 600 $\\mu$m$^3$. We demonstrate the detection of small ensembles of cold Rb atoms guided through such a cavity on an atom chip.

  14. All-plastic fiber-based pressure sensor.

    Science.gov (United States)

    Bundalo, Ivan-Lazar; Lwin, Richard; Leon-Saval, Sergio; Argyros, Alexander

    2016-02-01

    We present a feasibility study and a prototype of an all-plastic fiber-based pressure sensor. The sensor is based on long period gratings inscribed for the first time to the best of our knowledge by a CO2 laser in polymethyl methacrylate (PMMA) microstructured fibers and coupled to a pod-like transducer that converts pressure to strain. The sensor prototype was characterized for pressures up to 150 mbars, and various parameters related to its construction were also characterized in order to enhance sensitivity. We consider this sensor in the context of future applications in endoscopic pressure sensors.

  15. Tutorial on fiber-based sources for biophotonic applications

    Science.gov (United States)

    Taylor, James R.

    2016-06-01

    Fiber-based lasers and master oscillator power fiber amplifier configurations are described. These allow spectral versatility coupled with pulse width and pulse repetition rate selection in compact and efficient packages. This is enhanced through the use of nonlinear optical conversion in fibers and fiber-coupled nonlinear crystals, which can be integrated to provide all-fiber pump sources for diverse application. The advantages and disadvantages of sources based upon supercontinuum generation, stimulated Raman conversion, four-wave mixing, parametric generation and difference frequency generation, allowing spectral coverage from the UV to the mid-infrared, are considered.

  16. All-plastic fiber-based pressure sensor

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Lwin, Richard; Leon-Saval, Sergio

    2016-01-01

    We present a feasibility study and a prototype of an all-plastic fiber-based pressure sensor. The sensor is based on long period gratings inscribed for the first time to the best of our knowledge by a CO2 laser in polymethyl methacrylate (PMMA) microstructured fibers and coupled to a pod......-like transducer that converts pressure to strain. The sensor prototype was characterized for pressures up to 150 mbars, and various parameters related to its construction were also characterized in order to enhance sensitivity. We consider this sensor in the context of future applications in endoscopic pressure...... sensors....

  17. Design and prototyping of self-centering optical single-mode fiber alignment structures

    Science.gov (United States)

    Ebraert, Evert; Gao, Fei; Beri, Stefano; Watté, Jan; Thienpont, Hugo; Van Erps, Jürgen

    2016-06-01

    The European Commission’s goal of providing each European household with at least a 30 Mb s-1 Internet connection by 2020 would be facilitated by a widespread deployment of fibre-to-the-home, which would in turn be sped up by the development of connector essential components, such as high-precision alignment features. Currently, the performance of state-of-the-art physical contact optical fiber connectors is limited by the tolerance on the cladding of standard telecom-grade single-mode fiber (SMF), which is typically smaller than  ±1 μm. We propose to overcome this limit by developing micro-spring-based self-centering alignment structures (SCAS) for SMF-connectors. We design these alignment structures with robustness and low-cost replication in mind, allowing for large-scale deployment. Both theoretical and finite element analysis (FEA) models are used to determine the optimal dimensions of the beams of which the micro-springs of the SCAS are comprised. Two topologies of the SCAS, consisting of three and four micro-springs respectively, are investigated for two materials: polysulfone (PSU) and polyetherimide (PEI). These materials hold great potential for high-performance fiber connectors while being compatible with low-cost production and with the harsh environmental operation conditions of those connectors. The theory and FEA agree well (account in our theoretical model. Prototypes are successfully fabricated using deep proton writing and subsequently characterized. The controlled insertion of an SMF in the SCAS is investigated and we determine that a force of 0.11 N is required. The fiber insertion also causes an out-of-plane deformation of the micro-springs in the SCAS of about 7 μm, which is no problem for robustness according to the FEA model. Finally connector-assemblies are made with the alignment system and we show that an insertion loss down to 0.1 dB is achievable. The prototypes are subsequently used as a sacrificial master for mould

  18. Fabrication and characteristics of low loss and single-mode channel waveguides based on DNA-HCTAC biopolymer material

    Science.gov (United States)

    Zhang, Fei-yan; Wang, Zhen-yong; Yan, Cheng-en; Zhou, Jun

    2012-03-01

    A novel biopolymer, deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-HCTAC), is used as the core layer material in optical waveguide, and the cleanroom technology is successfully applied to fabricate the single-mode channel waveguides with low propagation loss. The prepared DNA-HCTAC material shows high optical quality at the optical telecommunication wavelengths, such as high transparency, relatively high refractive index and low birefringence. In the fabrication approach, polymethyl methacrylate (PMMA) is used as a barrier layer to protect the DNA-HCTAC material from the corrosive of photoresist developer, and the etching conditions are optimized to form the smooth wall and sharp cross-section of the waveguide. Lastly, the optical characteristics of DNA-HCTAC channel waveguides are measured. The results show that the DNA-HCTAC waveguide operates with single-mode propagation and has a low optical loss.

  19. Broadband single-mode operation of standard optical fibers by using a sub-wavelength optical wire filter.

    Science.gov (United States)

    Jung, Yongmin; Brambilla, Gilberto; Richardson, David J

    2008-09-15

    We report the use of a sub-wavelength optical wire (SOW) with a specifically designed transition region as an efficient tool to filter higher-order modes in multimode waveguides. Higher-order modes are effectively suppressed by controlling the transition taper profile and the diameter of the sub-wavelength optical wire. As a practical example, single-mode operation of a standard telecom optical fiber over a broad spectral window (400 approximately 1700 nm) was demonstrated with a 1microm SOW. The ability to obtain robust and stable single-mode operation over a very broad range of wavelengths offers new possibilities for mode control within fiber devices and is relevant to a range of application sectors including high performance fiber lasers, sensors, photolithography, and optical coherence tomography systems.

  20. Fabrication and characteristics of low loss and single-mode channel waveguides based on DNA-HCTAC biopolymer material

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fei-yan; WANG Zhen-yong; YAN Cheng-en; ZHOU Jun

    2012-01-01

    A novel biopolymer,deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-HCTAC),is used as the core layer material in optical waveguide,and the cleanroom technology is successfully applied to fabricate the single-mode channel waveguides with low propagation loss.The prepared DNA-HCTAC material shows high optical quality at the optical telecommunication wavelengths,such as high transparency,relatively high refractive index and low birefringence.In the fabrication approach,polymethyl methacrylate (PMMA) is used as a barrier layer to protect the DNA-HCTAC material from the corrosive ofphotoresist developer,and the etching conditions are optimized to form the smooth wall and sharp cross-section of the waveguide.Lastly,the optical characteristics of DNA-HCTAC channel waveguides are measured.The results show that the DNA-HCTAC waveguide operates with single-mode propagation and has a low optical loss.

  1. Measurement of the modal birefringence of single-mode K(+) ion-exchanged planar waveguides with polarimetric interferometry.

    Science.gov (United States)

    Qi, Z M; Itoh, K; Murabayashi, M

    2000-11-01

    The polarimetric interference pattern on the surface of single-mode planar waveguides made by potassium ion exchange in soda-lime glass substrates can be observed through a 45 degrees analyzer, which allows for the high-precision measurement of the modal birefringence of samples in a wide range of 0 to 5 x 10(-4). Using this method, believed to be new, we investigated the effects of exchange temperature and time on the modal birefringence of single-mode potassium ion-exchanged waveguides. The modal birefringence profile was achieved by measurement of the variation of the phase difference between the TE(0) and the TM(0) modes with hydrofluoric-acid-etching depth of the sample.

  2. Damage-free single-mode transmission of deep-UV light in hollow-core PCF

    CERN Document Server

    Gebert, F; Weiss, T; Wan, Y; Ermolov, A; Joly, N Y; Schmidt, P O; Russell, P St J

    2014-01-01

    Transmission of UV light with high beam quality and pointing stability is desirable for many experiments in atomic, molecular and optical physics. In particular, laser cooling and coherent manipulation of trapped ions with transitions in the UV require stable, single-mode light delivery. Transmitting even ~2 mW CW light at 280 nm through silica solid-core fibers has previously been found to cause transmission degradation after just a few hours due to optical damage. We show that photonic crystal fiber of the kagom\\'e type can be used for effectively single-mode transmission with acceptable loss and bending sensitivity. No transmission degradation was observed even after >100 hours of operation with 15 mW CW input power. In addition it is shown that implementation of the fiber in a trapped ion experiment significantly increases the coherence times of the internal state transfer due to an increase in beam pointing stability.

  3. Synthesis of the Einstein-Podolsky-Rosen entanglement in a sequence of two single-mode squeezers.

    Science.gov (United States)

    Fedorov, Ilya A; Ulanov, Alexander E; Kurochkin, Yury V; Lvovsky, A I

    2017-01-01

    We propose and implement a new scheme of generating the optical Einstein-Podolsky-Rosen entangled state. Parametric down-conversion in two nonlinear crystals, positioned back-to-back in the waist of a pump beam, produces single-mode squeezed vacuum states in orthogonal polarization modes; a subsequent beam splitting entangles them and generates the Einstein-Podolsky-Rosen state. The technique takes advantage of the strong nonlinearity associated with type-0 phase-matching configuration while, at the same time, eliminating the need for actively stabilizing the optical phase between the two single-mode squeezers. We demonstrate our method, preparing a 1.4 dB two-mode squeezed state and characterizing it via two-mode homodyne tomography.

  4. Laser Characteristics of Cladding-Pumped Short Er3+/yb3+ Codoped Single Mode Phosphate Glass Fibre

    Institute of Scientific and Technical Information of China (English)

    XU Shan-Hui; YANG Zhong-Min; XU Wen-Cheng; QIU Dong-Lai; ZHANG Qin-Yuan; JIANG Zhong-Hong

    2009-01-01

    We experimentally investigate the laser characteristics of a ser/es of short pieces of newly-developed Er3+/Yb3+ codoped single mode phosphate glass fibres via the cladding pump of a 976nm multimode laser diode. A stable continuous-wave single transverse mode laser with over 85 m W at 1553 nm is generated from a 5.5-cm-long active fibre. Single mode laser output power per unit length is up to 15 m W/cm. Moreover, the slope efficiency is 11.8% when the pump power is below 940mW and the 3dB linewidth is 0.06nm at the maximum pump power. The numerical simulation results show that the laser emission slope efficiency can exceed 20% by means of increasing the coupling efficiency of the pump to the fibre core further.

  5. Broadband robustly single-mode hollow-core PCF by resonant filtering of higher-order modes.

    Science.gov (United States)

    Uebel, Patrick; Günendi, Mehmet C; Frosz, Michael H; Ahmed, Goran; Edavalath, Nitin N; Ménard, Jean-Michel; Russell, Philip St J

    2016-05-01

    We report a hollow-core photonic crystal fiber that is engineered so as to strongly suppress higher-order modes, i.e., to provide robust LP01 single-mode guidance in all the wavelength ranges where the fiber guides with low loss. Encircling the core is a single ring of nontouching glass elements whose modes are tailored to ensure resonant phase-matched coupling to higher-order core modes. We show that the resulting modal filtering effect depends on only one dimensionless shape parameter, akin to the well-known d/Λ parameter for endlessly single-mode solid-core PCF. Fabricated fibers show higher-order mode losses some ∼100 higher than for the LP01 mode, with LP01 losses 110  THz bandwidth.

  6. Anisotropic anti-resonant elements gives broadband single-mode low-loss hollow-core fibers

    DEFF Research Database (Denmark)

    Habib, Selim; Bang, Ole; Bache, Morten

    2016-01-01

    Hollow-core fibers with node-free anisotropic anti-resonant elements give broadband low-loss fibers that are also single-moded. At 1.06 μm silica-based fiber designs show higher-order-mode extinction-ratio >1000 and losses below 10 dB/km over a broad wavelength range.......Hollow-core fibers with node-free anisotropic anti-resonant elements give broadband low-loss fibers that are also single-moded. At 1.06 μm silica-based fiber designs show higher-order-mode extinction-ratio >1000 and losses below 10 dB/km over a broad wavelength range....

  7. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres.

    Science.gov (United States)

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-06-24

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices.

  8. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres

    Science.gov (United States)

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-06-01

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices.

  9. Single mode step-index polymer optical fiber for humidity insensitive high temperature fiber Bragg grating sensors

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Stefani, Alessio;

    2016-01-01

    We have fabricated the first single-mode step-index and humidity insensitive polymer optical fiber operating in the 850 nm wavelength ranges. The step-index preform is fabricated using injection molding, which is an efficient method for cost effective, flexible and fast preparation of the fiber...... preform. The fabricated single-mode step-index (SI) polymer optical fiber (POF) has a 4.8µm core made from TOPAS grade 5013S-04 with a glass transition temperature of 134°C and a 150 µm cladding made from ZEONEX grade 480R with a glass transition temperature of 138°C. The key advantages of the proposed...... SIPOF are low water absorption, high operating temperature and chemical inertness to acids and bases and many polar solvents as compared to the conventional poly-methyl-methacrylate (PMMA) and polystyrene based POFs. In addition, the fiber Bragg grating writing time is short compared to microstructured...

  10. Stimulated Brillouin scattering in single-mode As(2)S(3) and As(2)Se(3) chalcogenide fibers.

    Science.gov (United States)

    Florea, Catalin; Bashkansky, Mark; Dutton, Zachary; Sanghera, Jasbinder; Pureza, Paul; Aggarwal, Ishwar

    2006-12-11

    Stimulated Brillouin scattering was investigated for the first time in As(2)S(3) single-mode fibers, and also in As(2)Se(3). The propagation loss and numerical aperture of the fibers at 1.56 mum, along with the threshold intensity for the stimulated Brillouin scattering process were measured. From the threshold values we estimate the Brillouin gain coefficient and demonstrate record figure of merit for slow-light based applications in chalcogenide fibers.

  11. Supercontinuum and four-wave mixing with Q-switched pulses in endlessly single-mode photonic crystal fibres.

    Science.gov (United States)

    Wadsworth, W; Joly, N; Knight, J; Birks, T; Biancalana, F; Russell, P

    2004-01-26

    Photonic crystal fibres exhibiting endlessly single-mode operation and dispersion zero in the range 1040 to 1100 nm are demonstrated. A sub-ns pump source at 1064 nm generates a parametric output at 732 nm with an efficiency of 35%, or parametric gain of 55 dB at 1315 nm. A broad, flat supercontinuum extending from 500 nm to beyond 1750 nm is also demonstrated using the same pump source.

  12. Fabrication of polarization-independent single-mode waveguides in lithium niobate crystal with femtosecond laser pulses

    CERN Document Server

    Qi, Jia; Liao, Yang; Chu, Wei; Liu, Zhengming; Wang, Zhaohui; Qiao, Lingling; Cheng, Ya

    2016-01-01

    We report on fabrication of depressed cladding optical waveguides buried in lithium niobate crystal with shaped femtosecond laser pulses. Depressed cladding waveguides of variable mode-field sizes are fabricated by forming the four sides of the cladding using a slit-beam shaping technique. We show that the waveguides fabricated by our technique allows single-mode propagation of the light polarized in both vertical and horizontal directions.

  13. Laser cutting of carbon fiber reinforced thermo-plastics (CFRTP) by single-mode fiber laser irradiation

    Science.gov (United States)

    Niino, Hiroyuki; Kawaguchi, Yoshizo; Sato, Tadatake; Narazaki, Aiko; Kurosaki, Ryozo; Muramatsu, Mayu; Harada, Yoshihisa; Anzai, Kenji; Aoyama, Mitsuaki; Matsushita, Masafumi; Furukawa, Koichi; Nishino, Michiteru; Fujisaki, Akira; Miyato, Taizo; Kayahara, Takashi

    2014-03-01

    We report on the laser cutting of carbon fiber reinforced thermo-plastics (CFRTP) with a cw IR fiber laser (single-mode fiber laser, average power: 350 W). CFRTP is a high strength composite material with a lightweight, and is increasingly being used various applications. A well-defined cutting of CFRTP which were free of debris and thermal-damages around the grooves, were performed by the laser irradiation with a fast beam galvanometer scanning on a multiple-scanpass method.

  14. Single-mode optical fiber design with wide-band ultra low bending-loss for FTTH application.

    Science.gov (United States)

    Watekar, Pramod R; Ju, Seongmin; Han, Won-Taek

    2008-01-21

    We propose a new design of a single-mode optical fiber (SMF) which exhibits ultra low bend sensitivity over a wide communication band (1.3 microm to 1.65 microm). A five-cladding fiber structure has been proposed to minimize the bending loss, estimated to be as low as 4.4x10(-10) dB/turn for the bend radius of 10 mm.

  15. Time-resolved particle image velocimetry measurements of the 3D single-mode Richtmyer-Meshkov instability

    Science.gov (United States)

    Xu, Qian; Krivets, Vitaliy V.; Sewell, Everest G.; Jacobs, Jeffrey W.

    2016-11-01

    A vertical shock tube is used to perform experiments on the single-mode three-dimensional Richtmyer-Meshkov Instability (RMI). The light gas (Air) and the heavy gas (SF6) enter from the top and the bottom of the shock tube driven section to form the interface. The initial perturbation is then generated by oscillating the gases vertically. Both gases are seeded with particles generated through vaporizing propylene glycol. An incident shock wave (M 1.2) impacts the interface to create an impulsive acceleration. The seeded particles are illuminated by a dual cavity 75W, Nd: YLF laser. Three high-speed CMOS cameras record time sequences of image pairs at a rate of 2 kHz. The initial perturbation used is that of a single, square-mode perturbation with either a single spike or a single bubble positioned at the center of the shock tube. The full time dependent velocity field is obtained allowing the determination of the circulation versus time. In addition, the evolution of time dependent amplitude is also determined. The results are compared with PIV measurements from previous two-dimensional single mode experiments along with PLIF measurements from previous three-dimensional single mode experiments.

  16. Design, fabrication and characterisation of nano-imprinted single mode waveguide structures for intra-chip optical communications

    Science.gov (United States)

    Justice, John; Khan, Umar; Korhonen, Tia; Boersma, Arjen; Wiegersma, Sjoukje; Karppinen, Mikko; Corbett, Brian

    2015-03-01

    In the Information and Communications Technology (ICT) sector, the demands on bandwidth continually grow due to increased microprocessor performance and the need to access ever increasing amounts of stored data. The introduction of optical data transmission (e.g. glass fiber) to replace electronic transmission (e.g. copper wire) has alleviated the bandwidth issue for communications over distances greater than 10 meters, however, the need has arisen for optical data transfer over shorter distances such as those found inside computers. A possible solution for this is the use of low-cost single mode polymer based optical waveguides fabricated by direct patterning Nanoimprint Lithography (NIL). NIL has emerged as a scalable manufacturing technology capable of producing features down to the hundred nanometer scale with the potential for large scale (roll-to-roll) manufacturing. In this paper, we present results on the modeling, fabrication and characterization of single mode waveguides and optical components in low-loss ORMOCER™ materials. Single mode waveguides with a mode field diameter of 7 μm and passive structures such as bends, directional couplers and multi-mode interferometers (MMIs) suitable for use in 1550 nm optical interconnects were fabricated using wafer scale NIL processes. Process issues arising from the nano-imprint technique such as residual layers and angled sidewalls are modeled and investigated for excess loss and higher order mode excitation. Conclusions are drawn on the applicability of nano-imprinting to the fabrication of circuits for intrachip/ board-level optical interconnect.

  17. Single mode wavelength control of modulated AlGaAs lasers with external and internal etalon feedback

    Science.gov (United States)

    Maynard, William L.

    1989-01-01

    Single mode lasing without mode hops has been obtained for VSIS and CSP laser diodes with an external etalon attached to the laser's front facet for up to an 8 C range CW and a 4 C range pulsed, with .07 nm/C tuning. Tests of thin tapered-thickness (TTT) laser diodes show CW and pulsed single mode lasing over 10 C and 2 C ranges, respectively, with .08 nm/C tuning. An analysis of the TTT structure reveals the equivalent of an internal etalon. The time-resolved pulsed behavior for both types of lasers show single mode lasing within the proper temperature ranges with minor modes present only early in the optical pulse, if at all. The external etalon produces noticeable interference fringes in the farfield pattern, while those of the TTT lasers are smooth. Ongoing CW lifetest results indicate stability to within one longitudinal mode after a few hundred hours of operation, along with at least several thousand hours lifetime.

  18. Comparison of epoxy- and siloxane-based single-mode optical waveguides defined by direct-write lithography

    Science.gov (United States)

    Elmogi, Ahmed; Bosman, Erwin; Missinne, Jeroen; Van Steenberge, Geert

    2016-02-01

    This paper reports on the fabrication and characterization of single-mode polymer optical waveguides at telecom and SOI compatible wavelengths; by making a comparison between an epoxy and a siloxane polymer waveguide material system (both commercially-available). The proposed waveguides can be used in short-reach optical interconnects targeting chip-to-chip communication on the interposer level or providing a coupling interface between single-mode optical fibers and photonic integrated circuits (PICs). This technology enables the integration of optoelectronic chips for photonic packaging purposes. First, the single-mode dimensions (4 × 4 μm2 and 5 × 5 μm2) for both materials at selected wavelengths (1.31 μm and 1.55 μm) were determined based on the refractive index measurements. Then, the waveguides were patterned by a direct-write lithography method. The fabricated waveguides show a high-quality surface with smooth sidewalls. The optical propagation losses were measured using the cut-back method. For the siloxane-based waveguides, the propagation losses were found to be 0.34 dB/cm and 1.36 dB/cm at 1.31 μm and 1.55 μm respectively while for the epoxy-based waveguides the losses were 0.49 dB/cm and 2.23 dB/cm at 1.31 μm and 1.55 μm respectively.

  19. A Flexible Fiber-Based Supercapacitor-Triboelectric-Nanogenerator Power System for Wearable Electronics.

    Science.gov (United States)

    Wang, Jie; Li, Xiuhan; Zi, Yunlong; Wang, Sihong; Li, Zhaoling; Zheng, Li; Yi, Fang; Li, Shengming; Wang, Zhong Lin

    2015-09-02

    A flexible self-charging power system is built by integrating a fiber-based supercapacitor with a fiber-based triboelectric nanogenerator for harvesting mechanical energy from human motion. The fiber-based supercapacitor exhibits outstanding electrochemical properties, owing to the excellent pseudocapacitance of well-prepared RuO2 ·xH2 O by a vapor-phase hydrothermal method as the active material. The approach is a step forward toward self-powered wearable electronics.

  20. Two-photon microscopy using fiber-based nanosecond excitation.

    Science.gov (United States)

    Karpf, Sebastian; Eibl, Matthias; Sauer, Benjamin; Reinholz, Fred; Hüttmann, Gereon; Huber, Robert

    2016-07-01

    Two-photon excitation fluorescence (TPEF) microscopy is a powerful technique for sensitive tissue imaging at depths of up to 1000 micrometers. However, due to the shallow penetration, for in vivo imaging of internal organs in patients beam delivery by an endoscope is crucial. Until today, this is hindered by linear and non-linear pulse broadening of the femtosecond pulses in the optical fibers of the endoscopes. Here we present an endoscope-ready, fiber-based TPEF microscope, using nanosecond pulses at low repetition rates instead of femtosecond pulses. These nanosecond pulses lack most of the problems connected with femtosecond pulses but are equally suited for TPEF imaging. We derive and demonstrate that at given cw-power the TPEF signal only depends on the duty cycle of the laser source. Due to the higher pulse energy at the same peak power we can also demonstrate single shot two-photon fluorescence lifetime measurements.

  1. Single-Mode Behaviour Judgment of Optical Waveguides by Imaginary-Distance Beam Propagation Method Under Perfectly Matched Layer Boundary Condition

    Institute of Scientific and Technical Information of China (English)

    LI Yan-Ping; YU Jin-Zhong; XIA Jin-Song; Chen Shao-Wu

    2004-01-01

    @@ Imaginary-distance beam propagation method under the perfectly matched layer boundary condition is applied to judge single-mode behaviour of optical waveguides, for the first time to our knowledge. A new kind of siliconon-insulator-based rib structures with half-circle cross-section is presented. The single-mode behaviour of this kind of waveguide with radius 2μm is investigated by this method. It is single-mode when the slab height is not smaller than the radius.

  2. 80-fs Nd:silicate glass laser pumped by a single-mode 200-mW diode.

    Science.gov (United States)

    Agnesi, Antonio; Greborio, Alessandro; Pirzio, Federico; Reali, Giancarlo

    2010-05-10

    A Nd(3+)-doped Schott LG680 silicate glass laser was pumped with a single-mode 200-mW diode. Efficient cw operation was demonstrated with 37.5 mW output power and 36% slope efficiency. Passive mode-locking with a semiconductor saturable absorber mirror yielded 80-fs pulses with a two-prism setup. Alternatively, pulses of approximately 200-fs, tunable over the range 1058-1076 nm, were obtained with either slit-tuning or a single-prism dispersive resonator. Output powers from 6 to 14 mW have been measured.

  3. 75 W 40% efficiency single-mode all-fiber erbium-doped laser cladding pumped at 976 nm.

    Science.gov (United States)

    Kotov, L V; Likhachev, M E; Bubnov, M M; Medvedkov, O I; Yashkov, M V; Guryanov, A N; Lhermite, J; Février, S; Cormier, E

    2013-07-01

    Optimization of Yb-free Er-doped fiber for lasers and amplifiers cladding pumped at 976 nm was performed in this Letter. The single-mode fiber design includes an increased core diameter of 34 μm and properly chosen erbium and co-dopant concentrations. We demonstrate an all-fiber high power laser and power amplifier based on this fiber with the record slope efficiency of 40%. To the best of our knowledge, the achieved output power of 75 W is the highest power reported for such lasers.

  4. Saving entangled photons from sudden death is a single-mode fiber --- Interplay of Decoherence and dynamical decoupling

    Science.gov (United States)

    Gupta, Manish Kumar; You, Chenglong; Dowling, Jonathan P.; Lee, Hwang

    2016-05-01

    We study the dynamics of decoherence in an optical fiber for the case of entangled photons. Such a study will allow us to increase the physical length of fiber for transmission of entangled photon from the sources such as SPDC. We analytically derive the model for Decoherence of entangled state photons in a single-mode fiber. We also show that entanglement lifetime can be increased for Bell state and Werner state with open loop control technique called Dynamical decoupling. The authors would like to acknowledge support from the Air Force Office of Scientific Research, the Army Research Office, the National Science Foundation and the Northrop Grumman Corporation.

  5. Output power spectrum of a single-mode laser driven by coloured pump and quantum noises with coloured correlation

    Institute of Scientific and Technical Information of China (English)

    Han Li-Bo; Cao Li; Wu Da-Jin

    2004-01-01

    By using the linear approximation method, the output power spectrum is calculated for a single-mode laser driven by coloured pump and quantum noises with coloured correlation. We have observed that the configuration of the output power spectrum is complicated: that is, it can be of single peak, two peaks or three peaks. The configurations of the power spectrum can be transformed from one into another by changing the cross-correlation time, the cross-correlation coefficient between the two noises, and pump noise intensity.

  6. Development of high-density single-mode polymer waveguides with low crosstalk for chip-to-chip optical interconnection.

    Science.gov (United States)

    Sugama, Akio; Kawaguchi, Kenichi; Nishizawa, Motoyuki; Muranaka, Hidenobu; Arakawa, Yasuhiko

    2013-10-01

    High-density single-mode polymer waveguides were fabricated for chip-to-chip optical interconnection. The waveguides were designed as minimized mode field diameters for the lowest inter-channel crosstalk caused by mode coupling. The optimum relative index difference chosen was 1.2% to ensure compatibility with low crosstalk and wide fabrication tolerances. The 60-mm-length linear waveguides demonstrated a low propagation loss of 0.6 dB/cm and -45 dB crosstalk at 1310 nm. Also, a new crosstalk mechanism for a curved waveguide was revealed.

  7. One-Wave Optical Phase Conjugation Mirror by Actively Coupling Arbitrary Light Fields into a Single-Mode Reflector

    Science.gov (United States)

    Lee, KyeoReh; Lee, Junsung; Park, Jung-Hoon; Park, Ji-Ho; Park, YongKeun

    2015-10-01

    Rewinding the arrow of time via phase conjugation is an intriguing phenomenon made possible by the wave property of light. Here, we demonstrate the realization of a one-wave optical phase conjugation mirror using a spatial light modulator. An adaptable single-mode filter is created, and a phase-conjugate beam is then prepared by reverse propagation through this filter. Our method is simple, alignment free, and fast while allowing high power throughput in the time-reversed wave, which has not been simultaneously demonstrated before. Using our method, we demonstrate high throughput full-field light delivery through highly scattering biological tissue and multimode fibers, even for quantum dot fluorescence.

  8. Stochastic resonance in a single-mode laser driven by quadratic Pump noise and amplitude-modulated signal

    Institute of Scientific and Technical Information of China (English)

    Zhang Li

    2009-01-01

    This paper investigates the phenomenon of stochastic resonance in a single-mode laser driven by quadratic pump noise and amplitude-modulated signal.A new linear approximation approach is advanced to calculate the signal-to-noise ratio.In the linear approximation only the drift term is linearized,the multiplicative noise term is unchangeable.It is found that there appears not only the standard form of stochastic resonance but also the broad sense of stochastic resonance,especially stochastic multiresonance appears in the curve of signal-to-noise ratio as a function of coupling strength λ between the real and imaginary parts of the pump noise.

  9. Stable single-mode operation of injection-seeded Q-switched Nd:YAG laser by sine voltage modulation

    Institute of Scientific and Technical Information of China (English)

    Yongfei Gao; Junxuan Zhang; Huaguo Zang; Xiaolei Zhu; Yingjie Yu; Weibiao Chen

    2016-01-01

    Based on the modified ramp and fire technique,a novel injection seeding approach with real-time resonance tracking is successfully demonstrated in a single-frequency Nd:YAG pulsed laser.Appling a high-frequency sinusoidal modulation voltage to one piezo actuator and an adjustable DC voltage to another piezo actuator for active feedback,single-mode laser output with high-frequency stability is obtained,and the effect of the piezo hysteresis on the frequency stability can be eliminated for a laser diode pumped Q-switched Nd:YAG laser at a repetition rate of 400 Hz.

  10. Transmission test in connection of different types of optical fibers: a dispersion-shifted single-mode optical fiber (DSF) and a single-mode optical fiber (SM); DSF-SM ishu hikari fiber setsuzoku ni okeru denso shiken

    Energy Technology Data Exchange (ETDEWEB)

    Uemura, J. [Chugoku Electric Power Co. Inc., Hiroshima (Japan)

    1998-08-25

    The currently used optical transmission system usually uses a single-mode optical fiber (SM) with 1.3 {mu} m band. For sections requiring long-distance transmission, a dispersion-shifted single-mode optical fiber (DSF) with 1.55 {mu} m band is beginning to be partly used. If, in using these fibers, the different types of optical fibers, SM and DSF, can be used directly connected with each other, structuring an economical optical communication network including the existing SM fibers may become possible. This paper describes measurements of connection loss between the different optical fibers of DSF and SM, a transmission test on the connection between the different optical fibers of DSF and SM by using an amplifier for optical fibers used in an actual field, and an optical wave multiplex transmission test. The measurements and the tests were carried out in winter and summer of 1997 by using the existing OPGW optical fibers among the Okayama substation, the Higashi-Okayama substation, and the Susai substation. The connection between the different optical fibers of DSF and SM generates greater connection loss than in connection with the same type of fibers due to difference in the mode field diameters. Therefore, it will be necessary in constituting an optical fiber line to incorporate connection loss of about 1 to 2 dB in connector connection and about 0.5 to 1 dB in welding connection. 1 ref., 17 figs., 7 tabs.

  11. Validation of measured microwave absorption and temperature change for development of a single-mode-type microwave heating thermogravimetry apparatus

    Science.gov (United States)

    Karisma, Achmad Dwitama; Hamaba, Taishu; Fukasawa, Tomonori; Huang, An-Ni; Segawa, Tomoomi; Fukui, Kunihiro

    2017-02-01

    The temperature distribution, microwave absorption efficiency, and dielectric properties of a copper (ii) oxide (CuO) pellet heated by microwave irradiation were investigated for use in developing a single-mode-type microwave heating thermogravimetry apparatus. The validity of the apparatus was confirmed by comparing the measured data with the results of numerical simulations. The dielectric properties and error margins of other parameters estimated using the apparatus were also examined. The temperature distribution of the CuO pellet was observed to decrease monotonously on moving from the outlet to the inlet side of the apparatus. A three-dimensional numerical simulation of the electromagnetic field accurately reproduced this temperature distribution, suggesting the one-way movement of microwaves in the single-mode-type microwave apparatus. The numerically determined dependency of the CuO absorption efficiency was also found to be in very good agreement with published data. The same was the case with the permittivity loss of the CuO at various temperatures, as estimated from the measured microwave absorption efficiency. However, a larger error was observed in the estimation of the permittivity loss of a material with a lower microwave absorption efficiency, which was apparently due to the measurement error of the absorption efficiency of such a material.

  12. A Sensitivity-Enhanced Refractive Index Sensor Using a Single-Mode Thin-Core Fiber Incorporating an Abrupt Taper

    Directory of Open Access Journals (Sweden)

    Jie Shi

    2012-04-01

    Full Text Available A sensitivity-enhanced fiber-optic refractive index (RI sensor based on a tapered single-mode thin-core diameter fiber is proposed and experimentally demonstrated. The sensor head is formed by splicing a section of tapered thin-core diameter fiber (TCF between two sections of single-mode fibers (SMFs. The cladding modes are excited at the first SMF-TCF interface, and then interfere with the core mode at the second interface, thus forming an inter-modal interferometer (IMI. An abrupt taper (tens of micrometers long made by the electric-arc-heating method is utilized, and plays an important role in improving sensing sensitivity. The whole manufacture process only involves fiber splicing and tapering, and all the fabrication process can be achieved by a commercial fiber fusion splicer. Using glycerol and water mixture solution as an example, the experimental results show that the refractive index sensitivity is measured to be 0.591 nm for 1% change of surrounding RI. The proposed sensor structure features simple structure, low cost, easy fabrication, and high sensitivity.

  13. Single-mode large-mode-area laser fiber with ultralow numerical aperture and high beam quality.

    Science.gov (United States)

    Peng, Kun; Zhan, Huan; Ni, Li; Wang, Xiaolong; Wang, Yuying; Gao, Cong; Li, Yuwei; Wang, Jianjun; Jing, Feng; Lin, Aoxiang

    2016-12-10

    By using the chelate precursor doping technique, we report on an ytterbium-doped aluminophosphosilicate (APS) large-mode-area fiber with ultralow numerical aperture of 0.036 and effective fundamental mode area of ∼550  μm2. With a bend diameter of 600 mm, the bending loss of fundamental mode LP01 was measured to be -3  dB/m, in agreement with the corresponding simulation results, while that of higher order mode LP11 is >100  dB/m at 1080 nm. Measured in an all-fiber oscillator laser cavity, 592 W single-mode laser output was obtained at 1079.64 nm with high-beam quality M2 of 1.12. The results indicate that the chelate precursor doping technique is a competitive method for ultralow numerical aperture fiber fabrication, which is very suitable for developing single-mode seed lasers for high power laser systems.

  14. Observing Exoplanets with High-dispersion Coronagraphy. II. Demonstration of an Active Single-mode Fiber Injection Unit

    Science.gov (United States)

    Mawet, D.; Ruane, G.; Xuan, W.; Echeverri, D.; Klimovich, N.; Randolph, M.; Fucik, J.; Wallace, J. K.; Wang, J.; Vasisht, G.; Dekany, R.; Mennesson, B.; Choquet, E.; Delorme, J.-R.; Serabyn, E.

    2017-04-01

    High-dispersion coronagraphy (HDC) optimally combines high-contrast imaging techniques such as adaptive optics/wavefront control plus coronagraphy to high spectral resolution spectroscopy. HDC is a critical pathway toward fully characterizing exoplanet atmospheres across a broad range of masses from giant gaseous planets down to Earth-like planets. In addition to determining the molecular composition of exoplanet atmospheres, HDC also enables Doppler mapping of atmosphere inhomogeneities (temperature, clouds, wind), as well as precise measurements of exoplanet rotational velocities. Here, we demonstrate an innovative concept for injecting the directly imaged planet light into a single-mode fiber, linking a high-contrast adaptively corrected coronagraph to a high-resolution spectrograph (diffraction-limited or not). Our laboratory demonstration includes three key milestones: close-to-theoretical injection efficiency, accurate pointing and tracking, and on-fiber coherent modulation and speckle nulling of spurious starlight signal coupling into the fiber. Using the extreme modal selectivity of single-mode fibers, we also demonstrated speckle suppression gains that outperform conventional image-based speckle nulling by at least two orders of magnitude.

  15. Single-mode surface-emitting distributed feedback quantum-cascade lasers based on hybrid waveguide structure

    Institute of Scientific and Technical Information of China (English)

    Wanhong Guo; Junqi Liu; Jianyan Chen; Lu Li; Lijun Wang; Fengqi Liu; Zhanguo Wang

    2011-01-01

    Surface-emitting distributed feedback quantum-cascade lasers operating at λ≈7.8 μm are demonstrated.The metal-covered second-order grating is shallow-etched into the surface of a thin InGaAs contact and cladding layer. This forms a hybrid waveguide and used to achieve relatively low waveguide losses and high coupling strengths. The devices exhibit stable single-mode operation from 90 to 130 K with a side mode suppression ratio above 20 dB. A slope efficiency of 194 mW/A is obtained at 90 K, which is twice higher than that of the Fabry-Perot counterpart.%@@ Surface-emitting distributed feedback quantum-cascade lasers operating at λ≈7.8 μm are demonstrated.The metal-covered second-order grating is shallow-etched into the surface of a thin InGaAs contact and cladding layer.This forms a hybrid waveguide and used to achieve relatively low waveguide losses and high coupling strengths.The devices exhibit stable single-mode operation from 90 to 130 K with a side mode suppression ratio above 20 dB.A slope efficiency of 194 mW/A is obtained at 90 K, which is twice higher than that of the Fabry-Perot counterpart.

  16. InGaAsP/InP laser development for single-mode, high-data-rate communications

    Science.gov (United States)

    Ladany, I.; Levin, E. R.; Magee, C. W.; Smith, R. T.

    1981-01-01

    Materials studies as well as general and specific device development were carried out in the InGaAsP system. A comparison was made of three standard methods of evaluating substrate quality by means of dislocation studies. A cause of reduced yield of good wafers, the pullover of melt from one bin to the next, has been analyzed. Difficulties with reproducible zinc acceptor doping have been traced to segregation of zinc in the In/Zn alloy used for the doping source. Using EBIC measurments, the pn junction was shown to drift in location depending on factors not always under control. An analysis of contact structures by SIMS showed that the depth to which the sintered Au/Zn contact penetrates into the structure is typically 0.13 microns, or well within the cap layer and out of the p-type cladding and thus not deleterious to laser prformance. The problem of single-mode laser development was investigated and it was shown to be related to the growth habit over four different possible substrate configurations. The fabrication of constricted double heterojunctions, mesa stripe buried heterostructures, and buried heterostructures was discussed, and measurements were presented on the device properties of single-mode buried heterostructure lasers. Results include single spectral line emission at 3 mW and a threshold current of 60 mA.

  17. Single-mode SOA-based 1kHz-linewidth dual-wavelength random fiber laser.

    Science.gov (United States)

    Xu, Yanping; Zhang, Liang; Chen, Liang; Bao, Xiaoyi

    2017-07-10

    Narrow-linewidth multi-wavelength fiber lasers are of significant interests for fiber-optic sensors, spectroscopy, optical communications, and microwave generation. A novel narrow-linewidth dual-wavelength random fiber laser with single-mode operation, based on the semiconductor optical amplifier (SOA) gain, is achieved in this work for the first time, to the best of our knowledge. A simplified theoretical model is established to characterize such kind of random fiber laser. The inhomogeneous gain in SOA mitigates the mode competition significantly and alleviates the laser instability, which are frequently encountered in multi-wavelength fiber lasers with Erbium-doped fiber gain. The enhanced random distributed feedback from a 5km non-uniform fiber provides coherent feedback, acting as mode selection element to ensure single-mode operation with narrow linewidth of ~1kHz. The laser noises are also comprehensively investigated and studied, showing the improvements of the proposed random fiber laser with suppressed intensity and frequency noises.

  18. On-chip coherent combining of angled-grating diode lasers toward bar-scale single-mode lasers.

    Science.gov (United States)

    Zhao, Yunsong; Zhu, Lin

    2012-03-12

    Single mode operation of broad-area diode lasers, which is the key to obtain high power, high brightness sources, is difficult due to highly nonlinear materials and strong coupling between gain and index. Conventional broad-area lasers usually operate with multiple modes and have poor beam quality. Laser bars usually consist of incoherently combined broad-area single emitters placed side by side. In this article, we have demonstrated a novel integrated laser architecture in which Bragg diffraction is used to realize simultaneous modal control and coherent combining of broad-area diode lasers. Our experimental results show that two 100 μm wide, 1.3mm long InP broad-area lasers provide near-diffraction-limited output beam and are coherently combined at the same time without any external optical components. Furthermore, our design can be expanded to a coherently combined broad-area laser array that turns a laser bar into a coherent single mode laser with diffraction-limited beam quality.

  19. Broad-band robustly single-mode hollow-core PCF by resonant filtering of higher order modes

    CERN Document Server

    Günendi, Mehmet C; Frosz, Michael H; Russell, Philip St J

    2015-01-01

    We propose and theoretically analyse a novel hollow-core photonic crystal fibre (PCF) that is engineered so as to strongly suppress higher order modes, i.e., to provide robust LP$_{01}$ single-mode guidance in all the wavelength ranges where the fibre guides with low loss. Encircling the core is a single ring of non-touching glass elements whose modes are tailored to ensure resonant phase-matched coupling to higher-order core modes, causing them to leak at a very high rate into the supporting solid glass sheath. Using a model based on coupled capillary waveguides, as well as full vectorial finite element modelling, we show that this modal filtering effect depends on only one dimensionless geometrical parameter, akin to the well-known $d/{\\Lambda}$ parameter for endlessly single-mode solid-core PCF. The design is scalable up to large core sizes and is predicted to deliver LP$_{01}$ mode losses of some $10$s of dB/km in multiple transmission windows, the broadest of which spans more than an octave. At the same ...

  20. Unified Scattering Parameters formalism in terms of Coupled-Mode Theory for investigating hybrid single-mode/two-mode photonic interconnects

    Directory of Open Access Journals (Sweden)

    Boucher Yann G.

    2017-01-01

    Full Text Available In terms of Linear Algebra, a directional coupler between a single-mode waveguide and a two-mode waveguide can be thought of as formally equivalent to a set of three mutually coupled single-mode waveguides. Its responses, easily derived in the frame of ternary Coupled-Mode Theory, are used to establish analytically the scattering parameters of a hybrid ring-based modal multiplexer.

  1. Unified Scattering Parameters formalism in terms of Coupled-Mode Theory for investigating hybrid single-mode/two-mode photonic interconnects

    Science.gov (United States)

    Boucher, Yann G.; Parini, Alberto; Féron, Patrice

    2017-03-01

    In terms of Linear Algebra, a directional coupler between a single-mode waveguide and a two-mode waveguide can be thought of as formally equivalent to a set of three mutually coupled single-mode waveguides. Its responses, easily derived in the frame of ternary Coupled-Mode Theory, are used to establish analytically the scattering parameters of a hybrid ring-based modal multiplexer.

  2. New fiber-based approaches for optical biopsy (Conference Presentation)

    Science.gov (United States)

    Weber, Jessie R.; Rivière, Christophe; Proulx, Antoine; Gallant, Pascal; Mermut, Ozzy

    2017-02-01

    Optical biopsy of tissue using fiber optic probes has proven to be a powerful tool for non-invasive and minimally invasive diagnostics. However, there are still many challenges to improving diagnostic value and commercial translation of these techniques. Many fiber-based methods are limited by background noise, which impairs sensitivity and specificity. Aspects of quality control, such as adequacy of the target of interest sampled and validation of optical measurements with histopathology can be problematic. Complexity, cost, and disposability or sterilizability are roadblocks to widespread clinical use. Here, we present new approaches to using fibers for optical biopsy aimed at solving these problems. Specifically, the new concepts are designed with the goals of being simple and disposable, to improve control of light delivery and collection from the sample, and to inherently enable better quality control of the biopsy process. A concept-of-operation aimed at nearly zero impact to the work flow of the biopsy and standard pathology procedures will be outlined. Several concepts for fiber implementations will be presented. A trade-off analysis of the concepts used to select a first implementation for testing will be presented. Preliminary experimental validation in phantoms and tissue samples will be presented for the selected configuration.

  3. Dataset on photonic crystal fiber based chemical sensor.

    Science.gov (United States)

    Ahmed, Kawsar; Paul, Bikash Kumar; Chowdhury, Sawrab; Islam, Md Shadidul; Sen, Shuvo; Islam, Md Ibadul; Asaduzzaman, Sayed; Bahar, Ali Newaz; Miah, Mohammad Badrul Alam

    2017-06-01

    This article represents the data set of micro porous core photonic crystal fiber based chemical sensor. The suggested structure is folded cladding porous shaped with circular air hole. Here is investigated four distinctive parameters including relative sensitivity, confinement loss, numerical aperture (NA), and effective area (Aeff). The numerical outcomes are computed over the E+S+C+L+U communication band. The useable sensed chemicals are methanol, ethanol, propanol, butanol, and pentanol whose are lies in the alcohol series (Paul et al., 2017) [1]. Furthermore, V-parameter (V), Marcuse spot size (MSS), and beam divergence (BD) are also investigated rigorously. All examined results have been obtained using finite element method based simulation software COMSOL Multiphysics 4.2 versions with anisotropic circular perfectly matched layer (A-CPML). The proposed PCF shows the high NA from 0.35 to 0.36; the low CL from ~10(-11) to ~10(-7) dB/m; the high Aeff from 5.50 to 5.66 µm(2); the MSS from 1.0 to 1.08 µm; the BD from 0.43 to 0.46 rad at the controlling wavelength λ = 1.55 µm for employing alcohol series respectively.

  4. Dataset on photonic crystal fiber based chemical sensor

    Directory of Open Access Journals (Sweden)

    Kawsar Ahmed

    2017-06-01

    Full Text Available This article represents the data set of micro porous core photonic crystal fiber based chemical sensor. The suggested structure is folded cladding porous shaped with circular air hole. Here is investigated four distinctive parameters including relative sensitivity, confinement loss, numerical aperture (NA, and effective area (Aeff. The numerical outcomes are computed over the E+S+C+L+U communication band. The useable sensed chemicals are methanol, ethanol, propanol, butanol, and pentanol whose are lies in the alcohol series (Paul et al., 2017 [1]. Furthermore, V-parameter (V, Marcuse spot size (MSS, and beam divergence (BD are also investigated rigorously. All examined results have been obtained using finite element method based simulation software COMSOL Multiphysics 4.2 versions with anisotropic circular perfectly matched layer (A-CPML. The proposed PCF shows the high NA from 0.35 to 0.36; the low CL from ~10–11 to ~10−7 dB/m; the high Aeff from 5.50 to 5.66 µm2; the MSS from 1.0 to 1.08 µm; the BD from 0.43 to 0.46 rad at the controlling wavelength λ = 1.55 µm for employing alcohol series respectively.

  5. Efficient single-mode operation of a cladding-pumped ytterbium-doped helical-core fiber laser.

    Science.gov (United States)

    Wang, P; Cooper, L J; Sahu, J K; Clarkson, W A

    2006-01-15

    A novel approach to achieving robust single-spatial-mode operation of cladding-pumped fiber lasers with multimode cores is reported. The approach is based on the use of a fiber geometry in which the core has a helical trajectory within the inner cladding to suppress laser oscillation on higher-order modes. In a preliminary proof-of-principle study, efficient single-mode operation of a cladding-pumped ytterbium-doped helical-core fiber laser with a 30 microm diameter core and a numerical aperture of 0.087 has been demonstrated. The laser yielded 60.4 W of output at 1043 nm in a beam with M2 diode stack at 976 nm. The slope efficiency at pump powers well above threshold was approximately 84%, which compares favorably with the slope efficiencies achievable with conventional straight-core Yb-doped double-clad fiber lasers.

  6. Demonstration of ultra-broadband single-mode and single-polarization operation in T-Guides

    CERN Document Server

    Chiles, Jeff

    2016-01-01

    Silica-based anchored-membrane waveguides (T-Guides) are fabricated and characterized from the visible to infrared with streak imaging. It is numerically shown that the T-Guides can have wideband single-mode and single-polarization (SMSP) properties over a span of 2.6 octaves. Experimentally, a polarization-dependent loss difference of up to 90 dB/cm is measured between orthogonal polarizations, and a record SMSP window of >1.27 octaves is observed, limited only by the available measurement equipment. These measurements make a strong case for T-Guides for SMSP photonics, particularly on high-index materials such as our previous demonstration on silicon.

  7. Demonstration of ultra-broadband single-mode and single-polarization operation in T-Guides.

    Science.gov (United States)

    Chiles, Jeff; Fathpour, Sasan

    2016-08-15

    Silica-based anchored-membrane waveguides (T-Guides) are fabricated and characterized from the visible to infrared with streak imaging. It is numerically shown that the T-Guides can have wideband single-mode and single-polarization (SMSP) properties over a span of 2.6 octaves. Experimentally, a polarization-dependent loss difference of up to 89±19 dB/cm is measured between orthogonal polarizations and a record SMSP window of >1.27 octaves is observed, limited only by the available measurement equipment. These measurements make a strong case for T-Guides for SMSP photonics, particularly in high-index materials such as those in our previous demonstration on silicon.

  8. High-temperature sensor based on an abrupt-taper Michelson interferometer in single-mode fiber.

    Science.gov (United States)

    Xu, Le; Jiang, Lan; Wang, Sumei; Li, Benye; Lu, Yongfeng

    2013-04-01

    This study proposes a high-temperature sensor based on an abrupt fiber-taper Michelson interferometer (FTMI) in single-mode fiber fabricated by a fiber-taper machine and electric-arc discharge. The proposed FTMI is applied to measure temperature and refractive index (RI). A high temperature sensitivity of 118.6 pm/°C is obtained in the temperature range of 500°C-800°C. The wavelength variation is only -0.335 nm for the maximum attenuation peak, with the external RI changed from 1.333 to 1.3902, which is desirable for high-temperature sensing to eliminate the cross sensitivity to RI.

  9. Attaining m s-1 level intrinsic Doppler precision with RHEA, a low-cost single-mode spectrograph

    Science.gov (United States)

    Feger, Tobias; Ireland, Michael J.; Schwab, Christian; Bento, Joao; Bacigalupo, Carlos; Coutts, David W.

    2016-08-01

    We present RHEA, a compact and inexpensive single-mode spectrograph which is built to exploit the capabilities of modest-sized telescopes in an economic way. The instrument is fed by up to seven optical waveguides with the aim of achieving an efficient and modal-noise-free unit, suitable for attaining extreme Doppler precision. The cross-dispersed layout features a wavelength coverage from 430-650 nm, with spectral resolution of R ˜75,000. When coupled to small telescopes using fast tip/tilt control, our instrument is well-suited to sensitive spectroscopy. Example science cases are accurate radial velocity studies of low to intermediate-mass giant stars with the purpose of searching for giant plants and using asteroseismology to simultaneously measure the host star parameters. In this paper we describe the final instrument design and present first results from testing the internal stability.

  10. Q-switching and efficient harmonic generation from a single-mode LMA photonic bandgap rod fiber laser

    DEFF Research Database (Denmark)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas T.;

    2011-01-01

    with a Mode-Field-Diameter (MFD) of 59 mu m. We further demonstrate high pulse energy Second-Harmonic-Generation (SHG) and Third Harmonic Generation (THG) using a simple Q-switched single-stage rod fiber laser cavity architecture reaching pulse energies up to 1mJ at 515nm and 0.5mJ at 343nm. (C) 2011 Optical......We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode...

  11. Q-switching and efficient harmonic generation from a single-mode LMA photonic bandgap rod fiber laser.

    Science.gov (United States)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas T; Scolari, Lara; Cocquelin, Benjamin; Salin, Francois; Broeng, Jes; Lægsgaard, Jesper

    2011-05-23

    We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode with a Mode-Field-Diameter (MFD) of 59μm. We further demonstrate high pulse energy Second-Harmonic-Generation (SHG) and Third Harmonic Generation (THG) using a simple Q-switched single-stage rod fiber laser cavity architecture reaching pulse energies up to 1mJ at 515nm and 0.5mJ at 343nm.

  12. All-fiber 194 W single-frequency single-mode Yb-doped master-oscillator power-amplifier

    Science.gov (United States)

    Mermelstein, M. D.; Brar, K.; Andrejco, M. J.; Yablon, A. D.; Fishteyn, M.; Headley, C., III; DiGiovanni, D. J.

    2008-02-01

    A four-stage all-fiber single-frequency single-mode continuous-wave (cw) master-oscillator power-amplifier (MOPA) at 1083 nm is presented. Small mode area (SMA) and large mode area (LMA) amplifier stages are mode matched with a fiber mode converter (MC) and the signal and pumps are combined with tapered fiber bundles (TFBs). The final power stage uses a LMA Yb doped SBS-suppressing fiber. A single-frequency output power of 194 W is demonstrated with optical net and slope efficiencies of 73% and 80%, respectively. Numerical simulations for the signal output power and the SBS-induced Stokes backscattered power in the 4th stage amplifier agree with the experimental results. Pulse amplifier measurements showed a 400 W peak power output that was limited by the forward output ASE. The SBS reflectivity at 400 W output was only 2.75 x 10 -4.

  13. Production of Squeezed State of Single Mode Cavity Field by the Coupling of Squeezed Vacunm Field Reservoir in Nonautonomous Case

    Institute of Scientific and Technical Information of China (English)

    安钧鸿; 王顺金; 罗洪刚; 贾成龙

    2004-01-01

    The dissipative and decoherence properties as well as the asymptotic behaviour of the single mode electromagnetic field interacting with the time-dependent squeezed vacuum field reservoir are investigated in detail by using the algebraic dynamical method. With the help of the left and right representations of the relevant hw( 4) algebra, the dynamical symmetry of the nonautonomous master equation of the system is found to be su(1, 1). The unique equilibrium steady solution is found to be the squeezed state and any initial state of the system is proven to approach the unique squeezed state asymptotically. Thus the squeezed vacuum field reservoir is found to play the role of a squeezing mold of the cavity field.

  14. Unconventional Geometric Phase-Shift Gates Based on Superconducting Quantum Interference Devices Coupled to a Single-Mode Cavity

    Institute of Scientific and Technical Information of China (English)

    SONG Ke-Hui; ZHOU Zheng-Wei; GUO Guang-Can

    2006-01-01

    We present a scheme to realize geometric phase-shift gate for two superconducting quantum interference device (SQUID) qubits coupled to a single-mode microwave field. The geometric phase-shift gate operation is performed transitions during the gate operation. Thus, the docoherence due to energy spontaneous emission based on the levels of SQUIDs are suppressed. The gate is insensitive to the cavity decay throughout the operation since the cavity mode is displaced along a circle in the phase space, acquiring a phase conditional upon the two lower flux states of the SQUID qubits, and the cavity mode is still in the original vacuum state. Based on the SQUID qubits interacting with the cavity mode, our proposed approach may open promising prospects for quantum logic in SQUID-system.

  15. Femtosecond laser direct writing of single mode polymer micro ring laser with high stability and low pumping threshold.

    Science.gov (United States)

    Parsanasab, Gholam-Mohammad; Moshkani, Mojtaba; Gharavi, Alireza

    2015-04-01

    We have demonstrated an optically pumped polymer microring laser fabricated by two photon polymerization (TPP) of SU-8. The gain medium is an organic dye (Rhodamine B) doped in SU-8, and the laser cavity is a double coupled microring structure. Single mode lasing was obtained from the two coupled rings each with 30 µm and 29 µm radii using Vernier effect. Low laser threshold of 0.4 µJ/mm(2) is achieved using 1 µm wide polymer waveguides and the quality factor is greater than 10(4) at 612.4 nm wavelength. The lasing remained stable with pump energies from threshold to energies as high as 125 times the threshold.

  16. ANALYTICAL EXPRESSION FOR THE ELECTRIC FIELD OF THE SINGLE MODE LASER HOMOGENEOUS BROADENING IN THE PULSE REGIME

    Directory of Open Access Journals (Sweden)

    S. Ayadi

    2015-07-01

    Full Text Available The simplest model of the laser is that of a single mode system homogenously broadened. The dynamical behavior of this laser is described by three differential equations, called Haken-Lorenz equations[1],  similar to the Lorenz model [1] already known to predict deterministic chaos. In previous recent work [5-7] we have proposed a simple harmonic expansion method to obtain a series of harmonics terms that yield analytical solutions to the laser equations. ¶This method allows us to derive an analytical expression of the laser field amplitude  when this last  undergoes a  periodic oscillations around zero mean value. We also obtain an analytical expression of the pulsing frequency.

  17. Integrated photonic building blocks for next-generation astronomical instrumentation II: the multimode to single mode transition

    CERN Document Server

    Spaleniak, Izabela; Gross, Simon; Ireland, Michael J; Lawrence, Jon S; Withford, Michael J

    2013-01-01

    There are numerous advantages to exploiting diffraction-limited instrumentation at astronomical observatories, which include smaller footprints, less mechanical and thermal instabilities and high levels of performance. To realize such instrumentation it is imperative to convert the atmospheric seeing-limited signal that is captured by the telescope into a diffraction-limited signal. This process can be achieved photonically by using a mode reformatting device known as a photonic lantern that performs a multimode to single-mode transition. With the aim of developing an optimized integrated photonic lantern, we undertook a systematic parameter scan of devices fabricated by the femtosecond laser direct-write technique. The devices were designed for operation around 1.55 {\\mu}m. The devices showed (coupling and transition) losses of less than 5% for F/# $\\geq$ 12 injection and the total device throughput (including substrate absorption) as high as 75-80%. Such devices show great promise for future use in astronom...

  18. Bifurcations, basin erosion and dynamic integrity in a single-mode model of noncontact atomic force microscopy

    Directory of Open Access Journals (Sweden)

    Settimi V.

    2012-07-01

    Full Text Available The nonlinear dynamical behavior of a single-mode model of noncontact AFM is analyzed in terms of attractors robustness and basin integrity. The model considered for the analyses, proposed by Hornstein and Gottlieb [7], consistently includes the nonlinear atomic interaction and the scan control, which appears as parametric excitation. Local bifurcation analyses are carried out to define the overall stability boundary in the excitation parameter space as the envelope of system local escapes, to be compared with the one obtained via numerical simulations. The dynamical integrity of the periodic bounded solutions is studied, and basin erosion is evaluated by means of IF and GIM integrity measures. The obtained erosion profiles allow us to dwell on the possible lack of homogeneous safeness of the stability boundary in terms of attractors robustness and to identify practical escape thresholds ensuring an a priori design safety target.

  19. Generation of Flat Supercontinuum in a Single-mode Optical Fiber with a Convex Chromatic Dispersion Profile

    Institute of Scientific and Technical Information of China (English)

    XU Yong-zhao; WANG Hong-chen; ZHOU Shou-li

    2009-01-01

    A single-mode optical fiber with a convex chromatic dispersion profile is proposed for generating a flat supercontinuum(SC). The fiber has normal dispersion and the dispersion parameter D(λ,z) is a convex function of wavelengths. It is shown from the numerical results that the chromatic dispersion, the flatness of the dispersion curve and the pump conditions have significant effect on SC generation. A flat and broad SC without strong residual pump component can be obtained when the pump wavelength is set in the vicinity of the wavelength at which the fiber has small normal group-velocity dispersion(GVD) and small dispersion slope. The fiber with a smaller normal GVD, a flatter dispersion profile and a higher nonlinear coefficient are more suitable for broad SC generation.

  20. Design of a High-Nonlinearity Single-Mode Holey Fiber with Flattened Dispersion around 800 nm

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; SOU Lan-Tian; LIU Zhao-Lun; ZHOU Gui-Yao

    2009-01-01

    We numerically demonstrate a high-nonlinearity single-mode holey fiber with flattened dispersion around the Ti-Za laser band at 800 nm. The dispersion profile of the fiber has the shape of a quadratic curve, which reaches its maximun 5.96ps·km~(-1)·nm~(-1)at 800nm and its minimum -0.897 ps·km-1·nm~(-1) at both 750 and 850 nm.The nonlinear coefficient is 170 W~(-1)km~(-1) at 800nm and so higher order modes exit. A six-layer air-hole cladding ensures a loss less than 0.067 db/m in the 750 to 850nm range. Two more air-hole rings will reduce the loss to below 0.1db/km.

  1. Nonlinear processes associated with the amplification of MHz-linewidth laser pulses in single-mode Tm:fiber

    Science.gov (United States)

    Sincore, Alex; Bodnar, Nathan; Bradford, Joshua; Abdulfattah, Ali; Shah, Lawrence; Richardson, Martin C.

    2017-03-01

    This work studies the accumulated nonlinearities when amplifying a narrow linewidth 2053 nm seed in a single mode Tm:fiber amplifier. A control of repetition rate and pulse duration (>30 ns). The pulses are subsequently amplified and the repetition rate is further reduced using a second acousto-optic modulator. It is well known that spectral degradation occurs in such fibers for peak powers over 100's of watts due to self-phase modulation, four-wave mixing, and stimulated Raman scattering. In addition to enabling a thorough test bed to study such spectral broadening, this system will also enable the investigation of stimulated Brillouin scattering thresholds in the same system. This detailed study of the nonlinearities encountered in 2 μm fiber amplifiers is important in a range of applications from telecommunications to the amplification of ultrashort laser pulses.

  2. Study of the normalized intensity correlation function of a single-mode laser system with colored cross-correlated noises

    Institute of Scientific and Technical Information of China (English)

    Bing Wang; Xiuqing Wu

    2007-01-01

    A single-mode laser system with colored cross-correlated additive and multiplicative noise terms is considered. By the means of projection operator method, we study the effects of the cross-correlation time τ and the cross-correlation intensity λ between noises on the normalized intensity correlation function C(s). It is found that if λ> 0 (λ< 0), the normalized intensity correlation function C(s) increases (decreases) with increasing the cross-correlation time τ, and at large value of τ, the variation of the normalized intensity correlation function C(s) becomes small. With the increase of the net gain a0, C(s) exhibits a maximum when λ is larger. However, a minimum and a maximum appear on C(s) curves with the increase of a0 when λ becomes smaller and smaller.

  3. Entanglement in a system of two two-level atoms interacting with a single-mode field

    Institute of Scientific and Technical Information of China (English)

    Jin Li-Juan; Fang Mao-Fa

    2006-01-01

    We investigate the entanglement in a system of two coupling atoms interacting with a single-mode field by means of quantum information entropy theory. The quantum entanglement between the two atoms and the coherent field is discussed by using the quantum reduced entropy, and the entanglement between the two coupling atoms is also investigated by using the quantum relative entropy. In addition, the influences of the atomic dipole-dipole interaction intensity and the average photon number of the coherent field on the degree of the entanglement is examined. The results show that the evolution of the degree of entanglement between the two atoms and the field is just opposite to that of the degree of entanglement between the two atoms. And the properties of the quantum entanglement in the system rely on the atomic dipole-dipole interaction and the average photon number of the coherent field.

  4. Intensity Correlation Function of a Single-Mode Laser Driven by Two Colored Noises with Colored Cross-Correlation

    Institute of Scientific and Technical Information of China (English)

    HANLi-Bo; CAOLi; WUDa-Jin; WANGJun

    2004-01-01

    By using the linear approximation method, the intensity correlation function and the intensity correlation time are calculated in a gain-noise model of a single-mode laser driven by colored cross-correlated pump noise and quantum noise, each of which is colored. We detect that, when the cross-correlation between both noises is negative, the behavior of the intensity correlation function C(t) versus time t, in addition to decreasing monotonously, also exhibits several other cases, such as one maximum, one minimum, and two extrema (one maximum and one minimum), i.e., some parameters of the noises can greatly change the dependence of the intensity correlation function upon time. Moreover, we find that there is a minimum Tmin in the curve of the intensity correlation time versus the pump noise intensity, and the depth and position of Train strongly depend on the quantum noise self-correlation time T2 and cross-correlation time T3.

  5. Analysis of surface plasmon resonance in bent single-mode waveguides with metal-coated cladding by eigenmode expansion method.

    Science.gov (United States)

    Kulchin, Yu N; Vitrik, O B; Dyshlyuk, A V

    2014-09-08

    A numerical study is presented of surface plasmon waves excitation in a metal film applied to the cladding of a standard bent single-mode optical fiber. It was shown that by adjusting the bend radius and metal film thickness one can achieve effective coupling between the fiber fundamental mode and symmetric surface plasmon mode through the intermediary of whispering gallery modes supported by the cladding of the bent fiber. This effect is demonstrated to allow for refractometric measurement both in the wavelength and intensity-modulated regimes with a resolution of up to 10⁻⁸ RIU. Usage of standard noise reduction techniques for intensity-modulated optical signals promises further increase in accuracy.

  6. One-wave optical time-reversal mirror by actively coupling arbitrary light fields into a single-mode reflector

    CERN Document Server

    Lee, KyeoReh; Park, Jung-Hoon; Park, Ji-Ho; Park, YongKeun

    2015-01-01

    Rewinding the arrow of time via phase conjugation is an intriguing phenomena made possible by the wave property of light. To exploit this phenomenon, many diverse research fields have pursed the realization of an ideal phase conjugation mirror, but the ideal phase conjugation mirror - an optical system that requires a single-input and a single-output beam, like natural conventional mirrors - has never been demonstrated. Here, we demonstrate the realization of a one-wave optical time-reversal mirror using a spatial light modulator and a single-mode reflector. Our method is simple, alignment free, and fast while allowing unlimited power throughput in the time reversed wave, which have not been simultaneously demonstrated before. Using our method, we demonstrate high throughput time-reversal full-field light delivery through highly scattering biological tissue and multimode fibers, even for quantum dot fluorescence.

  7. A high-efficiency grating coupler between single-mode fiber and silicon-on-insulator waveguide

    Science.gov (United States)

    Liu, Rongrui; Wang, Yubing; Yin, Dongdong; Ye, Han; Yang, Xiaohong; Han, Qin

    2017-06-01

    We present the design of a diffractive grating structure and get the optimal parameters which can achieve more than 75% coupling efficiency (CE) between single-mode fiber and silicon-on-insulator (SOI) waveguide through 2D finite-different time-domain (FDTD) simulation. The proposed architecture has a uniform structure with no bottom reflection element or silicon overlay. The structure, including grating couplers, adiabatic tapers and interconnection waveguides can be fabricated on the SOI waveguide with only a single electron-beam lithography (ICP) step, which is CMOS-compatible. A relatively high coupling efficiency of 47.2% was obtained at a wavelength of 1562 nm. Project supported by the National Key Research and Development Program of China (No. 2016YFB0402404), the High-Tech Research and Development Program of China (Nos. 2013AA031401, 2015AA016902, 2015AA016904), and the National Natural Foundation of China (Nos. 61674136, 61435002, 61176053, 61274069)

  8. Direct Determination of Harmonic and Inter-modulation distortions with an application to Single Mode Laser Diodes

    CERN Document Server

    Tannous, C

    2001-01-01

    Harmonic and Intermodulation distortions occur when a physical system is excited with a single or several frequencies and when the relationship between the input and output is non-linear. Working with non-linearities in the Frequency domain is not straightforward specially when the relationship between the input and output is not trivial. We outline the complete derivation of the Harmonic and Intermodulation distortions from basic principles to a general physical system. For illustration, the procedure is applied to the Single Mode laser diode where the relationship of input to output is non-trivial. The distortions terms are extracted directly from the Laser Diode rate equations and the method is tested by comparison to many results cited in the literature. This methodology is general enough to be applied to the extraction of distortion terms to any desired order in many physical systems in a general and systematic way.

  9. Single-mode oscillation of a diode-pumped Nd:YAG microchip laser at 1835 nm

    Science.gov (United States)

    Lan, Jinglong; Cui, Qin; Wang, Yi; Xu, Bin; Xu, Huiying; Cai, Zhiping

    2016-10-01

    Single-mode oscillation of a diode-pumped conventional Nd:YAG laser at 1835 nm is demonstrated, for the first time to our knowledge, in the form of microchip configuration. The achieved maximum output power reaches 189 mW with slope efficiency of about 5.5% with respect to absorbed pump power. The laser spectra are measured with linewidth less than 0.08 nm indicating a single longitudinal mode. The output laser beam is also measured to be near diffraction-limited with M2 factors of about 1.2 and 1.5 in x and y directions. Using a mechanical chopper with 50% duty cycle, the maximum output power is improved to 253 mW with slope efficiency of about 9.7%.

  10. Integrated photonic building blocks for next-generation astronomical instrumentation II: the multimode to single mode transition.

    Science.gov (United States)

    Spaleniak, Izabela; Jovanovic, Nemanja; Gross, Simon; Ireland, Michael J; Lawrence, Jon S; Withford, Michael J

    2013-11-04

    There are numerous advantages to exploiting diffraction-limited instrumentation at astronomical observatories, which include smaller footprints, less mechanical and thermal instabilities and high levels of performance. To realize such instrumentation it is imperative to convert the atmospheric seeing-limited signal that is captured by the telescope into a diffraction-limited signal. This process can be achieved photonically by using a mode reformatting device known as a photonic lantern that performs a multimode to single-mode transition. With the aim of developing an optimized integrated photonic lantern, we undertook a systematic parameter scan of devices fabricated by the femtosecond laser direct-write technique. The devices were designed for operation around 1.55 μm. The devices showed (coupling and transition) losses of less than 5% for F/# ≥ 12 injection and the total device throughput (including substrate absorption) as high as 75-80%. Such devices show great promise for future use in astronomy.

  11. Transmission of 2.5 Gbit/s Spectrum-sliced WDM System for 50 km Single-mode Fiber

    Science.gov (United States)

    Ahmed, Nasim; Aljunid, Sayed Alwee; Ahmad, R. Badlisha; Fadil, Hilal Adnan; Rashid, Mohd Abdur

    2011-06-01

    The transmission of a spectrum-sliced WDM channel at 2.5 Gbit/s for 50 km of single mode fiber using an system channel spacing only 0.4 nm is reported. We have investigated the system performance using NRZ modulation format. The proposed system is compared with conventional system. The system performance is characterized as the bit-error-rate (BER) received against the system bit rates. Simulation results show that the NRZ modulation format performs well for 2.5 Gbit/s system bit rates. Using this narrow channel spectrum-sliced technique, the total number of multiplexed channels can be increased greatly in WDM system. Therefore, 0.4 nm channel spacing spectrum-sliced WDM system is highly recommended for the long distance optical access networks, like the Metro Area Network (MAN), Fiber-to-the-Building (FTTB) and Fiber-to-the-Home (FTTH).

  12. Attaining m s-1 level intrinsic Doppler precision with RHEA, a low-cost single-mode spectrograph

    Science.gov (United States)

    Feger, Tobias; Ireland, Michael J.; Schwab, Christian; Bento, Joao; Bacigalupo, Carlos; Coutts, David W.

    2016-12-01

    We present RHEA, a compact and inexpensive single-mode spectrograph which is built to exploit the capabilities of modest-sized telescopes in an economic way. The instrument is fed by up to seven optical waveguides with the aim of achieving an efficient and modal-noise-free unit, suitable for attaining extreme Doppler precision. The cross-dispersed layout features a wavelength coverage from 430-650 nm, with spectral resolution of R ˜75,000. When coupled to small telescopes using fast tip/tilt control, our instrument is well-suited to sensitive spectroscopy. Example science cases are accurate radial velocity studies of low to intermediate-mass giant stars with the purpose of searching for giant plants and using asteroseismology to simultaneously measure the host star parameters. In this paper we describe the final instrument design and present first results from testing the internal stability.

  13. 'Modal-noise' in single-mode fibers: A cautionary note for high precision radial velocity instruments

    CERN Document Server

    Halverson, Samuel; Mahadevan, Suvrath; Schwab, Christian

    2015-01-01

    Exploring the use of single-mode fibers (SMFs) in high precision Doppler spectrometers has become increasingly attractive since the advent of diffraction-limited adaptive optics systems on large-aperture telescopes. Spectrometers fed with these fibers can be made significantly smaller than typical 'seeing-limited' instruments, greatly reducing cost and overall complexity. Importantly, classical mode interference and speckle issues associated with multi-mode fibers, also known as 'modal noise', are mitigated when using SMFs, which also provide perfect radial and azimuthal image scrambling. However, these fibers do support multiple polarization modes, an issue that is generally ignored for larger-core fibers given the large number of propagation modes. Since diffraction gratings used in most high resolution astronomical instruments have dispersive properties that are sensitive to incident polarization changes, any birefringence variations in the fiber can cause variations in the efficiency profile, degrading il...

  14. Gain-switching dynamics in optically pumped single-mode InGaN vertical-cavity surface-emitting lasers.

    Science.gov (United States)

    Chen, Shaoqiang; Asahara, Akifumi; Ito, Takashi; Zhang, Jiangyong; Zhang, Baoping; Suemoto, Tohru; Yoshita, Masahiro; Akiyama, Hidefumi

    2014-02-24

    The gain-switching dynamics of single-mode pulses were studied in blue InGaN multiple-quantum-well vertical-cavity surface-emitting lasers (VCSELs) through impulsive optical pumping. We measured the shortest single-mode pulses of 6.0 ps in width with a method of up-conversion, and also obtained the pulse width and the delay time as functions of pump powers from streak-camera measurements. Single-mode rate-equation calculations quantitatively and consistently explained the observed data. The calculations indicated that the pulse width in the present VCSELs was mostly limited by modal gain, and suggested that subpicosecond pulses should be possible within feasible device parameters.

  15. 107.5 Gb/s 850 nm multi- and single-mode VCSEL transmission over 10 and 100 m of multi-mode fiber

    DEFF Research Database (Denmark)

    Puerta Ramírez, Rafael; Agustin, M.; Chorchos, L.

    2016-01-01

    First time successful 107.5 Gb/s MultiCAP 850 nm OM4 MMF transmissions over 10 m with multi-mode VCSEL and up to 100 m with single-mode VCSEL are demonstrated, with BER below 7% overhead FEC limit measured for each case.......First time successful 107.5 Gb/s MultiCAP 850 nm OM4 MMF transmissions over 10 m with multi-mode VCSEL and up to 100 m with single-mode VCSEL are demonstrated, with BER below 7% overhead FEC limit measured for each case....

  16. 32-core Dense SDM Unidirectional Transmission of PDM-16QAM Signals Over 1600 km Using Crosstalk-managed Single-mode Heterogeneous Multicore Transmission Line

    DEFF Research Database (Denmark)

    Mizuno, Takayuki; Shibahara, K.; Ono, Hirotaka;

    2016-01-01

    We demonstrate 32-core dense space-division multiplexed (DSDM) unidirectional transmission of PDM-16QAM 20-WDM signals over 1644.8 km employing a low-crosstalk single-mode heterogeneous 32-core fiber in a partial recirculating-loop system.......We demonstrate 32-core dense space-division multiplexed (DSDM) unidirectional transmission of PDM-16QAM 20-WDM signals over 1644.8 km employing a low-crosstalk single-mode heterogeneous 32-core fiber in a partial recirculating-loop system....

  17. Proposal for the award of a blanket purchase contract, without competitive tendering, for the supply of radiation-resistant single-mode optical fibres for the LHC

    CERN Document Server

    2006-01-01

    This document concerns the award of a contract, without competitive tendering, for the supply of radiation-resistant single-mode optical fibres for the LHC. The Finance Committee is invited to agree to the negotiation of a contract, without competitive tendering, with FUJIKURA (JP), for the supply of radiation-resistant single-mode optical fibres for the LHC for a total amount of 660 000 US dollars (824 000 Swiss francs), not subject to revision. The rate of exchange used is the rate of 20 November 2006.

  18. Single-mode operation of an injection-seeded alexandrite ring laser for application in water-vapor and temperature differential absorption lidar.

    Science.gov (United States)

    Wulfmeyer, V; Bösenberg, J

    1996-08-01

    A major improvement of a differential absorption lidar (DIAL) system for measurements of tropospheric water vapor and temperature is introduced. A Q-switched unidirectional alexandrite ring laser is injection seeded by a cw Ti:sapphire ring laser. Using an especially developed single-mode electronic, one starts the Q switch when the slave resonator is in resonance with the frequency of the Ti:sapphire laser. Long-term single-mode operation of the alexandrite laser is achieved. A single-shot spectral linewidth of system in the near infrared is presented.

  19. Electro-opto-mechanical radio-frequency oscillator driven by guided acoustic waves in standard single-mode fiber

    Directory of Open Access Journals (Sweden)

    Yosef London

    2017-04-01

    Full Text Available An opto-electronic radio-frequency oscillator that is based on forward scattering by the guided acoustic modes of a standard single-mode optical fiber is proposed and demonstrated. An optical pump wave is used to stimulate narrowband, resonant guided acoustic modes, which introduce phase modulation to a co-propagating optical probe wave. The phase modulation is converted to an intensity signal at the output of a Sagnac interferometer loop. The intensity waveform is detected, amplified, and driven back to modulate the optical pump. Oscillations are achieved at a frequency of 319 MHz, which matches the resonance of the acoustic mode that provides the largest phase modulation of the probe wave. Oscillations at the frequencies of competing acoustic modes are suppressed by at least 40 dB. The linewidth of the acoustic resonance is sufficiently narrow to provide oscillations at a single longitudinal mode of the hybrid cavity. Competing longitudinal modes are suppressed by at least 38 dB as well. Unlike other opto-electronic oscillators, no radio-frequency filtering is required within the hybrid cavity. The frequency of oscillations is entirely determined by the fiber opto-mechanics.

  20. A power and wavelength detuning-dependent hysteresis loop in a single mode Fabry-Pérot laser diode

    Institute of Scientific and Technical Information of China (English)

    Wu Jian-Wei; Bikash Nakarmi

    2013-01-01

    In this paper,we observe experimentally the optical bistability induced by the side-mode injection power and wavelength detuning in a single mode Fabry-Pérot laser diode (SMFP-LD).Results show that the bistability characteristics of the dominant and injected modes are strongly dependent on the injected input optical power and wavelength detuning in an SMFP-LD.We observe three types of hysteresis loops:counterclockwise,clockwise,and butterfly hysteresis with various loop widths.In the case of a bistability loop caused by injection power,the transition from counterclockwise to clockwise in the hysteresis direction with the wavelength detuning from 0.028 nm to 0.112 nm is observed in a way of butterfly hysteresis for the dominant mode by increasing the wavelength detuning.The width of hysteresis loop,induced by wavelength detuning is also changed while the injection power is enhanced from-7 dBm to-5 dBm.

  1. Over 1000 mW single mode operation of planar inner stripe blue-violet laser diodes

    Energy Technology Data Exchange (ETDEWEB)

    Sasaoka, C.; Fukuda, K.; Ohya, M.; Shiba, K.; Sumino, M.; Kohmoto, S.; Naniwae, K.; Matsudate, M.; Mizuki, E.; Masumoto, I.; Kobayashi, R.; Kudo, K.; Sasaki, T.; Nishi, K. [System Devices Research Laboratories, NEC Corporation, 9-1, Seiran 2-chome, Otsu, Shiga 520-0833 (Japan)

    2006-05-15

    We report the 1000 mW single mode operation of a planar blue-violet laser diode with inner stripe waveguide. Kink-free output surpassed 400 mW (CW) and 600 mW (50 ns pulsed, duty 50%) at temperatures up to 90 C. Precise optical field design for narrow stripe waveguide as well as damage-free stripe formation was a key to achieving watt class output. By utilizing buried AlN as optical and current confinement layers, a damage-free inner stripe as narrow as 1.0 {mu}m wide was successfully fabricated. Planar inner stripe structure also has the advantage of a small increase in the electrical resistance for such a narrow stripe, which is favorable for high power operations. The results here indicate the potential of this planar blue-violet laser diode for high power applications as the next generation of optical disc systems. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Designing the Mode solving of the photonic crystal fiber via BPM and Exploring the Single-Mode Properties

    CERN Document Server

    Debbal, Mohammed

    2012-01-01

    Microstructured optical fibers (MOFs) are one of the most exciting recent developments in fiber optics. A MOF usually consists of a hexagonal arrangement of air holes running down the length of a silica fiber surrounding a central core of solid silica or, in some cases air. MOFs can exhibit a number of unique properties, including zero dispersion at visible wavelengths and low or high effective nonlinearity [3]-[17], By varying the size of the holes and their number and position, one can also design MOFs with carefully controlled dispersive and modal properties. In this paper, we analyze and modeling the behavior of the photonic crystal fiber (PCF) by using in the first step a propagator method based on the BPM method. With our BPM software, the electric field contour of the fundamental mode of PCF was demonstrated. We also used it to see the variation of the effective index; an effective index model confirms that such a fiber can be single mode for any wavelength. It would make a study of photonic crystal fi...

  3. Influence of the net gain on characteristic of stochastic resonance in a single-mode laser system

    Institute of Scientific and Technical Information of China (English)

    Qinghua Cheng(程庆华); Li Cao(曹力); Dahai Xu(徐大海); Dajin Wu(吴大进)

    2004-01-01

    The phenomenon of stochastic resonance (SR) is found in a single-mode laser system driven by the colored pump noise with signal modulation and the quantum noise with cross-correlation between the real and imaginary parts. When the net gain a0 changes, it is found that, 1) the shape of the curve of the signal-tonoise ratio (SNR) versus the pump noise self-correlation time T exhibits a changing process of multiform SR, from single-peak SR to simultaneous existence of resonances and suppressions; 2) the curve of SNR versus signal frequency Ω experiences a complicated changing process from the monotonous descending to the simultaneous appearances of a maximum and a minimum, and finally to monotonous descending; 3)the curve of SNR versus cross-correlation coefficient between the real and imaginary parts of the quantum noise λq appears an acute single-peak SR. Therefore, the net gain a0 greatly influences the characteristic of SR of laser system.

  4. High initial amplitude and high Mach number effects on the evolution of the single-mode Richtmyer-Meshkov instability.

    Science.gov (United States)

    Rikanati, A; Oron, D; Sadot, O; Shvarts, D

    2003-02-01

    Effects of high-Mach numbers and high initial amplitudes on the evolution of the single-mode Richtmyer-Meshkov shock-wave induced hydrodynamic instability are studied using theoretical models, experiments, and numerical simulations. Two regimes in which there is a significant deviation from the linear dependence of the initial velocity on the initial perturbation amplitude are defined and characterized. In one, the observed reduction of the initial velocity is primarily due to large initial amplitudes. This effect is accurately modeled by a vorticity deposition model, quantifying both the effect of the initial perturbation amplitude and the exact shape of the interface. In the other, the reduction is dominated by the proximity of the shock wave to the interface. This effect is modeled by a modified incompressible model where the shock wave is mimicked by a moving bounding wall. These results are supplemented with high initial amplitude Mach 1.2 shock-tube experiments, enabling separation of the two effects. It is shown that in most of the previous experiments, the observed reduction is predominantly due to the effect of high initial amplitudes.

  5. Single mode operation with mid-IR hollow fibers in the range 5.1-10.5 µm.

    Science.gov (United States)

    Sampaolo, Angelo; Patimisco, Pietro; Kriesel, Jason M; Tittel, Frank K; Scamarcio, Gaetano; Spagnolo, Vincenzo

    2015-01-12

    Single mode beam delivery in the mid-infrared spectral range 5.1-10.5 μm employing flexible hollow glass waveguides of 15 cm and 50 cm lengths, with metallic/dielectric internal layers and a bore diameter of 200 μm were demonstrated. Three quantum cascade lasers were coupled with the hollow core fibers. For a fiber length of 15 cm, we measured losses down to 1.55 dB at 5.4 μm and 0.9 dB at 10.5 μm. The influence of the launch conditions in the fiber on the propagation losses and on the beam profile at the waveguide exit was analyzed. At 10.5 µm laser wavelength we found near perfect agreement between measured and theoretical losses, while at ~5 µm and ~6 µm wavelengths the losses were higher than expected. This discrepancy can be explained considering an additional scattering loss effect, which scales as 1/λ(2) and is due to surface roughness of the metallic layer used to form the high-reflective internal layer structure of the hollow core waveguide.

  6. Highspeed laser welding of steel using a high-power single-mode continuous-wave fiber laser

    Science.gov (United States)

    Drechsel, J.; Loeschner, U.; Schwind, S.; Hartwig, L.; Schille, J.; Exner, H.; Huebner, P.; Eysert, A.

    2013-02-01

    Since a few years, high brilliance laser sources find their way into laser material processing. Laser micro processing by applying high brilliance laser radiation up to 3 kW of continuous wave laser power in combination with ultrafast beam deflection systems has been successfully demonstrated in 2008 for the first time. In the fields of laser welding, high brilliant laser radiation was mainly used for micro welding, but up to now the macro range is still insufficiently investigated. Hence, this study reports on detailed investigations of high speed laser welding of different steel grades, performed with a high power single mode fiber laser source. The laser beam was deflected relative to the sample by using both a fast galvanometer scanner system with f-theta focusing objective and a linear axis in combination with a welding optic, respectively. In the study, the mainly process influencing parameters such as laser power, welding speed, thickness of the metal sheets, angle of incidence and laser beam spot size were varied in a wide range. The weld seam quality was evaluated by structural analyses, static tensile tests and EDX measurements. Finally, the laser welding process has been optimized for different weld seam geometries, for example bead-on-plate welds and butt welds.

  7. Interaction of a two-level atom with single-mode optical field beyond the rotating wave approximation.

    Science.gov (United States)

    Liu, Ju; Li, Zhi-Yuan

    2014-11-17

    One of the simplest models involving the atom-field interaction is the coupling of a single two-level atom with single-mode optical field. Under the rotating wave approximation, this problem is reduced to a form that can be solved exactly. But the approximation is only valid when the two levels are resonant or nearly resonant with the applied electromagnetic radiation. Here we present an analytical solution without the rotating wave approximation and applicable to general atom-field interaction far away from the resonance. We find that there exists remarkable influence of the initial phase of optical field on the Rabi oscillations and Rabi splitting, and this issue cannot be explored in the context of the rotating wave approximation. Due to the retention of the counter-rotating terms, higher-order harmonic appears during the Rabi splitting. The analytical solution suggests a way to regulate and control the quantum dynamics of a two-level atom and allows for exploring more essential features of the atom-field interaction.

  8. “MODAL NOISE” IN SINGLE-MODE FIBERS: A CAUTIONARY NOTE FOR HIGH PRECISION RADIAL VELOCITY INSTRUMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Halverson, Samuel; Roy, Arpita; Mahadevan, Suvrath [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Schwab, Christian, E-mail: shalverson@psu.edu [Macquarie University, Sydney, NSW 2109 (Australia)

    2015-12-01

    Exploring the use of single-mode fibers (SMFs) in high precision Doppler spectrometers has become increasingly attractive since the advent of diffraction-limited adaptive optics systems on large-aperture telescopes. Spectrometers fed with these fibers can be made significantly smaller than typical “seeing-limited” instruments, greatly reducing cost and overall complexity. Importantly, classical mode interference and speckle issues associated with multi-mode fibers, also known as “modal noise,” are mitigated when using SMFs, which also provide perfect radial and azimuthal image scrambling. However, SMFs do support multiple polarization modes, an issue that is generally ignored for larger-core fibers given the large number of propagation modes. Since diffraction gratings used in most high resolution astronomical instruments have dispersive properties that are sensitive to incident polarization changes, any birefringence variations in the fiber can cause variations in the efficiency profile, degrading illumination stability. Here we present a cautionary note outlining how the polarization properties of SMFs can affect the radial velocity (RV) measurement precision of high resolution spectrographs. This work is immediately relevant to the rapidly expanding field of diffraction-limited, extreme precision RV spectrographs that are currently being designed and built by a number of groups.

  9. Electro-opto-mechanical radio-frequency oscillator driven by guided acoustic waves in standard single-mode fiber

    Science.gov (United States)

    London, Yosef; Diamandi, Hilel Hagai; Zadok, Avi

    2017-04-01

    An opto-electronic radio-frequency oscillator that is based on forward scattering by the guided acoustic modes of a standard single-mode optical fiber is proposed and demonstrated. An optical pump wave is used to stimulate narrowband, resonant guided acoustic modes, which introduce phase modulation to a co-propagating optical probe wave. The phase modulation is converted to an intensity signal at the output of a Sagnac interferometer loop. The intensity waveform is detected, amplified, and driven back to modulate the optical pump. Oscillations are achieved at a frequency of 319 MHz, which matches the resonance of the acoustic mode that provides the largest phase modulation of the probe wave. Oscillations at the frequencies of competing acoustic modes are suppressed by at least 40 dB. The linewidth of the acoustic resonance is sufficiently narrow to provide oscillations at a single longitudinal mode of the hybrid cavity. Competing longitudinal modes are suppressed by at least 38 dB as well. Unlike other opto-electronic oscillators, no radio-frequency filtering is required within the hybrid cavity. The frequency of oscillations is entirely determined by the fiber opto-mechanics.

  10. External cavity based single mode Fabry-Pérot laser diode and its application towards all-optical digital circuits

    Science.gov (United States)

    Nakarmi, Bikash; Zhang, Xuping; Won, Yong Hyub

    2012-11-01

    We have proposed a novel approach of realizing all-optical logic gates and combinational circuit using external cavity based single mode Fabry-Pérot laser diodes (SMFP-LDs). Different techniques and critical parameters for injection locking the any one of the modes of SMFP-LDs are discussed. Taking consideration of wavelength detuning and input injected power, we have proposed and demonstrated multi-input injection locking, supporting beam injection locking with the conventional injection locking which are used for demonstrating different logic gates (NAND, AND, XNOR, XOR, NOT, NOR) and digital circuits (Half adder and Comparator). Since we have used SMFP-LDs, there is no requirement of additional probe beam and associated components as required by other optical technologies making the realization simple in configuration, cost effective and power efficient. Clear output waveforms, eye diagrams, risingfalling times and BER are presented to verify the proposed method. All-optical logic units and digital circuit are demonstrated at the data rate of 10 Gbps with the waveform of NRZ signal waveform and measured eye diagram and BER of the PRBS of 231-1 signal. The maximum power penalty among all demonstrated units is below 1.4 dB at the BER of 10-9.

  11. Design and simulation of 1310 nm and 1480 nm single-mode photonic crystal fiber Raman lasers.

    Science.gov (United States)

    Varshney, S K; Sasaki, K; Saitoh, K; Koshiba, M

    2008-01-21

    We have numerically investigated the Raman lasing characteristics of a highly nonlinear photonic crystal fiber (HNPCF). HNPCF Raman lasers are designed to deliver outputs at 1.3 microm and 1.48 microm wavelengths through three and six cascades of Raman Stokes cavities when the pumps of 1117 nm and 1064 nm are injected into HNPCF module, respectively. A quantum efficiency of approximately 47% was achieved in a short length of HNPCF for 1.3 microm lasing wavelength. The HNPCF design is modified further to operate in single-mode fashion keeping intact its Raman lasing characteristics. The modified HNPCF design consists of two air-hole rings where the higher-order modes in the central core are suppressed by enhancing their leakage losses drastically, thus ceasing their propagation in the short length of HNPCF. On the other hand, the fundamental mode is well confined to the central core region, unaffecting its lasing performances. Further, the lasing characteristics of HNPCF at 1480 nm are compared with conventional highly nonlinear fiber Raman laser operating at 1480 nm. It is found that one can reduce the fiber length by five times in case of HNPCF with nearly similar conversion efficiency.

  12. Monolithic Ytterbium All-single-mode Fiber Laser with Direct Fiber-end Delivery of nJ-level Femtosecond Pulses

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry

    2008-01-01

    We demonstrate a monolithic, i.e. without any free-space coupling, all-single-mode passively modelocked Yb-fiber laser, with direct fiber-end delivery of 364−405 fs pulses of 4 nJ pulse energy using a low-loss hollow-core photonic crystal fiber compression....

  13. Single mode solid state distributed feedback dye laser fabricated by grey scale electron beam lithography on dye doped SU-8 resist

    DEFF Research Database (Denmark)

    Balslev, Søren; Rasmussen, Torben; Shi, Peixiong

    2005-01-01

    are optically pumped at 532 nm, and exhibit low lasing threshold from 530 nJ/mm2 and single mode output at selectable wavelengths from 580 to 630 nm, determined by the grating pitch. The lasers are well suited for integration into polymer based lab-on-chip circuits for interference based sensing....

  14. 7+1 to 1 pump/signal combiner for air-clad fiber with 15 m MFD PM single-mode signal feed-through

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Nielsen, Martin D.; Skovgaard, Peter M. W.;

    2010-01-01

    A 7+1 to 1 pump/signal combiner with single-mode (SM) polarization maintaining (PM) 15 µm mode-field-diameter (MFD) signal feed-through is demonstrated. The combiner is designed for pulse amplification in an active Yb-doped airclad fiber operated in backward pumped configuration. Signal coupling ...

  15. Performance analysis of fiber-based free-space optical communications with coherent detection spatial diversity.

    Science.gov (United States)

    Li, Kangning; Ma, Jing; Tan, Liying; Yu, Siyuan; Zhai, Chao

    2016-06-10

    The performances of fiber-based free-space optical (FSO) communications over gamma-gamma distributed turbulence are studied for multiple aperture receiver systems. The equal gain combining (EGC) technique is considered as a practical scheme to mitigate the atmospheric turbulence. Bit error rate (BER) performances for binary-phase-shift-keying-modulated coherent detection fiber-based free-space optical communications are derived and analyzed for EGC diversity receptions through an approximation method. To show the net diversity gain of a multiple aperture receiver system, BER performances of EGC are compared with a single monolithic aperture receiver system with the same total aperture area (same average total incident optical power on the aperture surface) for fiber-based free-space optical communications. The analytical results are verified by Monte Carlo simulations. System performances are also compared for EGC diversity coherent FSO communications with or without considering fiber-coupling efficiencies.

  16. An optical pulse width modulation generator based on the injection-locking property of single mode FP-LD

    Science.gov (United States)

    Tran, Quoc Hoai; Nakarmi, Bikash; Won, Yong Hyub

    2013-03-01

    A novel simple optical pulse width modulation generator (OPWMG) based on injection-locking property of a single mode FP-LD (SMFP-LD) has been proposed and experimentally verified. The OPWMG consists of a SMFP-LD (which acts as comparator), an optical sinusoidal wave source (analog input), and a continuous optical beam (control signal). The power required for fully injection-locking the SMFP-LD acts as the referent power whereas the combination power of continuous optical beam and analog optical sinusoidal signals work as control signals for changing the duty cycle of the proposed OPWMG. The presence of only continuous optical beam is not sufficient to suppress the dominant mode of SMFP-LD with high ON/OFF contrast ratio; however, the application of additional sinusoidal wave of constant amplitude and frequency, the dominant mode of SMFP-LD can be suppressed for the certain time window. Since, injection-locking power is dependent with the combined power of input injected continuous beam and sinusoidal optical wave, the time window of injection-locking can be varied by changing input beam power which provides different duty cycle of 13% to 68% at the output. Current available schemes for generating PWM signals are in electrical domain, hence, they need to convert electrical signals into optical domain by using expensive O/E converters for application in optical control and signal processing. The proposed OPWMG scheme has several advantages, such as low cost, low power consumption (~0.5 mW) which can be used for various applications where the effect of EMI/EMR is considered as an important factor such as control circuit for high voltage converters in power plant and electrical vehicles.

  17. Stationary Intensity Distribution of Single-Mode Laser Driven by Additive and Multiplicative Colored Noises with Colored Cross-Correlation

    Institute of Scientific and Technical Information of China (English)

    LIANG Gui-Yun; CAO Li; WANG Jun; Wu Da-Jin

    2003-01-01

    Applying the approximate Fokker-Planck equation we derived, we obtain the analytic expression of thestationary laser intensity distribution Pst(Ⅰ) by studying the single-mode laser cubic model subject to colored cross-correlation additive and multiplicative noise, each of which is colored. Based on it, we discuss the effects on the stationarylaser intensity distribution Pst(Ⅰ) by cross-correlation between noises and "color" of noises (non-Markovian effect) whenthe laser system is above the threshold. In detail, we analyze two cases: One is that the three correlation-times (i.e.the self-correlation and cross-correlation times of the additive and multiplicative noise) are chosen to be the same value(τ1 = τ2 = τ3 = τ). For this case, the effect of noise cross-correlation is investigated emphatically, and we detect thatonly when λ≠ 0 can the noise-induced transition occur in the Pst(Ⅰ) curve, and only when τ≠ 0 and λ≠ 0, can the"reentrant noise-induced transition" occur. The other case is that the three correlation times are not the same value,τ1 ≠τ2 ≠τ3. For this case, we find that the noise-induced transition occurring in the Pst (Ⅰ) curve is entirely differentwhen the values of τ1, τ2, and τ3 are changed respectively. In particular, when τ2 (self-correlation time of additivenoise) is changing, the ratio of the two maximums of the Pst(Ⅰ) curve R exhibits an interesting phenomenon, "reentrantnoise-induced transition", which demonstrates the effect of noise "color" (non-Markovian effect).

  18. Quantum dynamics of a BEC interacting with a single-mode quantized field in the presence of interatom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemian, E. [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of); Tavassoly, M.K., E-mail: mktavassoly@yazd.ac.ir [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of); Photonics Research Group, Engineering Research Center, Yazd University, Yazd (Iran, Islamic Republic of); The Laboratory of Quantum Information Processing, Yazd University, Yazd (Iran, Islamic Republic of)

    2016-09-23

    In this paper, we consider a model in which N two-level atoms in a Bose–Einstein condensate (BEC) interact with a single-mode quantized laser field. Our goal is to investigate the quantum dynamics of atoms in the BEC in the presence of interatom interactions. To achieve the purpose, at first, using the collective angular momentum operators, we try to reduce the dynamical Hamiltonian of the system to a well-known Jaynes–Cummings like model (JCM). We also use the Dicke model to construct the state of atomic subsystem, by which the analytical solution of the system may be obtained. Then, we analyze the atomic population inversion, the degree of entanglement between the “atoms in BEC” and the “field” as well as the Mandel parameter. Numerical results show that, the atomic population inversion, atom-field entanglement and quantum statistics of photons are very sensitive to the evolved parameters in the model (and so can be well-adjusted), such as the number of atoms in BEC, the intensity of initial field, the interatom coupling constant and detuning. To investigate the entanglement properties, we pay attention to the entropy and linear entropy. It is shown that, oscillations in the two entropy criteria may be seen, with some maxima of entanglement at some moments of time. Finally, looking for the quantum statistics, we evaluate the Mandel parameter, by which we demonstrate the sub-Poissonian statistics and so the nonclassical characteristics of the field state of system. Collapse-revival phenomenon, which is a distinguishable nonclassical characteristic of the system, can be apparently observed in the atomic population inversion and the Mandel parameter. - Highlights: • N two-level atoms in a BEC interacting with a laser field in the presence of interatom interactions is considered. • The atomic population inversion, degree of entanglement between the “atoms in BEC” and the “field” and the Mandel parameter are investigated. • Collapse

  19. Fiber-based wearable electronics: a review of materials, fabrication, devices, and applications.

    Science.gov (United States)

    Zeng, Wei; Shu, Lin; Li, Qiao; Chen, Song; Wang, Fei; Tao, Xiao-Ming

    2014-08-20

    Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable. Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions. The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns. However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation. This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products. In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices. Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption.

  20. Fiber-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

    2016-09-06

    A fiber-based adsorbent and a related method of manufacture are provided. The fiber-based adsorbent includes polymer fibers with grafted side chains and an increased surface area per unit weight over known fibers to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. The polymer fibers include a circular morphology in some embodiments, having a mean diameter of less than 15 microns, optionally less than about 1 micron. In other embodiments, the polymer fibers include a non-circular morphology, optionally defining multiple gear-shaped, winged-shaped or lobe-shaped projections along the length of the polymer fibers. A method for forming the fiber-based adsorbents includes irradiating high surface area polymer fibers, grafting with polymerizable reactive monomers, reacting the grafted fibers with hydroxylamine, and conditioning with an alkaline solution. High surface area fiber-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

  1. A selectively coated photonic crystal fiber based surface plasmon resonance sensor

    DEFF Research Database (Denmark)

    Yu, X; Zhang, Y.; Pan, S.S.

    2010-01-01

    We propose a novel design for a photonic crystal fiber based surface plasmonic resonance sensor. The sensor consists of selectively metal-coated air holes containing analyte channels, which enhance the phase matching between the plasmonic mode and the core-guided mode. Good refractive index sensi...

  2. Increased sensitivity in fiber-based spectroscopy using carbon-coated fiber.

    Science.gov (United States)

    Sudirman, Aziza; Norin, Lars; Margulis, Walter

    2012-12-17

    Carbon-coated optical fibers are used here for reducing the luminescence background created by the primary-coating and thus increase the sensitivity of fiber-based spectroscopy systems. The 2-3 orders of magnitude signal-to-noise ratio improvement with standard telecom fibers is sufficient to allow for their use as Raman probes in the identification of organic solvents.

  3. Design of homogeneous trench-assisted multi-core fibers based on analytical model

    DEFF Research Database (Denmark)

    Ye, Feihong; Tu, Jiajing; Saitoh, Kunimasa

    2016-01-01

    is the quasi-optimum core layout starting from an one-ring structured 12-core fiber. Based on the analytical model, a square-lattice structured 24-core fiber and a 32-core fiber are designed both for propagation-direction interleaving (PDI) and non-PDI transmission schemes. The proposed model provides...

  4. Fiber-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

    Science.gov (United States)

    Janke, Christopher J; Dai, Sheng; Oyola, Yatsandra

    2014-05-13

    A fiber-based adsorbent and a related method of manufacture are provided. The fiber-based adsorbent includes polymer fibers with grafted side chains and an increased surface area per unit weight over known fibers to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. The polymer fibers include a circular morphology in some embodiments, having a mean diameter of less than 15 microns, optionally less than about 1 micron. In other embodiments, the polymer fibers include a non-circular morphology, optionally defining multiple gear-shaped, winged-shaped or lobe-shaped projections along the length of the polymer fibers. A method for forming the fiber-based adsorbents includes irradiating high surface area polymer fibers, grafting with polymerizable reactive monomers, reacting the grafted fibers with hydroxylamine, and conditioning with an alkaline solution. High surface area fiber-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

  5. Multi-V-type and Λ-type electromagnetically induced transparency experiments in rubidium atoms with low-power low-cost free running single mode diode lasers

    Science.gov (United States)

    Lavín Varela, S.; León Suazo, J. A.; Gutierrez González, J.; Vargas Roco, J.; Buberl, T.; Aguirre Gómez, J. G.

    2016-05-01

    In this work we present the experimental realization of electromagnetically induced transparency (EIT) in A-type and multi-V-type configurations in a sample of rubidium atoms inside a vapor cell at room temperature. Typical EIT windows are clearly visible in the Doppler- broadened absorption signal of the weak probe beam. The coherent optical pump and probe fields are produced by two tunable low-cost, low-power, continuous-wave (cw), free-running and single mode operated diode laser systems, temperature stabilized and current controlled, tuned to the D2 line of rubidium atoms at 780.2 nm wavelength. The continuum wave and single mode operation of our laser systems are confirmed by direct and saturated absorption spectroscopy techniques. Among other applications, these simple experiments can be used as a low-cost undergraduate laboratory in atomic physics, laser physics, coherent light-atom interaction, and high resolution atomic spectroscopy.

  6. Adaptive optics correction into single mode fiber for a low Earth orbiting space to ground optical communication link using the OPALS downlink.

    Science.gov (United States)

    Wright, Malcolm W; Morris, Jeffery F; Kovalik, Joseph M; Andrews, Kenneth S; Abrahamson, Matthew J; Biswas, Abhijit

    2015-12-28

    An adaptive optics (AO) testbed was integrated to the Optical PAyload for Lasercomm Science (OPALS) ground station telescope at the Optical Communications Telescope Laboratory (OCTL) as part of the free space laser communications experiment with the flight system on board the International Space Station (ISS). Atmospheric turbulence induced aberrations on the optical downlink were adaptively corrected during an overflight of the ISS so that the transmitted laser signal could be efficiently coupled into a single mode fiber continuously. A stable output Strehl ratio of around 0.6 was demonstrated along with the recovery of a 50 Mbps encoded high definition (HD) video transmission from the ISS at the output of the single mode fiber. This proof of concept demonstration validates multi-Gbps optical downlinks from fast slewing low-Earth orbiting (LEO) spacecraft to ground assets in a manner that potentially allows seamless space to ground connectivity for future high data-rates network.

  7. Statistical propeties of a single-mode laser driven by additive and multiplicative coloured noises with a coloured cross-correlation for different correlation times

    Institute of Scientific and Technical Information of China (English)

    梁贵云; 曹力; 张莉; 吴大进

    2003-01-01

    We study a system for a single-mode laser driven by additive and multiplicative coloured noises with a coloured cross-correlation. The analytical expression of the stationary intensity distribution (SID) for the laser is derived in the case of three different correlation times. The influences of each stochastic parameter on the SID are discussed, the the skewness, λ3(O) of the single-mode laser are investigated. We find that there are colourful phase transitions for the SID above a threshold, and re-entrant transitions induced by the "colour" of the additive noises. Further research of the not only increases with the additive noise correlation time τ2 and the cross-correlation time τs, but also the quality of the output of laser beams is optimized.

  8. Effective 100 Gb/s IM/DD 850-nm Multi- and Single-Mode VCSEL Transmission Through OM4 MMF

    DEFF Research Database (Denmark)

    Puerta Ramírez, Rafael; Agustin, Mikel; Chorchos, Lukasz

    2017-01-01

    of OM4 multimode fiber (MMF) using a multimode VCSEL at 850 nm, and up to 100 m of OM4 MMF using a single-mode VCSEL at 850 nm. Measured bit error rates were below 7% overhead forward error correction limit of 3.8e−03, thus, achieving an effective bit rate of 100.5 Gb/s. These successful transmissions...

  9. Effects of {gamma} and neutron irradiation on the optical absorption of pure silica core single-mode optical fibres from Nufern

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, A. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Martinez-Rivero, C. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Matorras, F. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Rodrigo, T. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Sobron, M. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Vila, I. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Virto, A.L. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Alberdi, J. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Arce, P. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Barcala, J.M. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Calvo, E. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Ferrando, A. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain)]. E-mail: Antonio.Ferrando@ciemat.es; Josa, M.I. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Luque, J.M. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Molinero, A. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Navarrete, J. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Oller, J.C. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Valdivieso, P. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Yuste, C. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Fenyvesi, A. [Institute of Nuclear Research, ATOMKI, Debrecen (Hungary); Molnar, J. [Institute of Nuclear Research, ATOMKI, Debrecen (Hungary)

    2006-09-15

    A measurement of the optical absorption, induced by photon irradiation up to a dose of 0.9 MGy, in Nufern silica core single-mode optical fibres is presented. In addition, the fibres were irradiated with neutrons, up to a total fluence of 2x10{sup 14} cm{sup -2} and the induced optical absorption was evaluated for four different wavelengths: 630, 670, 681 and 785 nm.

  10. Coupled-Mode Theory derivation of the formal equivalence between a three-mode waveguide and a set of three mutually coupled single-mode waveguides

    Directory of Open Access Journals (Sweden)

    Boucher Yann G.

    2017-01-01

    Full Text Available The formal identification between a two-mode waveguide and a system of two mutually coupled single-mode waveguides stems from the symmetries of the evolution operator. When the gap tends to zero, the super-modes of the coupled system merge continuously into the modes of the multimode waveguide. For modelling purposes, it is very tempting to extend the analogy to three-mode waveguides (and beyond. But not without some precautions…

  11. Graded index profiles and loss-induced single-mode characteristics in vertical-cavity surface-emitting lasers with petal-shape holey structure

    Institute of Scientific and Technical Information of China (English)

    Liu An-Jin; Qu Hong-Wei; Chen Wei; Jiang Bin; Zhou Wen-Jun; Xing Ming-Xin; Zheng Wan-Hua

    2011-01-01

    The 850-nm oxide-confined vertical-cavity surface-emitting lasers with petal-shape holey structures are presented. An area-weighted average refractive index model is given to analyse their effective index profiles, and the graded index distribution in the holey region is demonstrated. The index step between the optical aperture and the holey region is obtained which is related merely to the etching depth. Four types of holey vertical-cavity surface-emitting lasers with different parameters are fabricated as well as the conventional oxide-confined vertical-cavity surface-emitting laser. Compared with the conventional oxide-confined vertical-cavity surface-emitting laser without etched holes, the holey vertical-cavity surface-emitting laser possesses an improved beam quality due to its graded index distribution, but has a lower output power, higher threshold current and lower slope efficiency. With the hole number increased, the holey vertical-cavity surface-emitting laser can realize the single-mode operation throughout the entire current range, and reduces the beam divergence further. The loss mechanism is used to explain the single-mode characteristic, and the reduced beam divergence is attributed to the shallow etching. High coupling efficiency of 86% to a multi-mode fibre is achieved for the single-mode device in the experiment.

  12. A multi-core fiber based interferometer for high temperature sensing

    Science.gov (United States)

    Zhou, Song; Huang, Bo; Shu, Xuewen

    2017-04-01

    In this paper, we have verified and implemented a Mach–Zehnder interferometer based on seven-core fiber for high temperature sensing application. This proposed structure is based on a multi-mode-multi-core-multi-mode fiber structure sandwiched by a single mode fiber. Between the single-mode and multi-core fiber, a 3 mm long multi-mode fiber is formed for lead-in and lead-out light. The basic operation principle of this device is the use of multi-core modes, single-mode and multi-mode interference coupling is also utilized. Experimental results indicate that this interferometer sensor is capable of accurate measurements of temperatures up to 800 °C, and the temperature sensitivity of the proposed sensor is as high as 170.2 pm/°C, which is much higher than the current existing MZI based temperature sensors (109 pm/°C). This type of sensor is promising for practical high temperature applications due to its advantages including high sensitivity, simple fabrication process, low cost and compactness.

  13. Experimental demonstration of an all-optical fiber-based Fredkin gate.

    Science.gov (United States)

    Kostinski, Natalie; Fok, Mable P; Prucnal, Paul R

    2009-09-15

    We propose and report on what we believe to be the first experimental demonstration of an all-optical fiber-based Fredkin gate for reversible digital logic. The simple 3-input/3-output fiber-based nonlinear optical loop mirror architecture requires only minor alignment for full operation. A short nonlinear element, heavily doped GeO(2) fiber (HDF), allows for a more compact design than typical nonlinear fiber gates. The HDF is ideal for studying reversibility, functioning as a noise-limited medium, as compared to the semiconductor optical amplifier, while allowing for cross-phase modulation, a nondissipative optical interaction. We suggest applications for secure communications, based on "cool" computing.

  14. Analysis of Scaling Law and Figure of Merit of Fiber-Based Biosensor

    Directory of Open Access Journals (Sweden)

    Jui-Teng Lin

    2012-01-01

    Full Text Available This paper presents a normalized transmitted signal (NTS of a fiber-based sensor using gold nanorods as the plasmon excitation medium of the evanescent wave. The NTS and the refractive index (RI sensitivity is calculated as a function of the gold aspect ratio (R, the RI of the sensing medium, and a scaling parameter given by the ratio of the fiber length and its diameter. Finally, the optimal value of gold aspect ratio is calculated to be R = (3.0–4.0 for maximum figure of merits (FOMs defined by the ratio of the refractive index sensitivity and the full width at half maximum. The scaling laws and the FOM presented in this paper may serve as the guidelines for optimal designs in fiber-based nanosensors.

  15. Statistical model of the efficiency for spatial light coupling into a single-mode fiber in the presence of atmospheric turbulence.

    Science.gov (United States)

    Ma, Jing; Ma, Lie; Yang, Qingbo; Ran, Qiwen

    2015-11-01

    The average efficiency of spatial light coupling into a single-mode optical fiber is widely used but cannot estimate the signal-to-noise ratio (SNR) and bit error rate (BER) in free-space optical communication. We provide a statistical model for coupling efficiency and derive the exact expression of the probability density function (PDF). The simulation results confirm that the model is reasonable in the condition of different turbulence intensities and wavefront compensation terms, which is also consistent with our outdoor experiment. We also estimate the average SNR and BER using the PDF. The model is quite useful in a satellite-to-ground laser communication downlink.

  16. Effect's of Cross-Correlation Between Real and Imaginary Parts of Colored Pump Noise in Transient Process of Single-Mode Laser

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; CAO Li; WU Da-Jin

    2006-01-01

    A two-dimensional single-mode laser model with cross-correlation between the real and imaginary parts of the colored quadric pump noise is investigated. A novel laser amplitude Langevin equation is obtained, in which the cross-correlation λp between the real and imaginary parts of the pump noise appears. The mean, variance, and skewness of first-passage-time are calculated. It is shown that the mean, variance, and skewness of first-passage-time are strongly affected by λp.

  17. Photon higher-order squeezing effects of the q analogue of a single-mode field interacting with a Ξ-type three-level atom

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui-Hui; SHEN Hua-Jun; ZHOU Jing-Tao; LIU Xin-Yu

    2009-01-01

    The nonlinear theory of interaction between the q analogue of a single-mode field and a Ξ-type three-level atom has been established. And the formal solution of the Schrodinger equation in the representation and its average number are obtained. Then, the photon squeezing effects are studied through numerical calculation. The results show that the q deformation nonlinear action has a lot of influence on the quantum coherence and quantum properties. When q approaches 1, the theory reduces to the common linear theory.

  18. Propagation of Single-Mode Fibre Laser Beams through an Optical ABCD System with Circular Aperture at the Fibre Output End

    Institute of Scientific and Technical Information of China (English)

    DUAN Sai-Liang; LI Jian-Feng; ZHAO Wei; WANG Yi-Shan

    2008-01-01

    @@ Based on the expansion expression of the fundamental mode of a single-mode fibre in terms of Laguerre-Gauss modes, the propagation of a beam of a weakly guiding fibre laser through an optical ABCD system with a circular aperture at the fibre end is studied. The results show that there is much difference between the propagation of the laser beam described by the expansion expression and by the Gaussian mode approximation. The depth of focus of the laser beam is longer than that of the Gaussian modes.

  19. Design and analysis of a novel single-mode single-polarization photonic crystal fibre based on polarization-dependent coupling and absorption effect

    Institute of Scientific and Technical Information of China (English)

    Liu Xiao-Yi; Zhang Fang-Di; Zhang Min; Ye Pei-Da

    2007-01-01

    A novel single-mode single-polarization (SMSP) photonic crystal fibre has been proposed and analysed based on the polarization-dependent coupling and absorption effect via a full-vector finite element method with perfectly matched layers. The numerical results predict that very efficient SMSP operation can be achieved with both high bandwidth and high extinction ratio at low loss penalty. Effects of the fibre structural parameters on the SMSP bandwidth and extinction ratio have been explored, which will provide useful guide for the design and fabrication of the fibre. The results obtained will be instructive for the realization of new SMSP fibres with high performance.

  20. Experimental study of a high speed quantum random number generation scheme based on measuring phase noise of a single mode laser

    CERN Document Server

    Qi, Bing; Lo, Hoi-Kwong; Qian, Li

    2009-01-01

    In this paper, we present a high speed random number generation scheme based on measuring the quantum phase noise of a single mode diode laser operating at a low intensity level near the lasing threshold. A delayed self-heterodyning system has been developed to measure the random phase fluctuation. We experimentally investigate this random number generation scheme under two different operating conditions: with or without active phase stabilization of the fiber interferometer in the self-heterodyning system. The achieved random number generation rates are 500Mbit/s and 50Mbit/s, respectively. The generated random numbers have passed all the DIEHARD tests.

  1. Investigation on the use of standard single mode fiber as a displacement sensor using 1050 nm LED light source

    Science.gov (United States)

    Bayuwati, Dwi; Waluyo, Tomi Budi

    2016-02-01

    The use of standard single mode fiber using 1050 nm LED as displacement sensor was studied by examining the bending loss of the fiber. Three standard single mode fibers: jacketed and unjacketed patchcords, 2 m long each; and a 140 m length Fujikura fiber were used in this experiment. To simulate the displacement process, a fiber loop was clamped between the jaws of a vernier caliper to form a loop. Then, one of the movable jaw was shifted gradually every 0.5 mm resulting in the change of the diameter of the fiber and also the fiber output power. The value of the bending loss was measured as the output power at each position of the vernier caliper when varied from 50 to 10 mm. Investigation of bending loss values for all the fibers resulted in measurement range of 40 mm and resolution of 0.65-1.2 mm, depended on the material coating and the physical diameter of the fiber. Furthermore, the whispering gallery modes effect was unnoticeable and the relationship between output (bending loss, dB) and input (displacement, mm) at wavelength 1050 nm was almost linear which makes this system more practical for displacement sensor.

  2. Single-mode electrically pumped GaSb-based VCSELs emitting continuous-wave at 2.4 and 2.6 {mu}m

    Energy Technology Data Exchange (ETDEWEB)

    Bachmann, Alexander; Arafin, Shamsul; Kashani-Shirazi, Kaveh [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, 85748 Garching (Germany)], E-mail: bachmann@wsi.tum.de

    2009-12-15

    Vertical-cavity surface-emitting lasers (VCSELs) are perfect light sources for spectroscopic applications, where properties such as continuous-wave (cw) operation, single-mode emission, high lifetime and often low power consumption are crucial. For applications such as tunable diode laser absorption spectroscopy (TDLAS), there is a growing interest in laser devices emitting in the near- to mid-infrared wavelength range, where many environmentally and technologically important gases show strong absorption lines. The (AlGaIn)(AsSb) material system based on GaSb is the material of choice for covering the 2.0-3.3 {mu}m range. In this paper, we report on electrically pumped single-mode VCSELs with emission wavelengths of 2.4 and 2.6 {mu}m, operating cw at room temperature and beyond. By (electro-) thermal tuning, the emission wavelength can be tuned mode-hop free over a range of several nanometers. In addition, low threshold currents of several milliamperes promise mobile application. In the devices, a structured buried tunnel junction with subsequent overgrowth has been used in order to achieve efficient current confinement, reduced optical losses and increased electrical conductivity. Furthermore, strong optical confinement is introduced in the lasers due to laterally differing cavity lengths.

  3. Endoluminal non-contact soft tissue ablation using fiber-based Er:YAG laser delivery

    Science.gov (United States)

    Kundrat, Dennis; Fuchs, Alexander; Schoob, Andreas; Kahrs, Lüder A.; Ortmaier, Tobias

    2016-03-01

    The introduction of Er:YAG lasers for soft and hard tissue ablation has proven promising results over the last decades due to strong absorption at 2.94 μm wavelength by water molecules. An extension to endoluminal applications demands laser delivery without mirror arms due to dimensional constraints. Therefore, fiber-based solutions are advanced to provide exible access while keeping space requirements to a minimum. Conventional fiber-based treatments aim at laser-tissue interactions in contact mode. However, this procedure is associated with disadvantages such as advancing decrease in power delivery due to particle coverage of the fiber tip, tissue carbonization, and obstructed observation of the ablation progress. The objective of this work is to overcome aforementioned limitations with a customized fiber-based module for non-contact robot-assisted endoluminal surgery and its associated experimental evaluation. Up to the authors knowledge, this approach has not been presented in the context of laser surgery at 2.94 μm wavelength. The preliminary system design is composed of a 3D Er:YAG laser processing unit enabling automatic laser to fiber coupling, a GeO2 solid core fiber, and a customized module combining collimation and focusing unit (focal length of 20 mm, outer diameter of 8 mm). The performance is evaluated with studies on tissue substitutes (agar-agar) as well as porcine samples that are analysed by optical coherence tomography measurements. Cuts (depths up to 3mm) with minimal carbonization have been achieved under adequate moistening and sample movement (1.5mms-1). Furthermore, an early cadaver study is presented. Future work aims at module miniaturization and integration into an endoluminal robot for scanning and focus adaptation.

  4. Microstructured Optical Fiber-based Biosensors: Reversible and Nanoliter-Scale Measurement of Zinc Ions.

    Science.gov (United States)

    Heng, Sabrina; McDevitt, Christopher A; Kostecki, Roman; Morey, Jacqueline R; Eijkelkamp, Bart A; Ebendorff-Heidepriem, Heike; Monro, Tanya M; Abell, Andrew D

    2016-05-25

    Sensing platforms that allow rapid and efficient detection of metal ions would have applications in disease diagnosis and study, as well as environmental sensing. Here, we report the first microstructured optical fiber-based biosensor for the reversible and nanoliter-scale measurement of metal ions. Specifically, a photoswitchable spiropyran Zn(2+) sensor is incorporated within the microenvironment of a liposome attached to microstructured optical fibers (exposed-core and suspended-core microstructured optical fibers). Both fiber-based platforms retains high selectivity of ion binding associated with a small molecule sensor, while also allowing nanoliter volume sampling and on/off switching. We have demonstrated that multiple measurements can be made on a single sample without the need to change the sensor. The ability of the new sensing platform to sense Zn(2+) in pleural lavage and nasopharynx of mice was compared to that of established ion sensing methodologies such as inductively coupled plasma mass spectrometry (ICP-MS) and a commercially available fluorophore (Fluozin-3), where the optical-fiber-based sensor provides a significant advantage in that it allows the use of nanoliter (nL) sampling when compared to ICP-MS (mL) and FluoZin-3 (μL). This work paves the way to a generic approach for developing surface-based ion sensors using a range of sensor molecules, which can be attached to a surface without the need for its chemical modification and presents an opportunity for the development of new and highly specific ion sensors for real time sensing applications.

  5. Photothermal optomechanics in superfluid helium coupled to a fiber-based cavity

    CERN Document Server

    Kashkanova, A D; Brown, C D; Flowers-Jacobs, N E; Childress, L; Hoch, S W; Hohmann, L; Ott, K; Reichel, J; Harris, J G E

    2016-01-01

    Presented in this paper are measurements of an optomechanical device in which various acoustic modes of a sample of superfluid helium couple to a fiber-based optical cavity. In contrast with recent work on the paraxial acoustic mode confined by the cavity mirrors, we focus specifically on the acoustic modes associated with the helium surrounding the cavity. This paper provides a framework for understanding how the acoustic modes depend on device geometry. The acoustic modes are observed using the technique of optomechanically induced transparency/amplification. The optomechanical coupling to these modes is found to be predominantly photothermal.

  6. Optical fiber-based core-shell coaxially structured hybrid cells for self-powered nanosystems

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Caofeng; Zhu, Guang [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia (United States); Guo, Wenxi [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia (United States); State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Dong, Lin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia (United States); School of Materials Science and Enginnering, Zhenzhou University, Zhenghou 450001 (China); Wang, Zhong Lin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia (United States); Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing (China)

    2012-07-03

    An optical fiber-based 3D hybrid cell consisting of a coaxially structured dye-sensitized solar cell (DSSC) and a nanogenerator (NG) for simultaneously or independently harvesting solar and mechanical energy is demonstrated. The current output of the hybrid cell is dominated by the DSSC, and the voltage output is dominated by the NG; these can be utilized complementarily for different applications. The output of the hybrid cell is about 7.65 {mu}A current and 3.3 V voltage, which is strong enough to power nanodevices and even commercial electronic components. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Thermo-tunable hybrid photonic crystal fiber based on solution-processed chalcogenide glass nanolayers

    DEFF Research Database (Denmark)

    Markos, Christos

    2016-01-01

    The possibility to combine silica photonic crystal fiber (PCF) as low-loss platform with advanced functional materials, offers an enormous range of choices for the development of fiber-based tunable devices. Here, we report a tunable hybrid silica PCF with integrated As2S3 glass nanolayers inside...... antiresonances by taking advantage the high thermo-optic coefficient of the solution-processed nanolayers. Two different hybrid fiber structures, with core diameter 10 and 5 mu m, were developed and characterized using a supercontinuum source. The maximum sensitivity was measured to be as high as 3.6 nm...

  8. Fiber-Based Laser Transmitter for Oxygen A-Band Spectroscopy and Remote Sensing

    Science.gov (United States)

    Stephen, Mark A.; Abshire, James B.

    2010-01-01

    A fiber-based laser transmitter has been designed for active remote-sensing spectroscopy. The transmitter uses a master-oscillator-power-amplifier (MOPA) configuration with a distributed feedback diode-laser master oscillator and an erbium-doped fiber amplifier. The output from the MOPA is frequency-doubled with a periodically poled nonlinear crystal. The utility of this single-frequency, wavelength-tunable, power-scalable laser has been demonstrated in a spectroscopic measurement of the diatomic oxygen A-band.

  9. Single-fiber-based hybridization of energy converters and storage units using graphene as electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Joonho; Lee, Minbaek; Wang, Zhong Lin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Park, Young Jun; Cha, Seung Nam; Kim, Jong Min [Frontier Research Lab, Samsung Advanced Institute of Technology, Samsung Electronics, Gyeonggi-Do (Korea, Republic of); Choi, Young Jin [Department of Physics, MyongJi University, Yongin (Korea, Republic of); Department of Nano Science and Engineering, MyongJi University, Yongin (Korea, Republic of); Lee, Churl Seung [Energy Nanomaterials Research Center, Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Seongnam-si, Gyeonggi-do (Korea, Republic of)

    2011-08-09

    The first integration of multiple energy harvesters and a storage device along single fiber using ZnO nanowires (NWs) and graphenes as the basic materials is reported. This energy generation and storage device allows simultaneous harvesting of solar and mechanical energy. The unique architecture of fiber-based electrodes and use of ZnO NWs, and graphenes as active material and electrodes could be useful for the future development of flexible and wearable electronics. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Vibration sensing using a tapered bend-insensitive fiber based Mach-Zehnder interferometer.

    Science.gov (United States)

    Xu, Yanping; Lu, Ping; Qin, Zengguang; Harris, Jeremie; Baset, Farhana; Lu, Ping; Bhardwaj, Vedula Ravi; Bao, Xiaoyi

    2013-02-11

    In this study, a novel fiber-optic sensor consisting of a tapered bend-insensitive fiber based Mach-Zehnder interferometer is presented to realize damped and continuous vibration measurement. The double cladding structure and the central coating region of the in-fiber interferometer ensure an enhanced mechanical strength, reduced external disturbance, and a more uniform spectrum. A damped vibration frequency range of 29-60 Hz as well as continuous vibration disturbances ranging from 1 Hz up to 500 kHz are successfully demonstrated.

  11. Research and education on fiber-based materials for nanofluidics at Clemson University

    Science.gov (United States)

    Kornev, Konstantin G.

    2007-11-01

    Advanced materials and the science and engineering related to their design, process, test and manufacture represents one of the fast growing sectors of the Materials Science and Engineering field. Awareness of existing process, performance, manufacturing or recycle-ability issues and limitations, often dictates the next generation of advances needed to improve existing or create new materials. To compete in this growing science and technology area, trained experts must possess strong academic skills in their discipline as well as advanced communication, networking and cultural teamwork experience. Clemson's School of Materials Science and Engineering (MSE), is continuing to expand our program to focus on unique capabilities which support local, regional and national needs in advanced materials. Specifically, MSE at Clemson is evolving to highlight intrinsic strengths in research and education areas related to optical materials, advanced fibers and composites (based on inorganic, organic and natural fibers), biomaterials and devices, and architectural and restoration material science (including the conservation and preservation of maritime structures). Additionally, we continue to invest in our expertise in materials design and fabrication, which has historically supported our well known programs in ceramics and textiles. In addition to a brief review of the School's forward-looking challenges to remain competitive among strong southeast regional materials science programs, this presentation will also highlight recent technical advances in fiber-based materials for nanofluidic applications. Specifically we will present recent results on design of fiber-based nanofluidics for sensor applications and we will discuss some physical phenomena associated with liquid transport at nanoscale.

  12. Heat and moisture transport in durian fiber based lightweight construction materials

    Energy Technology Data Exchange (ETDEWEB)

    Charoenvai, S.; Khedari, J.; Hirunlabh, J.; Asasutjarit, C. [King Mongkut' s Univ. of Technology, Building Scientific Research Center, Thonburi, Bangkok (Thailand); Zeghmati, B. [Perpignan Univ., Centre d' Etudes Fondamentales, Groupe de Mecanique, Acoustique et Instrumentation, Perpignan, 66 (France); Quenard, D.; Pratintong, N. [Centre Scientifique et Technique du Batiment (CSTB), Grenoble (France)

    2005-04-01

    This paper presents result on heat and moisture transport in durian (Durio zibethinus) fiber based lightweight construction materials composed of cement, sand and waste fiber from durian peel and the performance of the material was simulated with the surface treatment by using a computational tool. The commercial research software (WUFI 2D) was used to calculate heat and moisture transfer through a durian fiber based lightweight construction material. The materials were exposed to a climate condition similar to the one in Bangkok and the hygrothermal characteristics of the materials were investigated. The investigation reveals that the weekly mean water content on the surface of material was quite low. The effect of moisture on the apparent thermal performance of the composite was found to be higher as water absorbed in the pore structure contributed to higher thermal conductivity than the air it replaced. However, the mean value of thermal conductivity in material is still rather low as the mean value of water content in material is low. Coating the surface reduced the flow of moisture to or from the structure considerably. The results of simulation confirmed that the manufactured composite satisfied the requirement of construction materials. It is then reasonable to conclude that the use of such materials in the design and construction of passive solar buildings is promising. Laboratory investigation is undergoing to validate the simulated performance. (Author)

  13. Fiber-based modulated optical reflectance configuration allowing for offset pump and probe beams

    Science.gov (United States)

    Fleming, A.; Folsom, C.; Jensen, C.; Ban, H.

    2016-12-01

    A new fiber-based modulated optical reflectance configuration is developed in this work. The technique maintains the fiber-based heating laser (pump) and detection laser (probe) in close proximity at a fixed separation distance in a ceramic ferrule. The pump beam periodically heats the sample inducing thermal waves into the sample. The probe beam measures the temperature response at a known distance from the pump beam over a range of heating modulation frequencies. The thermal diffusivity of the sample may be calculated from the phase response between the input heat flux and the temperature response of a sample having a reflective surface. The unique measurement configuration is ideal for in situ measurements and has many advantages for laboratory-based systems. The design and development of the system are reported along with theoretical justification for the experimental design. The thermal diffusivities of Ge and SiC are measured and found to be within 10% of reported literature values. The diffusivity for SiO2 is measured with a relative difference of approximately 100% from the literature value when the ferrule is in contact with the sample. An additional measurement was made on the SiO2 sample with the ferrule not in contact resulting in a difference of less than 2% from the literature value. The difference in the SiO2 measurement when the ferrule is in contact with the sample is likely due to a parallel heat transfer path through the dual-fiber ferrule assembly.

  14. Measurement of CO2-laser-irradiation-induced refractive index modulation in single-mode fiber toward long-period fiber grating design and fabrication.

    Science.gov (United States)

    Li, Yanjun; Wei, Tao; Montoya, John A; Saini, Sandeep V; Lan, Xinwei; Tang, Xiling; Dong, Junhang; Xiao, Hai

    2008-10-10

    We report a new method to measure the CO(2)-laser-irradiation-induced refractive index modulation in the core of a single-mode optical fiber for the purpose of design and fabrication of long-period fiber gratings (LPFGs) without applying tension. Using an optical fiber Fabry-Perot interferometer, the laser-induced axial refractive index perturbation was measured. We found that the CO(2)-laser-irradiation-induced refractive index change in the fiber core had a negative value and that the magnitude was a sensitive function of the laser exposure time following almost a linear relation. Under the assumption of a Gaussian-shaped refractive index modulation profile and based on the first two terms of Fourier series approximation, the measured refractive index perturbations were used to simulate the LPFG transmission spectra. LPFGs with the same laser exposure parameters were fabricated without applying tension, and their spectra were compared with those obtained by simulations.

  15. Stable single-mode distributed feedback quantum cascade lasers at λ ∼ 4.25 μm with low power consumption

    Science.gov (United States)

    Jia, Zhiwei; Wang, Lijun; Zhang, Jinchuan; Liu, Fengqi; Zhuo, Ning; Zhai, Shenqiang; Liu, Junqi; Wang, Zhanguo

    2016-10-01

    Short-wavelength (4.25 μm) distributed-feedback quantum cascade laser operating in continuous wave (cw) mode at room temperature with low power consumption was presented. Stable single-mode operation with a side-mode-suppression-ratio above 25 dB was maintained for the whole measured current and temperature range by enlarging gain difference and strong grating coupling. Because of the strong coupling, very low threshold current and power consumption were achieved. For a device of 9-μm-wide and 2-mm-long, the cw threshold current and power consumption at 293 K were as low as 126 mA and 1.45 W, respectively. All results above were from the device without using buried heterostructure geometry.

  16. VCSEL Transmission at 10 Gb/s for 20 km Single Mode Fiber WDM-PON without Dispersion Compensation or Injection Locking

    DEFF Research Database (Denmark)

    Gibbon, Timothy Braidwood; Prince, Kamau; Pham, Tien Thang;

    2011-01-01

    how off-center wavelength filtering of the VCSEL spectrum at an array waveguide grating can be used to mitigate the effect of chirp and the dispersion penalty. Transmission at 10Gb/s VCSEL over 23.6 km of single mode fiber is experimentally demonstrated, with a dispersion penalty of only 2.9 d......B. Simulated results are also presented which show that off-center wavelength filtering can extend the 10 Gb/s network reach from 11.7 km to 25.8 km for a 4 dB dispersion penalty. This allows for cheap and simple dispersion mitigation in next generation VCSEL based optical access networks....

  17. Empirical relations to determine the normalized spot size of a single-mode trapezoidal index fiber and computation of its propagation characteristics

    Science.gov (United States)

    Mallick, Aswini Kumar; Sarkar, Somenath

    2014-07-01

    Simple and complete empirical relations are presented here to determine a normalized spot size in terms of normalized frequencies over a long range and aspect ratio of a trapezoidal index single-mode fiber considering Gaussian approximation of the fundamental mode following the Marcuse method for the first time. After verification of their validity for arbitrary values of aspect ratio and normalized frequency, we calculate various propagation characteristics viz. dispersion and splice loss by using our formulations. Upon comparison, we observe an excellent match and the validity of our results with exact values and other results available in the literature. These formulas should attract the attention of experimentalists as a simple alternative to the rigorous methods of estimating the propagation characteristics of such fibers.

  18. Merged beam laser design for reduction of gain-saturation and two-photon absorption in high power single mode semiconductor lasers.

    Science.gov (United States)

    Lysevych, M; Tan, H H; Karouta, F; Fu, L; Jagadish, C

    2013-04-08

    In this paper we report a method to overcome the limitations of gain-saturation and two-photon absorption faced by developers of high power single mode InP-based lasers and semiconductor optical amplifiers (SOA) including those based on wide-waveguide or slab-coupled optical waveguide laser (SCOWL) technology. The method is based on Y-coupling design of the laser cavity. The reduction in gain-saturation and two-photon absorption in the merged beam laser structures (MBL) are obtained by reducing the intensity of electromagnetic field in the laser cavity. Standard ridge-waveguide lasers and MBLs were fabricated, tested and compared. Despite a slightly higher threshold current, the reduced gain-saturation in MBLs results in higher output power. The MBLs also produced a single spatial mode, as well as a strongly dominating single spectral mode which is the inherent feature of MBL-type cavity.

  19. Multi-wavelength Erbium-doped fiber laser based on four-wave-mixing effect in single mode fiber and high nonlinear fiber.

    Science.gov (United States)

    Wang, Pinghe; Weng, Danmei; Li, Kun; Liu, Yong; Yu, Xuecai; Zhou, Xiaojun

    2013-05-20

    A multi-wavelength Erbium-doped fiber (EDF) laser based on four-wave-mixing is proposed and experimentally demonstrated. The 5 km single mode fiber in the cavity enhances the four-wave-mixing to suppress the homogenous broadening of the erbium-doped fiber and get the stable multi-wavelength comb. The lasing stability is investigated. When the pump power is 300 mW, the fiber laser has 5-lasing lines and the maximum fluctuation of the output power is about 3.18 dB. At the same time, a laser with 110 m high nonlinear fiber (HNFL) is demonstrated. When the pump power is 300 mW, it has 7-lasing lines (above -30 dBm) and the maximum fluctuation is 0.18dB.

  20. Optically tunable microwave, millimeter-wave and submillimeter-wave utilizing single-mode Fabry-Pérot laser diode subject to optical feedback.

    Science.gov (United States)

    Wu, Jian-Wei; Nakarmi, Bikash; Won, Yong Hyub

    2016-02-01

    In this paper, we use optical feedback injection technique to generate tunable microwave, millimeter-wave and submillimeter-wave signals using single-mode Fabry-Pérot laser diode. The beat frequency of the proposed generator ranges from 30.4 GHz to 3.40 THz. The peak power ratio between two resonating modes at the output spectrum of can be less than 0.5 dB by judiciously selecting feedback wavelength. In the stabilization test, the peak fluctuation of photonic signal is as low as 0.19 dB within half hour. Aside from locking regions, where the laser is easily locked by the injection beam, the side-mode suppression ratio is well over 25 dB with the maximum value of 36.6 dB at 30.4 GHz beat frequency. In addition, the minimum beat frequency interval between two adjacent photonic signals is as low as 10 GHz.

  1. Effects of Correlations Between the Real and Imaginary Parts of Quantum Noise on Intensity Fluctuation for a Single-Mode Laser

    Institute of Scientific and Technical Information of China (English)

    谢崇伟; 梅冬成

    2003-01-01

    We study the effects of correlations between the real and imaginary parts of quantum noise on the intensity fluctuation for a single-mode laser. The analytic expressions of the intensity correlation function C(τ) and the associated relaxation time Tc in the case of a stable locked phase resulting from the cross-correlation λq between the real and imaginary parts of quantum noise are derived by means of projection operator method. Based on numerical computations it is found that the presence of cross-correlations between the real and imaginary parts of quantum noise causes the intensity fluctuation to increase. A slowing-down phenomenon exists in the sense that Tc increases as a function of |λq|. Thus the decay of intensity fluctuation becomes slower.

  2. Stochastic Resonance in a Single-Mode Laser Driven by Quadratic Colored Pump Noise and Quantum Noise with Cross-Correlation Between Real and Imaginary Parts of Noise

    Science.gov (United States)

    Xu, De-Sheng; Cao, Li; Wu, Da-Jin

    Based on the single-mode laser noise model driven by quadratic colored pump noise and quantum noise with cross-correlation between real and imaginary parts of noise proposed in International Journal of Modern Physics B 20, 5383 (2006) and Phys. Rev. E 73, 023802 (2006), the stochastic resonance (SR) of laser intensity is investigated by virtue of the linearized approximation. The analytic expression of signal-to-noise ratio (SNR) is calculated. It is found that the phenomena of stochastic resonance respectively exist in the curves of the SNR versus the noise cross-correlation coefficient λp and the SNR versus the pump parameter a, as well as the SNR versus the signal frequency bar {ω } for the model. It is shown that there are three different types of SR in the model: the conventional form of SR, the SR in the broad sense and the bona fide SR.

  3. Mode size converter between high-index-contrast waveguide and cleaved single mode fiber using SiON as intermediate material.

    Science.gov (United States)

    Jia, Lianxi; Song, Junfeng; Liow, Tsung-Yang; Luo, Xianshu; Tu, Xiaoguang; Fang, Qing; Koh, Sing-Chee; Yu, Mingbin; Lo, Guoqiang

    2014-09-22

    High-index-contrast (HIC) waveguide such as Si and Si3N4 has small mode size enabling compact integration. However, the coupling loss with single mode fiber is also remarkable owning to the mode mismatching. Therefore, mode size converter, as the interface between HIC waveguide and optical fiber, takes an important role in the field of integrated optics. The material with refractive index (RI) between HIC waveguide and optical fiber can be used as a bridge to reduce the mode mismatching loss. In this letter, we employ silicon oxynitride (SiON) with RI about 1.50 as the intermediate material and optimize the structure of the SiON waveguide to match with cleaved single mode fiber and HIC waveguide separately. Combined with inverse taper and suspended structure, the mismatching loss is reduced and the dependence to the dimension of the structure is also released. The coupling loss is 1.2 and 1.4 dB/facet for TE and TM mode, respectively, with 3 dB alignment tolerance of ± 3.5 μm for Si(3)N(4) waveguide with just 200 nm-wide tip. While for Si waveguide, a critical dimension of 150 nm is applied due to the higher index contrast than Si(3)N(4) waveguide. Similar alignment tolerance is realized with coupling loss about 1.8 and 2.1 dB/facet for TE and TM mode. The polarization dependence loss (PDL) for both platforms is within 0.5 dB.

  4. Passive endoscopic polarization sensitive optical coherence tomography with completely fiber based optical components

    Science.gov (United States)

    Cahill, Lucas; Lee, Anthony M. D.; Pahlevaninezhad, Hamid; Ng, Samson; MacAulay, Calum E.; Poh, Catherine; Lane, Pierre

    2015-03-01

    Polarization Sensitive Optical Coherence Tomography (PSOCT) is a functional extension of Optical Coherence Tomography (OCT) that is sensitive to well-structured, birefringent tissue such as scars, smooth muscle and cartilage. In this work, we present a novel completely fiber based swept source PSOCT system using a fiber-optic rotary pullback catheter. This PSOCT implementation uses only passive optical components and requires no calibration while adding minimal additional cost to a standard structural OCT imaging system. Due to its complete fiber construction, the system can be made compact and robust, while the fiber-optic catheter allows access to most endoscopic imaging sites. The 1.5mm diameter endoscopic probe can capture 100 frames per second at pullback speeds up to 15 mm/s allowing rapid traversal of large imaging fields. We validate the PSOCT system with known birefringent tissues and demonstrate in vivo PSOCT imaging of human oral scar tissue.

  5. Optomechanics in superfluid helium coupled to a fiber-based cavity

    Science.gov (United States)

    Kashkanova, A. D.; Shkarin, A. B.; Brown, C. D.; Flowers-Jacobs, N. E.; Childress, L.; Hoch, S. W.; Hohmann, L.; Ott, K.; Reichel, J.; Harris, J. G. E.

    2017-03-01

    Presented in this paper are measurements of an optomechanical device in which various acoustic modes of a sample of superfluid helium couple to a fiber-based optical cavity. In contrast with recent work on the paraxial acoustic mode confined by the cavity mirrors (Kashkanova et al Nat. Phys. 2016 (https://doi.org/10.1038/NPHYS3900)), we focus specifically on the acoustic modes associated with the helium surrounding the cavity. This paper provides a framework for understanding how the acoustic modes depend on device geometry. The acoustic modes are observed using the technique of optomechanically induced transparency/amplification. The optomechanical coupling to these modes is found to be predominantly photothermal.

  6. Preparation and characterization of novel super-artificial hair fiber based on biomass materials.

    Science.gov (United States)

    Yang, Lijun; Guo, Jing; Zhang, Sen; Gong, Yumei

    2017-06-01

    A novel super-artificial hair fiber basing on sodium alginate (SA) and Antarctic Krill protein (AKP) was prepared by wet spinning successfully. Such SA/AKP fiber did not only have similar crystalline structure with human hair, but also had super flame resistance and mechanical performance. It should be noted that the whole preparation process was green without any incorporation of non-toxic solution. Moreover, comparing with human hair, the SA/AKP fiber had a lot of unique groove upon the fiber surface, which contributed a lot to excellent hygroscopicity. Meanwhile, the dyeing performance could be improved notably due to incorporation of protein into the matrix. Herein, the SA/AKP fiber with superior mechanical and functional performance had practical value for application in the field of synthetic wig. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Silk-based biomaterials in biomedical textiles and fiber-based implants.

    Science.gov (United States)

    Li, Gang; Li, Yi; Chen, Guoqiang; He, Jihuan; Han, Yifan; Wang, Xiaoqin; Kaplan, David L

    2015-06-03

    Biomedical textiles and fiber-based implants (BTFIs) have been in routine clinical use to facilitate healing for nearly five decades. Amongst the variety of biomaterials used, silk-based biomaterials (SBBs) have been widely used clinically viz. sutures for centuries and are being increasingly recognized as a prospective material for biomedical textiles. The ease of processing, controllable degradability, remarkable mechanical properties and biocompatibility have prompted the use of SBBs for various BTFIs for extracorporeal implants, soft tissue repair, healthcare/hygiene products and related needs. The present Review focuses on BTFIs from the perspective of types and physical and biological properties, and this discussion is followed with an examination of the advantages and limitations of BTFIs from SBBs. The Review covers progress in surface coatings, physical and chemical modifications of SBBs for BTFIs and identifies future needs and opportunities for the further development for BTFIs using SBBs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. High-power actively Q-switched single-mode 1342 nm Nd:YVO4 ring laser, injection-locked by a cw single-frequency microchip laser.

    Science.gov (United States)

    Koch, Peter; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-30

    In this paper we report on the realization of a single-mode Q-switched Nd:YVO4 ring laser at 1342 nm. Unidirectional and single-mode operation of the ring laser is achieved by injection-locking with a continuous wave Nd:YVO4 microchip laser, emitting a single-frequency power of up to 40 mW. The ring laser provides a single-mode power of 13.9 W at 10 kHz pulse repetition frequency with a pulse duration of 18.2 ns and an excellent beam quality (M2 laser, a power of 8.7 W at 671 nm with a pulse duration of 14.8 ns and a beam propagation factor of M2 < 1.1 is obtained. The 671 nm radiation features a long-term spectral width of 75 MHz.

  9. Single-mode displacement sensor

    Science.gov (United States)

    Duivenvoorden, Kasper; Terhal, Barbara M.; Weigand, Daniel

    2017-01-01

    We show that one can determine both parameters of a displacement acting on an oscillator with an accuracy which scales inversely with the square root of the number of photons in the oscillator. Our results are obtained by using a grid state as a sensor state for detecting small translations in phase space (displacements). Grid states were first proposed [D. Gottesman et al., Phys. Rev. A 64, 012310 (2001), 10.1103/PhysRevA.64.012310] for encoding a qubit into an oscillator: an efficient preparation protocol of such states, using a coupling to a qubit, was later developed [B. M. Terhal and D. Weigand, Phys. Rev. A 93, 012315 (2016), 10.1103/PhysRevA.93.012315]. We compare the performance of the grid state with the quantum compass or cat code state and place our results in the context of the two-parameter quantum Cramér-Rao lower bound on the variances of the displacement parameters. We show that the accessible information about the displacement for a grid state increases with the number of photons in the state when we measure and prepare the state using a phase estimation protocol. This is in contrast with the accessible information in the quantum compass state which we show is always upper bounded by a constant, independent of the number of photons. We present numerical simulations of a phase estimation based preparation protocol of a grid state in the presence of photon loss, nonlinearities, and qubit measurement, using no post-selection, showing how the two effective squeezing parameters which characterize the grid state change during the preparation. The idea behind the phase estimation protocol is a simple maximal-information gain strategy.

  10. Conventional and photonic crystal fiber based two-photon fluorescence biosensing

    Science.gov (United States)

    Myaing, Mon Thiri

    Optical fiber probes are widely used in the biomedical field for applications such as optical microscopy, endoscopy, and optical biopsy. Due to their flexibility and small size, optical fibers offer a minimally invasive light interface for imaging and spectroscopic analysis of internal tissue. The development of fluorescent probes for studies of biological processes has increased the importance of developing optical methods for quantitative, in vivo diagnosis. In this dissertation, we discuss the development of a novel two-photon optical fiber fluorescence (TPOFF) probe for real time, in vivo, quantitative fluorescence measurements in biological samples. In order to understand and optimize two-photon excitation through an optical fiber, pulse propagation effects must be considered. We found a simple phenomenological scaling behavior for the energy dependence of the pulse width for negatively pre-chirped pulses propagating in a normally dispersive fiber. As a consequence of this scaling behavior, the dependence of two-photon fluorescence (TPF) on the pulse intensity becomes sub-quadratic. The TPOFF probe employs a scheme where the same single-mode fiber (SMF) is used for both the excitation and collection of TPF. Using this fiber probe, we show quantification of tumor fluorescence both ex vivo and in vivo. In ex vivo measurements of tumors developed from cells expressing the green fluorescence protein (GFP), the TPOFF probe detected fluorescence from tumors with as little as 0.3% GFP cells. These results were similar to flow cytometry analysis of isolated cells from the tumors. The TPOFF measurements of GFP tumors in live, anesthetized mice showed a linear relationship between the measured fluorescence and the percentage of GFP expressing cells. The TPOFF probe was also used in targeted binding experiments of Herceptin antibody and folic acid-dendrimer nanoparticle conjugates. To improve the sensitivity of the TPOFF probe, a double-clad photonic crystal fiber (DCF

  11. Special Section Guest Editorial:Selected Topics in Biophotonics: Photoacoustic Tomography and Fiber-Based Lasers and Supercontinuum Sources

    DEFF Research Database (Denmark)

    Andersson-Engels, Stefan; Andersen, Peter E.

    2016-01-01

    The present special section entitled “Selected Topics in Biophotonics: Photoacoustic Tomography and Fiber-Based Lasers and Supercontinuum Sources” comprises two invited papers and several contributed papers from the summer school Biophotonics ’15, as well as contributed papers within this general...

  12. Orthogonal model and experimental data for analyzing wood-fiber-based tri-axial ribbed structural panels in bending

    Science.gov (United States)

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2017-01-01

    This paper presents an analysis of 3-dimensional engineered structural panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model...

  13. Performance analysis of a two-state quantum heat engine working with a single-mode radiation field in a cavity

    Science.gov (United States)

    Wang, Jianhui; He, Jizhou; He, Xian

    2011-10-01

    We present a performance analysis of a two-state heat engine model working with a single-mode radiation field in a cavity. The heat engine cycle consists of two adiabatic and two isoenergetic processes. Assuming the wall of the potential moves at a very slow speed, we determine the optimization region and the positive work condition of the heat engine model. Furthermore, we generalize the results to the performance optimization for a two-state heat engine with a one-dimensional power-law potential. Based on the generalized model with an arbitrary one-dimensional potential, we obtain the expression of efficiency as η=1-(EC)/(EH), with EH (EC) denoting the expectation value of the system Hamiltonian along the isoenergetic process at high (low) energy. This expression is an analog of the classical thermodynamical result of Carnot, ηc=1-(TC)/(TH), with TH (TC) being the temperature along the isothermal process at high (low) temperature. We prove that under the same conditions, the efficiency η=1-(EC)/(EH) is bounded from above the Carnot efficiency, ηc=1-(TC)/(TH), and even quantum dynamics is reversible.

  14. Periodic behavior of collapse-revival phenomenon in the full nonlinear interaction between a three-level atom and a single-mode field

    Science.gov (United States)

    Tavassoly, M. K.; Rastegarzadeh, M.

    2016-10-01

    In this paper based on a generalization of the Jaynes-Cummings model we solve the dynamical Hamiltonian describing the interaction between a (Λ or V-type) three-level atom and a single-mode field in the "full nonlinear regime" and then the analytical form of state vector of the system is explicitly obtained. In this manner, we encountered with "intensity-dependent detuning" as well as "intensity-dependent atom-field coupling" in our two models. Via choosing an appropriate deformation function (which imposes nonlinearity to the system) we consider the influence of Kerr-like medium from which the resonance condition for a selected number of quanta is achieved (selective transition is occurred). Furthermore, by these considerations, we may find the optimum values for atom-field coupling constants which provide a regular periodic behavior of probability amplitudes for the two considered atomic systems. Moreover, to show this periodic time behavior, the temporal evolution of the probability of the allowed atomic transitions as well as the Mandel parameter (as a non-classical sign) is depicted for various circumstances. As is observed, complete revivals may appear in some particular situations.

  15. Pulsed and CW adjustable 1942 nm single-mode all-fiber Tm-doped fiber laser system for surgical laser soft tissue ablation applications.

    Science.gov (United States)

    Huang, Yize; Jivraj, Jamil; Zhou, Jiaqi; Ramjist, Joel; Wong, Ronnie; Gu, Xijia; Yang, Victor X D

    2016-07-25

    A surgical laser soft tissue ablation system based on an adjustable 1942 nm single-mode all-fiber Tm-doped fiber laser operating in pulsed or CW mode with nitrogen assistance is demonstrated. Ex vivo ablation on soft tissue targets such as muscle (chicken breast) and spinal cord (porcine) with intact dura are performed at different ablation conditions to examine the relationship between the system parameters and ablation outcomes. The maximum laser average power is 14.4 W, and its maximum peak power is 133.1 W with 21.3 μJ pulse energy. The maximum CW power density is 2.33 × 106 W/cm2 and the maximum pulsed peak power density is 2.16 × 107 W/cm2. The system parameters examined include the average laser power in CW or pulsed operation mode, gain-switching frequency, total ablation exposure time, and the input gas flow rate. The ablation effects were measured by microscopy and optical coherence tomography (OCT) to evaluate the ablation depth, superficial heat-affected zone diameter (HAZD) and charring diameter (CD). Our results conclude that the system parameters can be tailored to meet different clinical requirements such as ablation for soft tissue cutting or thermal coagulation for future applications of hemostasis.

  16. Stochastic Resonance in a Single - Mode Laser Driven by Pump Noise and Quantum Noise with Cross-Correlated Real and Imaginary Parts

    Institute of Scientific and Technical Information of China (English)

    CHENG Qing-Hua; CAO Li; WANG Jun; WU Da-Jin

    2004-01-01

    We present an analytic investigation of the signal-to-noise ratio (SNR) by studying a signal modulated model of a single-mode laser system driven by pump noise and quantum noise with correlated real and imaginary parts,and find there is a maximum in the curve of the dependence of SNR upon the cross-correlation coefficient λq between the real part and the imaginary part, i.e., stochastic resonance appears in the SNR vs. λq curve. Moreover, when the SNR is at the maximum, the cross-correlation coefficient λq = 0, which is coincidentally at the minimum of the mean normalized intensity fluctuation. The influences on stochastic resonance by the intensities of the pump and the quantum noise, the amplitude of the modulation signal, and the net gain of the laser are also studied. Furthermore, in order to ensure that the results obtained in this paper is reliable, the valid range for the linear approximation method is discussed.

  17. Stochastic Resonance in a Single-Mode Laser Driven by Pump Noise and QuantumNoise with Cross-Correlated Real and Imaginary Parts

    Institute of Scientific and Technical Information of China (English)

    CHENGQing-Hua; CAOLi; WANGJun; WUDa-Jin

    2004-01-01

    We present an analytic investigation of the signal-to-noise ratio (SNR) by studying a signal modulated model of a single-mode laser system driven by pump noise and quantum noise with correlated real and imaginary parts,and find there is a maximum in the curve of the dependence of SNR upon the cross-correlation coefficient λq between the real part and the imaginary part, i.e., stochastic resonance appears in the SNR vs. λq curve. Moreover, when the SNR is at the maximum, the cross-correlation coefficient λq = O, which is coincidentally at the minimum of the mean normalized intensity fluctuation. The influences on stochastic resonance by the intensities of the pump and the quantum noise, the amplitude of the modulation signal, and the net gain of the laser are also studied. Furthermore, in order to ensure that the results obtained in this paper is reliable, the valid range for the linear approximation method is discussed.

  18. Analysis of Signal-to-Crosstalk Ratio Variations due to Four-Wave Mixing in Dense Wavelength Division Multiplexing Systems Implemented with Standard Single-Mode Fibers

    Directory of Open Access Journals (Sweden)

    Sait Eser KARLIK

    2016-10-01

    Full Text Available In this paper, variation of the signal-to-crosstalk ratio (SXR due to effects of four-wave mixing (FWM has been analyzed on center channels of 5-, 7-, 9-channel dense wavelength division multiplexing (DWDM systems implemented with G.652 standard single-mode fibers (SSMFs for 12.5 GHz, 25 GHz, 50 GHz and 100 GHz equal channel spacing values. Center channels on such systems are the most severely impacted channels by FWM. Therefore, results obtained are the worst-case values for the DWDM system performance and important for system design. Simulations have been performed for systems using three different commercially available SMFs having different design parameter values for chromatic dispersion, dispersion slope, nonlinearity coefficient and attenuation coefficient which are all in the scope of the G.652 Recommendation of Telecommunication Standardization Sector of International Telecommunication Union (ITU-T for SSMFs. In those simulations, under the impact of FWM, variation of SXR with variations in input powers, channel spacings and link lengths have been observed. Simulation results display the combined effect of the optical fiber and system design parameters on FWM performance of DWDM systems and give important clues for not only long-haul but also access network implementations of DWDM systems.

  19. Quantum dynamics of a BEC interacting with a single-mode quantized field under the influence of a dissipation process: thermal and squeezed vacuum reservoirs

    Science.gov (United States)

    Ghasemian, E.; Tavassoly, M. K.

    2017-09-01

    In this paper we consider a system consisting of a number of two-level atoms in a Bose-Einstein condensate (BEC) and a single-mode quantized field, which interact with each other in the presence of two different damping sources, i.e. cavity and atomic reservoirs. The reservoirs which we consider here are thermal and squeezed vacuum ones corresponding to field and atom modes. Strictly speaking, by considering both types of reservoirs for each of the atom and field modes, we investigate the quantum dynamics of the interacting bosons in the system. Then, via solving the quantum Langevin equations for such a dissipative BEC system, we obtain analytical expressions for the time dependence of atomic population inversion, mean atom as well as photon number and quadrature squeezing in the field and atom modes. Our investigations demonstrate that for modeling the real physical systems, considering the dissipation effects is essential. Also, numerical calculations which are presented show that the atomic population inversion, the mean number of atoms in the BEC and the photons in the cavity possess damped oscillatory behavior due to the presence of reservoirs. In addition, non-classical squeezing effects in the field quadrature can be observed especially when squeezed vacuum reservoirs are taken into account. As an outstanding property of this model, we may refer to the fact that one can extract the atom-field coupling constant from the frequency of oscillations in the mentioned quantities such as atomic population inversion.

  20. Temperature-dependent strain and temperature sensitivities of fused silica single mode fiber sensors with pulse pre-pump Brillouin optical time domain analysis

    Science.gov (United States)

    Bao, Yi; Chen, Genda

    2016-06-01

    This paper reports a distributed temperature and strain sensor based on pulse pre-pump Brillouin optical time domain analysis. An uncoated, telecom-grade fused silica single-mode fiber as a distributed sensor was calibrated for its sensitivity coefficients under various strains and temperatures up to 800 °C. The Brillouin frequency of fiber samples changed nonlinearly with temperature and linearly with strain. The temperature sensitivity decreased from 1.113 to 0.830 MHz /°C in the range of 22-800 °C. The strain sensitivity was reduced from 0.054 to 0.042 MHz /μɛ as the temperature increased from 22 to 700 °C and became unstable at higher temperatures due to creep effect. The strain measurement range was reduced from 19 100 to 6000 μɛ in the temperature range of 22-800 °C due to fused silica’s degradation. The calibrated fiber optic sensor demonstrated adequate accuracy and precision for strain and temperature measurements and stable performance in heating-cooling cycles. It was validated in an application setting.

  1. Coupling Characteristics of Fused Optical Fiber Coupler Formed with Single-Mode Fiber and Photonic Crystal Fiber Having Air Hole Collapsed Taper

    Directory of Open Access Journals (Sweden)

    Hirohisa Yokota

    2016-01-01

    Full Text Available Fused coupler forming with a single-mode fiber (SMF and a photonic crystal fiber (PCF is one of the solutions for optical coupling from a light source to a PCF. In this paper, we presented coupling characteristics of a fused fiber coupler formed with an ordinary SMF and a PCF having air hole collapsed taper. A prototype of SMF-PCF coupler with air hole collapsed taper was fabricated using CO2 laser irradiation. The coupling efficiency from SMF to PCF was −6.2 dB at 1554 nm wavelength in the fabricated coupler. The structure of the SMF-PCF coupler to obtain high coupling efficiency was theoretically clarified by beam propagation analysis using an equivalent model of the coupler with simplification. It was clarified that appropriately choosing the prestretched or etched SMF diameter and the length of air hole collapsed region was effective to obtain high coupling efficiency that was a result of high extinction ratio at cross port and low excess loss. We also demonstrated that the diameter of prestretched SMF to obtain high coupling efficiency was insensitive to the air hole diameter ratio to pitch of the PCF in the air hole collapsed SMF-PCF coupler.

  2. Opto-mechanical design of a buckling cavity in a novel high-performance outside-plant robust field installable single-mode fibre connector

    Science.gov (United States)

    Ebraert, Evert; Van Erps, Jürgen; Beri, Stefano; Watté, Jan; Thienpont, Hugo

    2014-05-01

    Fibre-to-the-home (FTTH) networks provide an ideal means to reach the goal the European Union has set to provide 50 % of the households with a broadband connection faster than 100 Mb/s. Deployment of FTTH networks, which is still costly today, could be significantly boosted by novel ferrule-less connectors which don't require highly skilled personnel and allow installation in the field. We propose a ferrule-less connector in which two single-mode fibres (SMFs) are aligned and maintain physical contact by ensuring that at least one fibre is in a buckled state. To this end, we design a cavity in which a fibre can buckle in a controlled way. Using finite element analysis simulations to investigate the shape of the formed buckle for various buckling cavity lengths, we show that it can be accurately approximated by a cosine function. In addition, the optical performance of a buckled SMF is investigated by bending loss calculations and simulations. We show a good agreement between the analytical and the simulated bending loss results for a G.652 fibre at a wavelength of 1550 nm. Buckling cavity lengths smaller than 20 mm should be avoided to keep the optical bending loss due to buckling below 0.1 dB. In this case the cavity height should at least be 2 mm to avoid mechanical confinement of the fibre.

  3. Dynamics of 1.55 μm Wavelength Single-Mode Vertical-Cavity Surface-Emitting Laser Output under External Optical Injection

    Directory of Open Access Journals (Sweden)

    Kyong Hon Kim

    2012-01-01

    Full Text Available We review the temporal dynamics of the laser output spectrum and polarization state of 1.55 μm wavelength single-mode (SM vertical-cavity surface-emitting lasers (VCSELs induced by external optical beam injection. Injection of an external continuous-wave laser beam to a gain-switched SM VCSEL near the resonance wavelength corresponding to its main polarization-mode output was critical for improvement of its laser pulse generation characteristics, such as pulse timing-jitter reduction, linewidth narrowing, pulse amplitude enhancement, and pulse width shortening. Pulse injection of pulse width shorter than the cavity photon lifetime into the SM VCSEL in the orthogonal polarization direction with respect to its main polarization mode caused temporal delay of the polarization recovery after polarization switching (PS, and its delay was found to be the minimum at an optimized bias current. Polarization-mode bistability was observed even in the laser output of an SM VCSEL of a standard circularly cylindrical shape and used for all-optical flip-flop operations with set and reset injection pulses of very low pulse energy of order of the 3.5~4.5 fJ.

  4. Wavefront measurement of single-mode quantum cascade laser beam for seed application in laser-produced plasma extreme ultraviolet system.

    Science.gov (United States)

    Nowak, Krzysztof M; Ohta, Takeshi; Suganuma, Takashi; Yokotsuka, Toshio; Fujimoto, Junichi; Mizoguchi, Hakaru

    2012-12-01

    Quantum cascade laser (QCL) is a very attractive seed source for a multikilowatt pulsed CO2 lasers applied for driving extreme ultraviolet emitting plasmas. In this Letter, we investigate output beam properties of a QCL designed to address P18 and P20 lines of 10.6 micron band of CO2 molecule. In particular, output beam quality and stability are investigated for the first time. A well-defined linear polarization and a single-mode operation enabled a use of phase retrieval method for full description of QCL output beam. A direct, multi-image numerical phase retrieval technique was developed and successfully applied to the measured intensity patterns of a QCL beam. Very good agreement between the measured and reconstructed beam profiles was observed at distances ranging from QCL aperture to infinity, proving a good understanding of the beam propagation. The results also confirm a high spatial coherence and high stability of the beam parameters, the features expected from an excellent seed source.

  5. Twin-core fiber-based sensor for measuring the strain and bending simultaneously

    Science.gov (United States)

    Yang, Yuanyuan; Zhang, Yaxun; Liu, Zhihai; Yang, Jun; Yuan, Libo

    2013-08-01

    A novel composite interferometer sensor is presented and its sensing characteristics are investigated. Based on the infiber integrated Michelson interferometer, a quartz tube is used to encapsulate the ends of the twin-core fiber and single mode fiber to form the dual extrinsic FP cavities. Thereby, the Michelson and FP configurations are integrated into a single fiber, which we call it Michelson-FP composite interferometer sensor. The novel sensor can respond to the axial strain and radial bending simultaneously. We have derived and analyzed the interferometer principle of the new structure. The analysis results show that the interferometer sensor could be considered as the superposition of Michelson interferometer and FP interferometer. Moreover, we establish a testing system and conduct a series of experiments to investigate the strain and bending characteristics. We measure the reflection spectra with the spectrum analyzer. The spectral response of the composite interferometer sensor presents two pattern fringes with different frequencies due to the respective optical path interferometers. The experimental results indicate that the composite interferometer sensor is very sensitive to the strain and bending characteristics, and the presented sensor has different strain and bending sensitivity coefficients. Due to these characteristics, the presented sensor might be able to measure the strain and bending characteristics simultaneously. In conclusion, the presented novel interferometer sensor is of compact structure, high integration and good strain and bending sensing characteristics. Thus, many types of fiber-optic sensors may be built based on it.

  6. Blood pulse wave velocity and pressure sensing via fiber based and free space based optical sensors

    Science.gov (United States)

    Sirkis, Talia; Beiderman, Yevgeny; Agdarov, Sergey; Beiderman, Yafim; Zalevsky, Zeev

    2017-02-01

    Continuous noninvasive measurement of vital bio-signs, such as cardiopulmonary parameters, is an important tool in evaluation of the patient's physiological condition and health monitoring. On the demand of new enabling technologies, some works have been done in continuous monitoring of blood pressure and pulse wave velocity. In this paper, we introduce two techniques for non-contact sensing of vital bio signs. In the first approach the optical sensor is based on single mode in-fibers Mach-Zehnder interferometer (MZI) to detect heartbeat, respiration and pulse wave velocity (PWV). The introduced interferometer is based on a new implanted scheme. It replaces the conventional MZI realized by inserting of discontinuities in the fiber to break the total internal reflection and scatter/collect light. The proposed fiber sensor was successfully incorporated into shirt to produce smart clothing. The measurements obtained from the smart clothing could be obtained in comfortable manner and there is no need to have an initial calibration or a direct contact between the sensor and the skin of the tested individual. In the second concept we show a remote noncontact blood pulse wave velocity and pressure measurement based on tracking the temporal changes of reflected secondary speckle patterns produced in human skin when illuminated by a laser beams. In both concept experimental validation of the proposed schemes is shown and analyzed.

  7. Development of a flexible optical fiber based high resolution integrated PET∕MRI system.

    Science.gov (United States)

    Yamamoto, Seiichi; Watabe, Hiroshi; Kanai, Yasukazu; Watabe, Tadashi; Aoki, Masaaki; Sugiyama, Eiji; Kato, Katsuhiko; Hatazawa, Jun

    2012-11-01

    The simultaneous measurement of PET and magnetic resonance imaging (MRI) is an emerging field for molecular imaging research. Although optical fiber based PET∕MRI systems have advantages on less interference between PET and MRI, there is a drawback in reducing the scintillation light due to the fiber. To reduce the problem, the authors newly developed flexible optical fiber bundle based block detectors and employed them for a high resolution integrated PET∕MRI system. The flexible optical fiber bundle used 0.5 mm diameter, 80 cm long double clad fibers which have dual 12 mm × 24 mm rectangular inputs and a single 24 mm × 24 mm rectangular output. In the input surface, LGSO scintillators of 0.025 mol.% (decay time: ∼31 ns: 0.9 mm × 1.3 mm × 5 mm) and 0.75 mol.% (decay time: ∼46 ns: 0.9 mm × 1.3 mm × 6 mm) were optically coupled in depth direction to form depth-of-interaction detector, arranged in 11 × 13 matrix and optically coupled to the fiber bundle. The two inputs of the bundle are bent for 90°, bound to one, and are optically coupled to a Hamamatsu 1-in. square position sensitive photomultiplier tube. Light loss due to the fiber bundle could be reduced and the performance of the block detectors was improved. Eight optical fiber based block detectors (16 LGSO blocks) were arranged in a 56 mm diameter ring to form a PET system. Spatial resolution and sensitivity were 1.2 mm full-width at half-maximum and 1.2% at the central field-of-view, respectively. Sensitivity change was less than 1% for 2 °C temperature changes. This PET system was integrated with a 0.3 T permanent magnet MRI system which has 17 cm diameter hole at the yoke area for insertion of the PET detector ring. There was no observable interference between PET and MRI. Simultaneous imaging of PET and MRI was successfully performed for small animal studies. The authors confirmed that the developed high resolution PET∕MRI system is promising for molecular

  8. Simultaneous removal of nitrate and chromate in groundwater by a spiral fiber based biofilm reactor.

    Science.gov (United States)

    Zhai, Siyuan; Zhao, Yinxin; Ji, Min; Qi, Wenfang

    2017-05-01

    A spiral fiber based biofilm reactor was developed to remove nitrate and chromate simultaneously. The denitrification and Cr(VI) removal efficiency was evaluated with synthetic groundwater (NO3(-)-N=50mg/L) under different Cr(VI) concentrations (0-1.0mg/L), carbon nitrogen ratios (C/N) (0.8-1.2), hydraulic retention times (HRT) (2-16h) and initial pHs (4-10). Nitrate and Cr(VI) were completely removed without nitrite accumulation when the Cr(VI) concentration was lower than 0.4mg/L. As Cr(VI) up to 1.0mg/L, the system was obviously inhibited, but it recovered rapidly within 6days due to the strong adaption and domestication of microorganisms in the biofilm reactor. The results demonstrated that high removal efficiency of nitrate (≥99%) and Cr(VI) (≥95%) were achieved at lower C/N=0.9, HRT=8h, initial pH=7, and Cr(VI)=1.0mg/L. The technology proposed in present study can be alternative for simultaneous removal of co-contaminants in groundwater.

  9. Fiber-based hybrid probe for non-invasive cerebral monitoring in neonatology

    Science.gov (United States)

    Rehberger, Matthias; Giovannella, Martina; Pagliazzi, Marco; Weigel, Udo; Durduran, Turgut; Contini, Davide; Spinelli, Lorenzo; Pifferi, Antonio; Torricelli, Alessandro; Schmitt, Robert

    2015-07-01

    Improved cerebral monitoring systems are needed to prevent preterm infants from long-term cognitive and motor restrictions. Combining advanced near-infrared diffuse spectroscopy measurement technologies, time-resolved spectroscopy (TRS) and diffuse correlation spectroscopy (DCS) will introduce novel indicators of cerebral oxygen metabolism and blood flow for neonatology. For non-invasive sensing a fiber-optical probe is used to send and receive light from the infant head. In this study we introduce a new fiber-based hybrid probe that is designed for volume production. The probe supports TRS and DCS measurements in a cross geometry, thus both technologies gain information on the same region inside the tissue. The probe is highly miniaturized to perform cerebral measurements on heads of extreme preterm infants down to head diameters of 6cm. Considerations concerning probe production focus on a reproducible accuracy in shape and precise optical alignment. In this way deviations in measurement data within a series of probes should be minimized. In addition to that, requirements for clinical use like robustness and hygiene are considered. An additional soft-touching sleeve made of FDA compatible silicone allows for a flexible attachment with respect to the individual anatomy of each patient. We present the technical concept of the hybrid probe and corresponding manufacturing methods. A prototype of the probe is shown and tested on tissue phantoms as well as in vivo to verify its operational reliability.

  10. Fiber-based 1150-nm femtosecond laser source for the minimally invasive harmonic generation microscopy

    Science.gov (United States)

    Huang, Jing-Yu; Guo, Lun-Zhang; Wang, Jing-Zun; Li, Tse-Chung; Lee, Hsin-Jung; Chiu, Po-Kai; Peng, Lung-Han; Liu, Tzu-Ming

    2017-03-01

    Harmonic generation microscopy (HGM) has become one unique tool of optical virtual biopsy for the diagnosis of cancer and the in vivo cytometry of leukocytes. Without labeling, HGM can reveal the submicron features of tissues and cells in vivo. For deep imaging depth and minimal invasiveness, people commonly adopt 1100- to 1300-nm femtosecond laser sources. However, those lasers are typically based on bulky oscillators whose performances are sensitive to environmental conditions. We demonstrate a fiber-based 1150-nm femtosecond laser source, with 6.5-nJ pulse energy, 86-fs pulse width, and 11.25-MHz pulse repetition rate. It was obtained by a bismuth borate or magnesium-doped periodically poled lithium niobate (MgO:PPLN) mediated frequency doubling of the 2300-nm solitons, generated from an excitation of 1550-nm femtosecond pulses on a large mode area photonic crystal fiber. Combined with a home-built laser scanned microscope and a tailor-made frame grabber, we achieve a pulse-per-pixel HGM imaging in vivo at a 30-Hz frame rate. This integrated solution has the potential to be developed as a stable HGM system for routine clinical use.

  11. Fabrication of an IR hollow-core Bragg fiber based on chalcogenide glass extrusion

    Science.gov (United States)

    Zhu, Minming; Wang, Xunsi; Pan, Zhanghao; Cheng, Ci; Zhu, Qingde; Jiang, Chen; Nie, Qiuhua; Zhang, Peiqing; Wu, Yuehao; Dai, Shixun; Xu, Tiefeng; Tao, Guangming; Zhang, Xianghua

    2015-05-01

    The theoretical analysis and experimental preparation of a hollow-core Bragg fiber based on chalcogenide glasses are demonstrated. The fiber has potential applications in bio-sensing and IR energy transmission. Two chalcogenide glasses with, respectively, high and low refractive indexes are investigated in detail for the fabrication of hollow-core Bragg fibers. The most appropriate structure is selected; this structure is composed of four concentric rings and a center air hole . Its band gap for the Bragg fiber is analyzed by the plane wave method. The chalcogenide glasses Ge15Sb20S58.5I13 and Ge15Sb10Se75 are chosen to extrude the robust multi-material glass preform with a specialized punch and glass container. The glass preform is simultaneously protected with a polyetherimide polymer. The hollow-core Bragg fibers are finally obtained after glass preform extrusion, fiber preform fabrication, and fiber drawing. Results showed that the fiber has a transparency window from 2.5 to 14 μm, including a low-loss transmission window from 10.5 to 12 μm. The location of this low-loss transmission window matches the predicted photonic band gap in the simulation.

  12. Fiber-Based, Trace-Gas, Laser Transmitter Technology Development for Space

    Science.gov (United States)

    Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Nicholson, Jeffrey; Engin, Doruk; Mathason, Brian; Wu, Stewart; Allan, Graham; Hasselbrack, William; Gonzalez, Brayler; Han, Lawrence; Numata, Kenji; Storm, Mark; Abshire, James

    2015-01-01

    NASA’s Goddard Space Flight Center (GSFC) is working on maturing the technology readiness of a laser transmitter designed for use in atmospheric CO2 remote-sensing. GSFC has been developing an airplane-based CO2 lidar instrument over several years to demonstrate the efficacy of the instrumentation and measurement technique and to link the science models to the instrument performance. The ultimate goal is to make space-based satellite measurements with global coverage. In order to accomplish this, we must demonstrate the technology readiness and performance of the components as well as demonstrate the required power-scaling to make the link with the required signal-to-noise-ratio (SNR). To date, all the instrument components have been shown to have the required performance with the exception of the laser transmitter.In this program we are working on a fiber-based master oscillator power amplifier (MOPA) laser transmitter architecture where we will develop a ruggedized package and perform the relevant environmental tests to demonstrate TRL-6. In this paper we will review our transmitter architecture and progress on the performance and packaging of the laser transmitter.

  13. An Exposed-Core Grapefruit Fibers Based Surface Plasmon Resonance Sensor

    Directory of Open Access Journals (Sweden)

    Xianchao Yang

    2015-07-01

    Full Text Available To solve the problem of air hole coating and analyte filling in microstructured optical fiber-based surface plasmon resonance (SPR sensors, we designed an exposed-core grapefruit fiber (EC-GFs-based SPR sensor. The exposed section of the EC-GF is coated with a SPR, supporting thin silver film, which can sense the analyte in the external environment. The asymmetrically coated fiber can support two separate resonance peaks (x- and y-polarized peaks with orthogonal polarizations and x-polarized peak, providing a much higher peak loss than y-polarized, also the x-polarized peak has higher wavelength and amplitude sensitivities. A large analyte refractive index (RI range from 1.33 to 1.42 is calculated to investigate the sensing performance of the sensor, and an extremely high wavelength sensitivity of 13,500 nm/refractive index unit (RIU is obtained. The silver layer thickness, which may affect the sensing performance, is also discussed. This work can provide a reference for developing a high sensitivity, real-time, fast-response, and distributed SPR RI sensor.

  14. Fiber-based tissue identification for electrode placement in deep brain stimulation neurosurgery (Conference Presentation)

    Science.gov (United States)

    DePaoli, Damon T.; Lapointe, Nicolas; Goetz, Laurent; Parent, Martin; Prudhomme, Michel; Cantin, Léo.; Galstian, Tigran; Messaddeq, Younès.; Côté, Daniel C.

    2016-03-01

    Deep brain stimulation's effectiveness relies on the ability of the stimulating electrode to be properly placed within a specific target area of the brain. Optical guidance techniques that can increase the accuracy of the procedure, without causing any additional harm, are therefore of great interest. We have designed a cheap optical fiber-based device that is small enough to be placed within commercially available DBS stimulating electrodes' hollow cores and that is capable of sensing biological information from the surrounding tissue, using low power white light. With this probe we have shown the ability to distinguish white and grey matter as well as blood vessels, in vitro, in human brain samples and in vivo, in rats. We have also repeated the in vitro procedure with the probe inserted in a DBS stimulating electrode and found the results were in good agreement. We are currently validating a second fiber optic device, with micro-optical components, that will result in label free, molecular level sensing capabilities, using CARS spectroscopy. The final objective will be to use this data in real time, during deep brain stimulation neurosurgery, to increase the safety and accuracy of the procedure.

  15. Development of a fiber based Raman probe compatible with interventional magnetic resonance imaging

    Science.gov (United States)

    Ashok, Praveen C.; Praveen, Bavishna B.; Rube, Martin; Cox, Benjamin; Melzer, Andreas; Dholakia, Kishan

    2014-02-01

    Raman spectroscopy has proven to be a powerful tool for discriminating between normal and abnormal tissue types. Fiber based Raman probes have demonstrated its potential for in vivo disease diagnostics. Combining Raman spectroscopy with Magnetic Resonance Imaging (MRI) opens up new avenues for MR guided minimally invasive optical biopsy. Although Raman probes are commercially available, they are not compatible with a MRI environment due to the metallic components which are used to align the micro-optic components such as filters and lenses at the probe head. Additionally they are not mechanically compatible with a typical surgical environment as factors such as sterility and length of the probe are not addressed in those designs. We have developed an MRI compatible fiber Raman probe with a disposable probe head hence maintaining sterility. The probe head was specially designed to avoid any material that would cause MR imaging artefacts. The probe head that goes into patient's body had a diameter biopsy needles and catheters. The probe has been tested in MR environment and has been proven to be capable of obtaining Raman signal while the probe is under real-time MR guidance.

  16. Frittage micro-ondes en cavité monomode de biocéramiques Microwaves sintering of bioceramics in a single mode cavity

    Directory of Open Access Journals (Sweden)

    Savary Etienne

    2013-11-01

    Full Text Available Le but premier de cette étude est de montrer la faisabilité du frittage direct en cavité micro-ondes monomode de deux biomatériaux céramiques : l'hydroxyapatite et le phosphate tri-calcique. Ainsi, cette étude montre que ce procédé a permis d'obtenir, en des temps très courts, inférieurs à 20 minutes, des échantillons denses présentant des microstructures fines. Les caractérisations mécaniques sur les échantillons frittés par micro-ondes ont révélé des valeurs de module d'élasticité et de dureté supérieures à celles généralement obtenues sur des échantillons frittés de manière conventionnelle. Ces résultats sont discutés en fonction de la microstructure obtenue et des différents paramètres expérimentaux : granulométrie des poudres, température de frittage, temps d'irradiation micro-ondes. The main purpose of this study consists in investigating the direct microwaves sintering in a single mode cavity of two bioceramics: hydroxyapatite and tri-calcium phosphate. Thus, dense samples presenting fine microstructures are successfully obtained in less than 20 minutes of irradiation. The resulting mechanical characterizations on microwaves sintered samples evidence higher Young's modulus and hardness values than those usually reported on conventionally sintered samples. Those results are discussed according to the microstructures observed and the experimental parameters such as powders granulometries, sintering temperatures, microwaves irradiation times.

  17. Steady-State Analysis of a Single-Mode Laser Driven by Colored Pump Noise withCross-Correlation Between Real and Imaginary Parts of Quantum Noise

    Institute of Scientific and Technical Information of China (English)

    ZHANGLi; CAOLi; WUDa-Jin

    2003-01-01

    Applying the method of the unified colored noise approximation and phase lock, we study in this paper the stationary intensity distribution of the single-mode laser driven by colored pump noise with cross-correlation between the real and imaginary parts of the quantum noise. We present a thorough discussion of how the cross-correlation λq between the real and imaginary parts of the quantum noise and the self-correlation time τ of the pump noise determine the behaviors of the stationary distribution Qst(I), the mean (I), and the variance λ2(0) of the laser intensity. It is shown that cross-correlation intensity λq of the complex quantum noise can induce a first-order-like transition. When the pump noise is colored noise (τ≠0), improving the pump parameters monotonously will make the curves of Qst(I) exhibit reentrant phase transition. The fluctuations of laser intensity are strongly influenced by λq and τ when the laser is operated near or below threshold. Especially when τ≠0, the heights of the peaks of the curves of λ2(0)-α0 and α3(0)-α0, (here a0 is the net gain coefficient) go up as λq increases. However the entire curves λ2(0)-α0 and λ3(0)-α0 are abruptly suppressed when λq = 1, in similarity to phase transition of stationary intensity distribution.

  18. Steady-State Analysis of a Single-Mode Laser Driven by Colored Pump Noise with Cross-Correlation Between Real and Imaginary Parts of Quantum Noise

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; CAO Li; WU Da-Jin

    2003-01-01

    Applying the method of the unified colored noise approximation and phase lock, we study in this paper the stationary intensity distribution of the single-mode laser driven by colored pump noise with cross-correlation between the real and imaginary parts of the quantum noise. We present a thorough discussion of how the cross-correlation λq between the realand imaginary parts of the quantum noise and the self-correlation time τ of the pump noise determine the behaviors of the stationary distribution Qst(I), the mean (I), and the variance λ2(0) of the laser intensity. It is shown that cross-correlation intensity λq of the complex quantum noise can induce a first-order-like transition. When the pump noise is colored noise (τ≠ 0), improving the pump parameters monotonously will make the curves of Qst(I)exhibit reentrant phase transition. The fluctuations of laser intensity are strongly influenced by λq and τ when the laser is operated near or below threshold. Especially when τ≠ 0, the heights of the peaks of the curves of λ2(0)-a0 and λ3(0)-a0, (here a0 is the net gain coefficient) go up as λq increases. However the entire curves of λ2(0)-a0 and λ3(0)-a0are abruptly suppressed when λq = 1, in similarity to phase transition of stationary intensity distribution.

  19. Discretely tunable Tm-doped fiber-based MOPA using FBG arrays as spectral filters

    Science.gov (United States)

    Tiess, T.; Junaid, S.; Becker, M.; Rothhardt, M.; Bartelt, H.; Jäger, M.

    2016-03-01

    Over the past years, Thulium (Tm) -doped fiber lasers in the 2μm region have gained a lot of interest due to many potential applications in materials processing and biophotonics. Based on the broad gain regions spanning from 1800nm to 2100nm, they offer the perfect basis to implement broadly tunable and user-friendly light sources like they are increasingly demanded in spectroscopic applications. Recently, a novel tuning mechanism based on a fiber Bragg grating (FBG) array as versatile spectral filter has been reported. This concept combines unique spectral freedom for customized tuning ranges and ultrabroad bandwidths with a fiber-integrated setup in order to maintain the advantages of the waveguide geometry. In this work, we demonstrate such a dispersion tuned and pulsed fiber laser in the Tm domain around 1950nm using a modulator and a discrete FBG array to control the emission wavelength. In order to comply with the demands of potential applications in biophotonics, for the first time, this tuning concept is realized in a polarization maintaining (PM) configuration ensuring linearly polarized output. While a simple FBG array is employed containing five gratings inscribed in PM fiber, we also outline the prospect to implement FBGs fabricated in a standard single mode fiber. The emission characteristics of the system are investigated showing pulse durations down to 11ns and a good spectral signal contrast. In order to highlight the prospect for tunable high-power operation, we have also implemented an amplification stage scaling the average power to more than 25W.

  20. A high-efficiency fiber-based imaging system for co-registered autofluorescence and optical coherence tomography.

    Science.gov (United States)

    Pahlevaninezhad, Hamid; Lee, Anthony M D; Shaipanich, Tawimas; Raizada, Rashika; Cahill, Lucas; Hohert, Geoffrey; Yang, Victor X D; Lam, Stephen; MacAulay, Calum; Lane, Pierre

    2014-09-01

    We present a power-efficient fiber-based imaging system capable of co-registered autofluorescence imaging and optical coherence tomography (AF/OCT). The system employs a custom fiber optic rotary joint (FORJ) with an embedded dichroic mirror to efficiently combine the OCT and AF pathways. This three-port wavelength multiplexing FORJ setup has a throughput of more than 83% for collected AF emission, significantly more efficient compared to previously reported fiber-based methods. A custom 900 µm diameter catheter ‒ consisting of a rotating lens assembly, double-clad fiber (DCF), and torque cable in a stationary plastic tube ‒ was fabricated to allow AF/OCT imaging of small airways in vivo. We demonstrate the performance of this system ex vivo in resected porcine airway specimens and in vivo in human on fingers, in the oral cavity, and in peripheral airways.

  1. Kagome fiber based ultrafast laser microsurgery probe delivering micro-Joule pulse energies.

    Science.gov (United States)

    Subramanian, Kaushik; Gabay, Ilan; Ferhanoğlu, Onur; Shadfan, Adam; Pawlowski, Michal; Wang, Ye; Tkaczyk, Tomasz; Ben-Yakar, Adela

    2016-11-01

    We present the development of a 5 mm, piezo-actuated, ultrafast laser scalpel for fast tissue microsurgery. Delivery of micro-Joules level energies to the tissue was made possible by a large, 31 μm, air-cored inhibited-coupling Kagome fiber. We overcome the fiber's low NA by using lenses made of high refractive index ZnS, which produced an optimal focusing condition with 0.23 NA objective. The optical design achieved a focused laser spot size of 4.5 μm diameter covering a 75 × 75 μm(2) scan area in a miniaturized setting. The probe could deliver the maximum available laser power, achieving an average fluence of 7.8 J/cm(2) on the tissue surface at 62% transmission efficiency. Such fluences could produce uninterrupted, 40 μm deep cuts at translational speeds of up to 5 mm/s along the tissue. We predicted that the best combination of speed and coverage exists at 8 mm/s for our conditions. The onset of nonlinear absorption in ZnS, however, limited the probe's energy delivery capabilities to 1.4 μJ for linear operation at 1.5 picosecond pulse-widths of our fiber laser. Alternatives like broadband CaF2 crystals should mitigate such nonlinear limiting behavior. Improved opto-mechanical design and appropriate material selection should allow substantially higher fluence delivery and propel such Kagome fiber-based scalpels towards clinical translation.

  2. Mathematical and experimental analyses of antibody transport in hollow-fiber-based specific antibody filters.

    Science.gov (United States)

    Hout, Mariah S; Federspiel, William J

    2003-01-01

    We are developing hollow fiber-based specific antibody filters (SAFs) that selectively remove antibodies of a given specificity directly from whole blood, without separation of the plasma and cellular blood components and with minimal removal of plasma proteins other than the targeted pathogenic antibodies. A principal goal of our research is to identify the primary mechanisms that control antibody transport within the SAF and to use this information to guide the choice of design and operational parameters that maximize the SAF-based antibody removal rate. In this study, we formulated a simple mathematical model of SAF-based antibody removal and performed in vitro antibody removal experiments to test key predictions of the model. Our model revealed three antibody transport regimes, defined by the magnitude of the Damköhler number Da (characteristic antibody-binding rate/characteristic antibody diffusion rate): reaction-limited (Da /= 10). For a given SAF geometry, blood flow rate, and antibody diffusivity, the highest antibody removal rate was predicted for diffusion-limited antibody transport. Additionally, for diffusion-limited antibody transport the predicted antibody removal rate was independent of the antibody-binding rate and hence was the same for any antibody-antigen system and for any patient within one antibody-antigen system. Using SAF prototypes containing immobilized bovine serum albumin (BSA), we measured anti-BSA removal rates consistent with transport in the intermediate regime (Da approximately 3). We concluded that initial SAF development work should focus on achieving diffusion-limited antibody transport by maximizing the SAF antibody-binding capacity (hence maximizing the characteristic antibody-binding rate). If diffusion-limited antibody transport is achieved, the antibody removal rate may be raised further by increasing the number and length of the SAF fibers and by increasing the blood flow rate through the SAF.

  3. Kagome fiber based ultrafast laser microsurgery probe delivering micro-Joule pulse energies

    Science.gov (United States)

    Subramanian, Kaushik; Gabay, Ilan; Ferhanoğlu, Onur; Shadfan, Adam; Pawlowski, Michal; Wang, Ye; Tkaczyk, Tomasz; Ben-Yakar, Adela

    2016-01-01

    We present the development of a 5 mm, piezo-actuated, ultrafast laser scalpel for fast tissue microsurgery. Delivery of micro-Joules level energies to the tissue was made possible by a large, 31 μm, air-cored inhibited-coupling Kagome fiber. We overcome the fiber’s low NA by using lenses made of high refractive index ZnS, which produced an optimal focusing condition with 0.23 NA objective. The optical design achieved a focused laser spot size of 4.5 μm diameter covering a 75 × 75 μm2 scan area in a miniaturized setting. The probe could deliver the maximum available laser power, achieving an average fluence of 7.8 J/cm2 on the tissue surface at 62% transmission efficiency. Such fluences could produce uninterrupted, 40 μm deep cuts at translational speeds of up to 5 mm/s along the tissue. We predicted that the best combination of speed and coverage exists at 8 mm/s for our conditions. The onset of nonlinear absorption in ZnS, however, limited the probe’s energy delivery capabilities to 1.4 μJ for linear operation at 1.5 picosecond pulse-widths of our fiber laser. Alternatives like broadband CaF2 crystals should mitigate such nonlinear limiting behavior. Improved opto-mechanical design and appropriate material selection should allow substantially higher fluence delivery and propel such Kagome fiber-based scalpels towards clinical translation. PMID:27896003

  4. Fiber-Based Laser Transmitter at 1.57 Micrometers for Remote Sensing of Atmospheric Carbon Dioxide from Satellites

    Science.gov (United States)

    Yu, Anthony W.; Abshire, James B.; Stephen, Mark A.; Chen, Jeffrey R.; Wu, Stewart; Gonzalez, Brayler; Han, Lawrence; Numata, Kenji; Allan, Graham R.; Hasselbrack, William; Nicholson, Jeffrey W.; Yan, Man; Wisk, Patrick; DeSantolo, Anthony; DeSantolo, Anthony; Mangan, Brian; Puc, Gabe; Engin, Doruk; Mathason, Brian; Storm, Mark

    2015-01-01

    Over the past 20 years, NASA Goddard has successfully developed space-based lidar for remote sensing studies of the Earth and planets. The lidar in all missions to date have used diode pumped Nd:YAG laser transmitters. Recently we have been concentrating work on developing integrated path differential absorption (IPDA) lidar to measure greenhouse gases, with the goal of measurements from space. Due to the absorption spectrum of CO2 a fiber-based master oscillator power amplifier (MOPA) laser with a tunable seed source is an attractive laser choice. Fiber-based lasers offer a number of potential advantages for space, but since they are relatively new, challenges exist in developing them. In order to reduce risks for new missions using fiber-based lasers, we developed a 30- month plan to mature the technology of a candidate laser transmitter for space-based CO2 measurements to TRL-6. This work is also intended to reduce development time and costs and increase confidence in future mission success.

  5. Low-Loss Coupling of Quantum Cascade Lasers into Hollow-Core Waveguides with Single-Mode Output in the 3.7–7.6 μm Spectral Range

    Directory of Open Access Journals (Sweden)

    Pietro Patimisco

    2016-04-01

    Full Text Available We demonstrated low-loss and single-mode laser beam delivery through hollow-core waveguides (HCWs operating in the 3.7–7.6 μm spectral range. The employed HCWs have a circular cross section with a bore diameter of 200 μm and metallic/dielectric internal coatings deposited inside a glass capillary tube. The internal coatings have been produced to enhance the spectral response of the HCWs in the range 3.5–12 µm. We demonstrated Gaussian-like outputs throughout the 4.5–7.6 µm spectral range. A quasi single-mode output beam with only small beam distortions was achieved when the wavelength was reduced to 3.7 μm. With a 15-cm-long HCW and optimized coupling conditions, we measured coupling efficiencies of >88% and transmission losses of <1 dB in the investigated infrared spectral range.

  6. Time evolution of the intensity correlation function in a single-mode laser driven by both the coloured pump noise with signal modulation and the quantum noise with cross-correlation between the real and imaginary parts

    Institute of Scientific and Technical Information of China (English)

    Cheng Qing-Hua; Cao Li; Xu Da-Hai; Wu Da-Jin

    2005-01-01

    Using the linear approximation, we have studied the time evolution of intensity correlation function C(t) in a single-mode laser driven by both the coloured pump noise with signal modulation and the quantum noise with crosscorrelation between its real and imaginary parts. In the case of the pump noise with self-correlation time τ 1, the time evolution of C(t) only exhibits a form of damping oscillation.

  7. Ball Lens Coupling Analysis of Semiconductor Laser to Single Mode fibers%半导体激光器与单模光纤的球透镜耦合分析

    Institute of Scientific and Technical Information of China (English)

    郑煜; 陆文龙; 邓圭玲; 赵文龙

    2012-01-01

    Optical transmission model of semiconductor laser and single-mode fiber by ball lens coupling was established, and dou-ble-heterostructure laser beam characteristics were analyzed. Based on Huygens-Fresnel principle, the far-field divergence angles and waist radius of laser beam were calculated. Combined with Gaussian beam and single-mode fiber coupling theory, and ABCD matrix theory, coupling efficiency analysis of ball lenses used in coupling of the semiconductor laser and single-mode fiber was carried out. Research gives the optimal values of the parameters which affecting the packaging, and the parameters' tolerances. The results would play an important role in the package of semiconductor laser and single-mode fiber through ball lens.%建立了半导体激光器与单模光纤通过球透镜耦合的光传输模型,对双异质结激光器光束特性进行了分析.基于Huygens-Fresnel原理计算了激光光束远场发散角以及光束束腰半径.运用高斯光束与单模光纤耦合理论以及ABCD矩阵理论进行了激光器与单模光纤的球透镜耦合效率分析,给出了最优化的耦合封装工艺参数,以及各个影响耦合效率的参数容忍度,对半导体激光器与单模光纤的球透镜耦合封装具有重要意义.

  8. The entanglement evolution of two coupling two-level atoms interacting with a single-mode vacuum field in multiphoton Tavis-Cummings model%The entanglement evolution of two coupling two-level atoms interacting with a single-mode vacuum field in multiphoton Tavis-Cummings model

    Institute of Scientific and Technical Information of China (English)

    Lu Daoming

    2012-01-01

    Using multipohton Tavis-Cummings model, the entanglement evolution of two coupling two-level atoms in Bell states interacting with a single-mode vacuum field is investigated by using negativity. The influences of coupling constants between atoms, the atomic initial states and the photon number of transition on the entanglement evolution of two coupling two-level atoms are discussed. The results obtained using the numerical method show that the entanglement of two atoms is related with coupling constants between atoms, the atomic initial states and the photon number of transition. The two-atom entanglement state will forever stay in the maximum entanglement state when the initial state is |β11 〉 . When the initial state of two atoms is |β 01 〉, the entanglement of two atoms displays periodic oscillation behavior. And its oscillation period decreases with increasing of coupling constant between atoms or the photon number of transition. On the other hand, when the initial state is |β 00 〉 or |β10 ), the entanglement of two atoms displays quasiperiodic oscillation behavior and its oscillation period decreases with increasing of coupling constant between atoms or the photon number of transition.

  9. Validation of a fiber-based confocal microscope for interventional image-guided procedures: correlation with multispectral optical imaging

    Science.gov (United States)

    Herzka, Daniel; Quijano, Jade; Xie, Jianwu; Krueger, Sascha; Weiss, Steffen; Abrat, Benjamin; Osdoit, Anne; Cavé, Charlotte; Burnett, Christopher; Danthi, S. Narasimhan; Li, King

    2006-03-01

    The concept of the biopsy is ubiquitous in current medical diagnosis of cancer and other diseases. The standard biopsy consists of removing a sample of tissue for evaluation and diagnosis, primarily to ascertain the presence of cancer cells by (histo)pathological analyses. However, the advent of new optical imaging modalities and targeted or "smart" agents, that have affinity for a select target, suggests the possibility of performing in vivo tissue characterization without the need for sample removal or the wait for histopathologic processing. Here we present work testing and validating a fiber-based confocal fluorescence microscopic imaging system intended for combination with a larger scale imaging modality (i.e. MRI or CT) to be used in image-guided in vivo tissue characterization. Fiber-based confocal fluorescence microscopic imaging experiments were performed (Cellvizio, Mauna Kea Technologies, Paris, France) in vivo in two mouse models including: 1) EGFP-expressing mouse melanoma model and 2) M21 mouse melanoma model. Both models are known to express integrin α νβ 3, a cell-surface receptor protein. We also performed an experiment in ex vivo chicken muscle tissue labelled with a fluorescein isothiocyanate-lectin targeted compound. In the mouse models, contrast agents that targeted the integrin were injected and the contrast agent localization in tumor was verified by a whole-body multispectral imager. The fiber-based tool was sensitive enough to detect and image the tissue of interest in all different experiments, and was found appropriate for use in interventional catheter-based procedures.

  10. Nanosecond Pulse Shaping with Fiber-Based Electro-Optical Modulators and a Double-Pass Tapered Amplifier

    CERN Document Server

    Rogers, Charles E

    2015-01-01

    We describe a system for generating frequency-chirped and amplitude-shaped pulses on time scales from sub-nanosecond to ten nanoseconds. The system starts with cw diode-laser light at 780 nm and utilizes fiber-based electro-optical phase and intensity modulators, driven by an arbitrary waveform generator, to generate the shaped pulses. These pulses are subsequently amplified to several hundred mW with a tapered amplifier in a delayed double-pass configuration. Frequency chirps up to 5 GHz in 2 ns and pulse widths as short as 0.15 ns have been realized.

  11. 不同参量下单模激光系统的特性研究%Research on Characteristics of Single-mode Laser System with Different Parameters

    Institute of Scientific and Technical Information of China (English)

    程世红; 吕娜

    2014-01-01

    Single-mode laser Lorenz system is a typical nonlinear model, which shows extremely complex and rich dynamic behaviors. It is very important to the research on characteristics. Based on a brief introduction of single-mode laser Lorenz system, which including model establishment, dynamic equations and relative system characteristics, the program is programmed by Matlab software and the phase maps of single-mode laser Lorenz system with different pa-rameters is simulated by a computer. With simulated images, dynamic behaviors of the system are analyzed and dis-cussed. The results show that when the parameter of the system is more than the value of a branch point, the system be-comes unstable and thus enters into a chaotic state.%单模激光Lorenz系统是一个典型的非线性模型,其本身能够呈现极其复杂和丰富的动力学行为,对其特性研究十分重要。在简介单模激光Lorenz系统模型,其中包括模型的建立、动力学方程以及相应的系统特性等相关内容的基础上,编制MATLAB程序,利用计算机仿真模拟不同参量下单模激光Lorenz系统的相图。并结合仿真模拟的图像,对单模激光系统在不同参量下的动力学行为进行简单的分析与讨论。结果表明,当系统参数大于分支点处的取值时,系统变为不稳定的,从而进入混沌状态。

  12. ABCD matrix for reflection and refraction of Gaussian light beams at surfaces of hyperboloid of revolution and efficiency computation for laser diode to single-mode fiber coupling by way of a hyperbolic lens on the fiber tip.

    Science.gov (United States)

    Gangopadhyay, S; Sarkar, S

    1997-11-20

    We report the formulation of an ABCD matrix for reflection and refraction of Gaussian light beams at the surfaces of the hyperboloid of revolution that separate media of different refractive indices. The analysis includes an arbitrary angle of incidence and is based on matching the optical phase at the interface. Finally, we deduce expressions for spot sizes and wave-front radii and use them to obtain the ABCD matrix. Based on the formulated ABCD matrix for refraction under paraxial approximation, we also report a simple theoretical investigation of the coupling efficiency of a laser diode to a single-mode fiber with a hyperbolic lens formed on its tip.

  13. All-solid very large mode area ytterbium-doped silica microstructured fiber based on accurate control on cladding index.

    Science.gov (United States)

    Wei, Huifeng; Chen, Kangkang; Yang, Yucheng; Li, Jinyan

    2016-04-18

    We have demonstrated a new approach for developing very large mode area silica-based microstructured Ytterbium (Yb)-doped fibers. The microstructured region acting as pump cladding around the core is composed by periodically arranged low-index Fluorine-doped silica inclusions with an extremely low filling ratio of 0.088. To the best of our knowledge, we achieved the most accurate controlling on cladding index by 1 × 10-5 via our passively doped cladding (PDC) method. Two fibers with 127μm and 50μm core diameter respectively were fabricated from the same final preform designed by this approach. It is verified that our 50μm core diameter fiber can maintain robust single mode behavior at 1064nm wavelength. The advantage of an all-solid structure along with a much simpler fabrication process makes our approach very suitable for realizing very large mode area fibers for high power fiber laser application.

  14. Coexistence of positive and negative refractive index sensitivity in the liquid-core photonic crystal fiber based plasmonic sensor.

    Science.gov (United States)

    Shuai, Binbin; Xia, Li; Liu, Deming

    2012-11-05

    We present and numerically characterize a liquid-core photonic crystal fiber based plasmonic sensor. The coupling properties and sensing performance are investigated by the finite element method. It is found that not only the plasmonic mode dispersion relation but also the fundamental mode dispersion relation is rather sensitive to the analyte refractive index (RI). The positive and negative RI sensitivity coexist in the proposed design. It features a positive RI sensitivity when the increment of the SPP mode effective index is larger than that of the fundamental mode, but the sensor shows a negative RI sensitivity once the increment of the fundamental mode gets larger. A maximum negative RI sensitivity of -5500nm/RIU (Refractive Index Unit) is achieved in the sensing range of 1.50-1.53. The effects of the structural parameters on the plasmonic excitations are also studied, with a view of tuning and optimizing the resonant spectrum.

  15. High-speed tunable photonic crystal fiber-based femtosecond soliton source without dispersion pre-compensation

    Directory of Open Access Journals (Sweden)

    Martín E. Masip

    2012-02-01

    Full Text Available We present a high-speed wavelength tunable photonic crystal fiber-based source capable of generating tunable femtosecond solitons in the infrared region. Through measurements and numerical simulation, we show that both the pulsewidth and the spectral width of the output pulses remain nearly constant over the entire tuning range from 860 to 1160 nm. This remarkable behavior is observed even when pump pulses are heavily chirped (7400 fs^2, which allows to avoid bulky compensation optics, or the use of another fiber, for dispersion compensation usually required by the tuning device. Received: 7 July 2011, Accepted: 1 February 2012; Edited by: A. Goñi; Reviewed by: J. Chavez Boggio, Leibniz Institut fur Astrophysik Potsdam, Germany; DOI: http://dx.doi.org/10.4279/PIP.040001 Cite as: M. Caldarola, V. A. Bettachini, A. A. Rieznik, P. G. Konig, M. E. Masip, D. F. Grosz, A. V. Bragas, Papers in Physics 4, 040001 (2012

  16. Hollow fiber-based liquid-liquid-liquid micro-extraction with osmosis: I. Theoretical simulation and verification.

    Science.gov (United States)

    Wu, Qian; Wu, Dapeng; Geng, Xuhui; Shen, Zheng; Guan, Yafeng

    2012-07-27

    Osmosis in hollow fiber-based liquid-liquid-liquid micro-extraction (HF-LLLME) was validated and utilized to improve enrichment factor of extraction in this study. When donor phase (sample solution) with higher ion strength than acceptor phase (extraction phase) was used, osmosis was established from acceptor phase, through organic membrane to donor phase. The mass flux expression of analytes across the organic membrane was established based on the convective-diffusive kinetic model, and the kinetic process for HF-LLLME with osmosis was simulated. Simulation results indicated that osmosis from acceptor phase to donor phase can increase enrichment factor of HF-LLLME, accelerate extraction process, and even result in the distribution ratio of analytes between donor and acceptor phase exceeding their partition coefficient. This phenomenon was verified by the experimental data of extraction with six organic acids and four organic bases as the model analytes.

  17. Numerical analysis of a photonic crystal fiber based on a surface plasmon resonance sensor with an annular analyte channel

    Science.gov (United States)

    Liu, Chao; Yang, Lin; Su, Weiquan; Wang, Famei; Sun, Tao; Liu, Qiang; Mu, Haiwei; Chu, Paul K.

    2017-01-01

    A sensing structure is designed with a photonic crystal fiber based on a surface plasmon resonance (PCF-SPR) sensor using gold as the sensitive material. The benefit of the structure is to reduce the difficulty in gold deposition, because the Au film is deposited on the outside of the fiber core instead of on the holes filled with analyte inside the core. The properties of the sensor are numerically calculated by the finite element method. The results show that the thickness of the gold film, refractive index of the analyte, and radius of the central hole affect the sensing performance of the PCF-SPR. By optimizing the model, an extra graphene layer with the thickness of 20 nm is deposited on the gold film in the model. The maximum spectral sensitivity can be as high as 7500 nm/RIU for the sensor with the gold-graphene composite film as the sensitive material.

  18. Reduction of phase-induced intensity noise in a fiber-based coherent Doppler lidar using polarization control

    DEFF Research Database (Denmark)

    Rodrigo, Peter John; Pedersen, Christian

    2010-01-01

    Optimization of signal-to-noise ratio is an important aspect in the design of optical heterodyne detection systems such as a coherent Doppler lidar (CDL). In a CDL, optimal performance is achieved when the noise in the detector signal is dominated by local oscillator shot-noise. Most modern CDL...... systems are built using rugged and cost-efficient fiber optic components. Unfortunately, leakage signals such as residual reflections inherent within fiber components (e.g. circulator) can introduce phaseinduced intensity noise (PIIN) to the Doppler spectrum in a CDL. Such excess noise may be a few orders...... of magnitude above the shot-noise level within the relevant CDL frequency bandwidth – corrupting the measurement of typically weak backscattered signals. In this study, observation of PIIN in a fiber-based CDL with a master-oscillator poweramplifier tapered semiconductor laser source is reported. Furthermore...

  19. Fiber based optical tweezers for simultaneous in situ force exertion and measurements in a 3D polyacrylamide gel compartment.

    Science.gov (United States)

    Ti, Chaoyang; Thomas, Gawain M; Ren, Yundong; Zhang, Rui; Wen, Qi; Liu, Yuxiang

    2015-07-01

    Optical tweezers play an important role in biological applications. However, it is difficult for traditional optical tweezers based on objective lenses to work in a three-dimensional (3D) solid far away from the substrate. In this work, we develop a fiber based optical trapping system, namely inclined dual fiber optical tweezers, that can simultaneously apply and measure forces both in water and in a 3D polyacrylamide gel matrix. In addition, we demonstrate in situ, non-invasive characterization of local mechanical properties of polyacrylamide gel by measurements on an embedded bead. The fiber optical tweezers measurements agree well with those of atomic force microscopy (AFM). The inclined dual fiber optical tweezers provide a promising and versatile tool for cell mechanics study in 3D environments.

  20. Photonic Crystal Fiber Attenuator

    Institute of Scientific and Technical Information of China (English)

    Joo; Beom; Eom; Hokyung; Kim; Jinchae; Kim; Un-Chul; Paek; Byeong; Ha; Lee

    2003-01-01

    We propose a novel fiber attenuator based on photonic crystal fibers. The difference in the modal field diameters of a conventional single mode fiber and a photonic crystal fiber was used. A variable optical attenuator was also achieved by applying macro-bending on the PCF part of the proposed attenuator

  1. 155 Mb/s-10 Gb/s combined FSK-IM/optical label-packet modulation signals 100 km transmission over standard single mode fiber using mid-span spectral inversion by four-wave mixing in an SOA

    Institute of Scientific and Technical Information of China (English)

    Xin Xiang-Jun; Ma Jian-Xin; Zhang Qi; Deng Chao-Gong; Wang Kui-Ru; Yu Chong-Xiu; Liu Bo

    2009-01-01

    This paper introduces the mid-span spectral inversion by four-wave mixing in a commercially available semiconductor optical amplifier (SOA) with a length of about 1.5 mm to optical label switching network based on combined frequency shift keying (FSK)-intensiy modulation (IM)/optical label-packet modulation to overcome the dispersion limitation of fiber.The 155 Mb/s-10 Gb/s combined FSK/IM signal is experimentally transmitted over a 100 km standard single mode fiber.10-10 and 10-9 BER (bit error ratio),or even better,is achieved for the FSK label and IM packet,respectively.The -19 dB power conversion efficiency is obtained for -1 nm wavelength detuning.

  2. Stochastic resonance in a gain-noise model of a single-mode laser driven by pump noise and quantum noise with cross-correlation between real and imaginary parts under direct signal modulation

    Institute of Scientific and Technical Information of China (English)

    Chen Li-Mei; Cao Li; Wu Da-Jin

    2007-01-01

    Stochastic resonance (SR) is studied in a gain-noise model of a single-mode laser driven by a coloured pump noise and a quantum noise with cross-correlation between real and imaginary parts under a direct signal modulation. By using a linear approximation method, we find that the SR appears during the variation of signal-to-noise ratio (SNR)separately with the pump noise self-correlation time τ, the noise correlation coefficient between the real part and the imaginary part of the quantum noise λq, the attenuation coefficient γ and the deterministic steady-state intensity I0.In addition, it is found that the SR can be characterized not only by the dependence of SNR on the noise variables of τand λq, but also by the dependence of SNR on the laser system variables of γ and I0. Thus our investigation extends the characteristic quantity of SR proposed before.

  3. An Optical Fiber-Based Sensor Array for the Monitoring of Zinc and Copper Ions in Aqueous Environments

    Directory of Open Access Journals (Sweden)

    Steven Kopitzke

    2014-02-01

    Full Text Available Copper and zinc are elements commonly used in industrial applications as aqueous solutions. Before the solutions can be discharged into civil or native waterways, waste treatment processes must be undertaken to ensure compliance with government guidelines restricting the concentration of ions discharged in solution. While currently there are methods of analysis available to monitor these solutions, each method has disadvantages, be it high costs, inaccuracy, and/or being time-consuming. In this work, a new optical fiber-based platform capable of providing fast and accurate results when performing solution analysis for these metals is described. Fluorescent compounds that exhibit a high sensitivity and selectivity for either zinc or copper have been employed for fabricating the sensors. These sensors demonstrated sub-part-per-million detection limits, 30-second response times, and the ability to analyze samples with an average error of under 10%. The inclusion of a fluorescent compound as a reference material to compensate for fluctuations from pulsed excitation sources has further increased the reliability and accuracy of each sensor. Finally, after developing sensors capable of monitoring zinc and copper individually, these sensors are combined to form a single optical fiber sensor array capable of simultaneously monitoring concentration changes in zinc and copper in aqueous environments.

  4. Multi-channel, fiber-based seed pulse distribution system for femtosecond-level synchronized chirped pulse amplifiers

    Science.gov (United States)

    Horáček, Martin; Indra, Lukáš; Green, Jonathan T.; Naylon, Jack A.; Tykalewicz, Boguslaw; Novák, Jakub; Batysta, František; Mazanec, Tomáš; Horáček, Jakub; Antipenkov, Roman; Hubka, Zbyněk; Boge, Robert; Bakule, Pavel; Rus, Bedřich

    2017-01-01

    We report on the design and performance of a fiber-based, multi-channel laser amplifier seed pulse distribution system. The device is designed to condition and distribute low energy laser pulses from a mode-locked oscillator to multiple, highly synchronized, high energy amplifiers integrated into a laser beamline. Critical functions such as temporal pulse stretching well beyond 100 ps/nm, pulse picking, and fine control over the pulse delay up to 300 ps are all performed in fiber eliminating the need for bulky and expensive grating stretchers, Pockels cells, and delay lines. These functions are characterized and the system as a whole is demonstrated by seeding two high energy amplifiers in the laser beamline. The design of this system allows for complete computer control of all functions, including tuning of dispersion, and is entirely hands-free. The performance of this device and its subsystems will be relevant to those developing lasers where reliability, size, and cost are key concerns in addition to performance; this includes those developing large-scale laser systems similar to ours and also those developing table-top experiments and commercial systems.

  5. HPLC determination of ibuprofen, diclofenac and salicylic acid using hollow fiber-based liquid phase microextraction (HF-LPME).

    Science.gov (United States)

    Ramos Payán, María; Bello López, Miguel Angel; Fernández-Torres, Rut; Pérez Bernal, Juan Luis; Callejón Mochón, Manuel

    2009-10-27

    This paper describes an extraction method using a polypropylene membrane supporting dihexyl ether (three-phase hollow fiber-based liquid phase microextraction (HF-LPME)) for the analysis of several pharmaceuticals (salicylic acid (SAC), ibuprofen (IBU) and diclofenac (DIC)) followed by a HPLC determination using a monolithic silica type HPLC column, that allows lower retention times than the usual packed columns with adequate resolution. Detection was realized by means of a coupled in series diode array (DAD) and fluorescence (FLD) detectors. HF-LPME is a relatively new technique employed in analytical chemistry for sample pretreatment which offers more selectivity and sensitivity than any traditional extraction technique. Detection limits by DAD are 12, 53 and 40 ng mL(-1) for salicylic acid, diclofenac and ibuprofen, respectively and by FLD 7 and 2 ng mL(-1) for salicylic acid, and ibuprofen. The method has been successfully applied to their direct determination in human urine and the results obtained demonstrated that could be also applied to the determination of the corresponding metabolites.

  6. Non-destructive dating of fiber-based gelatin silver prints using near-infrared spectroscopy and multivariate analysis.

    Science.gov (United States)

    Martins, Ana; Daffner, Lee Ann; Fenech, Ann; McGlinchey, Christopher; Strlič, Matija

    2012-02-01

    An innovative approach to date fiber-based gelatin silver prints using near-infrared spectroscopy (NIR) and multivariate analysis is presented. NIR spectra were acquired for 152 film stills printed in the USA between 1914 and 1986, and partial least square (PLS) analysis was used to correlate the spectra with the year the photographs were printed. Principal component analysis and spectral interpretation helped clarify the underlying correlation between the print date and the composition and ageing of the photographic papers. The method was successfully validated with an independent set of 66 film stills printed in the USA, and a prediction error (root mean square error of prediction) of 6 years was achieved. The method was also tested on films stills printed in Germany and Russia, as well as amateur prints and photographs in the collection of the Museum of Modern Art. The prediction error was significantly larger, with the exception of the amateur prints, due to differences in the composition and/or properties of the papers depending on their geographical origin and purpose as confirmed by discriminant analysis.

  7. Fiber-based laser transmitter and laser spectroscopy of the oxygen A-band for remote detection of atmospheric pressure

    Science.gov (United States)

    Stephen, Mark Andrew

    The Author reports on the design and construction of an oxygen spectroscopy laser sounding instrument designed to measure atmospheric pressure. This instrument was conceived and designed with a satellite application in mind so we discuss the requirements this places on the instrument and specifically the laser transmitter. We have developed a novel, pulsed, frequency-doubled, fiber-based laser transmitter for use in the instrument. The instrument concept uses the collision broadening of spectroscopic lines of the diatomic oxygen A-band to deduce atmospheric pressure. We report on the spectroscopic and instrument theory. We discuss the development of a high-power, narrow-frequency, tunable, single spatial mode pulsed laser transmitter. The transmitter is a master oscillator power amplifier (MOPA) design. The master oscillator is a fiber coupled DFB laser with external acousto-optic modulation. The amplifier is a diode pumped, erbium-doped fiber. We discuss the non-linear optical effect of stimulated Brillouin scattering (SBS) and how it limits the transmitter performance. We review various methods for overcoming SBS in erbium fiber amplifiers and then demonstrate the performance of a high SBS threshold fiber amplifier. We demonstrate the efficacy of this transmitter by integrating it into a spectroscopic instrument and make atmospheric measurements at a test site at Goddard. We also discuss future improvements.

  8. Reduction of phase-induced intensity noise in a fiber-based coherent Doppler lidar using polarization control.

    Science.gov (United States)

    Rodrigo, Peter John; Pedersen, Christian

    2010-03-01

    Optimization of signal-to-noise ratio is an important aspect in the design of optical heterodyne detection systems such as a coherent Doppler lidar (CDL). In a CDL, optimal performance is achieved when the noise in the detector signal is dominated by local oscillator shot-noise. Most modern CDL systems are built using rugged and cost-efficient fiber optic components. Unfortunately, leakage signals such as residual reflections inherent within fiber components (e.g. circulator) can introduce phase-induced intensity noise (PIIN) to the Doppler spectrum in a CDL. Such excess noise may be a few orders of magnitude above the shot-noise level within the relevant CDL frequency bandwidth--corrupting the measurement of typically weak backscattered signals. In this study, observation of PIIN in a fiber-based CDL with a master-oscillator power-amplifier tapered semiconductor laser source is reported. Furthermore, we experimentally demonstrate what we believe is a newly proposed method using a simple polarization scheme to reduce PIIN by more than an order of magnitude.

  9. Purification of Monoclonal Antibodies Using a Fiber Based Cation-Exchange Stationary Phase: Parameter Determination and Modeling

    Directory of Open Access Journals (Sweden)

    Jan Schwellenbach

    2016-10-01

    Full Text Available Monoclonal antibodies (mAb currently dominate the market for protein therapeutics. Because chromatography unit operations are critical for the purification of therapeutic proteins, the process integration of novel chromatographic stationary phases, driven by the demand for more economic process schemes, is a field of ongoing research. Within this study it was demonstrated that the description and prediction of mAb purification on a novel fiber based cation-exchange stationary phase can be achieved using a physico-chemical model. All relevant mass-transport phenomena during a bind and elute chromatographic cycle, namely convection, axial dispersion, boundary layer mass-transfer, and the salt dependent binding behavior in the fiber bed were described. This work highlights the combination of model adaption, simulation, and experimental parameter determination through separate measurements, correlations, or geometric considerations, independent from the chromatographic cycle. The salt dependent binding behavior of a purified mAb was determined by the measurement of adsorption isotherms using batch adsorption experiments. Utilizing a combination of size exclusion and protein A chromatography as analytic techniques, this approach can be extended to a cell culture broth, describing the salt dependent binding behavior of multiple components. Model testing and validation was performed with experimental bind and elute cycles using purified mAb as well as a clarified cell culture broth. A comparison between model calculations and experimental data showed a good agreement. The influence of the model parameters is discussed in detail.

  10. Body-monitoring and health supervision by means of optical fiber-based sensing systems in medical textiles.

    Science.gov (United States)

    Quandt, Brit M; Scherer, Lukas J; Boesel, Luciano F; Wolf, Martin; Bona, Gian-Luca; Rossi, René M

    2015-02-18

    Long-term monitoring with optical fibers has moved into the focus of attention due to the applicability for medical measurements. Within this Review, setups of flexible, unobtrusive body-monitoring systems based on optical fibers and the respective measured vital parameters are in focus. Optical principles are discussed as well as the interaction of light with tissue. Optical fiber-based sensors that are already used in first trials are primarily selected for the section on possible applications. These medical textiles include the supervision of respiration, cardiac output, blood pressure, blood flow and its saturation with hemoglobin as well as oxygen, pressure, shear stress, mobility, gait, temperature, and electrolyte balance. The implementation of these sensor concepts prompts the development of wearable smart textiles. Thus, current sensing techniques and possibilities within photonic textiles are reviewed leading to multiparameter designs. Evaluation of these designs should show the great potential of optical fibers for the introduction into textiles especially due to the benefit of immunity to electromagnetic radiation. Still, further improvement of the signal-to-noise ratio is often necessary to develop a commercial monitoring system.

  11. Performance analysis for IEEE 802.11 distributed coordination function in radio-over-fiber-based distributed antenna systems.

    Science.gov (United States)

    Fan, Yuting; Li, Jianqiang; Xu, Kun; Chen, Hao; Lu, Xun; Dai, Yitang; Yin, Feifei; Ji, Yuefeng; Lin, Jintong

    2013-09-09

    In this paper, we analyze the performance of IEEE 802.11 distributed coordination function in simulcast radio-over-fiber-based distributed antenna systems (RoF-DASs) where multiple remote antenna units (RAUs) are connected to one wireless local-area network (WLAN) access point (AP) with different-length fiber links. We also present an analytical model to evaluate the throughput of the systems in the presence of both the inter-RAU hidden-node problem and fiber-length difference effect. In the model, the unequal delay induced by different fiber length is involved both in the backoff stage and in the calculation of Ts and Tc, which are the period of time when the channel is sensed busy due to a successful transmission or a collision. The throughput performances of WLAN-RoF-DAS in both basic access and request to send/clear to send (RTS/CTS) exchange modes are evaluated with the help of the derived model.

  12. All-fiber pre- and post-data exchange in km-scale fiber-based twisted lights multiplexing.

    Science.gov (United States)

    Liu, Jun; Zhu, Long; Wang, Andong; Li, Shuhui; Chen, Shi; Du, Cheng; Mo, Qi; Wang, Jian

    2016-08-15

    Twisting light with orbital angular momentum (OAM) provides an alternative way to facilitate space-division multiplexing (SDM). Both twisted light (OAM modes) multiplexing transmission and data processing functions would be highly desired in a robust OAM-assisted SDM (OAM-SDM) network. In this Letter, we propose and demonstrate flexible all-fiber pre- and post-data exchange functions in a fiber-based OAM-SDM network. OAM+1 and OAM-1 modes carrying 5  Gbit/s four-level pulse amplitude modulation signals are multiplexed to transmit through a 1.1 km OAM fiber in the system. Two simple and controllable data exchange control units are placed at the front end and the back end of the OAM fiber to demonstrate pre- and post-data exchange functions between the OAM+1 and OAM-1 modes. The measured optical signal-to-noise ratio penalties at a bit-error rate of 2×10-3 (enhanced forward-error correction threshold) for pre- and post-data exchange operations are less than 3.2 dB with crosstalk. The OAM data exchange functions could potentially enhance the flexibility of data management at network nodes in OAM-SDM networks.

  13. 3D fiber-based hybrid nanogenerator for energy harvesting and as a self-powered pressure sensor.

    Science.gov (United States)

    Li, Xiuhan; Lin, Zong-Hong; Cheng, Gang; Wen, Xiaonan; Liu, Ying; Niu, Simiao; Wang, Zhong Lin

    2014-10-28

    In the past years, scientists have shown that development of a power suit is no longer a dream by integrating the piezoelectric nanogenerator (PENG) or triboelectric nanogenerator (TENG) with commercial carbon fiber cloth. However, there is still no design applying those two kinds of NG together to collect the mechanical energy more efficiently. In this paper, we demonstrate a fiber-based hybrid nanogenerator (FBHNG) composed of TENG and PENG to collect the mechanical energy in the environment. The FBHNG is three-dimensional and can harvest the energy from all directions. The TENG is positioned in the core and covered with PENG as a coaxial core/shell structure. The PENG design here not only enhances the collection efficiency of mechanical energy by a single carbon fiber but also generates electric output when the TENG is not working. We also show the potential that the FBHNG can be weaved into a smart cloth to harvest the mechanical energy from human motions and act as a self-powered strain sensor. The instantaneous output power density of TENG and PENG can achieve 42.6 and 10.2 mW/m(2), respectively. And the rectified output of FBHNG has been applied to charge the commercial capacitor and drive light-emitting diodes, which are also designed as a self-powered alert system.

  14. Microscale characterisation of stochastically reconstructed carbon fiber-based Gas Diffusion Layers; effects of anisotropy and resin content

    Science.gov (United States)

    Yiotis, Andreas G.; Kainourgiakis, Michael E.; Charalambopoulou, Georgia C.; Stubos, Athanassios K.

    2016-07-01

    A novel process-based methodology is proposed for the stochastic reconstruction and accurate characterisation of Carbon fiber-based matrices, which are commonly used as Gas Diffusion Layers in Proton Exchange Membrane Fuel Cells. The modeling approach is efficiently complementing standard methods used for the description of the anisotropic deposition of carbon fibers, with a rigorous model simulating the spatial distribution of the graphitized resin that is typically used to enhance the structural properties and thermal/electrical conductivities of the composite Gas Diffusion Layer materials. The model uses as input typical pore and continuum scale properties (average porosity, fiber diameter, resin content and anisotropy) of such composites, which are obtained from X-ray computed microtomography measurements on commercially available carbon papers. This information is then used for the digital reconstruction of realistic composite fibrous matrices. By solving the corresponding conservation equations at the microscale in the obtained digital domains, their effective transport properties, such as Darcy permeabilities, effective diffusivities, thermal/electrical conductivities and void tortuosity, are determined focusing primarily on the effects of medium anisotropy and resin content. The calculated properties are matching very well with those of Toray carbon papers for reasonable values of the model parameters that control the anisotropy of the fibrous skeleton and the materials resin content.

  15. Evaluation of Macrobend Loss on Long Distance Optical Ground Wire

    Directory of Open Access Journals (Sweden)

    M. F. M. Salleh

    2015-06-01

    Full Text Available Bend loss is a kind of loss that contributes to the power attenuation which is caused by the bending of optical fiber. For long distance optical fiber, bending might occur at joining point as there are many joining points along the link. Studies related to bend loss always relate the effect of bend radius on bend loss value. There is no study that relates the value of loss that can be affected by other factors like the natural environmental conditions. In this study, the evaluation of bend loss on existing long distance Optical Ground Wire (OPGW was studied since the cable was exposed to any climate condition.

  16. Superluminescent diode and single mode laser

    Energy Technology Data Exchange (ETDEWEB)

    Kwong, S.K.; Lau, K.Y.; Bar-Chaim, N.; Ury, I.

    1988-08-16

    A buried heterostructure superluminescent diode comprising: an elongated active gain layer having an output end and a non-output end; a first n-type cladding layer on one face of the gain layer and a second p-type cladding layer on the other face of the gain layer for pumping the active gain layer, the cladding layer having a lower index of refraction than the active gain layer; a blocking layer having a lower index of refraction than the active gain layer along each longitudinal edge of the active gain layer, a transparent window at the output end of the active gain layer; an antireflective coating on the window layer; and a light absorbing medium at the non-output end of the active gain layer.

  17. Superluminescent diode and single mode laser

    Energy Technology Data Exchange (ETDEWEB)

    Kwong, S.K.; Lau, K.Y.; BarChim, N.; Ury, I.

    1989-06-27

    A buried heterostructure superluminescent diode is described comprising: an elongated active gain layer having an output end and a non-output end; a first n-type cladding layer on one face of the gain layer and a second p-type cladding layer on the other face of the gain layer for pumping the active gain layer, the cladding layer having a lower index of refraction than the active gain layer; a blocking layer having a lower index of refraction than the active gain layer along each longitudinal edge of the active gain layer; and a light absorbing medium at the non-output end of the active gain layer.

  18. High Polarization Single Mode Photonic Crystal Microlaser

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; XING Ming-Xin; ZHOU Wen-Jun; LIU An-Jin; ZHENG Wan-Hua

    2009-01-01

    Generally,dipole mode is a doubly degenerate mode.Theoretical calculations have indicated that the single dipole mode of two-dimensional photonic crystal single point defect cavity shows high polarization property.We present a structure with elongated lattice,which only supports a single y-dipole mode.With this structure we can eliminate the degeneracy,control the lasing action of the cavity and demonstrate the high polarization property of the single dipole mode.In our experiment,the polarization extinction ratio of the y-dipole mode is as high as 51:1.

  19. 人眼安全高重频窄脉宽单模全光纤激光器特性研究%Characteristics of eye-safe high repetition frequency narrow pulse width single mode all fiber laser

    Institute of Scientific and Technical Information of China (English)

    张鑫; 刘源; 贺岩; 杨燕; 侯霞; 陈卫标

    2015-01-01

    介绍了基于主振荡功率放大结构的人眼安全全光纤激光器。首先对比了电光调制及直接调制产生的种子激光在百kHz重复频率、纳秒级脉冲宽度的激光放大器中优缺点,综合系统需求选择直接调制方式;之后对窄脉冲单模放大中出现的脉冲分裂现象进行了研究,选用10μm纤芯的双包层铒镱共掺光纤,仅通过两级放大即获得了1550 nm,重复频率为200 kHz,脉冲宽度为4.07 ns,峰值功率为1.02 kW的单模激光输出。具有结构紧凑、稳定可靠的特点,可用于三维视频激光雷达。%An eye-safe, all fiber, single mode, fiber laser based on master oscillator power amplifier configuration was presented. The advantages and disadvantages were compared between using a directly modulated diode laser and an electro-optical modulated continuous-wave diode as seed laser in sub-Mega Hertz, nanosecond fiber amplifier. The main restriction of power scaling in nanosecond fiber laser was pulse split. 10μm core double cladding erbium ytterbium co-doped fiber was employed as gain fiber of power amplifier. The directly modulated seed laser was then amplified by only two stage amplifiers. Finally, a peak power of 1.02 kW with 4.07 ns pulse duration at 200 kHz pulse repetition frequency with single-mode output was obtained and it is applicable in three dimensional video imaging lidar system.

  20. High SBS-Threshold Er/Yb Co-Doped Phosphate Glass Fiber Amplifiers for High Power, Sub-us Pulsed, Narrow Linewidth, All Fiber-Based Laser Transmitter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In order to implement the monolithic high power narrow linewidth pulsed all fiber-based laser transmitter by using a MOPA configuration for NASA's active remote...