WorldWideScience

Sample records for single waveguide mode

  1. 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…

  2. 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

  3. Low-loss single mode light waveguides in polymer

    Science.gov (United States)

    Sieber, Heinrich; Boehm, Hans-Jürgen; Hollenbach, Uwe; Mohr, Jürgen; Ostrzinski, Ute; Pfeiffer, Karl; Szczurowski, Marcin; Urbanczyk, Waclaw

    2012-06-01

    We report on the development of a UV-lithography manufacturing process for low loss single mode light waveguides in a novel polymer and the characterization of the fabricated components in a broad wavelength range from 808 nm to 1550 nm. The main focus of this work lies in providing a quick and cost efficient production technique for single mode waveguides and low loss integrated optical circuits. To achieve this goal we chose a novel photo-structurable polymer host-guest-system consisting of SU8 and a low refractive dopant monomer. Near and far-field measurements at different wavelengths show that the mode propagating within a well designed integrated waveguide structure and the mode of a standard fiber can exhibit a mode overlap value of approximately 1 and suffer only very low coupling losses. We demonstrate excess loss of 0.14 dB/cm for 808 nm, 0.33 dB/cm for 1310 nm and 2.86 dB/cm for 1550 nm. Typical insertion loss values of straight waveguides with a length of 36 mm are 0.9 dB for 808 nm, 1.5 dB for 1310 nm and 10.4 dB for 1550 nm. Polarization dependent loss was found to be less than 0.2 dB on sets of test structures of 36 mm length. We measured material attenuation in the novel polymer material before cross-linking of approximately 0.04 dB/cm for 808 nm and around 0.20 dB/cm for 1310 nm respectively. The presented production technique is suitable to provide low loss and low cost integrated optical circuits for sensor and communication applications in a broad wavelength range.

  4. Large-core single-mode rib SU8 waveguide using solvent-assisted microcontact molding.

    Science.gov (United States)

    Huang, Cheng-Sheng; Wang, Wei-Chih

    2008-09-01

    This paper describes a novel fabrication technique for constructing a polymer-based large-core single-mode rib waveguide. A negative tone SU8 photoresist with a high optical transmission over a large wavelength range and stable mechanical properties was used as a waveguide material. A waveguide was constructed by using a polydimethylsiloxane stamp combined with a solvent-assisted microcontact molding technique. The effects on the final pattern's geometry of four different process conditions were investigated. Optical simulations were performed using beam propagation method software. Single-mode beam propagation was observed at the output of the simulated waveguide as well as the actual waveguide through the microscope image.

  5. Adapting the mode profile of planar waveguides to single-mode fibers : a novel method

    NARCIS (Netherlands)

    Smit, M.K.; Vreede, De A.H.

    1991-01-01

    A novel method for coupling single-mode fibers to planar optical circuits with small waveguide dimensions is proposed. The method eliminates the need to apply microoptics or to adapt the waveguide dimensions within the planar circuit to the fiber dimensions. Alignment tolerances are comparable to

  6. Writing single-mode waveguides in lithium niobate by ultra-low intensity solitons

    International Nuclear Information System (INIS)

    Fazio, E.; Ramadan, W.; Petris, A.; Chauvet, M.; Bosco, A.; Vlad, V.I.; Bertolotti, M.

    2005-01-01

    Optical waveguides can be conveniently written in photorefractive materials by using spatial solitons. We have generated bright spatial solitons inside lithium niobate which allow single-mode light propagation. Efficient waveguides have been generated with CW light powers as high as few microwatts. According to the soliton formation, waveguides can be formed with different shapes. Due to the slow response time of the lithium niobate, both for soliton formation and relaxation, the soliton waveguide remains memorised for a long time, of the order of months

  7. Manipulating single second mode transparency in a corrugated waveguide via the thickness of sputtered gold

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Dan [Key Lab of In-fiber Integrated Optics, Ministry of Education of China, Harbin Engineering University, Harbin 150001 (China); Photonics Research Center, College of Science, Harbin Engineering University, Harbin 150001 (China); Fan, Ya-Xian, E-mail: yxfan@hrbeu.edu.cn [Key Lab of In-fiber Integrated Optics, Ministry of Education of China, Harbin Engineering University, Harbin 150001 (China); Photonics Research Center, College of Science, Harbin Engineering University, Harbin 150001 (China); Sang, Tang-Qing; Xu, Lan-Lan; Bibi, Aysha [Key Lab of In-fiber Integrated Optics, Ministry of Education of China, Harbin Engineering University, Harbin 150001 (China); Photonics Research Center, College of Science, Harbin Engineering University, Harbin 150001 (China); Tao, Zhi-Yong, E-mail: zytao@hrbeu.edu.cn [Key Lab of In-fiber Integrated Optics, Ministry of Education of China, Harbin Engineering University, Harbin 150001 (China); Photonics Research Center, College of Science, Harbin Engineering University, Harbin 150001 (China)

    2016-03-11

    We propose a classical analog of electromagnetically induced transparency in a cylindrical waveguide with undulated metallic walls. The transparency, induced by multi-mode interactions in waveguides, not only has a narrow line-width, but also consists of a single second-order transverse mode, which corresponds to the Bessel function distributions investigated extensively due to their unique characteristics. By increasing the thickness of sputtered gold layers of the waveguide, we demonstrate a frequency-agile single mode transparency phenomenon in a terahertz radiation. It is found that the center frequency of the transparency is linearly related to the gold thickness, indicating the achievement of a controllable single mode terahertz device. The field distributions at the cross-sections of outlets verify the single second mode transparency and indicate the mechanism of its frequency manipulation, which will significantly benefit the mode-control engineering in terahertz applications. - Highlights: • An analog of electromagnetically induced transparency in terahertz tubes is proposed. • A single second transverse mode of Bessel distributions is observed in the pass band. • The operating frequency can be linearly controlled by the sputtered gold thickness. • We can effectively manipulate the slow down factor of light by the gold thickness. • The transparency characteristics rely on the transition of multi-mode interactions.

  8. Manipulating single second mode transparency in a corrugated waveguide via the thickness of sputtered gold

    International Nuclear Information System (INIS)

    Xu, Dan; Fan, Ya-Xian; Sang, Tang-Qing; Xu, Lan-Lan; Bibi, Aysha; Tao, Zhi-Yong

    2016-01-01

    We propose a classical analog of electromagnetically induced transparency in a cylindrical waveguide with undulated metallic walls. The transparency, induced by multi-mode interactions in waveguides, not only has a narrow line-width, but also consists of a single second-order transverse mode, which corresponds to the Bessel function distributions investigated extensively due to their unique characteristics. By increasing the thickness of sputtered gold layers of the waveguide, we demonstrate a frequency-agile single mode transparency phenomenon in a terahertz radiation. It is found that the center frequency of the transparency is linearly related to the gold thickness, indicating the achievement of a controllable single mode terahertz device. The field distributions at the cross-sections of outlets verify the single second mode transparency and indicate the mechanism of its frequency manipulation, which will significantly benefit the mode-control engineering in terahertz applications. - Highlights: • An analog of electromagnetically induced transparency in terahertz tubes is proposed. • A single second transverse mode of Bessel distributions is observed in the pass band. • The operating frequency can be linearly controlled by the sputtered gold thickness. • We can effectively manipulate the slow down factor of light by the gold thickness. • The transparency characteristics rely on the transition of multi-mode interactions.

  9. Competition and evolution of dielectric waveguide mode and plasmonic waveguide mode

    Science.gov (United States)

    Yuan, Sheng-Nan; Fang, Yun-Tuan

    2017-10-01

    In order to study the coupling and evolution law of the waveguide mode and two plasmonic surface modes, we construct a line defect waveguide based on hexagonal honeycomb plasmonic photonic crystal. Through adjusting the radius of the edge dielectric rods, the competition and evolution behaviors occur between dielectric waveguide mode and plasmonic waveguide mode. There are three status: only plasmonic waveguide modes occur for rA 0.25a; two kinds of modes coexist for 0.09a advantages in achieving slow light.

  10. Investigation of single lateral mode for 852nm diode lasers with ridge waveguide design

    Science.gov (United States)

    Liu, Chu; Guan, Baolu; Mi, Guoxin; Liao, Yiru; Liu, Zhenyang; Li, Jianjun; Xu, Chen

    2016-11-01

    852nm Narrow linewidth lasers can be widely used in the field of ultra-fine spectrum measurement, Cs atomic clock control, satellite and optical fiber communication and so on. Furthermore, the stability of the single lateral mode is a very important condition to guarantee the narrow linewidth lasers. Here we investigate experimentally the influence of the narrow ridge structure and asymmetrical waveguide design on the stability single lateral mode of an 852nm diode laser. According to the waveguide theoretical analysis, ridge mesa etch depth (Δη , related to the refractive index difference of parallel to the junction) and ridge mesa width (the narrower the more control force to low order mode) are the main elements for lateral modes. In this paper, we designed different structures to investigate and verify major factors for lateral mode by experiment, and to confirm our thought. Finally, the 5μm mesa ridge laser, 800nm etch depth, with groove structure obtains excellent steady single lateral mode output by 150mA operating current and 30°C temperature. The optical spectrum FWHM is 0.5nm and side mode suppression ratio is 27dBm with uncoated. The laser with 1mm cavity length showed the threshold current of 50mA, a lasing wavelength of λ = 852.6nm, slope efficiency of above 0.7mW/mA. We accomplished single lateral mode of ridge waveguide edge-emitting lasers which can also be used as a laser source in the ultra-narrow linewidth external cavity laser system.

  11. 11-GHz waveguide Nd:YAG laser CW mode-locked with single-layer graphene.

    Science.gov (United States)

    Okhrimchuk, Andrey G; Obraztsov, Petr A

    2015-06-08

    We report stable, passive, continuous-wave (CW) mode-locking of a compact diode-pumped waveguide Nd:YAG laser with a single-layer graphene saturable absorber. The depressed cladding waveguide in the Nd:YAG crystal is fabricated with an ultrafast laser inscription method. The saturable absorber is formed by direct deposition of CVD single-layer graphene on the output coupler. The few millimeter-long cavity provides generation of 16-ps pulses with repetition rates in the GHz range (up to 11.3 GHz) and 12 mW average power. Stable CW mode-locking operation is achieved by controlling the group delay dispersion in the laser cavity with a Gires-Tournois interferometer.

  12. Attenuation Coefficient of Single-Mode Periodic Waveguides

    Science.gov (United States)

    Baron, A.; Mazoyer, S.; Smigaj, W.; Lalanne, P.

    2011-10-01

    It is widely accepted that, on ensemble average, the transmission T of guided modes decays exponentially with the waveguide length L due to small imperfections, leading to the important figure of merit defined as the attenuation-rate coefficient α=-⟨ln⁡(T)⟩/L. In this Letter, we evidence that the exponential-damping law is not valid in general for periodic monomode waveguides, especially as the group velocity decreases. This result, that contradicts common beliefs and experimental practices aiming at measuring α, is supported by a theoretical study of light transport in the limit of very small imperfections, and by numerical results obtained for two waveguide geometries that offer contrasted damping behaviors.

  13. Flexible long-range surface plasmon polariton single-mode waveguide for optical interconnects

    DEFF Research Database (Denmark)

    Vernoux, Christian; Chen, Yiting; Markey, Laurent

    2018-01-01

    We present the design, fabrication and characterization of long-range surface plasmon polariton waveguide arrays with materials, mainly silicones, carefully selected with the aim to be used as mechanically flexible single-mode optical interconnections, the socalled "plasmonic arc" working at 1.55μm...

  14. Multi-level single mode 2D polymer waveguide optical interconnects using nano-imprint lithography

    NARCIS (Netherlands)

    Khan, M.U.; Justice, J.; Petäjä, J.; Korhonen, T.; Boersma, A.; Wiegersma, S.; Karppinen, M.; Corbett, B.

    2015-01-01

    Single and multi-layer passive optical interconnects using single mode polymer waveguides are demonstrated using UV nano-imprint lithography. The fabrication tolerances associated with imprint lithography are investigated and we show a way to experimentally quantify a small variation in index

  15. Single-mode waveguides with SU-8 polymer core and cladding for MOEMS applications

    DEFF Research Database (Denmark)

    Nordström, Maria; Zauner, Dan; Boisen, Anja

    2007-01-01

    Fabrication and optical characterization of singlemode polymeric embedded waveguides are performed. A specific material combination (SU-8 2005 as core and the modified SU-8 mr-L 6050XP as cladding) is chosen in order to obtain a small refractive index difference for single-mode propagation combined...... can fabricate waveguides with an index difference in the order of 10−3, where both the core material and the cladding material are based on SU-8. The refractive index measurements are performed on thin polymeric films, while further optical characterizations are performed on waveguides with a height...

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

    Directory of Open Access Journals (Sweden)

    Richard R. Grote

    2016-10-01

    Full Text Available 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.

  17. Design of Slow and Fast Light Photonic Crystal Waveguides for Single-photon Emission Using a Bloch Mode Expansion Technique

    DEFF Research Database (Denmark)

    de Lasson, Jakob Rosenkrantz; Rigal, B.; Kapon, E.

    We design slow and fast light photonic crystal waveguides for single-photon emission using a Bloch mode expansion and scattering matrix technique. We propose slow light designs that increase the group index-waveguide mode volume ratio for larger Purcell enhancement, and address efficient slow-to-...

  18. Diffusion-cooled high-power single-mode waveguide CO2 laser for transmyocardial revascularization

    Science.gov (United States)

    Berishvili, I. I.; Bockeria, L. A.; Egorov, E. N.; Golubev, Vladimir S.; Galushkin, Michail G.; Kheliminsky, A. A.; Panchenko, Vladislav Y.; Roshin, A. P.; Sigaev, I. Y.; Vachromeeva, M. N.; Vasiltsov, Victor V.; Yoshina, V. I.; Zabelin, Alexandre M.; Zelenov, Evgenii V.

    1999-01-01

    The paper presents the results on investigations and development of multichannel waveguide CO2 laser with diffusion cooling of active medium excited by discharge of audio-frequency alternating current. The description of high-power single-mode CO2 laser with average beam power up to 1 kW is presented. The result of measurement of the laser basic parameters are offered, as well as the outcomes of performances of the laser head with long active zone, operating in waveguide mode. As an example of application of these laser, various capabilities a description of the developed medical system 'Genom' used in the transmyocardial laser revascularization (TMLR) procedure and clinical results of the possibilities of the TMLR in the surgical treatment are presented.

  19. Enhancement of single mode operation in coaxial optical waveguide using DB boundary conditions

    Science.gov (United States)

    Lohia, Pooja; Prajapati, Y.; Saini, J. P.; Rai, B. S.

    2014-11-01

    In this study, a competent numerical strategy to compute the dispersion of optical waveguides is presented and propagation of electromagnetic waves in a coaxial optical waveguide with DB boundary conditions is instigated. For this intend, cylindrical coordinates are here being used to derive the DB boundary conditions and to obtain field components for the modes. The propagation constant for the waveguide to be studied is determined by solving the Bessel and the modified Bessel functions. The cutoff frequencies for various lower order modes have been calculated and their dispersion characteristics are plotted correspondingly. The behavior of the coaxial optical waveguide under DB boundary conditions is shown to be significantly different from that of coaxial optical waveguide and conventional optical waveguide under traditional or tangential boundary conditions. Finally, the effect of waveguide dimensions on the mode cutoff frequencies and fabrication issues are also addressed.

  20. Index-antiguided planar waveguide lasers with large mode area

    Science.gov (United States)

    Liu, Yuanye

    The on-going research and application interests with high power large-mode-area (LMA) waveguide lasers, especially in fiber geometry, at the beginning of this century drive the development of many novel waveguide designs. Index antiguiding, proposed by Siegman in 2003, is among one of them. The goal for index antiguiding is to introduce transversal modal loss with the relative simple waveguide design while maintain single transverse mode operation for good beam quality. The idea which is selectively support of fundamental mode is facilitated by involving certain level of signal regeneration inside the waveguide core. Since the modal loss is closed associated with waveguide design parameters such as core size and refractive index, the amount of gain inside the core provides active control of transverse modes inside index-antiguiding waveguide. For example, fundamental transverse mode inside such waveguide can be excited and propagate lossless when sufficient optical gain is provided. This often requires doped waveguide core and optical pumping at corresponding absorption band. However, the involvement of optical pumping also has its consequences. Phenomena such as thermal-optic effect and gain spatial hole-burning which are commonly found in bulk lasers request attention when scaling up output power with LMA index-antiguided waveguide amplifiers and resonators. In response, three key challenges of index-antiguided planar waveguide lasers, namely, guiding mechanism, power efficiency and transverse mode discrimination, are analyzed theoretically and experimentally in this dissertation. Experiments are based on two index-antiguided planar waveguide chips, whose core thickness are 220 microm and 400 microm respectively. The material of waveguide core is 1% Neodymium-doped Yttrium Aluminium garnet, or Nd:YAG while the cladding is made from Terbium Gallium garnet, or TGG. Due to the face pumping and limited pump power, it is found, with 220 microm-thick-core chip, that

  1. Sub-wavelength grating mode transformers in silicon slab waveguides.

    Science.gov (United States)

    Bock, Przemek J; Cheben, Pavel; Schmid, Jens H; Delâge, André; Xu, Dan-Xia; Janz, Siegfried; Hall, Trevor J

    2009-10-12

    We report on several new types of sub-wavelength grating (SWG) gradient index structures for efficient mode coupling in high index contrast slab waveguides. Using a SWG, an adiabatic transition is achieved at the interface between silicon-on-insulator waveguides of different geometries. The SWG transition region minimizes both fundamental mode mismatch loss and coupling to higher order modes. By creating the gradient effective index region in the direction of propagation, we demonstrate that efficient vertical mode transformation can be achieved between slab waveguides of different core thickness. The structures which we propose can be fabricated by a single etch step. Using 3D finite-difference time-domain simulations we study the loss, polarization dependence and the higher order mode excitation for two types (triangular and triangular-transverse) of SWG transition regions between silicon-on-insulator slab waveguides of different core thicknesses. We demonstrate two solutions to reduce the polarization dependent loss of these structures. Finally, we propose an implementation of SWG structures to reduce loss and higher order mode excitation between a slab waveguide and a phase array of an array waveguide grating (AWG). Compared to a conventional AWG, the loss is reduced from -1.4 dB to < -0.2 dB at the slab-array interface.

  2. 3-D near-field imaging of guided modes in nanophotonic waveguides

    Directory of Open Access Journals (Sweden)

    Ziegler Jed I.

    2017-04-01

    Full Text Available Highly evanescent waveguides with a subwavelength core thickness present a promising lab-on-chip solution for generating nanovolume trapping sites using overlapping evanescent fields. In this work, we experimentally studied Si3N4 waveguides whose sub-wavelength cross-sections and high aspect ratios support fundamental and higher order modes at a single excitation wavelength. Due to differing modal effective indices, these co-propagating modes interfere and generate beating patterns with significant evanescent field intensity. Using near-field scanning optical microscopy (NSOM, we map the structure of these beating modes in three dimensions. Our results demonstrate the potential of NSOM to optimize waveguide design for complex field trapping devices. By reducing the in-plane width, the population of competing modes decreases, resulting in a simplified spectrum of beating modes, such that waveguides with a width of 650 nm support three modes with two observed beats. Our results demonstrate the potential of NSOM to optimize waveguide design for complex field trapping devices.

  3. Single-mode waveguides with SU-8 polymer core and cladding for MOEMS applications

    OpenAIRE

    Nordström, Maria; Zauner, Dan; Boisen, Anja; Hübner, Jörg

    2007-01-01

    Fabrication and optical characterization of singlemode polymeric embedded waveguides are performed. A specific material combination (SU-8 2005 as core and the modified SU-8 mr-L 6050XP as cladding) is chosen in order to obtain a small refractive index difference for single-mode propagation combined with the conventional fabrication method UV lithography to facilitate the integration of different types of optical detection methods on lab-on-a-chip systems. We analyze the behavior of the refrac...

  4. Cantilever-based sensor with integrated optical read-out using single mode waveguides

    DEFF Research Database (Denmark)

    Nordström, Maria; Zauner, Dan; Calleja, Montserrat

    2007-01-01

    This work presents the design, fabrication and mechanical characterisation of an integrated optical read-out scheme for cantilever-based biosensors. A cantilever can be used as a biosensor by monitoring its bending caused by the surface stress generated due to chemical reactions occurring on its...... surface. Here, we present a novel integrated optical read-out scheme based on single-mode waveguides that enables the fabrication of a compact system. The complete system is fabricated in the polymer SU-8. This manuscript shows the principle of operation and the design well as the fabrication...

  5. Coupled mode theory of periodic waveguides arrays

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Chigrin, Dmitry N.

    We apply the scalar coupled mode theory to the case of waveguides array consisting om two periodic waveguides. One of the waveguides is arbitrary shifted along another. A longitudinal shift acts as a parameter in the coupled mode theory. The proposed theory explains peculiarities of modes dispers...... dispersion and transmission in coupled periodic waveguides systems. Analytical results are compared with the numerical ones obtained by the plane wave expansion and FDTD methods....

  6. Zero-mode waveguide nanophotonic structures for single molecule characterization

    Science.gov (United States)

    Crouch, Garrison M.; Han, Donghoon; Bohn, Paul W.

    2018-05-01

    Single-molecule characterization has become a crucial research tool in the chemical and life sciences, but limitations, such as limited concentration range, inability to control molecular distributions in space, and intrinsic phenomena, such as photobleaching, present significant challenges. Recent developments in non-classical optics and nanophotonics offer promising routes to mitigating these restrictions, such that even low affinity (K D ~ mM) biomolecular interactions can be studied. Here we introduce and review specific nanophotonic devices used to support single molecule studies. Optical nanostructures, such as zero-mode waveguides (ZMWs), are usually fabricated in thin gold or aluminum films and serve to confine the observation volume of optical microspectroscopy to attoliter to zeptoliter volumes. These simple nanostructures allow individual molecules to be isolated for optical and electrochemical analysis, even when the molecules of interest are present at high concentration (µM–mM) in bulk solution. Arrays of ZMWs may be combined with optical probes such as single molecule fluorescence, single molecule fluorescence resonance energy transfer, and fluorescence correlation spectroscopy for distributed analysis of large numbers of single-molecule reactions or binding events in parallel. Furthermore, ZMWs may be used as multifunctional devices, for example by combining optical and electrochemical functions in a single discrete architecture to achieve electrochemical ZMWs. In this review, we will describe the optical properties, fabrication, and applications of ZMWs for single-molecule studies, as well as the integration of ZMWs into systems for chemical and biochemical analysis.

  7. Spatial mode discriminator based on leaky waveguides

    Science.gov (United States)

    Xu, Jing; Liu, Jialing; Shi, Hongkang; Chen, Yuntian

    2018-06-01

    We propose a conceptually simple and experimentally compatible configuration to discriminate the spatial mode based on leaky waveguides, which are inserted in-between the transmission link. The essence of such a spatial mode discriminator is to introduce the leakage of the power flux on purpose for detection. Importantly, the leaky angle of each individual spatial mode with respect to the propagation direction are different for non-degenerated modes, while the radiation patterns of the degenerated spatial modes in the plane perpendicular to the propagation direction are also distinguishable. Based on these two facts, we illustrate the operation principle of the spatial mode discriminators via two concrete examples; a w-type slab leaky waveguide without degeneracy, and a cylindrical leaky waveguide with degeneracy. The correlation between the leakage angle and the spatial mode distribution for a slab leaky waveguide, as well as differences between the in-plane radiation patterns of degenerated modes in a cylindrical leaky waveguide, are verified numerically and analytically. Such findings can be readily useful in discriminating the spatial modes for optical communication or optical sensing.

  8. Competition and transformation of modes of unidirectional air waveguide

    Science.gov (United States)

    Sun, Yu-xin; Kong, Xiang-kun; Fang, Yun-tuan

    2016-10-01

    In order to study the mode excitation of the unidirectional air waveguide, we place a line source at different positions in the waveguide. The source position plays an important role in determining the result of the competition of the even mode and the odd mode. For the source at the edge of the waveguide, the odd mode gets advantage over the even mode. As a result, the odd mode is excited, but the even mode is suppressed. For the source at the center of the waveguide, the even mode is excited, but the odd mode is suppressed. With two sources at two edges of the waveguide, the even mode is released because the two odd modes are canceled.

  9. 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.

  10. Matrix method for two-dimensional waveguide mode solution

    Science.gov (United States)

    Sun, Baoguang; Cai, Congzhong; Venkatesh, Balajee Seshasayee

    2018-05-01

    In this paper, we show that the transfer matrix theory of multilayer optics can be used to solve the modes of any two-dimensional (2D) waveguide for their effective indices and field distributions. A 2D waveguide, even composed of numerous layers, is essentially a multilayer stack and the transmission through the stack can be analysed using the transfer matrix theory. The result is a transfer matrix with four complex value elements, namely A, B, C and D. The effective index of a guided mode satisfies two conditions: (1) evanescent waves exist simultaneously in the first (cladding) layer and last (substrate) layer, and (2) the complex element D vanishes. For a given mode, the field distribution in the waveguide is the result of a 'folded' plane wave. In each layer, there is only propagation and absorption; at each boundary, only reflection and refraction occur, which can be calculated according to the Fresnel equations. As examples, we show that this method can be used to solve modes supported by the multilayer step-index dielectric waveguide, slot waveguide, gradient-index waveguide and various plasmonic waveguides. The results indicate the transfer matrix method is effective for 2D waveguide mode solution in general.

  11. Differential modal delay measurements in a graded-index multimode fibre waveguide, using a single-mode fibre pro mode selection

    International Nuclear Information System (INIS)

    Sunak, H.R.D.; Soares, S.M.

    1981-01-01

    Differential model delay (DMD) measurements in graded-index multimode optical fibre waveguides, which are very promising for many types of communication system were carried out. These DMD measurements give a direct indication of the deviation of the refractive index profile, from the optimum value, at a given wavelength. For the first time, by using a single-mode fibre, a few guided modes in the graded-index fibre were selected, in two different ways: launching a few modes at the input end or selecting a few modes at the output end. By doing so important features of propagation in the fibre were revealed, especially the intermodal coupling that may exist. The importance of this determination of intermodal coupling or mode mixing, particularly when many fibres are joined together in a link, and the merits of DMD measurements in general and their importance for the production of high bandwidth graded-index fibres are discussed. (Author) [pt

  12. Acoustic one-way mode conversion and transmission by sonic crystal waveguides

    Science.gov (United States)

    Ouyang, Shiliang; He, Hailong; He, Zhaojian; Deng, Ke; Zhao, Heping

    2016-09-01

    We proposed a scheme to achieve one-way acoustic propagation and even-odd mode switching in two mutually perpendicular sonic crystal waveguides connected by a resonant cavity. The even mode in the entrance waveguide is able to switch to the odd mode in the exit waveguide through a symmetry match between the cavity resonant modes and the waveguide modes. Conversely, the odd mode in the exit waveguide is unable to be converted into the even mode in the entrance waveguide as incident waves and eigenmodes are mismatched in their symmetries at the waveguide exit. This one-way mechanism can be applied to design an acoustic diode for acoustic integration devices and can be used as a convertor of the acoustic waveguide modes.

  13. Optical Splitters Based on Self-Imaging Effect in Multi-Mode Waveguide Made by Ion Exchange in Glass

    Directory of Open Access Journals (Sweden)

    O. Barkman

    2013-04-01

    Full Text Available Design and modeling of single mode optical multi-mode interference structures with graded refractive index is reported. Several samples of planar optical channel waveguides were obtained by Ag+, Na+ and K+, Na+ one step thermal ion exchange process in molten salt on GIL49 glass substrate and new special optical glass for ion exchange technology. Waveguide properties were measured by optical mode spectroscopy. Obtained data were used for further design and modeling of single mode channel waveguide and subsequently for the design of 1 to 3 multimode interference power splitter in order to improve simulation accuracy. Designs were developed by utilizing finite difference beam propagation method.

  14. General coupled mode theory in non-Hermitian waveguides.

    Science.gov (United States)

    Xu, Jing; Chen, Yuntian

    2015-08-24

    In the presence of loss and gain, the coupled mode equation on describing the mode hybridization of various waveguides or cavities, or cavities coupled to waveguides becomes intrinsically non-Hermitian. In such non-Hermitian waveguides, the standard coupled mode theory fails. We generalize the coupled mode theory with a properly defined inner product based on reaction conservation. We apply our theory to the non-Hermitian parity-time symmetric waveguides, and obtain excellent agreement with results obtained by finite element fullwave simulations. The theory presented here is typically formulated in space to study coupling between waveguides, which can be transformed into time domain by proper reformulation to study coupling between non-Hermitian resonators. Our theory has the strength of studying non-Hermitian optical systems with inclusion of the full vector fields, thus is useful to study and design non-Hermitian devices that support asymmetric and even nonreciprocal light propagations.

  15. Coaxial waveguide mode reconstruction and analysis with THz digital holography.

    Science.gov (United States)

    Wang, Xinke; Xiong, Wei; Sun, Wenfeng; Zhang, Yan

    2012-03-26

    Terahertz (THz) digital holography is employed to investigate the properties of waveguides. By using a THz digital holographic imaging system, the propagation modes of a metallic coaxial waveguide are measured and the mode patterns are restored with the inverse Fresnel diffraction algorithm. The experimental results show that the THz propagation mode inside the waveguide is a combination of four modes TE₁₁, TE₁₂, TM₁₁, and TM₁₂, which are in good agreement with the simulation results. In this work, THz digital holography presents its strong potential as a platform for waveguide mode charactering. The experimental findings provide a valuable reference for the design of THz waveguides.

  16. Modeling of mode-locked coupled-resonator optical waveguide lasers

    DEFF Research Database (Denmark)

    Agger, Christian; Skovgård, Troels Suhr; Gregersen, Niels

    2010-01-01

    Coupled-resonator optical waveguides made from coupled high-Q photonic crystal nanocavities are investigated for use as cavities in mode-locked lasers. Such devices show great potential in slowing down light and can serve to reduce the cavity length of a mode-locked laser. An explicit expression...... of the emerging pulse train. A range of tuning around this frequency allows for effective mode locking. Finally, noise is added to the generalized single-cavity eigenfrequencies in order to evaluate the effects of fabrication imperfections on the cold-cavity transmission properties and consequently on the locking...

  17. Fully quantum-mechanical dynamic analysis of single-photon transport in a single-mode waveguide coupled to a traveling-wave resonator

    International Nuclear Information System (INIS)

    Hach, Edwin E. III; Elshaari, Ali W.; Preble, Stefan F.

    2010-01-01

    We analyze the dynamics of single-photon transport in a single-mode waveguide coupled to a micro-optical resonator by using a fully quantum-mechanical model. We examine the propagation of a single-photon Gaussian packet through the system under various coupling conditions. We review the theory of single-photon transport phenomena as applied to the system and we develop a discussion on the numerical technique we used to solve for dynamical behavior of the quantized field. To demonstrate our method and to establish robust single-photon results, we study the process of adiabatically lowering or raising the energy of a single photon trapped in an optical resonator under active tuning of the resonator. We show that our fully quantum-mechanical approach reproduces the semiclassical result in the appropriate limit and that the adiabatic invariant has the same form in each case. Finally, we explore the trapping of a single photon in a system of dynamically tuned, coupled optical cavities.

  18. Guided modes of elliptical metamaterial waveguides

    International Nuclear Information System (INIS)

    Halterman, Klaus; Feng, Simin; Overfelt, P. L.

    2007-01-01

    The propagation of guided electromagnetic waves in open elliptical metamaterial waveguide structures is investigated. The waveguide contains a negative-index media core, where the permittivity ε and permeability μ are negative over a given bandwidth. The allowed mode spectrum for these structures is numerically calculated by solving a dispersion relation that is expressed in terms of Mathieu functions. By probing certain regions of parameter space, we find the possibility exists to have extremely localized waves that transmit along the surface of the waveguide

  19. Guided modes in silicene-based waveguides

    Science.gov (United States)

    Yu, Mengzhuo; He, Ying; Yang, Yanfang; Zhang, Huifang

    2018-02-01

    Silicene is a new Dirac-type electron system similar to graphene. A monolayer silicene sheet forms a quantum well induced by an electrostatic potential, which acts as an electron waveguide. The guided modes in the silicene waveguide have been investigated. Electron waves can propagate in the silicene-based waveguide in the cases of Klein tunneling and classical motion. The behavior of the wave function depends on the spin and valley indices. The amplitude of the electron wave function in the silicene waveguide can be controlled by the external electric field. These phenomena may be helpful for the potential applications of silicene-based electronic devices.

  20. Optical vortex propagation in few-mode rectangular polymer waveguides

    DEFF Research Database (Denmark)

    Lyubopytov, Vladimir S.; Chipouline, Arkadi; Zywietz, Urs

    2017-01-01

    We demonstrate that rectangular few-mode dielectric waveguides, fabricated with standard lithographic technique, can support on-chip propagation of optical vortices. We show that specific superpositions of waveguide eigenmodes form quasi-degenerate modes carrying light with high purity states...

  1. Characteristics of the Single-Longitudinal-Mode Planar-Waveguide External Cavity Diode Laser at 1064 nm

    Science.gov (United States)

    Numata, Kenji; Alalusi, Mazin; Stolpner, Lew; Margaritis, Georgios; Camp, Jordan; Krainak, Michael

    2014-01-01

    We describe the characteristics of the planar-waveguide external cavity diode laser (PW-ECL). To the best of our knowledge, it is the first butterfly-packaged 1064 nm semiconductor laser that is stable enough to be locked to an external frequency reference. We evaluated its performance from the viewpoint of precision experiments. Using a hyperfine absorption line of iodine, we suppressed its frequency noise by a factor of up to 104 at 10 mHz. The PWECL's compactness and low cost make it a candidate to replace traditional Nd:YAG nonplanar ring oscillators and fiber lasers in applications that require a single longitudinal mode.

  2. Mode analysis and structure parameter optimization of a novel SiGe-OI rib optical waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Feng Song; Gao Yong; Yang Yuan [Department of Electronic Engineering, Xi' an University of Technology, Xi' an 710048 (China); Feng Yuchun, E-mail: vonfs@yahoo.com.c [Key Laboratories of Optoelectronic Devices and Systems, Shenzhen University, Shenzhen 518060 (China)

    2009-08-15

    The mode of a novel SiGe-OI optical waveguide is analyzed, and its single-mode conditions are derived. The Ge content and structure parameters of SiGe-OI optical waveguides are respectively optimized. Under an operation wavelength of 1300 nm, the structures of SiGe-OI rib optical waveguides are built and analyzed with Optiwave software, and the optical field and transmission losses of the SiGe-OI rib optical waveguides are analyzed. The optimization results show that when the structure parameters H, h, W are respectively 500 nm, 250 nm, 500 nm and the Ge content is 5%, the total power loss of SiGe-OI rib waveguides is 0.3683 dB/cm considering the loss of radiation outside the waveguides and materials, which is less than the traditional value of 0.5 dB/cm. The analytical technique for SiGe-OI optical waveguides and structure parameters computed by this paper are proved to be accurate and computationally efficient compared with the beam propagation method (BPM) and the experimental results. (semiconductor devices)

  3. 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.

  4. Index matching of TE and TM modes in organic multilayer waveguides

    Science.gov (United States)

    Thompson, Jonathan; Schmitzer, Heidrun; Wagner, Hans Peter

    We investigate transverse electric (TE) and magnetic (TM) mode propagation in organic multilayers consisting of aluminum quinoline (Alq3) and perylenetetracarboxylic dianhydride (PTCDA). In particular, we analyze two multilayer waveguides, Alq3-PTCDA-Alq3 and PTCDA-Alq3-PTCDA, engineered to give index matching according to modeling. The waveguides were grown on a glass substrate via organic molecular beam deposition. Fabry-Perot oscillations observed from reflection measurements were used to confirm the individual layer thicknesses. We were able to observe refractive index matching between TE0 and TE1, as well as TE2 and TE3 modes for the PTCDA-Alq3-PTCDA waveguide due to the light propagation through the top and bottom PTCDA layers, respectively. In addition, we were able to match TE1 and TM1, as well as TE3 and TM3 modes in the Alq3-PTCDA-Alq3 multilayer due to the birefringence of the PTCDA layer. Furthermore, we are able to create mode matching for a range of wavelengths due to the similar effective refractive index dispersion of different waveguide modes. The ability to phase match different waveguide modes opens a wide range of potential applications including polarization-insensitive propagation and mode switching by adding a thin magnetic metal film within the waveguide and applying an external magnetic field.

  5. Fiber-chip edge coupler with large mode size for silicon photonic wire waveguides.

    Science.gov (United States)

    Papes, Martin; Cheben, Pavel; Benedikovic, Daniel; Schmid, Jens H; Pond, James; Halir, Robert; Ortega-Moñux, Alejandro; Wangüemert-Pérez, Gonzalo; Ye, Winnie N; Xu, Dan-Xia; Janz, Siegfried; Dado, Milan; Vašinek, Vladimír

    2016-03-07

    Fiber-chip edge couplers are extensively used in integrated optics for coupling of light between planar waveguide circuits and optical fibers. In this work, we report on a new fiber-chip edge coupler concept with large mode size for silicon photonic wire waveguides. The coupler allows direct coupling with conventional cleaved optical fibers with large mode size while circumventing the need for lensed fibers. The coupler is designed for 220 nm silicon-on-insulator (SOI) platform. It exhibits an overall coupling efficiency exceeding 90%, as independently confirmed by 3D Finite-Difference Time-Domain (FDTD) and fully vectorial 3D Eigenmode Expansion (EME) calculations. We present two specific coupler designs, namely for a high numerical aperture single mode optical fiber with 6 µm mode field diameter (MFD) and a standard SMF-28 fiber with 10.4 µm MFD. An important advantage of our coupler concept is the ability to expand the mode at the chip edge without leading to high substrate leakage losses through buried oxide (BOX), which in our design is set to 3 µm. This remarkable feature is achieved by implementing in the SiO 2 upper cladding thin high-index Si 3 N 4 layers. The Si 3 N 4 layers increase the effective refractive index of the upper cladding near the facet. The index is controlled along the taper by subwavelength refractive index engineering to facilitate adiabatic mode transformation to the silicon wire waveguide while the Si-wire waveguide is inversely tapered along the coupler. The mode overlap optimization at the chip facet is carried out with a full vectorial mode solver. The mode transformation along the coupler is studied using 3D-FDTD simulations and with fully-vectorial 3D-EME calculations. The couplers are optimized for operating with transverse electric (TE) polarization and the operating wavelength is centered at 1.55 µm.

  6. Dynamical theory of single-photon transport in a one-dimensional waveguide coupled to identical and nonidentical emitters

    Science.gov (United States)

    Liao, Zeyang; Nha, Hyunchul; Zubairy, M. Suhail

    2016-11-01

    We develop a general dynamical theory for studying a single-photon transport in a one-dimensional (1D) waveguide coupled to multiple emitters which can be either identical or nonidentical. In this theory, both the effects of the waveguide and non-waveguide vacuum modes are included. This theory enables us to investigate the propagation of an emitter excitation or an arbitrary single-photon pulse along an array of emitters coupled to a 1D waveguide. The dipole-dipole interaction induced by the non-waveguide modes, which is usually neglected in the literature, can significantly modify the dynamics of the emitter system as well as the characteristics of the output field if the emitter separation is much smaller than the resonance wavelength. Nonidentical emitters can also strongly couple to each other if their energy difference is less than or of the order of the dipole-dipole energy shift. Interestingly, if their energy difference is close but nonzero, a very narrow transparency window around the resonance frequency can appear which does not occur for identical emitters. This phenomenon may find important applications in quantum waveguide devices such as optical switches and ultranarrow single-photon frequency comb generator.

  7. All-solid-state cavity QED using Anderson-localized modes in disordered photonic crystal waveguides

    DEFF Research Database (Denmark)

    Lodahl, Peter; Sapienza, Luca; Nielsen, Henri Thyrrestrup

    2010-01-01

    We employ Anderson-localized modes in deliberately disordered photonic crystal waveguides to confine light and enhance the interaction with matter. A 15-fold enhancement of the decay rate of a single quantum dot is observed meaning that 94% of the emitted single photons are coupled to an Anderson...

  8. The LHC Beam Pipe Waveguide Mode Reflectometer

    CERN Document Server

    Kroyer, T; Caspers, Friedhelm; Sulek, Z; Williams, L R

    2007-01-01

    The waveguide-mode reflectometer for obstacle detection in the LHC beam pipe has been intensively used for more than 18 months. The â€ワAssembly” version is based on the synthetic pulse method using a modern vector network analyzer. It has mode selective excitation couplers for the first TE and TM mode and uses a specially developed waveguide mode dispersion compensation algorithm with external software. In addition there is a similar â€ワIn Situ” version of the reflectometer which uses permanently installed microwave couplers at the end of each of the nearly 3 km long LHC arcs. During installation a considerable number of unexpected objects have been found in the beam pipes and subsequently removed. Operational statistics and lessons learned are presented and the overall performance is discussed.

  9. Nonlinear digital out-of-plane waveguide coupler based on nonlinear scattering of a single graphene layer

    Science.gov (United States)

    Asadi, Reza; Ouyang, Zhengbiao

    2018-03-01

    A new mechanism for out-of-plane coupling into a waveguide is presented and numerically studied based on nonlinear scattering of a single nano-scale Graphene layer inside the waveguide. In this mechanism, the refractive index nonlinearity of Graphene and nonhomogeneous light intensity distribution occurred due to the interference between the out-of-plane incident pump light and the waveguide mode provide a virtual grating inside the waveguide, coupling the out-of-plane pump light into the waveguide. It has been shown that the coupling efficiency has two distinct values with high contrast around a threshold pump intensity, providing suitable condition for digital optical applications. The structure operates at a resonance mode due to band edge effect, which enhances the nonlinearity and decreases the required threshold intensity.

  10. Mode conversions by a discontinuous junction of two helix loaded waveguides

    International Nuclear Information System (INIS)

    Choe, J.Y.; Ahn, S.; Ganquly, A.K.; Uhm, H.S.

    1983-01-01

    For various reasons, it is desirable to vary the primary propagating mode from one section of the waveguide to another. We choose the base structure to be the sheath helix loaded waveguide. Specifically, we join two physically different helix loaded waveguides axisymmetrically, thereby providing the required discontinuities at the junction (Z = 0). The helix loaded waveguide is more advantageous to the simple waveguide in that the helix mode that exists uniquely in the helix waveguide in addition to the usual fast wave hybrid modes, is without cutoff and thus behaves like a transmission line. In order to obtain the mode conversion rates, we expand the waves in the both sides of the junction with its own eigenmodes including the evanescent modes, and by matching fields at the junction (Z = 0) obtain the matrix equation for the coefficients for the eigenmodes in both sides. By choosing the propagating incident wave (Z = 0) the resulting outgoing waves in the other end (Z > 0) will be computed from the matrix equation. A computer program is devised to solve the suitably truncated matrix equation, and the numerical examples for the mode conversion rates with the parameter variations will be presented. The relevant physical parameters to yield discontinuities at the junction are the radii of the outer conductor and the helix wire and the pitch angle of the helix. Special emphases are on the conversion rates from the helix mode (Z 0) for the application to the tapered gyrotron amplifier

  11. Mode converters for generating the HE11 (gaussian-like) mode from TE01 in circular waveguide

    International Nuclear Information System (INIS)

    Doane, J.L.

    1982-09-01

    The HE11 mode in corrugated waveguide has a field distribution very close to that of an ideal gaussian mode. Its radiation pattern is symmetric about the waveguide axis and exhibits virtually no cross polarization. This work reports measurements on mode converters to transform the TE01 mode into HE11 for electron cyclotron heating (ECH) experiments. The first mode converter is a 28 degree bend in 1.094-inch I.D. circular waveguide which generates TM11 from TE01 with a measured efficiency of over 95% at 60 GHz. A second converter consists of a straight corrugated waveguide section of the same I.D. in which the corrugation depth increases gradually from zero to nominally a quarter wavelength. This section converts TM11 to HE11 with an efficiency of about 97%. The overall efficiency of conversion from TE01 to HE11 exceeds 91% over a measured range of 59.2 to 60.1 GHz

  12. Single photon detection in a waveguide-coupled Ge-on-Si lateral avalanche photodiode.

    Science.gov (United States)

    Martinez, Nicholas J D; Gehl, Michael; Derose, Christopher T; Starbuck, Andrew L; Pomerene, Andrew T; Lentine, Anthony L; Trotter, Douglas C; Davids, Paul S

    2017-07-10

    We examine gated-Geiger mode operation of an integrated waveguide-coupled Ge-on-Si lateral avalanche photodiode (APD) and demonstrate single photon detection at low dark count for this mode of operation. Our integrated waveguide-coupled APD is fabricated using a selective epitaxial Ge-on-Si growth process resulting in a separate absorption and charge multiplication (SACM) design compatible with our silicon photonics platform. Single photon detection efficiency and dark count rate is measured as a function of temperature in order to understand and optimize performance characteristics in this device. We report single photon detection of 5.27% at 1310 nm and a dark count rate of 534 kHz at 80 K for a Ge-on-Si single photon avalanche diode. Dark count rate is the lowest for a Ge-on-Si single photon detector in this range of temperatures while maintaining competitive detection efficiency. A jitter of 105 ps was measured for this device.

  13. Resonant absorption in semiconductor nanowires and nanowire arrays: Relating leaky waveguide modes to Bloch photonic crystal modes

    Energy Technology Data Exchange (ETDEWEB)

    Fountaine, Katherine T., E-mail: kfountai@caltech.edu [Department of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Whitney, William S. [Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Department of Physics, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Atwater, Harry A. [Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Department of Applied Physics and Materials Science, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States)

    2014-10-21

    We present a unified framework for resonant absorption in periodic arrays of high index semiconductor nanowires that combines a leaky waveguide theory perspective and that of photonic crystals supporting Bloch modes, as array density transitions from sparse to dense. Full dispersion relations are calculated for each mode at varying illumination angles using the eigenvalue equation for leaky waveguide modes of an infinite dielectric cylinder. The dispersion relations along with symmetry arguments explain the selectivity of mode excitation and spectral red-shifting of absorption for illumination parallel to the nanowire axis in comparison to perpendicular illumination. Analysis of photonic crystal band dispersion for varying array density illustrates that the modes responsible for resonant nanowire absorption emerge from the leaky waveguide modes.

  14. Two-dimensional Kagome photonic bandgap waveguide

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo; Søndergaard, Thomas; Libori, Stig E. Barkou

    2000-01-01

    The transverse-magnetic photonic-bandgap-guidance properties are investigated for a planar two-dimensional (2-D) Kagome waveguide configuration using a full-vectorial plane-wave-expansion method. Single-moded well-localized low-index guided modes are found. The localization of the optical modes...... is investigated with respect to the width of the 2-D Kagome waveguide, and the number of modes existing for specific frequencies and waveguide widths is mapped out....

  15. Performance of Ar+-milled Ti:Sapphire rib waveguides as single transverse-mode broadband fluorescence sources

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, Markus; Crunteanu, A.; Jelinek, M.

    2003-01-01

    Rib waveguides have been fabricated in pulsed-laser-deposited Ti:sapphire layers using photolithographic patterning and subsequent Ar+-beam milling. Fluorescence output powers up to 300 W have been observed from the ribs following excitation by a 3-W multiline argon laser. Mode intensity profiles

  16. Design of tunable surface mode waveguide based on photonic crystal composite structure using organic liquid*

    International Nuclear Information System (INIS)

    Zhang Lan-Lan; Liu Wei; Li Ping; Yang Xi; Cao Xu

    2017-01-01

    With the method of replacing the surface layer of photonic crystal with tubes, a novel photonic crystal composite structure used as a tunable surface mode waveguide is designed. The tubes support tunable surface states. The tunable propagation capabilities of the structure are investigated by using the finite-difference time-domain. Simulation results show that the beam transmission distributions of the composite structure are sensitive to the frequency range of incident light and the surface morphology which can be modified by filling the tubes with different organic liquids. By adjusting the filler in tubes, the T-shaped, Y-shaped, and L-shaped propagations can be realized. The property can be applied to the tunable surface mode waveguide. Compared with a traditional single function photonic crystal waveguide, our designed structure not only has a small size, but also is a tunable device. (paper)

  17. Hemagglutination detection for blood typing based on waveguide-mode sensors

    Directory of Open Access Journals (Sweden)

    Hiroki Ashiba

    2015-03-01

    Full Text Available ABO and Rh(D blood typing is one of the most important tests performed prior to blood transfusion. Although on-site blood testing is desirable for expedient blood transfusion procedure, most conventional methods and instruments lack the required usability or portability. Here, we describe a novel method, based on the detection of hemagglutination using an optical waveguide-mode sensor, for on-site use. The reflectance spectrum of blood alone and that of blood mixed with antibody reagents was measured using the waveguide-mode sensor. Differences in reflectance by agglutinated and non-agglutinated blood samples were observed at the bottom of the spectral dips; due to differences in the manner in which red blood cells interacted with the surface of the sensor chip. Following the addition of the antibody, blood types A, B, O, and AB were clearly distinguishable and Rh(D typing was also possible using the waveguide-mode sensor. Furthermore, the waveguide-mode-based measurement exhibited the potential to detect weak agglutination, which is difficult for human eyes to distinguish. Thus, this method holds great promise for application in novel on-site test instruments.

  18. Single scan femtosecond laser transverse writing of depressed cladding waveguides enabled by three-dimensional focal field engineering.

    Science.gov (United States)

    Zhang, Qian; Yang, Dong; Qi, Jia; Cheng, Ya; Gong, Qihuang; Li, Yan

    2017-06-12

    We report single scan transverse writing of depressed cladding waveguides inside ZBLAN glass with the longitudinally oriented annular ring-shaped focal intensity distribution of the femtosecond laser. The entire region of depressed cladding at the cross section, where a negative change of refraction index is induced, can be modified simultaneously with the ring-shaped focal intensity profile. The fabricated waveguides exhibit good single guided mode.

  19. Spontaneous decay of a single quantum dot coupled to a metallic slot waveguide in the presence of leaky plasmonic modes

    DEFF Research Database (Denmark)

    Chen, Yuntian; Gregersen, Niels; Nielsen, Torben Roland

    2010-01-01

    in which the metallic slot waveguide is embedded. Compared to the ideal case of a homogenous dielectric environment, the coupling efficiency of an emitter to a metallic slot waveguide is significantly reduced. We attribute the reduction to the coupling to leaky plasmonic modes. By increasing the refractive...

  20. 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....

  1. Mode conversion in metal-insulator-metal waveguide with a shifted cavity

    Science.gov (United States)

    Wang, Yueke; Yan, Xin

    2018-01-01

    We propose a method, which is utilized to achieve the plasmonic mode conversion in metal-insulator-metal (MIM) waveguide, theoretically. Our proposed structure is composed of bus waveguides and a shifted cavity. The shifted cavity can choose out a plasmonic mode (a- or s-mode) when it is in Fabry-Perot (FP) resonance. The length of the shifted cavity L is carefully chosen, and our structure can achieve the mode conversion between a- and s-mode in the communication region. Besides, our proposed structure can also achieve plasmonic mode-division multiplexing. All the numerical simulations are carried on by the finite element method to verify our design.

  2. Ultra-compact Higher-Order-Mode Pass Filter in a Silicon Waveguide

    DEFF Research Database (Denmark)

    Guan, Xiaowei; Frandsen, Lars Hagedorn; Ding, Yunhong

    2015-01-01

    An 3.7 μm long higher-order-mode pass filter with an extinction ratio larger than 20 dB is demonstrated in a 1D corrugated silicon multimode waveguide......An 3.7 μm long higher-order-mode pass filter with an extinction ratio larger than 20 dB is demonstrated in a 1D corrugated silicon multimode waveguide...

  3. Finite mode analysis through harmonic waveguides

    NARCIS (Netherlands)

    Alieva, T.; Wolf, K.B.

    2000-01-01

    The mode analysis of signals in a multimodal shallow harmonic waveguide whose eigenfrequencies are equally spaced and finite can be performed by an optoelectronic device, of which the optical part uses the guide to sample the wave field at a number of sensors along its axis and the electronic part

  4. A magnetically tunable non-Bragg defect mode in a corrugated waveguide filled with liquid crystals

    Science.gov (United States)

    Zhang, Lu; Fan, Ya-Xian; Liu, Huan; Han, Xu; Lu, Wen-Qiang; Tao, Zhi-Yong

    2018-04-01

    A magnetically tunable, non-Bragg defect mode (NBDM) was created in the terahertz frequency range by inserting a defect in the middle of a periodically corrugated waveguide filled with liquid crystals (LCs). In the periodic waveguide, non-Bragg gaps beyond the Bragg ones, which appear in the transmission spectra, are created by different transverse mode resonances. The transmission spectra of the waveguide containing a defect showed that a defect mode was present inside the non-Bragg gap. The NBDM has quite different features compared to the Bragg defect mode, which includes more complex, high-order guided wave modes. In our study, we filled the corrugated waveguide with LCs to realize the tunability of the NBDM. The simulated results showed that the NBDM in a corrugated waveguide filled with LCs can be used in filters, sensors, switches, and other terahertz integrated devices.

  5. Single-mode propagation in optical waveguides and fibres: a critical review of its treatment in physics textbooks

    Energy Technology Data Exchange (ETDEWEB)

    Ruddock, Ivan S [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)], E-mail: i.s.ruddock@strath.ac.uk

    2009-03-15

    The derivation and description of the modes in optical waveguides and fibres are reviewed. The version frequently found in undergraduate textbooks is shown to be incorrect and misleading due to the assumption of an axial ray of light corresponding to the lowest order mode. It is pointed out that even the lowest order must still be represented in an elementary treatment by a ray reflecting between opposite core and cladding boundaries.

  6. Fundamental mode rf power dissipated in a waveguide attached to an accelerating cavity

    International Nuclear Information System (INIS)

    Kang, Y.W.

    1993-01-01

    An accelerating RF cavity usually requires accessory devices such as a tuner, a coupler, and a damper to perform properly. Since a device is attached to the wall of the cavity to have certain electrical coupling of the cavity field through the opening. RF power dissipation is involved. In a high power accelerating cavity, the RF power coupled and dissipated in the opening and in the device must be estimated to design a proper cooling system for the device. The single cell cavities of the APS storage ring will use the same accessories. These cavities are rotationally symmetric and the fields around the equator can be approximated with the fields of the cylindrical pillbox cavity. In the following, the coupled and dissipated fundamental mode RF power in a waveguide attached to a pillbox cavity is discussed. The waveguide configurations are (1) aperture-coupled cylindrical waveguide with matched load termination; (2) short-circuited cylindrical waveguide; and (3) E-probe or H-loop coupled coaxial waveguide. A short-circuited, one-wavelength coaxial structure is considered for the fundamental frequency rejection circuit of an H-loop damper

  7. Nonlinear defect localized modes and composite gray and anti-gray solitons in one-dimensional waveguide arrays with dual-flip defects

    Science.gov (United States)

    Liu, Yan; Guan, Yefeng; Li, Hai; Luo, Zhihuan; Mai, Zhijie

    2017-08-01

    We study families of stationary nonlinear localized modes and composite gray and anti-gray solitons in a one-dimensional linear waveguide array with dual phase-flip nonlinear point defects. Unstaggered fundamental and dipole bright modes are studied when the defect nonlinearity is self-focusing. For the fundamental modes, symmetric and asymmetric nonlinear modes are found. Their stable areas are studied using different defect coefficients and their total power. For the nonlinear dipole modes, the stability conditions of this type of mode are also identified by different defect coefficients and the total power. When the defect nonlinearity is replaced by the self-defocusing one, staggered fundamental and dipole bright modes are created. Finally, if we replace the linear waveguide with a full nonlinear waveguide, a new type of gray and anti-gray solitons, which are constructed by a kink and anti-kink pair, can be supported by such dual phase-flip defects. In contrast to the usual gray and anti-gray solitons formed by a single kink, their backgrounds on either side of the gray hole or bright hump have the same phase.

  8. Optical propagation of the HE11 mode and Gaussian beams in hollow circular waveguides

    International Nuclear Information System (INIS)

    Crenn, J.P.

    1993-05-01

    The propagation of the HE 11 mode and Gaussian beams in hollow oversized circular waveguides is analyzed using optical theories. Different types of waveguides are considered: hollow dielectric or conducting waveguides, dielectric-lined waveguides, corrugated waveguides. General formulas are derived which give the power transmission through these different guides. The best wall materials and structures are determined from a comparison of the waveguide transmissions, at the infrared and millimeter wavelengths. The question of the coupling between the HE 11 mode and Gaussian beams is discussed and from a review of coupling coefficients derived before, an optimum value is pointed out. The problem of matching a Gaussian beam into circular waveguides in order to achieve the maximum power transmission is analyzed

  9. Design and fabrication of three-dimensional polymer mode multiplexer based on asymmetric waveguide couplers

    Science.gov (United States)

    He, Guobing; Gao, Yang; Xu, Yan; Ji, Lanting; Sun, Xiaoqiang; Wang, Xibin; Yi, Yunji; Chen, Changming; Wang, Fei; Zhang, Daming; Wu, Yuanda

    2018-05-01

    A polymer mode multiplexer based on asymmetric couplers is theoretically designed and experimentally demonstrated. The proposed X-junction coupler is formed by waveguides overlapped with different crossing angles in the vertical direction. A beam propagation method is adopted to optimize the dimensional parameters of the mode multiplexer to convert LP01 mode of two lower waveguides to LP11a and LP21a mode of the upper waveguide. The ultraviolet lithography and wet chemical etching are used in the fabrication process. A conversion ratio over 98% for both LP11a and LP21a mode in the wavelength range from 1530 to 1570 nm are experimentally demonstrated. This mode multiplexer has potential in broadband mode-division multiplexing transmission systems.

  10. Using quasi-guided modes for modeling the transfer behavior of bent dielectric slab waveguides

    Directory of Open Access Journals (Sweden)

    M. Stallein

    2010-09-01

    Full Text Available The connection of two straight dielectric multimode slab waveguides by a circular bent waveguide is analyzed by means of quasi-guided modes. These modes correspond to the well known leaky modes, but own real eigenvalues, thus the mathematical description is simpler. Furthermore they are derived as approximate solutions of the exact theory. This work will first give a brief introduction to the basic theory, followed by a discussion of the properties of quasi-guided modes. After a validation by comparison with a numerical simulation using the Finite Integration Technique, results for the bending loss of multimode waveguides are presented.

  11. Structure of modes of smoothly irregular three-dimensional integrated optical four-layer waveguide

    International Nuclear Information System (INIS)

    Egorov, A.A.; Ajryan, Eh.A.; Sevast'yanov, A.L.; Sevast'yanov, L.A.

    2009-01-01

    As a method of research of an integrated optical multilayer waveguide, satisfying the condition of smooth modification of the shape of the studied three-dimensional structure, an asymptotic method is used. Three-dimensional fields of smoothly deforming modes of the integrated optical waveguide are circumscribed analytically. An evident dependence of the contributions of the first order of smallness in the amplitudes of the electrical and magnetic fields of the quasi-waveguide modes is obtained. The canonical type of the equations circumscribing propagation of quasi-TE and quasi-TM modes in the smoothly irregular part of a four-layer integrated optical waveguide is represented for an asymptotic method. With the help of the method of coupled waves and perturbation theory method, the shifts of complex propagation constants for quasi-TE and quasi-TM modes are obtained in an explicit form. The elaborated theory is applicable for the analysis of similar structures of dielectric, magnetic and metamaterials in a sufficiently broad band of electromagnetic wavelengths

  12. Selection of transverse modes in laser cavities containing waveguides and open parts

    International Nuclear Information System (INIS)

    Gurin, O V; Degtyarev, A V; Maslov, Vyacheslav A; Svich, V A; Tkachenko, V M; Topkov, A N

    2001-01-01

    The transverse modes of a submillimetre laser cavity that contains waveguides and open parts were studied theoretically and experimentally with the purpose of finding methods for mode selection. Two methods based on the filtering of the Fourier spectra of the waveguide modes and the use of their interference were substantiated numerically and realised in experiment. Special attention was paid to the mode selection in tunable lasers. Scaling laws allowing one to use the obtained results in a wide range of the cavity parameters and wavelengths are presented. (laser applications and other topics in quantum electronics)

  13. Fabrication of raised and inverted SU8 polymer waveguides

    Science.gov (United States)

    Holland, Anthony S.; Mitchell, Arnan; Balkunje, Vishal S.; Austin, Mike W.; Raghunathan, Mukund K.

    2005-01-01

    Polymer films with high optical transmission have been investigated for making optical devices for several years. SU8 photoresist and optical adhesives have been investigated for use as thin films for optical devices, not what they were originally designed for. Optical adhesives are typically a one component thermoset polymer and are convenient to use for making thin film optical devices such as waveguides. They are prepared in minutes as thin films unlike SU8, which has to be carefully thermally cured over several hours for optimum results. However SU8 can be accurately patterned to form the geometry of structures required for single mode optical waveguides. SU8 in combination with the lower refractive index optical adhesive films such as UV15 from Master Bond are used to form single and multi mode waveguides. SU8 is photopatternable but we have also used dry etching of the SU8 layer or the other polymer layers e.g. UV15 to form the ribs, ridges or trenches required to guide single modes of light. Optical waveguides were also fabricated using only optical adhesives of different refractive indices. The resolution obtainable is poorer than with SU8 and hence multi mode waveguides are obtained. Loss measurements have been obtained for waveguides of different geometries and material combinations. The process for making polymer waveguides is demonstrated for making large multi mode waveguides and microfluidic channels by scaling the process up in size.

  14. Waveguide modes of 1D photonic crystals in a transverse magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Sylgacheva, D. A., E-mail: sylgacheva.darjja@physics.msu.ru; Khokhlov, N. E.; Kalish, A. N.; Belotelov, V. I. [Moscow State University, Physics Department (Russian Federation)

    2016-11-15

    We analyze waveguide modes in 1D photonic crystals containing layers magnetized in the plane. It is shown that the magnetooptical nonreciprocity effect emerges in such structures during the propagation of waveguide modes along the layers and perpendicularly to the magnetization. This effect involves a change in the phase velocity of the mode upon reversal of the direction of magnetization. Comparison of the effects in a nonmagnetic photonic crystal with an additional magnetic layer and in a photonic crystal with magnetic layers shows that the magnitude of this effect is several times larger in the former case in spite of the fact that the electromagnetic field of the modes in the latter case is localized in magnetic regions more strongly. This is associated with asymmetry of the dielectric layers contacting with the magnetic layer in the former case. This effect is important for controlling waveguide structure modes with the help of an external magnetic field.

  15. Active composite waveguides with a suppressed competition of optical modes

    International Nuclear Information System (INIS)

    Vysotskii, D V; Elkin, N N; Napartovich, A P

    2008-01-01

    The possibilities of separating the fundamental optical mode in composite waveguides by selecting the structure of amplifying regions are analysed. Conditions are presented under which the fundamental mode preserves the highest gain at any saturation. (letters)

  16. Nanoscale devices based on plasmonic coaxial waveguide resonators

    Science.gov (United States)

    Mahigir, A.; Dastmalchi, P.; Shin, W.; Fan, S.; Veronis, G.

    2015-02-01

    Waveguide-resonator systems are particularly useful for the development of several integrated photonic devices, such as tunable filters, optical switches, channel drop filters, reflectors, and impedance matching elements. In this paper, we introduce nanoscale devices based on plasmonic coaxial waveguide resonators. In particular, we investigate threedimensional nanostructures consisting of plasmonic coaxial stub resonators side-coupled to a plasmonic coaxial waveguide. We use coaxial waveguides with square cross sections, which can be fabricated using lithography-based techniques. The waveguides are placed on top of a silicon substrate, and the space between inner and outer coaxial metals is filled with silica. We use silver as the metal. We investigate structures consisting of a single plasmonic coaxial resonator, which is terminated either in a short or an open circuit, side-coupled to a coaxial waveguide. We show that the incident waveguide mode is almost completely reflected on resonance, while far from the resonance the waveguide mode is almost completely transmitted. We also show that the properties of the waveguide systems can be accurately described using a single-mode scattering matrix theory. The transmission and reflection coefficients at waveguide junctions are either calculated using the concept of the characteristic impedance or are directly numerically extracted using full-wave three-dimensional finite-difference frequency-domain simulations.

  17. Coherent single-photon absorption by single emitters coupled to one-dimensional nanophotonic waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yuntian; Wubs, Martijn; Moerk, Jesper [DTU Fotonik, Department of Photonics Engineering, Oersteds Plads, DK-2800 Kgs Lyngby (Denmark); Koenderink, A Femius, E-mail: yche@fotonik.dtu.dk [Center for Nanophotonics, FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 104, 1098 XG Amsterdam (Netherlands)

    2011-10-15

    We study the dynamics of single-photon absorption by a single emitter coupled to a one-dimensional waveguide that simultaneously provides channels for spontaneous emission (SE) decay and a channel for the input photon. We have developed a time-dependent theory that allows us to specify any input single-photon wavepacket guided by the waveguide as the initial condition, and calculate the excitation probability of the emitter, as well as the time evolution of the transmitted and reflected fields. For single-photon wavepackets with a Gaussian spectrum and temporal shape, we obtain analytical solutions for the dynamics of absorption, with maximum atomic excitation {approx}40%. We furthermore propose a terminated waveguide to aid the single-photon absorption. We found that for an emitter placed at an optimal distance from the termination, the maximum atomic excitation due to an incident single-photon wavepacket can exceed 70%. This high value is a direct consequence of the high SE {beta}-factor for emission into the waveguide. Finally, we have also explored whether waveguide dispersion could aid single-photon absorption by pulse shaping. For a Gaussian input wavepacket, we found that the absorption efficiency can be improved by a further 4% by engineering the dispersion. Efficient single-photon absorption by a single emitter has potential applications in quantum communication and quantum computation. (paper)

  18. Single-transverse-mode Ti:sapphire rib waveguide laser

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, Markus

    2005-01-01

    Laser operation of Ti:sapphire rib waveguides fabricated using photolithography and ion beam etching in pulsed laser deposited layers is reported. Polarized laser emission was observed at 792.5 nm with an absorbed pump power threshold of 265 mW, which is more than a factor of 2 lower in comparison

  19. Comparison of coupled mode theory and FDTD simulations of coupling between bent and straight optical waveguides

    NARCIS (Netherlands)

    Bertolotti, M.; Symes, W.W.; Stoffer, Remco; Hiremath, K.R.; Driessen, A.; Michelotti, F; Hammer, Manfred

    Analysis of integrated optical cylindrical microresonators involves the coupling between a straight waveguide and a bent waveguide. Our (2D) variant of coupled mode theory is based on analytically represented mode profiles. With the bend modes expressed in Cartesian coordinates, coupled mode

  20. Strong diameter-dependence of nanowire emission coupled to waveguide modes

    Energy Technology Data Exchange (ETDEWEB)

    Dam, Dick van, E-mail: a.d.v.dam@tue.nl; Haverkort, Jos E. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Abujetas, Diego R.; Sánchez-Gil, José A. [Instituto de Estructura de la Materia (IEM-CSIC), Consejo Superior de Investigaciones Científicas Serrano, 121, 28006 Madrid (Spain); Bakkers, Erik P. A. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Gómez Rivas, Jaime, E-mail: j.gomezrivas@differ.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Dutch Institute for Fundamental Energy Research DIFFER, P.O. Box 6336, 5600 HH Eindhoven (Netherlands)

    2016-03-21

    The emission from nanowires can couple to waveguide modes supported by the nanowire geometry, thus governing the far-field angular pattern. To investigate the geometry-induced coupling of the emission to waveguide modes, we acquire Fourier microscopy images of the photoluminescence of nanowires with diameters ranging from 143 to 208 nm. From the investigated diameter range, we conclude that a few nanometers difference in diameter can abruptly change the coupling of the emission to a specific mode. Moreover, we observe a diameter-dependent width of the Gaussian-shaped angular pattern in the far-field emission. This dependence is understood in terms of interference of the guided modes, which emit at the end facets of the nanowire. Our results are important for the design of quantum emitters, solid state lighting, and photovoltaic devices based on nanowires.

  1. FIBER AND INTEGRATED OPTICS: Bandgap modes in a coupled waveguide array

    Science.gov (United States)

    Usievich, B. A.; Nurligareev, D. Kh; Svetikov, V. V.; Sychugov, V. A.

    2009-08-01

    This work examines a waveguide array that consists of ten Nb2O5/SiO2 double layers and supports a 0.63-μm surface wave. The deposition of a Nb2O5 capping layer on top of the waveguide array enables a marked increase in the wave field intensity on its surface. The efficiency of surface-wave excitation in the Kretschmann configuration can be optimised by adjusting the number of double layers. We analyse the behaviour of the Bragg mode in relation to the thickness of the layer exposed to air and the transition of this mode from the second allowed band to the first through the bandgap of the system. In addition, the conventional leaky mode converts to a surface mode and then to a guided mode.

  2. Transverse magnetic field impact on waveguide modes of photonic crystals.

    Science.gov (United States)

    Sylgacheva, Daria; Khokhlov, Nikolai; Kalish, Andrey; Dagesyan, Sarkis; Prokopov, Anatoly; Shaposhnikov, Alexandr; Berzhansky, Vladimir; Nur-E-Alam, Mohammad; Vasiliev, Mikhail; Alameh, Kamal; Belotelov, Vladimir

    2016-08-15

    This Letter presents a theoretical and experimental study of waveguide modes of one-dimensional magneto-photonic crystals magnetized in the in-plane direction. It is shown that the propagation constants of the TM waveguide modes are sensitive to the transverse magnetization and the spectrum of the transverse magneto-optical Kerr effect has resonant features at mode excitation frequencies. Two types of structures are considered: a non-magnetic photonic crystal with an additional magnetic layer on top and a magneto-photonic crystal with a magnetic layer within each period. We found that the magneto-optical non-reciprocity effect is greater in the first case: it has a magnitude of δ∼10-4, while the second structure type demonstrates δ∼10-5 only, due to the higher asymmetry of the claddings of the magnetic layer. Experimental observations show resonant features in the optical and magneto-optical Kerr effect spectra. The measured dispersion properties are in good agreement with the theoretical predictions. An amplitude of light intensity modulation of up to 2.5% was observed for waveguide mode excitation within the magnetic top layer of the non-magnetic photonic crystal structure. The presented theoretical approach may be utilized for the design of magneto-optical sensors and modulators requiring pre-determined spectral features.

  3. Cutoff-mesa isolated rib optical waveguide for III-V heterostructure photonic integrated circuits

    Science.gov (United States)

    Vawter, G.A.; Smith, R.E.

    1998-04-28

    A cutoff mesa rib waveguide provides single-mode performance regardless of any deep etches that might be used for electrical isolation between integrated electrooptic devices. Utilizing a principle of a cutoff slab waveguide with an asymmetrical refractive index profile, single mode operation is achievable with a wide range of rib widths and does not require demanding etch depth tolerances. This new waveguide design eliminates reflection effects, or self-interference, commonly seen when conventional rib waveguides are combined with deep isolation etches and thereby reduces high order mode propagation and crosstalk compared to the conventional rib waveguides. 7 figs.

  4. AN EFFICIENT ANALYSIS FOR ABSORPTION AND GAIN COEFFICIENTS IN 'SINGLE STEP-INDEX WAVEGUIDE'S BY USING THE ALPHA METHOD

    Directory of Open Access Journals (Sweden)

    Mustafa TEMİZ

    2008-02-01

    Full Text Available In this study, some design parameters such as normalized frequency and especially normalized propagation constant have been obtained, depending on some parameters which are functions of energy eigenvalues of the carriers such as electrons and holes confined in a single step-index waveguide laser (SSIWGL or single stepindex waveguide (SSIWG. Some optical expressions about the optical power and probability quantities for the active region and cladding layers of the SSIWG or SSIWGL have been investigated. Investigations have been undertaken in terms of these parameters and also individually the optical even and odd electric field waves with the lowest-modes were theoretically computed. Especially absorption coefficients and loss coefficients addition to some important quantities of the single step-index waveguide lasers for the even and odd electric field waves are evaluated.

  5. Analysis of Waveguides on Lithium Niobate Thin Films

    Directory of Open Access Journals (Sweden)

    Yiwen Wang

    2018-04-01

    Full Text Available Waveguides formed by etching, proton-exchange (PE, and strip-loaded on single-crystal lithium niobate (LN thin film were designed and simulated by a full-vectorial finite difference method. The single-mode condition, optical power distribution, and bending loss of these kinds of waveguides were studied and compared systematically. For the PE waveguide, the optical power distributed in LN layer had negligible change with the increase of PE thickness. For the strip-loaded waveguide, the relationships between optical power distribution in LN layer and waveguide thickness were different for quasi-TE (q-TE and quasi-TM (q-TM modes. The bending loss would decrease with the increase of bending radius. There was a bending loss caused by the electromagnetic field leakage when the neff of q-TM waveguide was smaller than that of nearby TE planar waveguide. LN ridge waveguides possessed a low bending loss even at a relatively small bending radius. This study is helpful for the understanding of waveguide structures as well as for the optimization and the fabrication of high-density integrated optical components.

  6. Torsional mode ultrasonic helical waveguide sensor for re-configurable temperature measurement

    Directory of Open Access Journals (Sweden)

    Suresh Periyannan

    2016-06-01

    Full Text Available This paper introduces an ultrasonic torsional mode based technique, configured in the form of a helical “spring-like” waveguide, for multi-level temperature measurement. The multiple sensing levels can be repositioned by stretching or collapsing the spring to provide simultaneous measurements at different desired spacing in a given area/volume. The transduction is performed using piezo-electric crystals that generate and receive T(0,1 mode in a pulse echo mode. The gage lengths and positions of measurements are based on machining multiple reflector notches in the waveguide at required positions. The time of fight (TOF measurements between the reflected signals from the notches provide local temperatures that compare well with co-located thermocouples.

  7. Mixed Non-Uniform Width / Evanescent Mode Ceramic Resonator Waveguide Filter With Wide Spurious Free Bandwidth

    OpenAIRE

    Afridi, S; Sandhu, M; Hunter, I

    2016-01-01

    This paper presents a method to improve the spurious performance of integrated ceramic waveguide filters. Nonuniform width ceramic waveguide resonator and evanescent mode ceramic resonators are employed together to the resonant frequencies of higher order modes. The proposed designs give 75% improvement in stop band response when compared to uniform width ceramic waveguide filter. Simulated results of two six pole chebyshev filters are presented here with improved stop band performance.

  8. Coherent single-photon absorption by single emitters coupled to 1D nanophotonic waveguides

    DEFF Research Database (Denmark)

    Chen, Yuntian; Wubs, Martijn; Mørk, Jesper

    2012-01-01

    We have derived an efficient model that allows calculating the dynamical single-photon absorption of an emitter coupled to a waveguide. We suggest a novel and simple structure that leads to strong single-photon absorption.......We have derived an efficient model that allows calculating the dynamical single-photon absorption of an emitter coupled to a waveguide. We suggest a novel and simple structure that leads to strong single-photon absorption....

  9. Engineering spin-wave channels in submicrometer magnonic waveguides

    Directory of Open Access Journals (Sweden)

    XiangJun Xing

    2013-03-01

    Full Text Available Based on micromagnetic simulations and model calculations, we demonstrate that degenerate well and barrier magnon modes can exist concurrently in a single magnetic waveguide magnetized perpendicularly to the long axis in a broad frequency band, corresponding to copropagating edge and centre spin waves, respectively. The dispersion relations of these magnon modes clearly show that the edge and centre modes possess much different wave characteristics. By tailoring the antenna size, the edge mode can be selectively activated. If the antenna is sufficiently narrow, both the edge and centre modes are excited with considerable efficiency and propagate along the waveguide. By roughening the lateral boundary of the waveguide, the characteristics of the relevant channel can be easily engineered. Moreover, the coupling of the edge and centre modes can be conveniently controlled by scaling the width of the waveguide. For a wide waveguide with a narrow antenna, the edge and centre modes travel relatively independently in spatially-separate channels, whereas for a narrow strip, these modes strongly superpose in space. These discoveries might find potential applications in emerging magnonic devices.

  10. Hybrid finite element/waveguide mode analysis of passive RF devices

    Science.gov (United States)

    McGrath, Daniel T.

    1993-07-01

    A numerical solution for time-harmonic electromagnetic fields in two-port passive radio frequency (RF) devices has been developed, implemented in a computer code, and validated. Vector finite elements are used to represent the fields in the device interior, and field continuity across waveguide apertures is enforced by matching the interior solution to a sum of waveguide modes. Consequently, the mesh may end at the aperture instead of extending into the waveguide. The report discusses the variational formulation and its reduction to a linear system using Galerkin's method. It describes the computer code, including its interface to commercial CAD software used for geometry generation. It presents validation results for waveguide discontinuities, coaxial transitions, and microstrip circuits. They demonstrate that the method is an effective and versatile tool for predicting the performance of passive RF devices.

  11. Hybrid rib-slot-rib plasmonic waveguide with deep-subwavelength mode confinement and long propagation length

    Directory of Open Access Journals (Sweden)

    Kai Zheng

    2016-08-01

    Full Text Available We propose a hybrid plasmonic waveguide where a combined rib-slot-rib structure is added on the metal substrate within a low-index gap region. The optical properties of the quasi-TM fundamental mode are numerically calculated using the finite element method. Compared to the traditional hybrid plasmonic waveguide, our designed waveguiding structure can support modes with tighter confinement and longer propagation length, by properly adjusting the geometry of the rib-slot-rib structure and the gap height. In details, it can provide the hybrid mode with mode area λ2/12000 and reasonable propagation distance 23.78 μm, simultaneously. Its excellent optical performance can facilitate potential applications in ultra-compact nanophotonic devices and circuits.

  12. Circular waveguide mode converters at 140 GHz

    International Nuclear Information System (INIS)

    Trulsen, J.; Woskoboinikow, P.; Temkin, R.J.

    1986-01-01

    A unified derivation of the coupled mode equations for circular waveguide is presented. Also, approximate design criteria for TE/sub 0n/ to TE/sub 0n'/ axisymmetric, TE 01 to TE 11 wriggle, and TE 01 to TM 11 bend converters are reviewed. Numerically solving the coupled mode equations, an optimized set of mode converters has been designed for conversion of a 2 millimeter wave TE 03 mode into TE 11 . This set consists of axisymmetric TE 03 to TE 02 and TE 02 to TE 01 converters followed by a wriggle TE 01 to TE 11 converter. This mode converter set was fabricated and tested using a 3 kW, 137 GHz gyrotron. A TE 11 mode purity of better than 97% was achieved. The TE 01 to TE 11 wriggle converter was experimentally optimized for a measured conversion efficiency of better than 99% not including ohmic losses

  13. Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures

    Energy Technology Data Exchange (ETDEWEB)

    Sevastianov, L. A., E-mail: sevast@sci.pfu.edu.ru [Peoples' Friendship University of Russia (Russian Federation); Egorov, A. A. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Sevastyanov, A. L. [Peoples' Friendship University of Russia (Russian Federation)

    2013-02-15

    Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell's equations is made to obey 'inclined' boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of 'entanglement' of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lueneburg lens.

  14. Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures

    International Nuclear Information System (INIS)

    Sevastianov, L. A.; Egorov, A. A.; Sevastyanov, A. L.

    2013-01-01

    Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell’s equations is made to obey “inclined” boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of “entanglement” of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lüneburg lens.

  15. Measurement of guided light-mode intensity: An alternative waveguide sensing principle

    DEFF Research Database (Denmark)

    Horvath, R.; Skivesen, N.; Pedersen, H.C.

    2004-01-01

    An alternative transduction mechanism for planar optical waveguide sensors is reported. Based on a simple measurement of the mode intensity, the presented transduction is an interesting alternative to the conventional mode-angle transduction, because the expensive, high-precision angular rotation...

  16. Broadband enhancement of single photon emission and polarization dependent coupling in silicon nitride waveguides.

    Science.gov (United States)

    Bisschop, Suzanne; Guille, Antoine; Van Thourhout, Dries; Hens, Zeger; Brainis, Edouard

    2015-06-01

    Single-photon (SP) sources are important for a number of optical quantum information processing applications. We study the possibility to integrate triggered solid-state SP emitters directly on a photonic chip. A major challenge consists in efficiently extracting their emission into a single guided mode. Using 3D finite-difference time-domain simulations, we investigate the SP emission from dipole-like nanometer-sized inclusions embedded into different silicon nitride (SiNx) photonic nanowire waveguide designs. We elucidate the effect of the geometry on the emission lifetime and the polarization of the emitted SP. The results show that highly efficient and polarized SP sources can be realized using suspended SiNx slot-waveguides. Combining this with the well-established CMOS-compatible processing technology, fully integrated and complex optical circuits for quantum optics experiments can be developed.

  17. Focussed MeV ion beam implanted waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Von Bibra, M.L.; Roberts, A.; Nugent, K.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Single mode buried optical waveguides have been fabricated in fused silica by MeV proton implantation using a focussed hydrogen ion beam. The technique has the potential to direct write waveguide devices and produce multi-layered structures, without the need for intermediate steps such as mask fabrication or layered depositions. A micron resolution Confocal Raman Spectrometer has been used to map the distribution of atomic vacancies that forms the waveguiding region. The results are compared with theoretical calculations. Losses of 3 dB cm{sup -1} have been measured in unannealed samples, which decreases to less than 0.5 dB cm{sup -1} after annealing at 500 degrees Celsius. We describe methods for determining the refractive index distribution of single mode buried waveguides from their output intensity distributions via an inversion of the scalar wave equation. (authors). 5 figs.

  18. Focussed MeV ion beam implanted waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Von Bibra, M L; Roberts, A; Nugent, K; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    Single mode buried optical waveguides have been fabricated in fused silica by MeV proton implantation using a focussed hydrogen ion beam. The technique has the potential to direct write waveguide devices and produce multi-layered structures, without the need for intermediate steps such as mask fabrication or layered depositions. A micron resolution Confocal Raman Spectrometer has been used to map the distribution of atomic vacancies that forms the waveguiding region. The results are compared with theoretical calculations. Losses of 3 dB cm{sup -1} have been measured in unannealed samples, which decreases to less than 0.5 dB cm{sup -1} after annealing at 500 degrees Celsius. We describe methods for determining the refractive index distribution of single mode buried waveguides from their output intensity distributions via an inversion of the scalar wave equation. (authors). 5 figs.

  19. Analytical relation between effective mode field area and waveguide dispersion in microstructure fibers.

    Science.gov (United States)

    Moenster, Mathias; Steinmeyer, Günter; Iliew, Rumen; Lederer, Falk; Petermann, Klaus

    2006-11-15

    For optical fibers exhibiting a radially symmetric refractive index profile, there exists an analytical relation that connects waveguide dispersion and the Petermann-II mode field radius. We extend the usefulness of this relation to the nonradially symmetric case of microstructure fibers in the anomalous dispersion regime, yielding a simple relation between dispersion and effective mode field area. Assuming a Gaussian mode distribution, we derive a fundamental upper limit for the effective mode field area that is required to obtain a certain amount of anomalous waveguide dispersion. This relation is demonstrated to show excellent agreement for fiber designs suited for supercontinuum generation and soliton lasers in the near infrared.

  20. Propagation of Finite Amplitude Sound in Multiple Waveguide Modes.

    Science.gov (United States)

    van Doren, Thomas Walter

    1993-01-01

    This dissertation describes a theoretical and experimental investigation of the propagation of finite amplitude sound in multiple waveguide modes. Quasilinear analytical solutions of the full second order nonlinear wave equation, the Westervelt equation, and the KZK parabolic wave equation are obtained for the fundamental and second harmonic sound fields in a rectangular rigid-wall waveguide. It is shown that the Westervelt equation is an acceptable approximation of the full nonlinear wave equation for describing guided sound waves of finite amplitude. A system of first order equations based on both a modal and harmonic expansion of the Westervelt equation is developed for waveguides with locally reactive wall impedances. Fully nonlinear numerical solutions of the system of coupled equations are presented for waveguides formed by two parallel planes which are either both rigid, or one rigid and one pressure release. These numerical solutions are compared to finite -difference solutions of the KZK equation, and it is shown that solutions of the KZK equation are valid only at frequencies which are high compared to the cutoff frequencies of the most important modes of propagation (i.e., for which sound propagates at small grazing angles). Numerical solutions of both the Westervelt and KZK equations are compared to experiments performed in an air-filled, rigid-wall, rectangular waveguide. Solutions of the Westervelt equation are in good agreement with experiment for low source frequencies, at which sound propagates at large grazing angles, whereas solutions of the KZK equation are not valid for these cases. At higher frequencies, at which sound propagates at small grazing angles, agreement between numerical solutions of the Westervelt and KZK equations and experiment is only fair, because of problems in specifying the experimental source condition with sufficient accuracy.

  1. Remote detection of single emitters via optical waveguides

    Science.gov (United States)

    Then, Patrick; Razinskas, Gary; Feichtner, Thorsten; Haas, Philippe; Wild, Andreas; Bellini, Nicola; Osellame, Roberto; Cerullo, Giulio; Hecht, Bert

    2014-05-01

    The integration of lab-on-a-chip technologies with single-molecule detection techniques may enable new applications in analytical chemistry, biotechnology, and medicine. We describe a method based on the reciprocity theorem of electromagnetic theory to determine and optimize the detection efficiency of photons emitted by single quantum emitters through truncated dielectric waveguides of arbitrary shape positioned in their proximity. We demonstrate experimentally that detection of single quantum emitters via such waveguides is possible, confirming the predicted behavior of the detection efficiency. Our findings blaze the trail towards efficient lensless single-emitter detection compatible with large-scale optofluidic integration.

  2. Analytical study of optimal design and gain parameters of double-slot plasmonic waveguides

    International Nuclear Information System (INIS)

    Handapangoda, Dayan; Rukhlenko, Ivan D; Premaratne, Malin

    2013-01-01

    We theoretically analyze guided modes in optically active and passive double-slot plasmonic waveguides. We show that for one of the two different mode symmetries supported by the waveguide, a most productive guiding condition can be realized by adjusting the thicknesses of the layers to optimal values. We also derive approximate analytic expressions to calculate the optimal geometrical parameters of the waveguide. Interestingly, our analysis shows that the propagation losses associated with the inverse mode symmetry of the double-slot waveguide are comparatively low, regardless of the dimensions of the waveguide. We further show that the propagation losses become the smallest in the limiting case of a single-slot (metal–dielectric–metal (MDM)) waveguide. For both double- and single-slot waveguides, we show that the gain required to overcome the losses can be reduced by choosing a dielectric with a low refractive index. We also derive accurate analytical expressions to readily estimate the critical gain and modal gain of the waveguides. (paper)

  3. Low loss depressed cladding waveguide inscribed in YAG:Nd single crystal by femtosecond laser pulses.

    Science.gov (United States)

    Okhrimchuk, Andrey; Mezentsev, Vladimir; Shestakov, Alexander; Bennion, Ian

    2012-02-13

    A depressed cladding waveguide with record low loss of 0.12 dB/cm is inscribed in YAG:Nd(0.3at.%) crystal by femtosecond laser pulses with an elliptical beam waist. The waveguide is formed by a set of parallel tracks which constitute the depressed cladding. It is a key element for compact and efficient CW waveguide laser operating at 1064 nm and pumped by a multimode laser diode. Special attention is paid to mechanical stress resulting from the inscription process. Numerical calculation of mode distribution and propagation loss with the elasto-optical effect taken into account leads to the conclusion that the depressed cladding is a dominating factor in waveguide mode formation, while the mechanical stress only slightly distorts waveguide modes.

  4. Planar waveguide nanolaser configured by dye-doped hybrid nanofilm on substrate

    Science.gov (United States)

    Tikhonov, E. A.; Yashchuk, V. P.; Telbiz, G. M.

    2018-04-01

    Dye-doped hybrid silicate/titanium nanofilms on the glass substrate structures of asymmetrical waveguides were studied by way of laser systems. The threshold, spatial and spectral features of the laser oscillation of genuine and hollow waveguides were determined. The pattern of stimulated radiation included two concurrent processes: single-mode waveguide lasing and lateral small divergence emission. Comparison of the open angle of the lateral beams and grazing angles of the waveguide lasing mode provides an insight into the effect of leaky mode emission followed by Lummer-Gehrcke interference.

  5. Silicon microphotonic waveguides

    International Nuclear Information System (INIS)

    Ta'eed, V.; Steel, M.J.; Grillet, C.; Eggleton, B.; Du, J.; Glasscock, J.; Savvides, N.

    2004-01-01

    Full text: Silicon microphotonic devices have been drawing increasing attention in the past few years. The high index-difference between silicon and its oxide (Δn = 2) suggests a potential for high-density integration of optical functions on to a photonic chip. Additionally, it has been shown that silicon exhibits strong Raman nonlinearity, a necessary property as light interaction can occur only by means of nonlinearities in the propagation medium. The small dimensions of silicon waveguides require the design of efficient tapers to couple light to them. We have used the beam propagation method (RSoft BeamPROP) to understand the principles and design of an inverse-taper mode-converter as implemented in several recent papers. We report on progress in the design and fabrication of silicon-based waveguides. Preliminary work has been conducted by patterning silicon-on-insulator (SOI) wafers using optical lithography and reactive ion etching. Thus far, only rib waveguides have been designed, as single-mode ridge-waveguides are beyond the capabilities of conventional optical lithography. We have recently moved to electron beam lithography as the higher resolutions permitted will provide the flexibility to begin fabricating sub-micron waveguides

  6. Development of IR single mode optical fibers for DARWIN-nulling interferometry

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.M.; Cheng, L.K.; Bosch, B. van den; Dijkhuizen, N.; Nieuwland, R.A.; Gielesen, W.L.M.; Lucas, J.; Boussard-Plédel, C.; Conseil, C.; Bureau, B.; Carmo, J.P. do

    2014-01-01

    The DARWIN mission aims to detect weak infra-red emission lines from distant orbiting earth-like planets using nulling interferometry. This requires filtering of wavefront errors using single mode waveguides operating at a wavelength range of 6.5-20 μm. This article describes the optical design of

  7. General technique for the integration of MIC/MMIC'S with waveguides

    Science.gov (United States)

    Geller, Bernard D. (Inventor); Zaghloul, Amir I. (Inventor)

    1987-01-01

    A technique for packaging and integrating of a microwave integrated circuit (MIC) or monolithic microwave integrated circuit (MMIC) with a waveguide uses a printed conductive circuit pattern on a dielectric substrate to transform impedance and mode of propagation between the MIC/MMIC and the waveguide. The virtually coplanar circuit pattern lies on an equipotential surface within the waveguide and therefore makes possible single or dual polarized mode structures.

  8. Low-index discontinuity terahertz waveguides

    Science.gov (United States)

    Nagel, Michael; Marchewka, Astrid; Kurz, Heinrich

    2006-10-01

    A new type of dielectric THz waveguide based on recent approaches in the field of integrated optics is presented with theoretical and experimental results. Although the guiding mechanism of the low-index discontinuity (LID) THz waveguide is total internal reflection, the THz wave is predominantly confined in the virtually lossless low-index air gap within a high-index dielectric waveguide due to the continuity of electric flux density at the dielectric interface. Attenuation, dispersion and single-mode confinement properties of two LID structures are discussed and compared with other THz waveguide solutions. The new approach provides an outstanding combination of high mode confinement and low transmission losses currently not realizable with any other metal-based or photonic crystal approach. These exceptional properties might enable the breakthrough of novel integrated THz systems or endoscopy applications with sub-wavelength resolution.

  9. Penetration of internal gravity waveguide modes into the upper atmosphere

    Directory of Open Access Journals (Sweden)

    Rudenko G.V.

    2016-03-01

    Full Text Available The paper describes internal gravity waveguide modes, using dissipative solutions above the source. We compare such a description with an accurate approach and a WKB approximation for dissipationless equations. For waveguide disturbances, dispersion relations calculated by any method are shown to be close to each other and to be in good agreement with observed characteristics of traveling ionospheric disturbances. Unlike other methods, dissipative solutions above the source allow us to adequately describe the spatial structure of disturbances in the upper atmosphere.

  10. Constructive and destructive quantum interference sensitive to quantum vacuum mode structure in a metallic waveguide

    International Nuclear Information System (INIS)

    Shen Jianqi

    2011-01-01

    Quantum vacuum mode structure can be changed due to length scale fluctuation of the cross section of a metallic waveguide. Such a structure change in vacuum modes (particularly in cutoff vacuum modes) would lead to dramatic enhancement or inhibition of spontaneous emission decay of atoms and, if the waveguide is filled with a dilute atomic vapor consisting of quantum-coherent atoms of a four-level tripod-configuration system, an optical wave propagating inside the waveguide can be coherently manipulated by tunable constructive and destructive quantum interference between two control transitions (driven by two control fields) in a quite unusual way (e.g., the optical response, in which a three-level dark state is involved, is sensitive to the waveguide dimension variations at certain positions of resonance of the atomic spontaneous emission decay rate). Therefore, an intriguing effect that can be employed to designs of new photonic and quantum optical devices could be achieved based on the present mechanisms of quantum-vacuum manipulation and quantum coherence control.

  11. Evanescent-wave coupled right angled buried waveguide: Applications in carbon nanotube mode-locking

    International Nuclear Information System (INIS)

    Mary, R.; Thomson, R. R.; Kar, A. K.; Brown, G.; Beecher, S. J.; Popa, D.; Sun, Z.; Torrisi, F.; Hasan, T.; Milana, S.; Bonaccorso, F.; Ferrari, A. C.

    2013-01-01

    We present an evanescent-field device based on a right-angled waveguide. This consists of orthogonal waveguides, with their points of intersection lying along an angled facet of the chip. Light guided along one waveguide is incident at the angled dielectric-air facet at an angle exceeding the critical angle, so that the totally internally reflected light is coupled into the second waveguide. By depositing a nanotube film on the angled surface, the chip is then used to mode-lock an Erbium doped fiber ring laser with a repetition rate of 26 MHz, and pulse duration of 800 fs

  12. Hollow core waveguide as mid-infrared laser modal beam filter

    Energy Technology Data Exchange (ETDEWEB)

    Patimisco, P.; Giglio, M.; Spagnolo, V. [Dipartimento Interateneo di Fisica, Università e Politecnico di Bari, CNR-IFN UOS BARI, Via Amendola 173, 70126 Bari (Italy); Sampaolo, A. [Dipartimento Interateneo di Fisica, Università e Politecnico di Bari, CNR-IFN UOS BARI, Via Amendola 173, 70126 Bari (Italy); Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005 (United States); Kriesel, J. M. [Opto-Knowledge Systems, Inc. (OKSI), 19805 Hamilton Ave., Torrance, California 90502-1341 (United States); Tittel, F. K. [Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005 (United States)

    2015-09-21

    A novel method for mid-IR laser beam mode cleaning employing hollow core waveguide as a modal filter element is reported. The influence of the input laser beam quality on fiber optical losses and output beam profile using a hollow core waveguide with 200 μm-bore size was investigated. Our results demonstrate that even when using a laser with a poor spatial profile, there will exist a minimum fiber length that allows transmission of only the Gaussian-like fundamental waveguide mode from the fiber, filtering out all the higher order modes. This essentially single mode output is preserved also when the waveguide is bent to a radius of curvature of 7.5 cm, which demonstrates that laser mode filtering can be realized even if a curved light path is required.

  13. Geometric variations in high index-contrast waveguides, coupled mode theory in curvilinear coordinates.

    Science.gov (United States)

    Skorobogatiy, Maksim; Jacobs, Steven; Johnson, Steven; Fink, Yoel

    2002-10-21

    Perturbation theory formulation of Maxwell's equations gives a theoretically elegant and computationally efficient way of describing small imperfections and weak interactions in electro-magnetic systems. It is generally appreciated that due to the discontinuous field boundary conditions in the systems employing high dielectric contrast profiles standard perturbation formulations fail when applied to the problem of shifted material boundaries. In this paper we developed a novel coupled mode and perturbation theory formulations for treating generic non-uniform (varying along the direction of propagation) perturbations of a waveguide cross-section based on Hamiltonian formulation of Maxwell equations in curvilinear coordinates. We show that our formulation is accurate and rapidly converges to an exact result when used in a coupled mode theory framework even for the high index-contrast discontinuous dielectric profiles. Among others, our formulation allows for an efficient numerical evaluation of induced PMD due to a generic distortion of a waveguide profile, analysis of mode filters, mode converters and other optical elements such as strong Bragg gratings, tapers, bends etc., and arbitrary combinations of thereof. To our knowledge, this is the first time perturbation and coupled mode theories are developed to deal with arbitrary non-uniform profile variations in high index-contrast waveguides.

  14. High-performance 16-way Ku-band radial power combiner based on the TE01-circular waveguide mode

    Science.gov (United States)

    Montejo-Garai, José R.; Saracho-Pantoja, Irene O.; Ruiz-Cruz, Jorge A.; Rebollar, Jesús M.

    2018-03-01

    This work presents a 16-way Ku-band radial power combiner for high power and high frequency applications, using the very low loss TE01 circular waveguide mode. The accomplished design shows an excellent performance: the experimental prototype has a return loss better than 30 dB, with a balance for the amplitudes of (±0.15 dB) and (±2.5°) for the phases, in a 16.7% fractional bandwidth (2 GHz centered at 12 GHz). For obtaining these outstanding specifications, required, for instance, in high-frequency amplification or on plasma systems, a rigorous step-by-step procedure is presented. First, a high-purity mode transducer has been designed, from the TE10 mode in the rectangular waveguide to the TE01 mode in the circular waveguide, with very high attenuation (>50 dB) for the other propagating and evanescent modes in the circular waveguide. This transducer has been manufactured and measured in a back-to-back configuration, validating the design process. Second, an E-plane 16-way radial power divider has been designed, where the power is coupled from the 16 non-reduced-height radial standard waveguides into the TE01 circular waveguide mode, improving the insertion loss response and removing the usual tapered transformers of previous designs limiting the power handling. Finally, both the transducer and the divider have been assembled to make the final radial combiner. The prototype has been carefully manufactured, showing very good agreement between the measurements and the full-wave simulations.

  15. Scalable electro-photonic integration concept based on polymer waveguides

    NARCIS (Netherlands)

    Bosman, E.; Steenberge, G. van; Boersma, A.; Wiegersma, S.; Harmsma, P.J.; Karppinen, M.; Korhonen, T.; Offrein, B.J.; Dangel, R.; Daly, A.; Ortsiefer, M.; Justice, J.; Corbett, B.; Dorrestein, S.; Duis, J.

    2016-01-01

    A novel method for fabricating a single mode optical interconnection platform is presented. The method comprises the miniaturized assembly of optoelectronic single dies, the scalable fabrication of polymer single mode waveguides and the coupling to glass fiber arrays providing the I/O's. The low

  16. The Main Principles of Formation of the Transverse Modes in the Multilayered Waveguides of Surface Acoustic Waves

    Science.gov (United States)

    Sveshnikov, B. V.; Bagdasaryan, A. S.

    2016-07-01

    We develop a self-consistent model allowing one to analyze the properties of the interdigital transducer of the surface acoustic waves as a symmetric five-layered waveguide on a piezoelectric substrate with three possible values of the phase velocity of the acoustic-wave propagation along the longitudinal axis of the system. The transcendental dispersion relation for describing the waves in such a system is derived and the method for its instructive graphic analysis is proposed. The condition under which only the fundamental transverse mode is excited in the waveguide is formulated. The method for calculating the normalized power and the transverse distribution of the field of the continuous-spectrum waves radiated from the considered waveguide is described. It is shown that the characteristic spatial scale of the longitudinal damping of the amplitude of this field at the waveguide center can be a qualitative estimate of the transverse-mode formation length. The efficiency of a new method for suppressing the higher-order transverse waveguide modes is demonstrated.

  17. Waveguide superconducting single-photon autocorrelators for quantum photonic applications

    NARCIS (Netherlands)

    Sahin, D.; Gaggero, A.; Frucci, G.; Jahanmirinejad, S.; Sprengers, J.P.; Mattioli, F.; Leoni, R.; Beetz, J.; Lermer, M.; Kamp, M.; Höfling, S.; Fiore, A.; Hasan, Z.U.; Hemmer, P.R.; Lee, H.; Santori, C.M.

    2013-01-01

    We report a novel component for integrated quantum photonic applications, a waveguide single-photon autocorrelator. It is based on two superconducting nanowire detectors patterned onto the same GaAs ridge waveguide. Combining the electrical output of the two detectors in a correlation card enables

  18. An experimental analysis of the waveguide modes in a high-gain free-electron laser amplifier

    International Nuclear Information System (INIS)

    Anderson, B.R.

    1989-01-01

    The presence, growth, and interaction of transverse waveguide modes in high-gain free-electron laser (FEL) amplifiers has been observed and studied. Using the Electron Laser Facility at Lawrence Livermore National Laboratory, a 3 MeV, 800 A electron beam generated by the Experimental Test Accelerator was injected into a planar wiggler. Power was then extracted and measured in the fundamental (TE 01 ) an higher-order modes (Te 21 and TM 21 ) under various sets of operating conditions. Horizontal focusing through the wiggler was provided by external quadrupole magnets. There was no axial guide field. The input microwave signal for amplification was generated by a 100 kW magnetron operating at 34.6 Ghz. Power measurements were taken for both flat and tapered wigglers, for two sizes of waveguide, and for both flat and tapered wigglers, for two sizes of waveguide, and for both fundamental and higher mode injection. Mode content was determined by sampling the radiated signal at specific points in the radiation patter. For the flat wiggler and with the large waveguide (2.9 cm x 9.8 cm) the power in the higher modes was comparable to power in the fundamental. both exhibited gains greater than 30 dB/m prior to saturation and both reached powers in excess of 80 MW. Choice of injection mode had little effect on the operation of the system. Operation with the smaller guide (WR-229) provided much better mode selectivity. The fundamental mode continued to show optimum gain in excess of 30 dB/m while the higher-mode gain was of order 20 dB/m. As expected, power output increased significantly with the tapered wigglers. The relative mode content depended on the specific taper used

  19. Periodically modulated single-photon transport in one-dimensional waveguide

    Science.gov (United States)

    Li, Xingmin; Wei, L. F.

    2018-03-01

    Single-photon transport along a one-dimension waveguide interacting with a quantum system (e.g., two-level atom) is a very useful and meaningful simplified model of the waveguide-based optical quantum devices. Thus, how to modulate the transport of the photons in the waveguide structures by adjusting certain external parameters should be particularly important. In this paper, we discuss how such a modulation could be implemented by periodically driving the energy splitting of the interacting atom and the atom-photon coupling strength. By generalizing the well developed time-independent full quantum mechanical theory in real space to the time-dependent one, we show that various sideband-transmission phenomena could be observed. This means that, with these modulations the photon has certain probabilities to transmit through the scattering atom in the other energy sidebands. Inversely, by controlling the sideband transmission the periodic modulations of the single photon waveguide devices could be designed for the future optical quantum information processing applications.

  20. Ultra-low loss nano-taper coupler for Silicon-on-Insulator ridge waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    A nano-taper coupler is optimized specially for the transverse-magnetic mode for interfacing light between a silicon-on-insulator ridge waveguide and a single-mode fiber. An ultra-low coupling loss of ~0.36dB is achieved for the nano-taper coupler.......A nano-taper coupler is optimized specially for the transverse-magnetic mode for interfacing light between a silicon-on-insulator ridge waveguide and a single-mode fiber. An ultra-low coupling loss of ~0.36dB is achieved for the nano-taper coupler....

  1. Quantum Dots in Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Sollner, Immo Nathanael

    This Thesis is focused on the study of quantum electrodynamics in photonic crystal waveguides. We investigate the interplay between a single quantum dot and the fundamental mode of the photonic crystal waveguide. We demonstrate experimental coupling eciencies for the spontaneous emission...... into the mode exceeding 98% for emitters spectrally close to the band-edge of the waveguide mode. In addition we illustrate the broadband nature of the underlying eects, by obtaining coupling eciencies above 90% for quantum dots detuned from the band edge by as far as 20nm. These values are in good agreement...... with numerical simulations. Such a high coupling eciency implies that the system can be considered an articial 1D-atom, and we theoretically show that this system can generate strong photon-photon interaction, which is an essential functionality for deterministic optical quantum information processing. We...

  2. Coherent single-photon absorption by single emitters coupled to one-dimensional nanophotonic waveguides

    DEFF Research Database (Denmark)

    Chen, Yuntian; Wubs, Martijn; Mørk, Jesper

    2011-01-01

    -photon wavepacket can exceed 70%. This high value is a direct consequence of the high SE β-factor for emission into the waveguide. Finally, we have also explored whether waveguide dispersion could aid single-photon absorption by pulse shaping. For a Gaussian input wavepacket, we found that the absorption efficiency...

  3. Mode-field half-widths of Gaussian approximation for the fundamental mode of two kinds of optical waveguides

    International Nuclear Information System (INIS)

    Lian-Huang, Li; Fu-Yuan, Guo

    2009-01-01

    This paper analyzes the characteristic of matching efficiency between the fundamental mode of two kinds of optical waveguides and its Gaussian approximate field. Then, it presents a new method where the mode-field half-width of Gaussian approximation for the fundamental mode should be defined according to the maximal matching efficiency method. The relationship between the mode-field half-width of the Gaussian approximate field obtained from the maximal matching efficiency and normalized frequency is studied; furthermore, two formulas of mode-field half-widths as a function of normalized frequency are proposed

  4. Terahertz light-emitting graphene-channel transistor toward single-mode lasing

    Science.gov (United States)

    Yadav, Deepika; Tamamushi, Gen; Watanabe, Takayuki; Mitsushio, Junki; Tobah, Youssef; Sugawara, Kenta; Dubinov, Alexander A.; Satou, Akira; Ryzhii, Maxim; Ryzhii, Victor; Otsuji, Taiichi

    2018-03-01

    A distributed feedback dual-gate graphene-channel field-effect transistor (DFB-DG-GFET) was fabricated as a current-injection terahertz (THz) light-emitting laser transistor. We observed a broadband emission in a 1-7.6-THz range with a maximum radiation power of 10 μW as well as a single-mode emission at 5.2 THz with a radiation power of 0.1 μW both at 100 K when the carrier injection stays between the lower cutoff and upper cutoff threshold levels. The device also exhibited peculiar nonlinear threshold-like behavior with respect to the current-injection level. The LED-like broadband emission is interpreted as an amplified spontaneous THz emission being transcended to a single-mode lasing. Design constraints on waveguide structures for better THz photon field confinement with higher gain overlapping as well as DFB cavity structures with higher Q factors are also addressed towards intense, single-mode continuous wave THz lasing at room temperature.

  5. Spontaneous emission of quantum dots in disordered photonic crystal waveguides

    DEFF Research Database (Denmark)

    Sapienza, Luca; Nielsen, Henri Thyrrestrup; Stobbe, Søren

    2010-01-01

    We report on the enhancement of the spontaneous emission rate of single semiconductor quantum dots embedded in a photonic crystal waveguide with engineered disorder. Random high-Q cavities, that are signature of Anderson localization, are measured in photoluminescence experiments and appear...... in the slow light regime of the waveguide mode. Time resolved experiments show a 15-fold enhancement of the spontaneous emission rate, with coupling efficiencies of single photons into Anderson localized cavity modes of 94%. These results show that the performances of Anderson-localized cavities...

  6. Semi-analytical quasi-normal mode theory for the local density of states in coupled photonic crystal cavity-waveguide structures

    DEFF Research Database (Denmark)

    de Lasson, Jakob Rosenkrantz; Kristensen, Philip Trøst; Mørk, Jesper

    2015-01-01

    We present and validate a semi-analytical quasi-normal mode (QNM) theory for the local density of states (LDOS) in coupled photonic crystal (PhC) cavity-waveguide structures. By means of an expansion of the Green's function on one or a few QNMs, a closed-form expression for the LDOS is obtained, ......-trivial spectrum with a peak and a dip is found, which is reproduced only when including both the two relevant QNMs in the theory. In both cases, we find relative errors below 1% in the bandwidth of interest.......We present and validate a semi-analytical quasi-normal mode (QNM) theory for the local density of states (LDOS) in coupled photonic crystal (PhC) cavity-waveguide structures. By means of an expansion of the Green's function on one or a few QNMs, a closed-form expression for the LDOS is obtained......, and for two types of two-dimensional PhCs, with one and two cavities side-coupled to an extended waveguide, the theory is validated against numerically exact computations. For the single cavity, a slightly asymmetric spectrum is found, which the QNM theory reproduces, and for two cavities a non...

  7. Quantum Electrodynamics in Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Nielsen, Henri Thyrrestrup

    In this thesis we have performed quantum electrodynamics (QED) experiments in photonic crystal (PhC) waveguides and cavity QED in the Anderson localized regime in disordered PhC waveguides. Decay rate measurements of quantum dots embedded in PhC waveguides has been used to map out the variations...... in the local density of states (LDOS) in PhC waveguides. From decay rate measurements on quantum dot lines temperature tuned in the vicinity of the waveguide band edge, a β-factor for a single quantum dot of more then 85% has been extracted. Finite difference time domain simulations (FDTD) for disordered Ph...... is shown to increase from 3 − 7 um for no intentional disorder to 25 um for 6% disorder. A distribution of losses is seen to be necessary to explain the measured Q-factor distributions. Finally we have performed a cavity QED experiment between single quantum dots and an Anderson localized mode, where a β...

  8. Tuning the dispersion and single/multi-modeness of a hole-assisted fiber by the hole's geometrical parameters

    NARCIS (Netherlands)

    Uranus, H.P.; Hoekstra, Hugo; van Groesen, Embrecht W.C.

    2008-01-01

    Using a vectorial finite element mode solver developed earlier, we studied a hole-assisted multi-ring fiber. We report the role of the hole’s geometrical parameters in tuning the waveguide dispersion and the single/multi-modeness of the particular fiber. By correctly selecting the hole’s size and

  9. Guided wave mode selection for inhomogeneous elastic waveguides using frequency domain finite element approach.

    Science.gov (United States)

    Chillara, Vamshi Krishna; Ren, Baiyang; Lissenden, Cliff J

    2016-04-01

    This article describes the use of the frequency domain finite element (FDFE) technique for guided wave mode selection in inhomogeneous waveguides. Problems with Rayleigh-Lamb and Shear-Horizontal mode excitation in isotropic homogeneous plates are first studied to demonstrate the application of the approach. Then, two specific cases of inhomogeneous waveguides are studied using FDFE. Finally, an example of guided wave mode selection for inspecting disbonds in composites is presented. Identification of sensitive and insensitive modes for defect inspection is demonstrated. As the discretization parameters affect the accuracy of the results obtained from FDFE, effect of spatial discretization and the length of the domain used for the spatial fast Fourier transform are studied. Some recommendations with regard to the choice of the above parameters are provided. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. High performance waveguide-coupled Ge-on-Si linear mode avalanche photodiodes.

    Science.gov (United States)

    Martinez, Nicholas J D; Derose, Christopher T; Brock, Reinhard W; Starbuck, Andrew L; Pomerene, Andrew T; Lentine, Anthony L; Trotter, Douglas C; Davids, Paul S

    2016-08-22

    We present experimental results for a selective epitaxially grown Ge-on-Si separate absorption and charge multiplication (SACM) integrated waveguide coupled avalanche photodiode (APD) compatible with our silicon photonics platform. Epitaxially grown Ge-on-Si waveguide-coupled linear mode avalanche photodiodes with varying lateral multiplication regions and different charge implant dimensions are fabricated and their illuminated device characteristics and high-speed performance is measured. We report a record gain-bandwidth product of 432 GHz for our highest performing waveguide-coupled avalanche photodiode operating at 1510nm. Bit error rate measurements show operation with BER-12, in the range from -18.3 dBm to -12 dBm received optical power into a 50 Ω load and open eye diagrams with 13 Gbps pseudo-random data at 1550 nm.

  11. TE01 mode converter for highly overmoded circular waveguide at 188 GHz

    DEFF Research Database (Denmark)

    Rybalko, Oleksandr; Zhurbenko, Vitaliy; Ardenkjær-Larsen, Jan Henrik

    2016-01-01

    A design of a G-band TE01 mode converter is presented in this work. It consists of a TE01 mode launcher followed by a tapered waveguide section. Full-wave simulated reflection coefficient of stainless steel converter is better than −15 dB and transmission coefficient is better than −1.5 d...

  12. A Broadband Terahertz Waveguide T-Junction Variable Power Splitter

    Science.gov (United States)

    Reichel, Kimberly S.; Mendis, Rajind; Mittleman, Daniel M.

    2016-06-01

    In order for the promise of terahertz (THz) wireless communications to become a reality, many new devices need to be developed, such as those for routing THz waves. We demonstrate a power splitting router based on a parallel-plate waveguide (PPWG) T-junction excited by the TE1 waveguide mode. By integrating a small triangular septum into the waveguide plate, we are able to direct the THz light down either one of the two output channels with precise control over the ratio between waveguide outputs. We find good agreement between experiment and simulation in both amplitude and phase. We show that the ratio between waveguide outputs varies exponentially with septum translation offset and that nearly 100% transmission can be achieved. The splitter operates over almost the entire range in which the waveguide is single mode, providing a sensitive and broadband method for THz power splitting.

  13. TE modes of UV-laser generated waveguides in a planar polymer chip of parabolic refractive index profile

    Science.gov (United States)

    Shams El-Din, M. A.

    2018-04-01

    The UV-laser lithographic method is used for the preparation of Polymeric integrated-optical waveguides in a planar polymer chip. The waveguide samples are irradiated by an excimer laser of wavelength 248 nm with different doses and with the same fluencies. The refractive index depth profile for the waveguides, in the first zone is found to have a parabolic shape and Gaussian shape in the second one that can be determined by Mach-Zehnder interferometer. Both the mode field distribution and the effective mode indices for the first zone only are determined by making use of the theoretical mode and the experimental data. It is found that the model field distribution is strongly dependent on the refractive indices for each zone.

  14. 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.

  15. Ultra-low-loss inverted taper coupler for silicon-on-insulator ridge waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    An ultra-low-loss coupler for interfacing a silicon-on-insulator ridge waveguide and a single-mode fiber in both polarizations is presented. The inverted taper coupler, embedded in a polymer waveguide, is optimized for both the transverse-magnetic and transverse-electric modes through tapering...... the width of the silicon-on-insulator waveguide from 450 nm down to less than 15 nm applying a thermal oxidation process. Two inverted taper couplers are integrated with a 3-mm long silicon-on-insulator ridge waveguide in the fabricated sample. The measured coupling losses of the inverted taper coupler...... for transverse-magnetic and transverse-electric modes are ~0.36 dB and ~0.66 dB per connection, respectively....

  16. Integrated phononic crystal resonators based on adiabatically-terminated phononic crystal waveguides

    Directory of Open Access Journals (Sweden)

    Razi Dehghannasiri

    2016-12-01

    Full Text Available In this letter, we demonstrate a new design for integrated phononic crystal (PnC resonators based on confining acoustic waves in a heterogeneous waveguide-based PnC structure. In this architecture, a PnC waveguide that supports a single mode at the desired resonance frequencies is terminated by two waveguide sections with no propagating mode at those frequencies (i.e., have mode gap. The proposed PnC resonators are designed through combining the spatial-domain and the spatial-frequency domain (i.e., the k-domain analysis to achieve a smooth mode envelope. This design approach can benefit both membrane-based and surface-acoustic-wave-based architectures by confining the mode spreading in k-domain that leads to improved electromechanical excitation/detection coupling and reduced loss through propagating bulk modes.

  17. Propagation and radiation characteristics of the circular electric, circular magnetic and hybrid waveguide modes

    International Nuclear Information System (INIS)

    Crenn, J.P.

    1996-06-01

    The field distributions and propagation constants of the circular electric, circular magnetic and hybrid modes of oversized waveguides are expressed, taking the effects of walls into account. The near and far field patterns are derived in the case of real wall functions. It is shown that, for very oversized waveguides, the terms containing wall functions can be ignored in the calculations, and it results that the expressions of fields and propagation constants become independent of the types of waveguides. An application to corrugated waveguides for Electron Cyclotron Resonance Heating experiments shows the variations of the radiation characteristics versus geometric parameters of the corrugations and determines the ranges of interest for these parameters. (author)

  18. Low-Loss Hollow Waveguide Fibers for Mid-Infrared Quantum Cascade Laser Sensing Applications

    Directory of Open Access Journals (Sweden)

    James A. Harrington

    2013-01-01

    Full Text Available We report on single mode optical transmission of hollow core glass waveguides (HWG coupled with an external cavity mid-IR quantum cascade lasers (QCLs. The QCL mode results perfectly matched to the hybrid HE11 waveguide mode and the higher losses TE-like modes have efficiently suppressed by the deposited inner dielectric coating. Optical losses down to 0.44 dB/m and output beam divergence of ~5 mrad were measured. Using a HGW fiber with internal core size of 300 µm we obtained single mode laser transmission at 10.54 µm and successful employed it in a quartz enhanced photoacoustic gas sensor setup.

  19. A microwave FEL [free electron laser] code using waveguide modes

    International Nuclear Information System (INIS)

    Byers, J.A.; Cohen, R.H.

    1987-08-01

    A free electron laser code, GFEL, is being developed for application to the LLNL tokamak current drive experiment, MTX. This single frequency code solves for the slowly varying complex field amplitude using the usual wiggler-averaged equations of existing codes, in particular FRED, except that it describes the fields by a 2D expansion in the rectangular waveguide modes, using coupling coefficients similar to those developed by Wurtele, which include effects of spatial variations in the fields seen by the wiggler motion of the particles. Our coefficients differ from those of Wurtele in two respects. First, we have found a missing √2γ/a/sub w/ factor in his C/sub z/; when corrected this increases the effect of the E/sub z/ field component and this in turn reduces the amplitude of the TM mode. Second, we have consistently retained all terms of second order in the wiggle amplitude. Both corrections are necessary for accurate computation. GFEL has the capability of following the TE/sub 0n/ and TE(M)/sub m1/ modes simultaneously. GFEL produces results nearly identical to those from FRED if the coupling coefficients are adjusted to equal those implied by the algorithm in FRED. Normally, the two codes produce results that are similar but different in detail due to the different treatment of modes higher than TE/sub 01/. 5 refs., 2 figs., 1 tab

  20. Waveguide-Coupled Superconducting Nanowire Single-Photon Detectors

    Science.gov (United States)

    Beyer, Andrew D.; Briggs, Ryan M.; Marsili, Francesco; Cohen, Justin D.; Meenehan, Sean M.; Painter, Oskar J.; Shaw, Matthew D.

    2015-01-01

    We have demonstrated WSi-based superconducting nanowire single-photon detectors coupled to SiNx waveguides with integrated ring resonators. This photonics platform enables the implementation of robust and efficient photon-counting detectors with fine spectral resolution near 1550 nm.

  1. Suppression of Higher Order Modes in an Array of Cavities Using Waveguides

    Science.gov (United States)

    Shashkov, Ya. V.; Sobenin, N. P.; Bazyl, D. S.; Kaminskiy, V. I.; Mitrofanov, A. A.; Zobov, M. M.

    An application of additional harmonic cavities operating at multiplies of the main RF system frequency of 400 MHz is currently under discussionin the framework of the High Luminosity LHC upgrade program [1,2]. A structure consisting of two 800 MHz single cell superconducting cavities with grooved beam pipes coupled by drift tubes has been suggested for implementation. However, it is desirable to increase the number of single cells installed in one cryomodule in order to decrease the number of transitions between "warm" and "cold" parts of the collider vacuum chamber. Unfortunately, it can lead to the appearance of higher order modes (HOM) trapped between the cavities. In order to solve this problem the methods of HOM damping with rectangular waveguides connected to the drift tubes were investigated and compared. We describe the results obtained for arrays of 2, 4 and 8 cavitiesin this paper.

  2. Towards single photon generation using NV centers in diamond coupled to thin layer optical waveguides

    International Nuclear Information System (INIS)

    Toshiyuki Tashima

    2014-01-01

    Single photon emitters like the nitrogen-vacancy (NV) center in diamond are important for quantum communication such as quantum cryptography and quantum metrology. In this context, e.g. tapered optical nano-fibers are a promising approach as they allow efficient coupling of single photons into a single spatial mode. Yet, integration of such fibers in a compact integrated quantum circuit is demanding. Here we propose a NV defect center in diamond as a single photon emitter coupled to a thin layer photonic waveguide. The benefit is to allow smaller size devices while having a similar strong evanescent field like tapered nano-optical fibers. We present numerical simulations and fabrication steps of such structures. (author)

  3. Scalable electro-photonic integration concept based on polymer waveguides

    Science.gov (United States)

    Bosman, E.; Van Steenberge, G.; Boersma, A.; Wiegersma, S.; Harmsma, P.; Karppinen, M.; Korhonen, T.; Offrein, B. J.; Dangel, R.; Daly, A.; Ortsiefer, M.; Justice, J.; Corbett, B.; Dorrestein, S.; Duis, J.

    2016-03-01

    A novel method for fabricating a single mode optical interconnection platform is presented. The method comprises the miniaturized assembly of optoelectronic single dies, the scalable fabrication of polymer single mode waveguides and the coupling to glass fiber arrays providing the I/O's. The low cost approach for the polymer waveguide fabrication is based on the nano-imprinting of a spin-coated waveguide core layer. The assembly of VCSELs and photodiodes is performed before waveguide layers are applied. By embedding these components in deep reactive ion etched pockets in the silicon substrate, the planarity of the substrate for subsequent layer processing is guaranteed and the thermal path of chip-to-substrate is minimized. Optical coupling of the embedded devices to the nano-imprinted waveguides is performed by laser ablating 45 degree trenches which act as optical mirror for 90 degree deviation of the light from VCSEL to waveguide. Laser ablation is also implemented for removing parts of the polymer stack in order to mount a custom fabricated connector containing glass fiber arrays. A demonstration device was built to show the proof of principle of the novel fabrication, packaging and optical coupling principles as described above, combined with a set of sub-demonstrators showing the functionality of the different techniques separately. The paper represents a significant part of the electro-photonic integration accomplishments in the European 7th Framework project "Firefly" and not only discusses the development of the different assembly processes described above, but the efforts on the complete integration of all process approaches into the single device demonstrator.

  4. Optical Cladding Waveguides in Dielectric Crystals Produced by Femtosecond Laser Inscription

    Directory of Open Access Journals (Sweden)

    Chen Feng

    2013-11-01

    Full Text Available In this work, the recent progress of our research on optical cladding waveguides in dielectric crystals produced by femtosecond laser inscription has been overviewed. With different scales at cross sections, the cladding waveguides support guidance from single mode to highly multi-modes, and work for wavelength till mid-infrared regimes. Applications of the fabricated cladding structures as new integrated light sources are introduced.

  5. Mesoscale cavities in hollow-core waveguides for quantum optics with atomic ensembles

    Directory of Open Access Journals (Sweden)

    Haapamaki C.M.

    2016-08-01

    Full Text Available Single-mode hollow-core waveguides loaded with atomic ensembles offer an excellent platform for light–matter interactions and nonlinear optics at low photon levels. We review and discuss possible approaches for incorporating mirrors, cavities, and Bragg gratings into these waveguides without obstructing their hollow cores. With these additional features controlling the light propagation in the hollow-core waveguides, one could potentially achieve optical nonlinearities controllable by single photons in systems with small footprints that can be integrated on a chip. We propose possible applications such as single-photon transistors and superradiant lasers that could be implemented in these enhanced hollow-core waveguides.

  6. High-power millimeter-wave mode converters in overmoded circular waveguides using periodic wall perturbations

    International Nuclear Information System (INIS)

    Thumm, M.

    1984-07-01

    This work reports on measurements and calculations (coupled mode equations) on the conversion of circular elecric TEsub(0n) gyrotron mode compositions (TE 01 to TE 04 ) at 28 and 70 GHz to the linearly polarized TE 11 mode by means of a mode converter system using periodic waveguide wall perturbations. Mode transducers with axisymmetric radius perturbations transform the TEsub(0n) gyrotron mode mixture to the more convenient TE 01 mode for long-distance transmission through overmoded waveguides. Proper matching of the phase differences between the TEsub(0n) modes and of lengths and perturbation amplitudes of the several converter sections is required. A mode converter with constant diameter and periodically perturbed curvature transfers the unpolarized TE 01 mode into the TE 11 mode which produces an almost linearly polarized millimeter-wave beam needed for efficient electron cyclotron heating (ECRH) of plasmas in thermonuclear fusion devices. The experimentally determined TEsub(0n)-to-TE 01 conversion efficiency is (98+-1)% at 28 and 70 GHz (99% predicted) while the TE 01 -to-TE 11 converter has a (96+-2)% conversion efficiency at 28 GHz (95% predicted) and (94+-2)% at 70 GHz (93% predicted); ohmic losses are included. (orig./AH)

  7. Waveguide image-slicers for ultrahigh resolution spectroscopy

    Science.gov (United States)

    Beckert, Erik; Strassmeier, Klaus G.; Woche, Manfred; Eberhardt, Ramona; Tünnermann, Andreas; Andersen, Michael

    2008-07-01

    Waveguide image-slicer prototypes with resolutions up to 310.000 for the fiber fed PEPSI echelle spectrograph at the LBT and single waveguide thicknesses of down to 30 μm have been manufactured. The waveguides were macroscopically prepared, stacked up to an order of 7 and thinned back to square stack cross sections. A high filling ratio was achieved by realizing homogenous adhesive gaps of 4.6 μm, using index matching adhesives for TIR within the waveguides. The image-slicer stacks can be used in immersion mode and are miniaturized to be implemented in a set of four, measurements indicate an overall efficiency of above 80% for them.

  8. Cavity mode control in side-coupled periodic waveguides: theory and experiment

    DEFF Research Database (Denmark)

    Ha, Sangwoo; Sukhorukov, A.; Lavrinenko, Andrei

    2010-01-01

    We demonstrate that the modes of coupled cavities created in periodic waveguides can depend critically on the longitudinal shift between the cavities. In the absence of such shift, the modes feature symmetric or antisymmetric profiles, and their frequency splitting generally increases...... as the cavities are brought closer. We show that the longitudinal shift enables flexible control over the fundamental modes, whose frequency detuning can be reduced down to zero. Our coupled-mode theory analysis reveals an intrinsic link between the mode tuning and the transformation of slow-light dispersion...... at the photonic band-edge.We illustrate our approach through numerical modeling of cavities created in arrays of dielectric rods, and confirm our predictions with experimental observations....

  9. Mode-Selective Wavelength Conversion Based on Four-Wave Mixing in a Multimode Silicon Waveguide

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan

    2013-01-01

    We report all-optical mode-selective wavelength conversion based on four-wave mixing in a multimode Si waveguide. A two-mode division multiplexing circuit using tapered directional coupler based (de)multiplexers is used for the application. Experimental results show clear eye-diagrams and moderate...

  10. Paired modes of heterostructure cavities in photonic crystal waveguides with split band edges

    DEFF Research Database (Denmark)

    Mahmoodian, Sahand; Sukhorukov, Andrey A.; Ha, Sangwoo

    2010-01-01

    We investigate the modes of double heterostructure cavities where the underlying photonic crystal waveguide has been dispersion engineered to have two band-edges inside the Brillouin zone. By deriving and using a perturbative method, we show that these structures possess two modes. For unapodized...... cavities, the relative detuning of the two modes can be controlled by changing the cavity length, and for particular lengths, a resonant-like effect makes the modes degenerate. For apodized cavities no such resonances exist and the modes are always non-degenerate....

  11. Simulations of the spontaneous emission of a quantum dot near a gap plasmon waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Perera, Chamanei S., E-mail: cp.hettiarachchige@qut.edu.au; Vernon, Kristy C.; Mcleod, Angus [Plasmonic Device Group, Queensland University of Technology, GPO box 2434, Brisbane, Queensland (Australia)

    2014-02-07

    In this paper, we modeled a quantum dot at near proximity to a gap plasmon waveguide to study the quantum dot-plasmon interactions. Assuming that the waveguide is single mode, this paper is concerned about the dependence of spontaneous emission rate of the quantum dot on waveguide dimensions such as width and height. We compare coupling efficiency of a gap waveguide with symmetric configuration and asymmetric configuration illustrating that symmetric waveguide has a better coupling efficiency to the quantum dot. We also demonstrate that optimally placed quantum dot near a symmetric waveguide with 50 nm × 50 nm cross section can capture 80% of the spontaneous emission into a guided plasmon mode.

  12. Simulations of the spontaneous emission of a quantum dot near a gap plasmon waveguide

    International Nuclear Information System (INIS)

    Perera, Chamanei S.; Vernon, Kristy C.; Mcleod, Angus

    2014-01-01

    In this paper, we modeled a quantum dot at near proximity to a gap plasmon waveguide to study the quantum dot-plasmon interactions. Assuming that the waveguide is single mode, this paper is concerned about the dependence of spontaneous emission rate of the quantum dot on waveguide dimensions such as width and height. We compare coupling efficiency of a gap waveguide with symmetric configuration and asymmetric configuration illustrating that symmetric waveguide has a better coupling efficiency to the quantum dot. We also demonstrate that optimally placed quantum dot near a symmetric waveguide with 50 nm × 50 nm cross section can capture 80% of the spontaneous emission into a guided plasmon mode

  13. Robust Seismic Normal Modes Computation in Radial Earth Models and A Novel Classification Based on Intersection Points of Waveguides

    Science.gov (United States)

    Ye, J.; Shi, J.; De Hoop, M. V.

    2017-12-01

    We develop a robust algorithm to compute seismic normal modes in a spherically symmetric, non-rotating Earth. A well-known problem is the cross-contamination of modes near "intersections" of dispersion curves for separate waveguides. Our novel computational approach completely avoids artificial degeneracies by guaranteeing orthonormality among the eigenfunctions. We extend Wiggins' and Buland's work, and reformulate the Sturm-Liouville problem as a generalized eigenvalue problem with the Rayleigh-Ritz Galerkin method. A special projection operator incorporating the gravity terms proposed by de Hoop and a displacement/pressure formulation are utilized in the fluid outer core to project out the essential spectrum. Moreover, the weak variational form enables us to achieve high accuracy across the solid-fluid boundary, especially for Stoneley modes, which have exponentially decaying behavior. We also employ the mixed finite element technique to avoid spurious pressure modes arising from discretization schemes and a numerical inf-sup test is performed following Bathe's work. In addition, the self-gravitation terms are reformulated to avoid computations outside the Earth, thanks to the domain decomposition technique. Our package enables us to study the physical properties of intersection points of waveguides. According to Okal's classification theory, the group velocities should be continuous within a branch of the same mode family. However, we have found that there will be a small "bump" near intersection points, which is consistent with Miropol'sky's observation. In fact, we can loosely regard Earth's surface and the CMB as independent waveguides. For those modes that are far from the intersection points, their eigenfunctions are localized in the corresponding waveguides. However, those that are close to intersection points will have physical features of both waveguides, which means they cannot be classified in either family. Our results improve on Okal

  14. Distributed temperature sensors development using an stepped-helical ultrasonic waveguide

    Science.gov (United States)

    Periyannan, Suresh; Rajagopal, Prabhu; Balasubramaniam, Krishnan

    2018-04-01

    This paper presents the design and development of the distributed ultrasonic waveguide temperature sensors using some stepped-helical structures. Distributed sensing has several applications in various industries (oil, glass, steel) for measurement of physical parameters such as level, temperature, viscosity, etc. This waveguide incorporates a special notch or bend for obtaining ultrasonic wave reflections from the desired locations (Gage-lengths) where local measurements are desired. In this paper, a multi-location measurement wave-guide, with a measurement capability of 18 locations in a single wire, has been fabricated. The distribution of these sensors is both in the axial as well as radial directions using a stepped-helical spring configuration. Also, different high temperature materials have been chosen for the wave-guide. Both lower order axi-symmetric guided ultrasonic modes (L(0,1) and T(0,1)) were employed. These wave modes were generated/received (pulse-echo approach) using conventional longitudinal and shear transducers, respectively. Also, both the wave modes were simultaneously generated/received and compared using shear transducer for developing the distributed helical wave-guide sensors. The effect of dispersion of the wave modes due to curvature effects will also be discussed.

  15. Narrow ridge waveguide high power single mode 1.3-μm InAs/InGaAs ten-layer quantum dot lasers

    Directory of Open Access Journals (Sweden)

    Cao Q

    2007-01-01

    Full Text Available AbstractTen-layer InAs/In0.15Ga0.85As quantum dot (QD laser structures have been grown using molecular beam epitaxy (MBE on GaAs (001 substrate. Using the pulsed anodic oxidation technique, narrow (2 μm ridge waveguide (RWG InAs QD lasers have been fabricated. Under continuous wave operation, the InAs QD laser (2 × 2,000 μm2 delivered total output power of up to 272.6 mW at 10 °C at 1.3 μm. Under pulsed operation, where the device heating is greatly minimized, the InAs QD laser (2 × 2,000 μm2 delivered extremely high output power (both facets of up to 1.22 W at 20 °C, at high external differential quantum efficiency of 96%. Far field pattern measurement of the 2-μm RWG InAs QD lasers showed single lateral mode operation.

  16. Low power excitation of gyrotron-type modes in cylindrical waveguide using quasi-optical techniques

    International Nuclear Information System (INIS)

    Alexandrov, N.L.; Whaley, D.R.; Tran, M.Q.; Denisov, D.R.

    1995-03-01

    Experimental results of low power excitation of a 118 GHz TE 22,6 rotating mode are presented. A rectangular mode is converted to a TE 22,6 circular waveguide using quasi-optical techniques. A good conversion efficiency is measured and the experimentally observed field intensity profiles show the percentage of unwanted modes to be small. (author) 10 figs., 10 refs

  17. Unified approach for calculating the number of confined modes in multilayered waveguiding structures

    Science.gov (United States)

    Ruschin, S.; Griffel, G.; Hardy, A.; Croitoru, N.

    1986-01-01

    A general formalism is developed in order to find the number of modes and mode cutoff conditions in multilayer waveguiding structures. An explicit expression is presented for the number of confined modes that allows the modes to be counted without having to analyze the specific eigenvalue equation of the structure. The method is illustrated by its application to several structures: the buried layer, the directional coupler, and the three-guide symmetrical arrangement. By a suitable extension of the formalism, the number of well-confined modes is found for a four-layer structure.

  18. Integration of a terahertz quantum cascade laser with a hollow waveguide

    Science.gov (United States)

    Wanke, Michael C [Albuquerque, NM; Nordquist, Christopher D [Albuquerque, NM

    2012-07-03

    The present invention is directed to the integration of a quantum cascade laser with a hollow waveguide on a chip to improve both the beam pattern and manufacturability. By coupling the QCL output into a single-mode rectangular waveguide the radiation mode structure can be known and the propagation, manipulation, and broadcast of the QCL radiation can then be entirely controlled by well-established rectangular waveguide techniques. By controlling the impedance of the interface, enhanced functions, such as creating amplifiers, efficient coupling to external cavities, and increasing power output from metal-metal THz QCLs, are also enabled.

  19. Longitudinal Modes along Thin Piezoelectric Waveguides for Liquid Sensing Applications

    Directory of Open Access Journals (Sweden)

    Cinzia Caliendo

    2015-06-01

    Full Text Available The propagation of longitudinally polarized acoustic modes along thin piezoelectric plates (BN, ZnO, InN, AlN and GaN is theoretically studied, aiming at the design of high frequency electroacoustic devices suitable for work in liquid environments. The investigation of the acoustic field profile across the plate revealed the presence of longitudinally polarized Lamb modes, travelling at velocities close to that of the longitudinal bulk acoustic wave propagating in the same direction. Such waves are suitable for the implementation of high-frequency, low-loss electroacoustic devices operating in liquid environments. The time-averaged power flow density, the phase velocity and the electroacoustic coupling coefficient K2 dispersion curves were studied, for the first (S0 and four higher order (S1, S2, S3, S4 symmetrical modes for different electrical boundary conditions. Two electroacoustic coupling configurations were investigated, based on interdigitated transducers, with or without a metal floating electrode at the opposite plate surface. Enhanced performances, such as a K2 as high as 8.5% and a phase velocity as high as 16,700 m/s, were demostrated for the ZnO- and BN-based waveguides, as an example. The relative velocity changes, and the inertial and viscous sensitivities of the first symmetric and anti-symmetric mode, S0 and A0, propagating along thin plates bordered by a viscous liquid were derived using the perturbation approach. The present study highlights the feasibility of the piezoelectric waveguides to the development of high-frequency, integrated-circuits compatible electroacoustic devices suitable for working in liquid environment.

  20. Low loss hollow-core waveguide on a silicon substrate

    Science.gov (United States)

    Yang, Weijian; Ferrara, James; Grutter, Karen; Yeh, Anthony; Chase, Chris; Yue, Yang; Willner, Alan E.; Wu, Ming C.; Chang-Hasnain, Connie J.

    2012-07-01

    Optical-fiber-based, hollow-core waveguides (HCWs) have opened up many new applications in laser surgery, gas sensors, and non-linear optics. Chip-scale HCWs are desirable because they are compact, light-weight and can be integrated with other devices into systems-on-a-chip. However, their progress has been hindered by the lack of a low loss waveguide architecture. Here, a completely new waveguiding concept is demonstrated using two planar, parallel, silicon-on-insulator wafers with high-contrast subwavelength gratings to reflect light in-between. We report a record low optical loss of 0.37 dB/cm for a 9-μm waveguide, mode-matched to a single mode fiber. Two-dimensional light confinement is experimentally realized without sidewalls in the HCWs, which is promising for ultrafast sensing response with nearly instantaneous flow of gases or fluids. This unique waveguide geometry establishes an entirely new scheme for low-cost chip-scale sensor arrays and lab-on-a-chip applications.

  1. Deterministic fabrication of dielectric loaded waveguides coupled to single nitrogen vacancy centers in nanodiamonds

    DEFF Research Database (Denmark)

    Siampour, Hamidreza; Kumar, Shailesh; Bozhevolnyi, Sergey I.

    We report on the fabrication of dielectric-loaded-waveguides which are excited by single-nitrogen-vacancy (NV) centers in nanodiamonds. The waveguides are deterministically written onto the pre-characterized nanodiamonds by using electron beam lithography of hydrogen silsesquioxane (HSQ) resist...... on silver-coated silicon substrate. Change in lifetime for NV-centers is observed after fabrication of waveguides and an antibunching in correlation measurement confirms that nanodiamonds contain single NV-centers....

  2. Nonlinear equation of the modes in circular slab waveguides and its application.

    Science.gov (United States)

    Zhu, Jianxin; Zheng, Jia

    2013-11-20

    In this paper, circularly curved inhomogeneous waveguides are transformed into straight inhomogeneous waveguides first by a conformal mapping. Then, the differential transfer matrix method is introduced and adopted to deduce the exact dispersion relation for modes. This relation itself is complex and difficult to solve, but it can be approximated by a simpler nonlinear equation in practical applications, which is close to the exact relation and quite easy to analyze. Afterward, optimized asymptotic solutions are obtained and act as initial guesses for the following Newton's iteration. Finally, very accurate solutions are achieved in the numerical experiment.

  3. Mode selection in two-dimensional Bragg resonators based on planar dielectric waveguides

    International Nuclear Information System (INIS)

    Baryshev, V R; Ginzburg, N S; Zaslavskii, V Yu; Malkin, A M; Sergeev, A S; Thumm, M

    2009-01-01

    Two-dimensional Bragg resonators based on planar dielectric waveguides are analysed. It is shown that the doubly periodic corrugation deposited on the dielectric surface in the form of two gratings with translational vectors directed perpendicular to each other ensures effective selection of modes along two coordinates at large Fresnel parameters. This result is obtained both by the method of coupled waves (geometrical optics approximation) and by the direct numerical simulations. Two-dimensional Bragg resonators make it possible to fabricate two-dimensional distributed feedback lasers and to provide generation of spatially coherent radiation in large-volume active media. (waveguides)

  4. Full-vectorial propagation model and modified effective mode area of four-wave mixing in straight waveguides

    DEFF Research Database (Denmark)

    Guo, Kai; Friis, Søren Michael Mørk; Christensen, Jesper Bjerge

    2017-01-01

    We derive from Maxwell's equations full-vectorial nonlinear propagation equations of four-wave mixing valid in straight semiconductor-on-insulator waveguides. Special attention is given to the resulting effective mode area, which takes a convenient form known from studies in photonic crystal fibers......, but has not been introduced in the context of integrated waveguides. We show that the difference between our full-vectorial effective mode area and the scalar equivalent often referred to in the literature may lead to mistakes when evaluating the nonlinear refractive index and optimizing designs of new...

  5. Large-bandwidth planar photonic crystal waveguides

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Lavrinenko, Andrei

    2002-01-01

    A general design principle is presented for making finite-height photonic crystal waveguides that support leakage-free guidance of light over large frequency intervals. The large bandwidth waveguides are designed by introducing line defects in photonic crystal slabs, where the material in the line...... defect has appropriate dispersion properties relative to the photonic crystal slab material surrounding the line defect. A three-dimensional theoretical analysis is given for large-bandwidth waveguide designs based on a silicon-air photonic crystal slab suspended in air. In one example, the leakage......-free single-mode guidance is found for a large frequency interval covering 60% of the photonic band-gap....

  6. Resonances in a two-dimensional electron waveguide with a single δ-function scatterer

    International Nuclear Information System (INIS)

    Boese, Daniel; Lischka, Markus; Reichl, L. E.

    2000-01-01

    We study the conductance properties of a straight two-dimensional electron waveguide with an s-like scatterer modeled by a single δ-function potential with a finite number of modes. Even such a simple system exhibits interesting resonance phenomena. These resonances are explained in terms of quasibound states both by using a direct solution of the Schroedinger equation and by studying the Green's function of the system. Using the Green's function we calculate the survival probability as well as the power absorption, and show the influence of the quasibound states on these two quantities. (c) 2000 The American Physical Society

  7. Atom-field dressed states in slow-light waveguide QED

    Science.gov (United States)

    Calajó, Giuseppe; Ciccarello, Francesco; Chang, Darrick; Rabl, Peter

    2016-03-01

    We discuss the properties of atom-photon bound states in waveguide QED systems consisting of single or multiple atoms coupled strongly to a finite-bandwidth photonic channel. Such bound states are formed by an atom and a localized photonic excitation and represent the continuum analog of the familiar dressed states in single-mode cavity QED. Here we present a detailed analysis of the linear and nonlinear spectral features associated with single- and multiphoton dressed states and show how the formation of bound states affects the waveguide-mediated dipole-dipole interactions between separated atoms. Our results provide both a qualitative and quantitative description of the essential strong-coupling processes in waveguide QED systems, which are currently being developed in the optical and microwave regimes.

  8. Nanoscale Plasmonic V-Groove Waveguides for the Interrogation of Single Fluorescent Bacterial Cells.

    Science.gov (United States)

    Lotan, Oren; Bar-David, Jonathan; Smith, Cameron L C; Yagur-Kroll, Sharon; Belkin, Shimshon; Kristensen, Anders; Levy, Uriel

    2017-09-13

    We experimentally demonstrate the interrogation of an individual Escherichia coli cell using a nanoscale plasmonic V-groove waveguide. Several different configurations were studied. The first involved the excitation of the cell in a liquid environment because it flows on top of the waveguide nanocoupler, while the obtained fluorescence is coupled into the waveguide and collected at the other nanocoupler. The other two configurations involved the positioning of the bacterium within the nanoscale waveguide and its excitation in a dry environment either directly from the top or through waveguide modes. This is achieved by taking advantage of the waveguide properties not only for light guiding but also as a mechanical tool for trapping the bacteria within the V-grooves. The obtained results are supported by a set of numerical simulations, shedding more light on the mechanism of excitation. This demonstration paves the way for the construction of an efficient bioplasmonic chip for diverse cell-based sensing applications.

  9. Selection of modes in transverse-mode waveguides for semiconductor lasers based on asymmetric heterostructures

    International Nuclear Information System (INIS)

    Slipchenko, S. O.; Bondarev, A. D.; Vinokurov, D. A.; Nikolaev, D. N.; Fetisova, N. V.; Sokolova, Z. N.; Pikhtin, N. A.; Tarasov, I. S.

    2009-01-01

    Asymmetric Al 0.3 Ga 0.7 As/GaAs/InGaAs heterostructures with a broadened waveguide produced by the method of MOCVD epitaxy are studied. It is established that the precision shift of the active region to one of the cladding layers ensures the generation of the chosen mode of high order in the transverse broadened waveguide. It is experimentally established that this shift brings about an increase in internal optical losses and a decrease in the internal quantum efficiency of stimulated emission. It is shown experimentally that the shift of the active region to the n-type cladding layer governs the sublinear form of the power-current characteristic for semiconductor lasers; in the case of a shift of the active region towards the p-type cladding layer, the laser diodes demonstrated a linear dependence of optical power on the pump current in the entire range of pump currents.

  10. Femtosecond-laser inscribed double-cladding waveguides in Nd:YAG crystal: a promising prototype for integrated lasers.

    Science.gov (United States)

    Liu, Hongliang; Chen, Feng; Vázquez de Aldana, Javier R; Jaque, D

    2013-09-01

    We report on the design and implementation of a prototype of optical waveguides fabricated in Nd:YAG crystals by using femtosecond-laser irradiation. In this prototype, two concentric tubular structures with nearly circular cross sections of different diameters have been inscribed in the Nd:YAG crystals, generating double-cladding waveguides. Under 808 nm optical pumping, waveguide lasers have been realized in the double-cladding structures. Compared with single-cladding waveguides, the concentric tubular structures, benefiting from the large pump area of the outermost cladding, possess both superior laser performance and nearly single-mode beam profile in the inner cladding. Double-cladding waveguides of the same size were fabricated and coated by a thin optical film, and a maximum output power of 384 mW and a slope efficiency of 46.1% were obtained. Since the large diameters of the outer claddings are comparable with those of the optical fibers, this prototype paves a way to construct an integrated single-mode laser system with a direct fiber-waveguide configuration.

  11. Femtosecond laser inscribed cladding waveguide lasers in Nd:LiYF4 crystals

    Science.gov (United States)

    Li, Shi-Ling; Huang, Ze-Ping; Ye, Yong-Kai; Wang, Hai-Long

    2018-06-01

    Depressed circular cladding, buried waveguides were fabricated in Nd:LiYF4 crystals with an ultrafast Yb-doped fiber master-oscillator power amplifier laser. Waveguides were optimized by varying the laser writing conditions, such as pulse energy, focus depth, femtosecond laser polarization and scanning velocity. Under optical pump at 799 nm, cladding waveguides showed continuous-wave laser oscillation at 1047 nm. Single- and multi-transverse modes waveguide laser were realized by varying the waveguide diameter. The maximum output power in the 40 μm waveguide is ∼195 mW with a slope efficiency of 34.3%. The waveguide lasers with hexagonal and cubic cladding geometry were also realized.

  12. Polymer waveguides for electro-optical integration in data centers and high-performance computers.

    Science.gov (United States)

    Dangel, Roger; Hofrichter, Jens; Horst, Folkert; Jubin, Daniel; La Porta, Antonio; Meier, Norbert; Soganci, Ibrahim Murat; Weiss, Jonas; Offrein, Bert Jan

    2015-02-23

    To satisfy the intra- and inter-system bandwidth requirements of future data centers and high-performance computers, low-cost low-power high-throughput optical interconnects will become a key enabling technology. To tightly integrate optics with the computing hardware, particularly in the context of CMOS-compatible silicon photonics, optical printed circuit boards using polymer waveguides are considered as a formidable platform. IBM Research has already demonstrated the essential silicon photonics and interconnection building blocks. A remaining challenge is electro-optical packaging, i.e., the connection of the silicon photonics chips with the system. In this paper, we present a new single-mode polymer waveguide technology and a scalable method for building the optical interface between silicon photonics chips and single-mode polymer waveguides.

  13. Diluted melt proton exchange slab waveguides in LiNbO3: A new fabrication and characterization method

    DEFF Research Database (Denmark)

    Veng, Torben; Skettrup, Torben

    1997-01-01

    A method of dilute-melt proton exchange employing a mixture of glycerol and KHSO4 with lithium benzoate added is used to fabricate planar waveguides in c-cut LiNbO3. With this exchange melt system the waveguide refractive index profiles can be fabricated with a high degree of reproducibility...... the waveguide refractive index profile from the measured mode indices is introduced. The main advantage of this characterization method compared with other methods is that it also applies to single-mode waveguides. Using the new characterization method we investigate in detail the relation between waveguide...

  14. Nanoporous polymer liquid core waveguides

    DEFF Research Database (Denmark)

    Gopalakrishnan, Nimi; Christiansen, Mads Brøkner; Ndoni, Sokol

    2010-01-01

    We demonstrate liquid core waveguides defined by UV to enable selective water infiltration in nanoporous polymers, creating an effective refractive index shift Δn=0.13. The mode confinement and propagation loss in these waveguides are presented.......We demonstrate liquid core waveguides defined by UV to enable selective water infiltration in nanoporous polymers, creating an effective refractive index shift Δn=0.13. The mode confinement and propagation loss in these waveguides are presented....

  15. Observaton of tunneling of slow and fast electromagnetic modes in coupled periodic waveguides

    DEFF Research Database (Denmark)

    Ha, Sangwoo; Sukhorukov, Andrey A.; Lavrinenko, Andrei

    2011-01-01

    We report the experimental observation of tunneling of slow and fast electromagnetic modes in coupled periodic waveguides shifted longitudinally by half of modulation period. According to the symmetry analysis, such a coupler supports two electromagnetic modes with exactly matched slow or fast...... group velocities but different phase velocities for frequencies close to the edge of the photonic band. We confirm the predicted properties of the modes by directly extracting their dispersion and group velocities from the near-field measurements using specialized Bloch-wave spectral analysis method....

  16. On the Theory of Coupled Modes in Optical Cavity-Waveguide Structures

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; de Lasson, Jakob Rosenkrantz; Heuck, Mikkel

    2017-01-01

    Light propagation in systems of optical cavities coupled to waveguides can be conveniently described by a general rate equation model known as (temporal) coupled mode theory (CMT). We present an alternative derivation of the CMT for optical cavitywaveguide structures, which explicitly relies...... in the coupled systems. Practical application of the theory is illustrated using example calculations in one and two dimensions....

  17. Analytical expression of giant Goos-Hänchen shift in terms of proper and improper modes in waveguide structures with arbitrary refractive index profile.

    Science.gov (United States)

    Alishahi, Fatemeh; Mehrany, Khashayar

    2010-06-01

    We analytically relate the giant Goos-Hänchen shift, observed at the interface of a high refractive index prism and a waveguide structure with an arbitrary refractive index profile, to the spatial resonance phenomenon. The proximity effect of the high refractive index prism on modal properties of the waveguide is discussed, and the observed shift is expressed in terms of proper and improper electromagnetic modes supported by the waveguide with no prism. The transversely increasing improper modes are shown playing an increasingly important role as the high refractive index prism comes closer to the waveguide.

  18. Fabrication of triangular nanobeam waveguide networks in bulk diamond using single-crystal silicon hard masks

    International Nuclear Information System (INIS)

    Bayn, I.; Mouradian, S.; Li, L.; Goldstein, J. A.; Schröder, T.; Zheng, J.; Chen, E. H.; Gaathon, O.; Englund, Dirk; Lu, M.; Stein, A.; Ruggiero, C. A.; Salzman, J.; Kalish, R.

    2014-01-01

    A scalable approach for integrated photonic networks in single-crystal diamond using triangular etching of bulk samples is presented. We describe designs of high quality factor (Q = 2.51 × 10 6 ) photonic crystal cavities with low mode volume (V m  = 1.062 × (λ/n) 3 ), which are connected via waveguides supported by suspension structures with predicted transmission loss of only 0.05 dB. We demonstrate the fabrication of these structures using transferred single-crystal silicon hard masks and angular dry etching, yielding photonic crystal cavities in the visible spectrum with measured quality factors in excess of Q = 3 × 10 3

  19. Dry-film polymer waveguide for silicon photonics chip packaging.

    Science.gov (United States)

    Hsu, Hsiang-Han; Nakagawa, Shigeru

    2014-09-22

    Polymer waveguide made by dry film process is demonstrated for silicon photonics chip packaging. With 8 μm × 11.5 μm core waveguide, little penalty is observed up to 25 Gbps before or after the light propagate through a 10-km long single-mode fiber (SMF). Coupling loss to SMF is 0.24 dB and 1.31 dB at the polymer waveguide input and output ends, respectively. Alignment tolerance for 0.5 dB loss increase is +/- 1.0 μm along both vertical and horizontal directions for the coupling from the polymer waveguide to SMF. The dry-film polymer waveguide demonstrates promising performance for silicon photonics chip packaging used in next generation optical multi-chip module.

  20. Waveguide harmonic damper for klystron amplifier

    International Nuclear Information System (INIS)

    Kang, Y.

    1998-01-01

    A waveguide harmonic damper was designed for removing the harmonic frequency power from the klystron amplifiers of the APS linac. Straight coaxial probe antennas are used in a rectangular waveguide to form a damper. A linear array of the probe antennas is used on a narrow wall of the rectangular waveguide for damping klystron harmonics while decoupling the fundamental frequency in dominent TE 01 mode. The klystron harmonics can exist in the waveguide as waveguide higher-order modes above cutoff. Computer simulations are made to investigate the waveguide harmonic damping characteristics of the damper

  1. Phase Radiation Characteristics of an Open-Ended Circular Waveguide

    DEFF Research Database (Denmark)

    Shishkova, A.V.; Pivnenko, Sergiy; Kim, O.S.

    2002-01-01

    Analytic expressions for phase radiation characteristics of a semi-infinite open-ended circular waveguide regardless of its aperture size and operating frequency have been obtained making use of the rigorous Weinstein's theory. The analysis of phase radiation patterns has been carried out...... for the dominant mode (TE11) as well as for the high order modes TM01 and TE01, both for a single and multimode propagation. The measurement of radiation characteristics of an open-ended circular waveguide has been carried out at the DTU-ESA Spherical Near-Field Antenna Test Facility. It is shown...

  2. Photon control by multi-periodic binary grating waveguides: A coupled-mode theory approach

    DEFF Research Database (Denmark)

    Adam, Jost; Lüder, Hannes; Gerken, Martina

    only lead to quantitative results outside the device’s band gaps, since only radiative propagation loss is calculated.n order to provide more physical and quantitative insight to grating-induced waveguide losses, we implemented a coupled-mode theory (CMT) approach for the semi-analytical treatment...

  3. Synthesis and Characterization of Germanium Dioxide - Dioxide Waveguides

    Science.gov (United States)

    Chen, Din-Guo

    The increasing use of single mode fibers in local -area networks (LAN) and customer premises networks (CPN) will increase the need for passive optical components, such as branching devices, mixers, etc. Integrated optical devices are potentially ideal for these applications, provided that they can be made compatible with single mode fibers. The use of GeO_2 as the core dopant and SiO_2 as the substrate ensures that these waveguides will have virtually identical characteristics to single mode fibers. Additionally, glasses in the form of waveguides have recently been used to study various nonlinear optical phenomena, which provide great potential applications such as data storage and information processing. The present study has for the first time demonstrated the feasibility of employing both sol-gel multiple dip -coating and low pressure chemical vapor deposition (LPCVD) in the production of GeO_2-SiO _2 waveguiding films with various germania contents. The thin film characteristics were studied by various analytical techniques (e.g. ellipsometry, waveguiding Raman spectroscopy, FTIR, XPS, SEM/TEM, etc.). The composition dependence of the linear refractive index of GeO _2-SiO_2 films follows that predicted by the Lorenz-Lorenz model. Vibrational spectroscopy revealed the existence of Si-O-Ge linkages in GeO_2-SiO_2 glass network. The addition of GeO_2 in SiO_2 caused a decrease in the size of both the D1 and D2 defect bands in the SiO _2 Raman spectra. The structure of the LPCVD film appears to be dominated by D1 and D2 defect bands. Using a three-prism loss measurement technique, the propagation losses were found to be 3.31 dB/cm and 2.59dB/cm for sol-gel and LPCVD films, respectively. These losses are attributed to various scattering processes in the films. The mode indices of the waveguide were measured using a prism coupling technique. The measured mode indices were found to agree with the calculated value based upon a step-index profile assumption. The

  4. Multi-resolution waveguide image slicer for the PEPSI instrument

    Science.gov (United States)

    Beckert, Erik; Strassmeier, Klaus G.; Woche, Manfred; Harnisch, Gerd; Hornaff, Marcel; Weber, Michael; Barnes, Stuart

    2016-07-01

    A waveguide image slicer with resolutions up to 270.000 (planned: 300.000) for the fiber fed PEPSI echelle spectrograph at the LBT and single waveguide thicknesses of down to 70 μm has been manufactured and tested. The waveguides were macroscopically prepared, stacked up to an order of seven and thinned back to square stack cross sections. A high filling ratio was achieved by realizing homogenous adhesive gaps of 3.6 μm, using index matching adhesives for TIR within the waveguides. The image slicer stacks are used in immersion mode and are miniaturized to enable implementation in a set of 2x8. The overall efficiency is between 92 % and 96 %.

  5. Metallic and 3D-printed dielectric helical terahertz waveguides.

    Science.gov (United States)

    Vogt, Dominik Walter; Anthony, Jessienta; Leonhardt, Rainer

    2015-12-28

    We investigate guidance of Terahertz (THz) radiation in metallic and 3D-printed dielectric helical waveguides in the frequency range from 0.2 to 1 THz. Our experimental results obtained from THz time-domain spectroscopy (THz-TDS) measurements are in very good agreement with finite-difference time-domain (FDTD) simulations. We observe single-mode, low loss and low dispersive propagation of THz radiation in metallic helical waveguides over a broad bandwidth. The 3D-printed dielectric helical waveguides have substantially extended the bandwidth of a low loss dielectric tube waveguide as observed from the experimental and simulation results. The high flexibility of the helical design allows an easy incorporation into bench top THz devices.

  6. Single-photon switch: Controllable scattering of photons inside a one-dimensional resonator waveguide

    Science.gov (United States)

    Zhou, L.; Gong, Z. R.; Liu, Y. X.; Sun, C. P.; Nori, F.

    2010-03-01

    We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. References: L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons inside a one-dimensional resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). L. Zhou, H. Dong, Y.X. Liu, C.P. Sun, F. Nori, Quantum super-cavity with atomic mirrors, Phys. Rev. A 78, 063827 (2008).

  7. Mode structure of a quantum cascade laser

    Science.gov (United States)

    Bogdanov, A. A.; Suris, R. A.

    2011-03-01

    We analyze the mode structure of a quantum cascade laser (QCL) cavity considering the surface plasmon-polariton modes and familiar modes of hollow resonator jointly, within a single model. We present a comprehensive mode structure analysis of the laser cavity, varying its geometric parameters and free electron concentration inside cavity layers within a wide range. Our analysis covers, in particular, the cases of metal-insulator-metal and insulator-metal-insulator waveguides. We discuss the phenomenon of negative dispersion for eigenmodes in detail and explain the nature of this phenomenon. We specify a waveguide parameters domain in which negative dispersion exists. The mode structure of QCL cavity is considered in the case of the anisotropic electrical properties of the waveguide materials. We show that anisotropy of the waveguide core results in propagation of Langmuir modes that are degenerated in the case of the isotropic core. Comparative analysis of optical losses due to free carrier absorption is presented for different modes within the frequency range from terahertz to ultraviolet frequencies.

  8. Gaussian beam-to-slab waveguide coupler by graded index photonic crystal lens

    International Nuclear Information System (INIS)

    Bahari, B; Abrishamian, M S

    2013-01-01

    In this numerical study, a Gaussian beam-to-slab waveguide coupler for both modes of TM and TE has been studied. For this purpose, a concrete structure is suggested, in which the graded index photonic crystal lens and the slab waveguide are in the same structure composed of Si material, and can be fabricated with a single-step lithography process. For maximum power coupling, half-holes have been used as an input matching layer. Power coupling of 80% over a 450 nm bandwidth for the TM mode, and 60% over a 180 nm bandwidth for the TE mode is achieved. (paper)

  9. Fano resonances in a high-Q terahertz whispering-gallery mode resonator coupled to a multi-mode waveguide.

    Science.gov (United States)

    Vogt, Dominik Walter; Leonhardt, Rainer

    2017-11-01

    We report on Fano resonances in a high-quality (Q) whispering-gallery mode (WGM) spherical resonator coupled to a multi-mode waveguide in the terahertz (THz) frequency range. The asymmetric line shape and phase of the Fano resonances detected with coherent continuous-wave (CW) THz spectroscopy measurements are in excellent agreement with the analytical model. A very high Q factor of 1600, and a finesse of 22 at critical coupling is observed around 0.35 THz. To the best of our knowledge this is the highest Q factor ever reported for a THz WGM resonator.

  10. Cavity-photon-switched coherent transient transport in a double quantum waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Nzar Rauf, E-mail: nra1@hi.is; Gudmundsson, Vidar, E-mail: vidar@raunvis.hi.is [Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Tang, Chi-Shung [Department of Mechanical Engineering, National United University, 1, Lienda, 36003 Miaoli, Taiwan (China); Manolescu, Andrei [School of Science and Engineering, Reykjavik University, Menntavegur 1, IS-101 Reykjavik (Iceland)

    2014-12-21

    We study a cavity-photon-switched coherent electron transport in a symmetric double quantum waveguide. The waveguide system is weakly connected to two electron reservoirs, but strongly coupled to a single quantized photon cavity mode. A coupling window is placed between the waveguides to allow electron interference or inter-waveguide transport. The transient electron transport in the system is investigated using a quantum master equation. We present a cavity-photon tunable semiconductor quantum waveguide implementation of an inverter quantum gate, in which the output of the waveguide system may be selected via the selection of an appropriate photon number or “photon frequency” of the cavity. In addition, the importance of the photon polarization in the cavity, that is, either parallel or perpendicular to the direction of electron propagation in the waveguide system is demonstrated.

  11. Self-imaging effect of TM modes in photonic crystal multimode waveguides only exhibiting band gaps for TE modes

    International Nuclear Information System (INIS)

    Yu Tianbao; Jiang Xiaoqing; Yang Jianyi; Zhou Haifeng; Liao Qinghua; Wang Minghua

    2007-01-01

    This Letter presents the properties of transverse-magnetic (TM) modes in multimode photonic crystal waveguides (PCWs), which only exhibit photonic band gaps for transverse-electric (TE) modes. A good equivalent model is applied to analysis the designed structures on the basis of multimode interference effect and self-imaging principle. The performance shows that the TM modes can also be propagated with high efficiency, and resemble index-guided modes owing to the combination of total internal reflection (TIR) and distribution Bragg reflection. It provides a novel way to realize the components for both TM and TE polarizations by combining PBG and TIR effect in PCWs. As one of potential applications, polarization-insensitive power splitter based on the proposed structures can be designed

  12. Waveguide Cavity Resonator as a Source of Optical Squeezing

    Science.gov (United States)

    Stefszky, M.; Ricken, R.; Eigner, C.; Quiring, V.; Herrmann, H.; Silberhorn, C.

    2017-04-01

    We present the generation of continuous-wave optical squeezing from a titanium-in-diffused lithium niobate waveguide resonator. We directly measure 2.9 ±0.1 dB of single-mode squeezing, which equates to a produced level of 4.9 ±0.1 dB after accounting for detection losses. This device showcases the current capabilities of this waveguide architecture and precipitates more complicated integrated continuous-wave quantum devices in the continuous-variable regime.

  13. A novel fabrication technique for free-hanging homogeneous polymeric cantilever waveguides

    DEFF Research Database (Denmark)

    Nordström, M.; Calleja, M.; Hübner, Jörg

    2008-01-01

    We present a novel bonding technique developed for the fabrication of a cantilever-based biosensing system with integrated optical read-out. The read-out mechanism is based on single-mode waveguides fabricated monolithically in SU-8. For optimal operation of the read-out mode, the cantilever...

  14. Mode-selective wavelength conversion based on four-wave mixing in a multimode silicon waveguide

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan

    2014-01-01

    to phase mismatch. A two-mode division multiplexing circuit with tapered directional coupler based (de)multiplexers and a multimode waveguide is designed and fabricated for this application. Experimental results show clear eye-diagrams and moderate power penalties for the wavelength conversion of both...

  15. 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.

  16. Coupled-resonator optical waveguides

    DEFF Research Database (Denmark)

    Raza, Søren; Grgic, Jure; Pedersen, Jesper Goor

    2010-01-01

    Coupled-resonator optical waveguides hold potential for slow-light propagation of optical pulses. The dispersion properties may adequately be analyzed within the framework of coupled-mode theory. We extend the standard coupled-mode theory for such structures to also include complex-valued paramet......Coupled-resonator optical waveguides hold potential for slow-light propagation of optical pulses. The dispersion properties may adequately be analyzed within the framework of coupled-mode theory. We extend the standard coupled-mode theory for such structures to also include complex...

  17. Multi reflection of Lamb wave emission in an acoustic waveguide sensor.

    Science.gov (United States)

    Schmitt, Martin; Olfert, Sergei; Rautenberg, Jens; Lindner, Gerhard; Henning, Bernd; Reindl, Leonhard Michael

    2013-02-27

    Recently, an acoustic waveguide sensor based on multiple mode conversion of surface acoustic waves at the solid-liquid interfaces has been introduced for the concentration measurement of binary and ternary mixtures, liquid level sensing, investigation of spatial inhomogenities or bubble detection. In this contribution the sound wave propagation within this acoustic waveguide sensor is visualized by Schlieren imaging for continuous and burst operation the first time. In the acoustic waveguide the antisymmetrical zero order Lamb wave mode is excited by a single phase transducer of 1 MHz on thin glass plates of 1 mm thickness. By contact to the investigated liquid Lamb waves propagating on the first plate emit pressure waves into the adjacent liquid, which excites Lamb waves on the second plate, what again causes pressure waves traveling inside the liquid back to the first plate and so on. The Schlieren images prove this multi reflection within the acoustic waveguide, which confirms former considerations and calculations based on the receiver signal. With this knowledge the sensor concepts with the acoustic waveguide sensor can be interpreted in a better manner.

  18. Cavity quantum electrodynamics with Anderson-localized modes

    DEFF Research Database (Denmark)

    Sapienza, Luca; Nielsen, Henri Thyrrestrup; Stobbe, Søren

    2010-01-01

    by a factor of 15 on resonance with the Anderson-localized mode, and 94% of the emitted single photons coupled to the mode. Disordered photonic media thus provide an efficient platform for quantum electrodynamics, offering an approach to inherently disorder-robust quantum information devices.......A major challenge in quantum optics and quantum information technology is to enhance the interaction between single photons and single quantum emitters. This requires highly engineered optical cavities that are inherently sensitive to fabrication imperfections. We have demonstrated a fundamentally...... different approach in which disorder is used as a resource rather than a nuisance. We generated strongly confined Anderson-localized cavity modes by deliberately adding disorder to photonic crystal waveguides. The emission rate of a semiconductor quantum dot embedded in the waveguide was enhanced...

  19. An ultrasonic waveguide for nuclear power plants

    International Nuclear Information System (INIS)

    Watkins, R.D.; Gillespie, A.B.; Deighton, M.O.; Pike, R.B.

    1983-01-01

    The value of ultrasonic techniques in nuclear plants is well established. However, in most cases nuclear power plants present an extremely hostile environment for an ultrasonic transducer. The paper presents a novel technique for introducing an ultrasound into hostile liquid environments using a new form of ultrasonic waveguide. Using this approach, a standard transducer arrangement is sited in a hospitable area and conveys the ultrasound along the guide to the required beam-emission collection position. The design of a single-mode ultrasonic waveguide is described. The ultrasound is conveyed along a stainless steel strip of rectangular cross-section. The transference of energy between the strip and the liquid is achieved through a highly efficient mode-conversion process. This process overcomes the usual problems of mis-match of acoustic impedances of stainless steel and liquids, and also produces a highly collimated beam of ultrasound. Tests of a 10-m-long waveguide using these techniques are described, achieving signal-to-noise ratios in the region of 40 dB. (author)

  20. 1.9 W continuous-wave single transverse mode emission from 1060 nm edge-emitting lasers with vertically extended lasing area

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. J., E-mail: jarez.miah@tu-berlin.de; Posilovic, K.; Kalosha, V. P.; Rosales, R.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Kettler, T. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); PBC Lasers GmbH, Hardenbergstr. 36, 10623 Berlin (Germany); Skoczowsky, D. [PBC Lasers GmbH, Hardenbergstr. 36, 10623 Berlin (Germany); Pohl, J.; Weyers, M. [Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany)

    2014-10-13

    High-brightness edge-emitting semiconductor lasers having a vertically extended waveguide structure emitting in the 1060 nm range are investigated. Ridge waveguide (RW) lasers with 9 μm stripe width and 2.64 mm cavity length yield highest to date single transverse mode output power for RW lasers in the 1060 nm range. The lasers provide 1.9 W single transverse mode optical power under continuous-wave (cw) operation with narrow beam divergences of 9° in lateral and 14° (full width at half maximum) in vertical direction. The beam quality factor M{sup 2} is less than 1.9 up to 1.9 W optical power. A maximum brightness of 72 MWcm{sup −2}sr{sup −1} is obtained. 100 μm wide and 3 mm long unpassivated broad area lasers provide more than 9 W optical power in cw operation.

  1. Broadband single-transverse-mode fluorescence sources based on ribs fabricated in pulsed laser deposited Ti: sapphire waveguides

    NARCIS (Netherlands)

    Grivas, C.; May-Smith, T.C.; Shepherd, D.P.; Eason, R.W.; Pollnau, Markus; Jelinek, M.

    2004-01-01

    Active rib waveguides with depths and widths varying from 3 to 5 μm and from 9 to 24 μm, respectively, have been structured by $Ar^{+}$-beam etching in pulsed laser deposited Ti:sapphire layers. Losses in the channel structures were essentially at the same levels as the unstructured planar waveguide

  2. MHD waveguides in space plasma

    International Nuclear Information System (INIS)

    Mazur, N. G.; Fedorov, E. N.; Pilipenko, V. A.

    2010-01-01

    The waveguide properties of two characteristic formations in the Earth's magnetotail-the plasma sheet and the current (neutral) sheet-are considered. The question of how the domains of existence of different types of MHD waveguide modes (fast and slow, body and surface) in the (k, ω) plane and their dispersion properties depend on the waveguide parameters is studied. Investigation of the dispersion relation in a number of particular (limiting) cases makes it possible to obtain a fairly complete qualitative pattern of all the branches of the dispersion curve. Accounting for the finite size of perturbations across the wave propagation direction reveals new additional effects such as a change in the critical waveguide frequencies, the excitation of longitudinal current at the boundaries of the sheets, and a change in the symmetry of the fundamental mode. Knowledge of the waveguide properties of the plasma and current sheets can explain the occurrence of preferred frequencies in the low-frequency fluctuation spectra in the magnetotail. In satellite observations, the type of waveguide mode can be determined from the spectral properties, as well as from the phase relationships between plasma oscillations and magnetic field oscillations that are presented in this paper.

  3. Interference of guiding modes in 'traffic' circle waveguides composed of dielectric spherical particles

    International Nuclear Information System (INIS)

    Polishchuk, I.Ya.; Gozman, M.I.; Samoylova, O.M.; Burin, A.L.

    2009-01-01

    The interference of guiding polariton modes propagating through the waveguide composed of dielectric spherical particles forming a 'traffic' circle docked by two linear entrance and exit chains is investigated. The dependence of intensity of the polariton wave on the position of the particle on the circle was studied using the multisphere Mie scattering formalism. We show that, if the frequency of light belongs to the pass-band of the circular part of this waveguide, the electromagnetic waves may be considered as two optical beams running along the circle in opposite directions and interfering with each other. Indeed, the obtained intensity behavior can be represented as a simple superposition of two waves propagating along the circle in opposite directions. The applications of this interference are discussed

  4. Graphene Q-switched Yb:KYW planar waveguide laser

    NARCIS (Netherlands)

    Kim, Jun Wan; Choi, Sun Young; Aravazhi, S.; Pollnau, Markus; Griebner, Uwe; Petrov, Valentin; Bae, Sukang; Ahn, Kwang Jun; Yeom, Dong-Il; Rotermund, Fabian

    A diode-pumped Yb:KYW planar waveguide laser, single-mode Q-switched by evanescent-field interaction with graphene, is demonstrated for the first time. Few-layer graphene grown by chemical vapor deposition is transferred onto the top of a guiding layer, which initiates stable Q-switched operation in

  5. High-current electron beam coupling to hybrid waveguide and plasma modes in a dielectric Cherenkov maser with a plasma layer

    International Nuclear Information System (INIS)

    Shlapakovski, Anatoli S.

    2002-01-01

    The linear theory of a dielectric Cherenkov maser with a plasma layer has been developed. The dispersion relation has been derived for the model of infinitely thin, fully magnetized, monoenergetic hollow electron beam, in the axisymmetric case. The results of the numerical solution of the dispersion relation and the analysis of the beam coupling to hybrid waves, both hybrid waveguide and hybrid plasma modes, are presented. For the hybrid waveguide mode, spatial growth rate dependences on frequency at different plasma densities demonstrate improvement in gain for moderate densities, but strong shifting the amplification band and narrowing the bandwidth. For the hybrid plasma mode, the case of mildly relativistic, 200-250 keV beams is of interest, so that the wave phase velocity is just slightly greater than the speed of light in a dielectric medium. It has been shown that depending on beam and plasma parameters, the hybrid plasma mode can be separated from the hybrid waveguide mode, or be coupled to it through the beam resulting in strong gain increase, or exhibit a flat gain vs frequency dependence over a very broad band. The parameters, at which the -3 dB bandwidth calculated for 30 dB peak gain exceeds an octave, have been found

  6. Influence of disorder on electromagnetically induced transparency in chiral waveguide quantum electrodynamics

    Science.gov (United States)

    Mirza, Imran M.; Schotland, John C.

    2018-05-01

    We study single photon transport in a one-dimensional disordered lattice of three-level atoms coupled to an optical waveguide. In particular, we study atoms of \\Lambda-type that are capable of exhibiting electromagnetically induced transparency (EIT) and separately consider disorder in the atomic positions and transition frequencies. We mainly address the question of how preferential emission into waveguide modes (chirality) can influence the formation of spatially localized states. Our work has relevance to experimental studies of cold atoms coupled to nanoscale waveguides and has possible applications to quantum communications.

  7. Light-emitting waveguide-plasmon polaritions

    NARCIS (Netherlands)

    Rodriguez, S.R.K.; Murai, S.; Verschuuren, M.A.; Gómez Rivas, J.

    2012-01-01

    We demonstrate the generation of light in an optical waveguide strongly coupled to a periodic array of metallic nanoantennas. This coupling gives rise to hybrid waveguide-plasmon polaritons (WPPs), which undergo a transmutation from plasmon to waveguide mode and vice versa as the eigenfrequency

  8. Ultra-compact broadband higher order-mode pass filter fabricated in a silicon waveguide for multimode photonics

    DEFF Research Database (Denmark)

    Guan, Xiaowei; Ding, Yunhong; Frandsen, Lars Hagedorn

    2015-01-01

    An ultra-compact and broadband higher order-mode pass filter in a 1D photonic crystal silicon waveguide is proposed and experimentally demonstrated. The photonic crystal is designed for the lower order mode to work in the photonic band gap, while the higher order mode is located in the air band....... Consequently, light on the lower order mode is prohibited to pass through the filter, while light on a higher order mode can be converted to a Bloch mode in the photonic crystal and pass through the filter with low insertion loss. As an example, we fabricate a similar to 15-mu m-long first-order-mode pass...

  9. Fundamental losses in planar Bragg waveguides

    NARCIS (Netherlands)

    Vinogradov, A. V.; Mitrofanov, A. N.; Popov, A. V.; Fedin, M. A.

    2007-01-01

    This paper considers a planar Bragg waveguide. The guided modes and their dissipation due to the fundamental absorption are described. In the interacting-wave approximation, an analytical relation between the characteristics of the modes and parameters of the Bragg-waveguide geometry was

  10. Analytical solutions of coupled-mode equations for microring ...

    Indian Academy of Sciences (India)

    equivalent to waveguide and single microring coupled system. The 3 × 3 coupled system is equivalent to waveguide and double microring coupled system. In this paper, we adopt a novel approach for obtaining coupled-mode equations for linearly distributed and circularly distributed multiwaveguide systems with different ...

  11. Tunable THz notch filter with a single groove inside parallel-plate waveguides.

    Science.gov (United States)

    Lee, Eui Su; Jeon, Tae-In

    2012-12-31

    A single groove in a parallel-plate waveguide (PPWG) has been applied to a tunable terahertz (THz) notch filter with a transverse-electromagnetic (TEM) mode. When the air gap between the metal plates of the PPWG is controlled from 60 to 240 μm using a motor controlled translation stage or a piezo-actuator, the resonant frequency of the notch filter is changed from 1.75 up to 0.62 THz, respectively. Therefore, the measured tunable sensitivity of the notch filter increases to 6.28 GHz/μm. The measured resonant frequencies were found to be in good agreement with the calculation using an effective groove depth. Using a finite-difference time-domain (FDTD) simulation, we also demonstrate that the sensitivity of a THz microfluidic sensor can be increased via a small air gap, a narrow groove width, and a deep groove depth.

  12. Waveguides with Absorbing Boundaries: Nonlinearity Controlled by an Exceptional Point and Solitons

    Science.gov (United States)

    Midya, Bikashkali; Konotop, Vladimir V.

    2017-07-01

    We reveal the existence of continuous families of guided single-mode solitons in planar waveguides with weakly nonlinear active core and absorbing boundaries. Stable propagation of TE and TM-polarized solitons is accompanied by attenuation of all other modes, i.e., the waveguide features properties of conservative and dissipative systems. If the linear spectrum of the waveguide possesses exceptional points, which occurs in the case of TM polarization, an originally focusing (defocusing) material nonlinearity may become effectively defocusing (focusing). This occurs due to the geometric phase of the carried eigenmode when the surface impedance encircles the exceptional point. In its turn, the change of the effective nonlinearity ensures the existence of dark (bright) solitons in spite of focusing (defocusing) Kerr nonlinearity of the core. The existence of an exceptional point can also result in anomalous enhancement of the effective nonlinearity. In terms of practical applications, the nonlinearity of the reported waveguide can be manipulated by controlling the properties of the absorbing cladding.

  13. Topology-optimized silicon photonic wire mode (de)multiplexer

    DEFF Research Database (Denmark)

    Frellsen, Louise Floor; Frandsen, Lars Hagedorn; Ding, Yunhong

    2015-01-01

    We have designed and for the first time experimentally verified a topology optimized mode (de)multiplexer, which demultiplexes the fundamental and the first order mode of a double mode photonic wire to two separate single mode waveguides (and multiplexes vice versa). The device has a footprint...

  14. Single Mode SU8 Polymer Based Mach-Zehnder Interferometer for Bio-Sensing Application

    Science.gov (United States)

    Boiragi, Indrajit; Kundu, Sushanta; Makkar, Roshan; Chalapathi, Krishnamurthy

    2011-10-01

    This paper explains the influence of different parameters to the sensitivity of an optical waveguide Mach-Zehnder Interferometer (MZI) for real time detection of biomolecules. The sensing principle is based on the interaction of evanescence field with the biomolecules that get immobilized on sensing arm. The sensitivity has been calculated by varying the sensing window length, wavelength and concentration of bio-analyte. The maximum attainable sensitivity for the preferred design is the order of 10-8 RIU at 840 nm wavelength with a sensing window length of 1cm. All the simulation work has been carried out with Opti-BPMCAD for the optimization of MZI device parameters. The SU8 polymers are used as a core and clad material to fabricate the waveguide. The refractive index of cladding layer is optimized by varying the curing temperature for a fixed time period and the achieved index difference between core and clad is Δn = 0.0151. The fabricated MZI device has been characterized with LASER beam profiler at 840 nm wavelength. This study demonstrates the effectiveness of the different parameter to the sensitivity of a single mode optical waveguide Mach-Zehnder Interferometer for bio-sensing application.

  15. A novel fabrication technique for free-hanging homogeneous polymeric cantilever waveguides

    International Nuclear Information System (INIS)

    Nordström, Maria; Hübner, Jörg; Boisen, Anja; Calleja, Montserrat

    2008-01-01

    We present a novel bonding technique developed for the fabrication of a cantilever-based biosensing system with integrated optical read-out. The read-out mechanism is based on single-mode waveguides fabricated monolithically in SU-8. For optimal operation of the read-out mode, the cantilever waveguides should be homogenous and this bonding technique ensures free-hanging cantilevers that are surrounded by the same material for bottom and top claddings. The bonding step is necessary because SU-8 is a negative resist where free-hanging structures cannot be fabricated directly. This paper gives details on the processing aspects and the parameters of the fabrication steps

  16. Multi-mode interference revealed by two photon absorption in silicon rich SiO2 waveguides

    International Nuclear Information System (INIS)

    Manna, S.; Ramiro-Manzano, F.; Mancinelli, M.; Turri, F.; Pavesi, L.; Ghulinyan, M.; Pucker, G.

    2015-01-01

    Photoluminescence (PL) from Si nanocrystals (NCs) excited by two-photon absorption (TPA) has been observed in Si nanocrystal-based waveguides fabricated by plasma enhanced chemical vapor deposition. The TPA excited photoluminescence emission resembles the one-photon excited photoluminescence arising from inter-band transitions in the quantum confined Si nanocrystals. By measuring the non-linear transmission of waveguides, a large TPA coefficient of β up to 10 −8  cm/W has been measured at 1550 nm. These values of β depend on the Si NCs size and are two orders of magnitude larger than the bulk silicon value. Here, we propose to use the TPA excited visible PL emission as a tool to map the spatial intensity profile of the 1550 nm propagating optical modes in multimode waveguides. In this way, multimode interference has been revealed experimentally and confirmed through a finite element simulation

  17. Energy flow in photonic crystal waveguides

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Dridi, Kim

    2000-01-01

    Theoretical and numerical investigations of energy flow in photonic crystal waveguides made of line defects and branching points are presented. It is shown that vortices of energy flow may occur, and the net energy flow along: the line defect is described via the effective propagation velocity....... Single-mode and multimode operations are studied, and dispersion relations are computed for different waveguide widths. Both strong positive, strong negative, and zero dispersion an possible. It is shown that geometric parameters such as the nature of the lattice, the line defect orientation, the defect...... width, and the branching-point geometry have a significant influence on the electrodynamics. These are important issues for the fabrication of photonic crystal structures....

  18. Experiences with rectangular waveguide

    International Nuclear Information System (INIS)

    Beltran, J.; Sepulveda, J. J.; Navarro, E. A.

    2000-01-01

    A simple and didactic experimental arrangement is presented to show wave propagation along a structure with translational symmetry, particularly the rectangular waveguide. Parameters of this waveguide as cutoff frequency, guide wavelength and field distribution of fundamental mode can be measured. For this purpose a large paralelepipedical waveguide structure is designed and built, its dimensions can be varied in order to change its parameters. (Author) 9 refs

  19. Directly UV written silica-on-silicon planar waveguides with low insertion loss

    DEFF Research Database (Denmark)

    Zauner, Dan; Svalgaard, Mikael; Kristensen, Martin

    1998-01-01

    in waveguide geometry, and excellent control of the refractive index step. Direct UV writing of waveguides became a realistic alternative to other fabrication methods when propagation losses below 0.2 dB/cm were reported in single-mode waveguides. However, the coupling loss to optical fibers remained high......, typically 1.8 dB/facet, which is significantly more than that obtained with other techniques. In this paper we present results in which the coupling loss to optical fibers has been lowered substantially. In addition, the glass photosensitivity has been increased, thus permitting shorter fabrication times......The photosensitive properties of germanosilica may be utilized to directly induce waveguide patterns into thin-film structures using ultraviolet (UV) light. The advantages of fabricating planar waveguides with UV light include the absence of photolithography and reactive ion etching, flexibility...

  20. Two-mode PLC-based mode multi/demultiplexer for mode and wavelength division multiplexed transmission.

    Science.gov (United States)

    Hanzawa, Nobutomo; Saitoh, Kuimasa; Sakamoto, Taiji; Matsui, Takashi; Tsujikawa, Kyozo; Koshiba, Masanori; Yamamoto, Fumihiko

    2013-11-04

    We proposed a PLC-based mode multi/demultiplexer (MUX/DEMUX) with an asymmetric parallel waveguide for mode division multiplexed (MDM) transmission. The mode MUX/DEMUX including a mode conversion function with an asymmetric parallel waveguide can be realized by matching the effective indices of the LP(01) and LP(11) modes of two waveguides. We report the design of a mode MUX/DEMUX that can support C-band WDM-MDM transmission. The fabricated mode MUX/DEMUX realized a low insertion loss of less than 1.3 dB and high a mode extinction ratio that exceeded 15 dB. We used the fabricated mode MUX/DEMUX to achieve a successful 2 mode x 4 wavelength x 10 Gbps transmission over a 9 km two-mode fiber with a penalty of less than 1 dB.

  1. A Hybrid Circuit for Spoof Surface Plasmons and Spatial Waveguide Modes to Reach Controllable Band-Pass Filters.

    Science.gov (United States)

    Zhang, Qian; Zhang, Hao Chi; Wu, Han; Cui, Tie Jun

    2015-11-10

    We propose a hybrid circuit for spoof surface plasmon polaritons (SPPs) and spatial waveguide modes to develop new microwave devices. The hybrid circuit includes a spoof SPP waveguide made of two anti-symmetric corrugated metallic strips and a traditional substrate integrated waveguide (SIW). From dispersion relations, we show that the electromagnetic waves only can propagate through the hybrid circuit when the operating frequency is less than the cut-off frequency of the SPP waveguide and greater than the cut-off frequency of SIW, generating efficient band-pass filters. We demonstrate that the pass band is controllable in a large range by designing the geometrical parameters of SPP waveguide and SIW. Full-wave simulations are provided to show the large adjustability of filters, including ultra wideband and narrowband filters. We fabricate a sample of the new hybrid device in the microwave frequencies, and measurement results have excellent agreements to numerical simulations, demonstrating excellent filtering characteristics such as low loss, high efficiency, and good square ratio. The proposed hybrid circuit gives important potential to accelerate the development of plasmonic integrated functional devices and circuits in both microwave and terahertz frequencies.

  2. Devices Based on Parallel-Plate Waveguides for Terahertz Applications

    Science.gov (United States)

    Reichel, Kimberly S.

    a PPWG. EOT is an effect where at a particular frequency 100% of the light is transmitted through an array of holes with diameters much smaller than the wavelength. We demonstrate that the output resonant frequency depends strongly on the input mode of the waveguide, where excitation with the TEM waveguide mode mimics EOT in a 2D array in free space, while the TE1 waveguide mode is vastly different. Through this disparity of outcomes between the two different waveguide excitation modes, we can better understand the resonant transmission process. We show that the surface plasmon theoretical description is invalid for the TE1 resonance, and instead use impedance matching to properly predict the resonances in both TE1 and TEM. Additionally, we show that the device can be used as a tunable filter fat THz frequencies by simply changing the separation between the two waveguide plates. Third, we demonstrate a THz variable power splitter based on a PPWG T-junction excited by the TE1 waveguide mode. By integrating a small triangular septum into the waveguide plate, we are able to direct the THz light down to either one of the two output channels with precise control over the coupling ratio between the waveguide outputs. We find good agreement between experiment and simulation in both amplitude and phase. We show that the coupling ratio varies exponentially with the septum translation offset and that nearly 100% transmission can be achieved. The splitter operates over almost the entire range in which the waveguide is single mode, providing a sensitive and broadband method for power splitting. By incorporating our innovations along the already propagating path of THz waves inside a waveguide, we establish multiple functional capabilities into one universal platform. The hope of this work is that these devices will ultimately serve as fundamental building blocks to make everyday THz applications a reality.

  3. Experimental realization of highly efficient broadband coupling of single quantum dots to a photonic crystal waveguide

    DEFF Research Database (Denmark)

    Lund-Hansen, Toke; Stobbe, Søren; Julsgaard, Brian

    2008-01-01

    We present time-resolved spontaneous emission measurements of single quantum dots embedded in photonic crystal waveguides. Quantum dots that couple to a photonic crystal waveguide are found to decay up to 27 times faster than uncoupled quantum dots. From these measurements -factors of up to 0.89 ...... taking into account that the light-matter coupling is strongly enhanced due to the significant slow-down of light in the photonic crystal waveguides....

  4. Synthesis of the Thickness Profile of the Waveguide Layer of the Thin Film Generalized Waveguide Luneburg Lens

    Directory of Open Access Journals (Sweden)

    Ayryan E.A.

    2016-01-01

    Full Text Available A local variation in the thickness of the waveguide layer of integrated optics waveguide causes a local decrease of phase velocity, and hence bending of rays and of the wave front. The relationship of the waveguide layer thickness profile h (y, z with the distribution of the effective refractive index of the waveguide β (y, z is described in terms of a particular model of waveguide solutions of the Maxwell equations. In the model of comparison waveguides the support of the thickness irregularity of the waveguide layer Δh coincides with the support of inhomogeneity of the effective refractive index Δβ. A more adequate but more cumbersome model of the adiabatic waveguide modes allows them to mismatch supp Δh ⊃ supp Δβ. In this paper, we solve the problem of the Δh reconstruction on the base of given Δβ of the thin film generalized waveguide Luneburg lens in a model of adiabatic waveguide modes. The solution is found in the form of a linear combination of Gaussian exponential functions and in the form of a cubic spline for the cylindrically symmetric Δh (r and in the form of a cubic spline for Δβ (r.

  5. Ultra-wideband and high-gain parametric amplification in telecom wavelengths with an optimally mode-matched PPLN waveguide.

    Science.gov (United States)

    Sua, Yong Meng; Chen, Jia-Yang; Huang, Yu-Ping

    2018-06-15

    We report a wideband optical parametric amplification (OPA) over 14 THz covering telecom S, C, and L bands with observed maximum parametric gain of 38.3 dB. The OPA is realized through cascaded second-harmonic generation and difference-frequency generation (cSHG-DFG) in a 2 cm periodically poled LiNbO 3 (PPLN) waveguide. With tailored cross section geometry, the waveguide is optimally mode matched for efficient cascaded nonlinear wave mixing. We also identify and study the effect of competing nonlinear processes in this cSHG-DFG configuration.

  6. Quasi-TEM electromagnetic modes of a plasma waveguide with a nonsimply connected cross section in an external magnetic field

    International Nuclear Information System (INIS)

    Kartashov, I. N.; Kuzelev, M. V.

    2014-01-01

    Electromagnetic modes of a plasma waveguide with a nonsimply connected cross section in an external magnetic field are investigated. The existence of quasi-TEM modes in a finite-strength magnetic field is demonstrated. It is shown that, in the limits of infinitely strong and zero magnetic fields, this mode transforms into a true TEM mode. The possibility of excitation of such modes by an electron beam in the regime of the anomalous Doppler effect is analyzed

  7. Enhanced Raman scattering assisted by ultrahigh order modes of the double metal cladding waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tian; Huang, Liming; Jin, Yonglong; Fang, Jinghuai, E-mail: cyin.phys@gmail.com, E-mail: fjhuai@ntu.edu.cn [Physics Department, Nantong University, No. 9, Seyuan Road, Nantong, Jiangsu 226007 (China); Yin, Cheng, E-mail: cyin.phys@gmail.com, E-mail: fjhuai@ntu.edu.cn [Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology, Hohai University, Changzhou 213022 (China); Huang, Meizhen [Department of Instrument Science and Engineering, Shanghai Jiaotong University, No. 800, DongChuan Road, Shanghai 200240 (China)

    2014-10-20

    Distinguished from the usual strategy to enhance the Raman scattering such as creating hot spots in the surface-enhanced Raman scattering, this paper takes a quite different approach based on the double metal cladding waveguide. The target analyte is located in the guiding layer of sub-millimeter scale, where several ultrahigh order modes with high intensity are simultaneously excited via a focused laser beam. The experimental setup is simple, and both simulation and experimental results confirm the enhancement mechanism of these oscillating modes. Other appealing features include the large detection area and the ability to excite guided modes via both polarizations. This scheme can be applied to large molecules detection and readily integrated with other Raman enhancement techniques.

  8. Development of a novel rf waveguide vacuum valve

    CERN Document Server

    Grudiev, A

    2006-01-01

    The development of a novel rf waveguide vacuum valve is presented. The rf design is based on the use of TE0n modes of circular waveguides. In the device, the TE01 mode at the input is converted into a mixture of several TE0n modes which provide low-loss rf power transmission across the vacuum valve gap, these modes are then converted back into the TE01 mode at the output. There are a number of advantages associated with the absence of surface fields in the region of the valve: • Possibility to use commercially available vacuum valves equipped with two specially designed mode converter sections. • No necessity for an rf contact between these two sections. • Increased potential for high power rf transmission. This technology can be used for all frequencies for which vacuum waveguides are used. In rectangular waveguides, mode converters from the operating mode into the TE01 mode and back again are necessary. Experimental results for the 30 GHz valves developed for the CLIC Test Facility 3 (CTF3) a...

  9. Polarization effects in silicon-clad optical waveguides

    Science.gov (United States)

    Carson, R. F.; Batchman, T. E.

    1984-01-01

    By changing the thickness of a semiconductor cladding layer deposited on a planar dielectric waveguide, the TE or TM propagating modes may be selectively attenuated. This polarization effect is due to the periodic coupling between the lossless propagating modes of the dielectric slab waveguide and the lossy modes of the cladding layer. Experimental tests involving silicon claddings show high selectivity for either polarization.

  10. Gap Surface Plasmon Waveguide Analysis

    DEFF Research Database (Denmark)

    Nielsen, Michael Grøndahl; Bozhevolnyi, Sergey I.

    2014-01-01

    Plasmonic waveguides supporting gap surface plasmons (GSPs) localized in a dielectric spacer between metal films are investigated numerically and the waveguiding properties at telecommunication wavelengths are presented. Especially, we emphasize that the mode confinement can advantageously...

  11. Schroedinger covariance states in anisotropic waveguides

    International Nuclear Information System (INIS)

    Angelow, A.; Trifonov, D.

    1995-03-01

    In this paper Squeezed and Covariance States based on Schroedinger inequality and their connection with other nonclassical states are considered for particular case of anisotropic waveguide in LiNiO 3 . Here, the problem of photon creation and generation of squeezed and Schroedinger covariance states in optical waveguides is solved in two steps: 1. Quantization of electromagnetic field is provided in the presence of dielectric waveguide using normal-mode expansion. The photon creation and annihilation operators are introduced, expanding the solution A-vector(r-vector,t) in a series in terms of the Sturm - Liouville mode-functions. 2. In terms of these operators the Hamiltonian of the field in a nonlinear waveguide is derived. For such Hamiltonian we construct the covariance states as stable (with nonzero covariance), which minimize the Schroedinger uncertainty relation. The evolutions of the three second momenta of q-circumflex j and p-circumflex j are calculated. For this Hamiltonian all three momenta are expressed in terms of one real parameters s only. It is found out how covariance, via this parameter s, depends on the waveguide profile n(x,y), on the mode-distributions u-vector j (x,y), and on the waveguide phase mismatching Δβ. (author). 37 refs

  12. Zero-Dispersion Slow Light with Wide Bandwidth in Photonic Crystal Coupled Waveguides

    International Nuclear Information System (INIS)

    Xiao-Yu, Mao; Geng-Yan, Zhang; Yi-Dong, Huang; Wei, Zhang; Jiang-De, Peng

    2008-01-01

    By introducing an adjustment waveguide besides the incident waveguide, zero-dispersion slow light with wide bandwidth can be realized due to anticrossing of the incident waveguide mode and the adjustment waveguide mode. The width of the adjustment waveguide (W 2 ) and the hole radii of the coupling region (r') will change the dispersion of incident waveguide mode. Theoretical investigation reveals that zero dispersion at various low group velocity ν g in incident waveguide can be achieved. In particular, proper W 2 and r' can lead to the lowest ν g of 0.0085c at 1550 nm with wide bandwidth of 202 GHz for zero dispersion

  13. High-Q energy trapping of temperature-stable shear waves with Lamé cross-sectional polarization in a single crystal silicon waveguide

    Science.gov (United States)

    Tabrizian, R.; Daruwalla, A.; Ayazi, F.

    2016-03-01

    A multi-port electrostatically driven silicon acoustic cavity is implemented that efficiently traps the energy of a temperature-stable eigen-mode with Lamé cross-sectional polarization. Dispersive behavior of propagating and evanescent guided waves in a ⟨100⟩-aligned single crystal silicon waveguide is used to engineer the acoustic energy distribution of a specific shear eigen-mode that is well known for its low temperature sensitivity when implemented in doped single crystal silicon. Such an acoustic energy trapping in the central region of the acoustic cavity geometry and far from substrate obviates the need for narrow tethers that are conventionally used for non-destructive and high quality factor (Q) energy suspension in MEMS resonators; therefore, the acoustically engineered waveguide can simultaneously serve as in-situ self-oven by passing large uniformly distributed DC currents through its body and without any concern about perturbing the mode shape or deforming narrow supports. Such a stable thermo-structural performance besides large turnover temperatures than can be realized in Lamé eigen-modes make this device suitable for implementation of ultra-stable oven-controlled oscillators. 78 MHz prototypes implemented in arsenic-doped single crystal silicon substrates with different resistivity are transduced by in- and out-of-plane narrow-gap capacitive ports, showing high Q of ˜43k. The low resistivity device shows an overall temperature-induced frequency drift of 200 ppm over the range of -20 °C to 80 °C, which is ˜15× smaller compared to overall frequency drift measured for the similar yet high resistivity device in the same temperature range. Furthermore, a frequency tuning of ˜2100 ppm is achieved in high resistivity device by passing 45 mA DC current through its body. Continuous operation of the device under such a self-ovenizing current over 10 days did not induce frequency instability or degradation in Q.

  14. Simulation of light propagation in the thin-film waveguide lens

    Science.gov (United States)

    Malykh, M. D.; Divakov, D. V.; Sevastianov, L. A.; Sevastianov, A. L.

    2018-04-01

    In this paper we investigate the solution of the problem of modeling the propagation of electromagnetic radiation in three-dimensional integrated optical structures, such as waveguide lenses. When propagating through three-dimensional waveguide structures the waveguide modes can be hybridized, so the mathematical model of their propagation must take into account the connection of TE- and TM-mode components. Therefore, an adequate consideration of hybridization of the waveguide modes is possible only in vector formulation of the problem. An example of three-dimensional structure that hybridizes waveguide modes is the Luneburg waveguide lens, which also has focusing properties. If the waveguide lens has a radius of the order of several tens of wavelengths, its variable thickness at distances of the order of several wavelengths is almost constant. Assuming in this case that the electromagnetic field also varies slowly in the direction perpendicular to the direction of propagation, one can introduce a small parameter characterizing this slow varying and decompose the solution in powers of the small parameter. In this approach, in the zeroth approximation, scalar diffraction problems are obtained, the solution of which is less resource-consuming than the solution of vector problems. The calculated first-order corrections of smallness describe the connection of TE- and TM-modes, so the solutions obtained are weakly-hybridized modes. The formulation of problems and methods for their numerical solution in this paper are based on the authors' research on waveguide diffraction on a lens in a scalar formulation.

  15. Waveguiding with surface plasmon polaritons

    DEFF Research Database (Denmark)

    Han, Zhanghua; Bozhevolnyi, Sergey I.

    2014-01-01

    the diffraction limit, i.e., on the nanoscale, while enhancing local field strengths by several orders of magnitude. This unique feature of SPP modes along with ever increasing demands for miniaturization of photonic components and circuits generates an exponentially growing interest to SPP-mediated radiation...... guiding and SPP-based waveguide components. Here we review the current status of this rapidly developing field, starting with a brief presentation of main planar SPP modes, and then describing in detail various SPP-based waveguide configurations that ensure two-dimensional mode confinement. Excitation...

  16. Design of nanostrip magnonic crystal waveguides with a single magnonic band gap

    International Nuclear Information System (INIS)

    Wang, Qi; Zhong, Zhiyong; Jin, Lichuan; Tang, Xiaoli; Bai, Feiming; Zhang, Huaiwu; Beach, Geoffrey S.D.

    2013-01-01

    A novel planar structure of magnonic-crystal waveguide (MCW) with periodic rectangular-shaped holes embedded in a magnetic nanostrip film was designed. The effects of the distance between rectangular-shaped holes in the width direction of MCW on magnonic band structures were studied by micromagnetic simulations. The results show that a MCW with a single magnonic band gap can be obtained by adjusting the distance to meet the condition of Bragg reflection of spin waves in the width direction of MCW. Moreover, the center frequency and width of magnonic gap can be regulated by changing the period and length of rectangular-shaped holes. - Highlights: • Design a novel planar structure of magnonic-crystal waveguide. • The physical origin of a single magnonic band gap. • Study of the center frequency and width of magnonic gap

  17. Graphene antidot lattice waveguides

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Gunst, Tue; Markussen, Troels

    2012-01-01

    We introduce graphene antidot lattice waveguides: nanostructured graphene where a region of pristine graphene is sandwiched between regions of graphene antidot lattices. The band gaps in the surrounding antidot lattices enable localized states to emerge in the central waveguide region. We model...... the waveguides via a position-dependent mass term in the Dirac approximation of graphene and arrive at analytical results for the dispersion relation and spinor eigenstates of the localized waveguide modes. To include atomistic details we also use a tight-binding model, which is in excellent agreement...... with the analytical results. The waveguides resemble graphene nanoribbons, but without the particular properties of ribbons that emerge due to the details of the edge. We show that electrons can be guided through kinks without additional resistance and that transport through the waveguides is robust against...

  18. Terraced-heterostructure large-optical-cavity AlGaAs diode laser - A new type of high-power CW single-mode device

    Science.gov (United States)

    Botez, D.; Connolly, J. C.

    1982-01-01

    A new terraced lateral wave confining structure is obtained by liquid phase epitaxy over channeled substrates misoriented perpendicular to the channels' direction. Single spatial and longitudinal mode CW operation is achieved to 50 mW from one facet, in large spot sizes (2 x 7.5 micron, 1/e squared points in intensity) and narrow beams (6 deg x 23 deg), full width half-power). At 70 C ambient temperature CW lasing is obtained to 15 mW from one facet. Weak mode confinement in an asymmetric lateral waveguides provides discrimination against high-order mode oscillation.

  19. Position dependent spin wave spectrum in nanostrip magnonic waveguides

    International Nuclear Information System (INIS)

    Wang, Qi; Zhang, Huaiwu; Ma, Guokun; Liao, Yulong; Zhong, Zhiyong; Zheng, Yun

    2014-01-01

    The dispersion curves of propagating spin wave along different positions in nanostrip magnonic waveguides were studied by micromagnetic simulation. The results show that the modes of spin wave in the nanostrip magnonic waveguide are dependent on the position and the weak even modes of spin wave are excited even by symmetric excitation fields in a nanostrip magnonic waveguide. The reasons of the position dependent dispersion curve are explained by associating with geometrical confinement in the nanostrip magnonic waveguide

  20. Finite-element modeling of spontaneous emission of a quantum emitter at nanoscale proximity to plasmonic waveguides

    DEFF Research Database (Denmark)

    Chen, Yuntian; Nielsen, Torben Roland; Gregersen, Niels

    2010-01-01

    of the plasmonic waveguide can be arbitrary. The fraction of the energy coupled to the plasmonic mode can be calculated exactly, which can be used to determine the efficiency with which single optical plasmons are generated. We apply our numerical method to calculate the coupling of a quantum emitter......We develop a self-consistent finite-element method to quantitatively study spontaneous emission from emitters in nanoscale proximity of plasmonic waveguides. In the model, it is assumed that only one guided mode is dominatingly excited by the quantum emitter, while the cross section...

  1. Analysis and synthesis of (SAR) waveguide phased array antennas

    Science.gov (United States)

    Visser, H. J.

    1994-02-01

    This report describes work performed due to ESA contract No. 101 34/93/NL/PB. Started is with a literature study on dual polarized waveguide radiators, resulting in the choice for the open ended square waveguide. After a thorough description of the mode matching infinite waveguide array analysis method - including finiteness effects - that forms the basis for all further described analysis and synthesis methods, the accuracy of the analysis software is validated by comparison with measurements on two realized antennas. These antennas have centered irises in the waveguide apertures and a dielectric wide angle impedance matching sheet in front of the antenna. A synthesis method, using simulated annealing and downhill simplex, is described next and different antenna designs, based on the analysis of a single element in an infinite array environment, are presented. Next, designs of subarrays are presented. Shown is the paramount importance of including the array environment in the design of a subarray. A microstrip patch waveguide exciter and subarray feeding network are discussed and the depth of the waveguide radiator is estimated. Chosen is a rectangular grid array with waveguides of 2.5 cm depth without irises and without dielectric sheet, grouped in linear 8 elements subarrays.

  2. Copper nanorod array assisted silicon waveguide polarization beam splitter.

    Science.gov (United States)

    Kim, Sangsik; Qi, Minghao

    2014-04-21

    We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology.

  3. Formation of discrete solitons as a function of waveguide array geometry under the well-confined mode condition

    International Nuclear Information System (INIS)

    Vergara-Betancourt, A; Martí-Panameño, E; Luis-Ramos, A; Parada-Alfonso, R

    2013-01-01

    Based on numerical techniques, in this paper, we study light propagation in two types of waveguide arrays. One array contains hexagonal cells, and the second contains honeycomb cells. The waveguides demonstrate the well-confined mode condition and possess Kerr nonlinearity. The mathematical model is based on the modified discrete nonlinear Schrödinger equation, which allows us to evaluate the influence of the array geometry on nonlinear light propagation, primarily the process of discrete soliton formation. The main conclusion involves the role of the coupling length; the greater the coupling length, the lower the power threshold required for discrete soliton formation. (paper)

  4. Numerical simulation of terahertz-wave propagation in photonic crystal waveguide based on sapphire shaped crystal

    International Nuclear Information System (INIS)

    Zaytsev, Kirill I; Katyba, Gleb M; Mukhina, Elena E; Kudrin, Konstantin G; Karasik, Valeriy E; Yurchenko, Stanislav O; Kurlov, Vladimir N; Shikunova, Irina A; Reshetov, Igor V

    2016-01-01

    Terahertz (THz) waveguiding in sapphire shaped single crystal has been studied using the numerical simulations. The numerical finite-difference analysis has been implemented to characterize the dispersion and loss in the photonic crystalline waveguide containing hollow cylindrical channels, which form the hexagonal lattice. Observed results demonstrate the ability to guide the THz-waves in multi-mode regime in wide frequency range with the minimal power extinction coefficient of 0.02 dB/cm at 1.45 THz. This shows the prospectives of the shaped crystals for highly-efficient THz waveguiding. (paper)

  5. Resonator modes and mode dynamics for an external cavity-coupled laser array

    Science.gov (United States)

    Nair, Niketh; Bochove, Erik J.; Aceves, Alejandro B.; Zunoubi, Mohammad R.; Braiman, Yehuda

    2015-03-01

    Employing a Fox-Li approach, we derived the cold-cavity mode structure and a coupled mode theory for a phased array of N single-transverse-mode active waveguides with feedback from an external cavity. We applied the analysis to a system with arbitrary laser lengths, external cavity design and coupling strengths to the external cavity. The entire system was treated as a single resonator. The effect of the external cavity was modeled by a set of boundary conditions expressed by an N-by-N frequency-dependent matrix relation between incident and reflected fields at the interface with the external cavity. The coupled mode theory can be adapted to various types of gain media and internal and external cavity designs.

  6. Micro-concave waveguide antenna for high photon extraction from nitrogen vacancy centers in nanodiamond

    Science.gov (United States)

    Rajasekharan, Ranjith; Kewes, Günter; Djalalian-Assl, Amir; Ganesan, Kumaravelu; Tomljenovic-Hanic, Snjezana; McCallum, Jeffrey C.; Roberts, Ann; Benson, Oliver; Prawer, Steven

    2015-01-01

    The negatively charged nitrogen-vacancy colour center (NV− center) in nanodiamond is an excellent single photon source due to its stable photon generation in ambient conditions, optically addressable nuclear spin state, high quantum yield and its availability in nanometer sized crystals. In order to make practical devices using nanodiamond, highly efficient and directional emission of single photons in well-defined modes, either collimated into free space or waveguides are essential. This is a Herculean task as the photoluminescence of the NV centers is associated with two orthogonal dipoles arranged in a plane perpendicular to the NV defect symmetry axis. Here, we report on a micro-concave waveguide antenna design, which can effectively direct single photons from any emitter into either free space or into waveguides in a narrow cone angle with more than 80% collection efficiency irrespective of the dipole orientation. The device also enhances the spontaneous emission rate which further increases the number of photons available for collection. The waveguide antenna has potential applications in quantum cryptography, quantum computation, spectroscopy and metrology. PMID:26169682

  7. Acoustic multimode interference and self-imaging phenomena realized in multimodal phononic crystal waveguides

    International Nuclear Information System (INIS)

    Zou, Qiushun; Yu, Tianbao; Liu, Jiangtao; Wang, Tongbiao; Liao, Qinghua; Liu, Nianhua

    2015-01-01

    We report an acoustic multimode interference effect and self-imaging phenomena in an acoustic multimode waveguide system which consists of M parallel phononic crystal waveguides (M-PnCWs). Results show that the self-imaging principle remains applicable for acoustic waveguides just as it does for optical multimode waveguides. To achieve the dispersions and replicas of the input acoustic waves produced along the propagation direction, we performed the finite element method on M-PnCWs, which support M guided modes within the target frequency range. The simulation results show that single images (including direct and mirrored images) and N-fold images (N is an integer) are identified along the propagation direction with asymmetric and symmetric incidence discussed separately. The simulated positions of the replicas agree well with the calculated values that are theoretically decided by self-imaging conditions based on the guided mode propagation analysis. Moreover, the potential applications based on this self-imaging effect for acoustic wavelength de-multiplexing and beam splitting in the acoustic field are also presented. (paper)

  8. Coupled-resonator waveguide perfect transport single-photon by interatomic dipole-dipole interaction

    Science.gov (United States)

    Yan, Guo-an; Lu, Hua; Qiao, Hao-xue; Chen, Ai-xi; Wu, Wan-qing

    2018-06-01

    We theoretically investigate single-photon coherent transport in a one-dimensional coupled-resonator waveguide coupled to two quantum emitters with dipole-dipole interactions. The numerical simulations demonstrate that the transmission spectrum of the photon depends on the two atoms dipole-dipole interactions and the photon-atom couplings. The dipole-dipole interactions may change the dip positions in the spectra and the coupling strength may broaden the frequency band width in the transmission spectrum. We further demonstrate that the typical transmission spectra split into two dips due to the dipole-dipole interactions. This phenomenon may be used to manufacture new quantum waveguide devices.

  9. Single-mode fiber laser based on core-cladding mode conversion.

    Science.gov (United States)

    Suzuki, Shigeru; Schülzgen, Axel; Peyghambarian, N

    2008-02-15

    A single-mode fiber laser based on an intracavity core-cladding mode conversion is demonstrated. The fiber laser consists of an Er-doped active fiber and two fiber Bragg gratings. One Bragg grating is a core-cladding mode converter, and the other Bragg grating is a narrowband high reflector that selects the lasing wavelength. Coupling a single core mode and a single cladding mode by the grating mode converter, the laser operates as a hybrid single-mode laser. This approach for designing a laser cavity provides a much larger mode area than conventional large-mode-area step-index fibers.

  10. Rectangular waveguide-to-coplanar waveguide transitions at U-band using e-plane probe and wire bonding

    DEFF Research Database (Denmark)

    Dong, Yunfeng; Johansen, Tom Keinicke; Zhurbenko, Vitaliy

    2016-01-01

    This paper presents rectangular waveguide-to-coplanar waveguide (CPW) transitions at U-band (40–60 GHz) using E-plane probe and wire bonding. The designs of CPWs based on quartz substrate with and without aluminum cover are explained. The single and double layer rectangular waveguide-to-CPW trans......This paper presents rectangular waveguide-to-coplanar waveguide (CPW) transitions at U-band (40–60 GHz) using E-plane probe and wire bonding. The designs of CPWs based on quartz substrate with and without aluminum cover are explained. The single and double layer rectangular waveguide......-to-CPW transitions using E-plane probe and wire bonding are designed. The proposed rectangular waveguide-to-CPW transition using wire bonding can provide 10 GHz bandwidth at U-band and does not require extra CPWs or connections between CPWs and chips. A single layer rectangular waveguide-to-CPW transition using E......-plane probe with aluminum package has been fabricated and measured to validate the proposed transitions. To the authors' best knowledge, this is the first time that a wire bonding is used as a probe for rectangular waveguide-to-CPW transition at U-band....

  11. Emission characteristics of laser and superluminescent diodes with a gradient-index waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Bazarov, A.E.; Garmash, I.A.; Goldobin, I.S.; Eliukhin, V.A.; Pak, G.T.

    1987-05-01

    A study is made of the emission characteristics of laser and superluminescent diodes with gradient-index waveguides based on Al(x)Ga(1-x)As solid solutions, operating in the CW mode at room temperature. The coupling coefficients for a single-mode fiber are 25 and 18 percent for laser and superluminescent diodes, respectively, when an interface device consisting of three microlenses is used. 6 references.

  12. Launching transverse-electric Localized Waves from a circular waveguide

    KAUST Repository

    Salem, Mohamed; Niver, Edip

    2011-01-01

    Axially symmetric transverse electric (TE) modes of a circular waveguide section are used to synthesize the vector TE Localized Wave (LW) field at the open end of the waveguide section. The necessary excitation coefficients of these modes

  13. On the determination of proper modes in waveguides with wall losses

    International Nuclear Information System (INIS)

    Dahlberg, E.

    1977-02-01

    Various attempts at determining the proper modes (propagating with exponential attenuation but without change of form) in a straight waveguide with wall losses are discussed. It appears that for a general cross section a stringent treatment would require a quadruple series expansion along lines indicated by C.C. Johnson in 'Field and wave electrodynamics (McGraw-Hill, 1965). For the most usual cross sections, circular and rectangular, valid derivations can however be made using simpler means. Earlier, incomplete, treatments seem to have caused several widely accepted misconceptions, some of which are discussed. Detailed calculations for a rectangular guide are given in a companion note

  14. Systematic design of loss-engineered slow-light waveguides

    DEFF Research Database (Denmark)

    Wang, Fengwen; Jensen, Jakob Søndergaard; Mørk, Jesper

    2012-01-01

    This paper employs topology optimization to systematically design free-topology loss-engineered slow-light waveguides with enlarged group index bandwidth product (GBP). The propagation losses of guided modes are evaluated by the imaginary part of eigenvalues in complex band structure calculations......, where the scattering losses due to manufacturing imperfections are represented by an edge-related effective dissipation. The loss engineering of slow-light waveguides is realized by minimizing the propagation losses of design modes. Numerical examples illustrate that the propagation losses of free......-topology dispersion-engineered waveguides can be significantly suppressed by loss engineering. Comparisons between fixed- and free-topology loss-engineered waveguides demonstrate that the GBP can be enhanced significantly by the free-topology loss-engineered waveguides with a small increase of the propagation losses....

  15. Effects of design geometry on SU8 polymer waveguides

    Science.gov (United States)

    Holland, Anthony S.; Balkunje, Vishal S.; Mitchell, Arnan; Austin, Michael W.; Raghunathan, Mukund K.; Kostovski, Gorgi

    2005-02-01

    The spin-on photoresist SU8 from MicroChem has a relatively high refractive index (n=1.57 at 1550nm) compared with other polymers. It is stable and has high optical transmission at optical communication wavelengths. In this paper we study rib waveguides fabricated using SU8 as the core layer and thermoset polymers UV15 (n=1.50 at 1550nm) from Master Bond and NOA61 (n=1.54 at 1550nm) from Gentec as the cladding layers. The rib height is varied from 0.3 to 1.7μm high. This is part of the SU8 layer sandwiched between the cladding layers. The waveguides are tested to determine the effects of varying this geometry for single mode optical transmission. The lengths of the waveguides were 1.5 cm to 5 cm.

  16. Bismuth telluride topological insulator nanosheet saturable absorbers for q-switched mode-locked Tm:ZBLAN waveguide lasers

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xiantao; Gross, Simon; Withford, Michael J.; Fuerbach, Alexander [Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) and MQ Photonics Research Centre, Dept. of Physics and Astronomy, Macquarie Univ., NSW (Australia); Zhang, Han; Guo, Zhinan [SZU-NUS Collaborative Innovation Centre for Optoelectronic Science and Technology, Key Lab. of Optoelectronic Devices and Systems of Ministry of Education, College of Optoelectronic Engineering, Shenzhen Univ. (China)

    2016-08-15

    Nanosheets of bismuth telluride (Bi{sub 2}Te{sub 3}), a topological insulator material that exhibits broadband saturable absorption due to its non-trivial Dirac-cone like energy structure, are utilized to generate short pulses from Tm:ZBLAN waveguide lasers. By depositing multiple layers of a carefully prepared Bi{sub 2}Te{sub 3} solution onto a glass substrate, the modulation depth and the saturation intensity of the fabricated devices can be controlled and optimized. This approach enables the realization of saturable absorbers that feature a modulation depth of 13% and a saturation intensity of 997 kW/cm{sup 2}. For the first time to our knowledge, Q-switched mode-locked operation of a linearly polarized mid-IR ZBLAN waveguide chip laser was realized in an extended cavity configuration using the topological insulator Bi{sub 2}Te{sub 3}. The maximum average output power of the laser is 16.3 mW and the Q-switched and mode-locked repetition rates are 44 kHz and 436 MHz, respectively. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Hyperbolic-cosine waveguide tapers and oversize rectangular waveguide for reduced broadband insertion loss in W-band electron paramagnetic resonance spectroscopy. II. Broadband characterization

    Energy Technology Data Exchange (ETDEWEB)

    Sidabras, Jason W.; Anderson, James R.; Mainali, Laxman; Hyde, James S. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 (United States); Strangeway, Robert A. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 (United States); Department of Electrical Engineering and Computer Science, Milwaukee School of Engineering, Milwaukee, Wisconsin 53201 (United States); Mett, Richard R. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 (United States); Department of Chemistry and Physics, Milwaukee School of Engineering, Milwaukee, Wisconsin 53201 (United States)

    2016-03-15

    Experimental results have been reported on an oversize rectangular waveguide assembly operating nominally at 94 GHz. It was formed using commercially available WR28 waveguide as well as a pair of specially designed tapers with a hyperbolic-cosine shape from WR28 to WR10 waveguide [R. R. Mett et al., Rev. Sci. Instrum. 82, 074704 (2011)]. The oversize section reduces broadband insertion loss for an Electron Paramagnetic Resonance (EPR) probe placed in a 3.36 T magnet. Hyperbolic-cosine tapers minimize reflection of the main mode and the excitation of unwanted propagating waveguide modes. Oversize waveguide is distinguished from corrugated waveguide, overmoded waveguide, or quasi-optic techniques by minimal coupling to higher-order modes. Only the TE{sub 10} mode of the parent WR10 waveguide is propagated. In the present work, a new oversize assembly with a gradual 90° twist was implemented. Microwave power measurements show that the twisted oversize waveguide assembly reduces the power loss in the observe and pump arms of a W-band bridge by an average of 2.35 dB and 2.41 dB, respectively, over a measured 1.25 GHz bandwidth relative to a straight length of WR10 waveguide. Network analyzer measurements confirm a decrease in insertion loss of 2.37 dB over a 4 GHz bandwidth and show minimal amplitude distortion of approximately 0.15 dB. Continuous wave EPR experiments confirm these results. The measured phase variations of the twisted oversize waveguide assembly, relative to an ideal distortionless transmission line, are reduced by a factor of two compared to a straight length of WR10 waveguide. Oversize waveguide with proper transitions is demonstrated as an effective way to increase incident power and the return signal for broadband EPR experiments. Detailed performance characteristics, including continuous wave experiment using 1 μM 2,2,6,6-tetramethylpiperidine-1-oxyl in aqueous solution, provided here serve as a benchmark for other broadband low-loss probes in

  18. Hyperbolic-cosine waveguide tapers and oversize rectangular waveguide for reduced broadband insertion loss in W-band electron paramagnetic resonance spectroscopy. II. Broadband characterization

    International Nuclear Information System (INIS)

    Sidabras, Jason W.; Anderson, James R.; Mainali, Laxman; Hyde, James S.; Strangeway, Robert A.; Mett, Richard R.

    2016-01-01

    Experimental results have been reported on an oversize rectangular waveguide assembly operating nominally at 94 GHz. It was formed using commercially available WR28 waveguide as well as a pair of specially designed tapers with a hyperbolic-cosine shape from WR28 to WR10 waveguide [R. R. Mett et al., Rev. Sci. Instrum. 82, 074704 (2011)]. The oversize section reduces broadband insertion loss for an Electron Paramagnetic Resonance (EPR) probe placed in a 3.36 T magnet. Hyperbolic-cosine tapers minimize reflection of the main mode and the excitation of unwanted propagating waveguide modes. Oversize waveguide is distinguished from corrugated waveguide, overmoded waveguide, or quasi-optic techniques by minimal coupling to higher-order modes. Only the TE 10 mode of the parent WR10 waveguide is propagated. In the present work, a new oversize assembly with a gradual 90° twist was implemented. Microwave power measurements show that the twisted oversize waveguide assembly reduces the power loss in the observe and pump arms of a W-band bridge by an average of 2.35 dB and 2.41 dB, respectively, over a measured 1.25 GHz bandwidth relative to a straight length of WR10 waveguide. Network analyzer measurements confirm a decrease in insertion loss of 2.37 dB over a 4 GHz bandwidth and show minimal amplitude distortion of approximately 0.15 dB. Continuous wave EPR experiments confirm these results. The measured phase variations of the twisted oversize waveguide assembly, relative to an ideal distortionless transmission line, are reduced by a factor of two compared to a straight length of WR10 waveguide. Oversize waveguide with proper transitions is demonstrated as an effective way to increase incident power and the return signal for broadband EPR experiments. Detailed performance characteristics, including continuous wave experiment using 1 μM 2,2,6,6-tetramethylpiperidine-1-oxyl in aqueous solution, provided here serve as a benchmark for other broadband low-loss probes in

  19. Single- and double energy N{sup +} ion irradiated planar optical waveguides in Er: Tungsten–tellurite oxide glass and sillenite type Bismuth Germanate crystals working up to telecommunications wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Bányász, I., E-mail: banyasz@sunserv.kfki.hu [Department of Crystal Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Zolnai, Z.; Fried, M.; Lohner, T. [Research Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Berneschi, S.; Righini, G.C. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); “Enrico Fermi” Center for Study and Research, Piazza del Viminale 2, 00184 Roma (Italy); Pelli, S.; Nunzi-Conti, G. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2013-07-15

    Ion implantation proved to be a universal technique for producing waveguides in most optical materials. Tellurite glasses are good hosts of rare-earth elements for the development of fibre and integrated optical amplifiers and lasers covering all the main telecommunication bands. Er{sup 3+}-doped tellurite glasses are good candidates for the fabrication of broadband amplifiers in wavelength division multiplexing around 1.55 μm, as they exhibit large stimulated cross sections and broad emission bandwidth. Fabrication of channel waveguides in such a material via N{sup +} ion implantation was reported recently. Sillenite type Bismuth Germanate (BGO) crystals are good nonlinear optical materials. Parameters of waveguide fabrication in both materials via implantation of MeV-energy N{sup +} ions were optimized. First single-energy implantations at 3.5 MeV at various fluences were applied. Waveguide operation up to 1.5 μm was observed in both materials. Then double-energy implantations at a fixed upper energy of 3.5 MeV and lower energies between 2.5 and 3.1 MeV were performed to suppress leaky modes by increasing barrier width. Improvement of waveguide characteristics was found by m-line spectroscopy and spectroscopic ellipsometry.

  20. Transverse Writing of Multimode Interference Waveguides inside Silica Glass by Femtosecond Laser Pulses

    International Nuclear Information System (INIS)

    Da-Yong, Liu; Yan, Li; Yan-Ping, Dou; Heng-Chang, Guo; Hong, Yang; Qi-Huang, Gong

    2008-01-01

    Multi-mode interference waveguides are fabricated inside silica glass by transverse writing geometry with femtosecond laser pulses. The influences of several writing and reading factors on the output mode are systematically studied. The experimental results of straight waveguides are in good agreement with the simulations by the beam propagation method. By integrating a straight waveguide with a bent waveguide, a 1 × 2 multi-mode splitter is formed and 2 × 3 lobes are observed in the output mode. (fundamental areas of phenomenology (including applications))

  1. Calculation of normal modes of the closed waveguides in general vector case

    Science.gov (United States)

    Malykh, M. D.; Sevastianov, L. A.; Tiutiunnik, A. A.

    2018-04-01

    The article is devoted to the calculation of normal modes of the closed waveguides with an arbitrary filling ɛ, μ in the system of computer algebra Sage. Maxwell equations in the cylinder are reduced to the system of two bounded Helmholtz equations, the notion of weak solution of this system is given and then this system is investigated as a system of ordinary differential equations. The normal modes of this system are an eigenvectors of a matrix pencil. We suggest to calculate the matrix elements approximately and to truncate the matrix by usual way but further to solve the truncated eigenvalue problem exactly in the field of algebraic numbers. This approach allows to keep the symmetry of the initial problem and in particular the multiplicity of the eigenvalues. In the work would be presented some results of calculations.

  2. 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.

  3. Launching transverse-electric Localized Waves from a circular waveguide

    KAUST Repository

    Salem, Mohamed

    2011-07-01

    Axially symmetric transverse electric (TE) modes of a circular waveguide section are used to synthesize the vector TE Localized Wave (LW) field at the open end of the waveguide section. The necessary excitation coefficients of these modes are obtained by the method of matching, taking advantage of the modal power orthogonality relations. The necessary excitation of modes provided by a number of coaxial loop antennas inserted inside the waveguide section. The antennas currents are computed from the solution of the waveguide excitation inverse problem. The accuracy of the synthesized wave field (compared to the mathematical model) and the power efficiency of the generation technique are evaluated in order to practically realize a launcher for LWs in the microwave regime. © 2011 IEEE.

  4. Long-range propagation of plasmon and phonon polaritons in hyperbolic-metamaterial waveguides

    Science.gov (United States)

    Babicheva, Viktoriia E.

    2017-12-01

    We study photonic multilayer waveguides that include layers of materials and metamaterials with a hyperbolic dispersion (HMM). We consider the long-range propagation of plasmon and phonon polaritons at the dielectric-HMM interface in different waveguide geometries (single boundary or different layers of symmetric cladding). In contrast to the traditional analysis of geometrical parameters, we make an emphasis on the optical properties of constituent materials: solving dispersion equations, we analyze how dielectric and HMM permittivities affect propagation length and mode size of waveguide eigenmodes. We derive figures of merit that should be used for each waveguide in a broad range of permittivity values as well as compare them with plasmonic waveguides. We show that the conventional plasmonic quality factor, which is the ratio of real to imaginary parts of permittivity, is not applicable to the case of waveguides with complex structure. Both telecommunication wavelengths and mid-infrared spectral ranges are of interest considering recent advances in van der Waals materials, such as hexagonal boron nitride. We evaluate the performance of the waveguides with hexagonal boron nitride in the range where it possesses hyperbolic dispersion (wavelength 6.3-7.3 μm), and we show that these waveguides with natural hyperbolic properties have higher propagation lengths than metal-based HMM waveguides.

  5. Coupled seismic modes and earthquake hazard in Mexico City

    Science.gov (United States)

    Lomnitz, C.

    2007-05-01

    Wave-to-wave coupling can arise when an acoustic pulse selects a Rayleigh mode of the same speed and both travel together swapping energy across an interface. A similar effect may cause severe damage at distances of several hundred kilometers when an Lg wavetrain incides upon a soft remote sedimentary waveguide, as in Mexico City. Energy at a single dominant frequency is then trapped in the waveguide. When the input power exceeds the damping losses, the trapped mode reverberates in the layer for up to five minutes, causing severe resonant damage to structures.

  6. Heralded quantum repeater based on the scattering of photons off single emitters in one-dimensional waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Song, Guo-Zhu; Zhang, Mei; Ai, Qing; Yang, Guo-Jian [Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875 (China); Alsaedi, Ahmed; Hobiny, Aatef [NAAM-Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Deng, Fu-Guo, E-mail: fgdeng@bnu.edu.cn [Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875 (China); NAAM-Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)

    2017-03-15

    We propose a heralded quantum repeater based on the scattering of photons off single emitters in one-dimensional waveguides. We show the details by implementing nonlocal entanglement generation, entanglement swapping, and entanglement purification modules with atoms in waveguides, and discuss the feasibility of the repeater with currently achievable technology. In our scheme, the faulty events can be discarded by detecting the polarization of the photons. That is, our protocols are accomplished with a fidelity of 100% in principle, which is advantageous for implementing realistic long-distance quantum communication. Moreover, additional atomic qubits are not required, but only a single-photon medium. Our scheme is scalable and attractive since it can be realized in solid-state quantum systems. With the great progress on controlling atom-waveguide systems, the repeater may be very useful in quantum information processing in the future.

  7. Hyperentangled photon sources in semiconductor waveguides

    DEFF Research Database (Denmark)

    Kang, Dongpeng; Helt, L. G.; Zhukovsky, Sergei

    2014-01-01

    We propose and analyze the performance of a technique to generate mode and polarization hyperentangled photons in monolithic semiconductor waveguides using two concurrent type-II spontaneous parametric down-conversion (SPDC) processes. These two SPDC processes are achieved by waveguide engineering...

  8. Coupled nanopillar waveguides: optical properties and applications

    DEFF Research Database (Denmark)

    Chigrin, Dmitry N.; Zhukovsky, Sergei V.; Lavrinenko, Andrei

    2007-01-01

    , while guided modes dispersion is strongly affected by the waveguide structure. We present a systematic analysis of the optical properties of coupled nanopillar waveguides and discuss their possible applications for integrated optics. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim......In this paper we review basic properties of coupled periodic and aperiodic nanopillar waveguides. A coupled nanopillar waveguide consists of several rows of periodically or aperiodically placed dielectric rods (pillars). In such a waveguide, light confinement is due to the total internal reflection...

  9. Thermal considerations in the cryogenic regime for the BNL double ridge higher order mode waveguide

    Directory of Open Access Journals (Sweden)

    Dhananjay K. Ravikumar

    2017-09-01

    Full Text Available Brookhaven National Laboratory (BNL has proposed to build an electron ion collider (EIC as an upgrade to the existing Relativistic Heavy Ion Collider (RHIC. A part of the new design is to use superconducting radio frequency (SRF cavities for acceleration, which sit in a bath of superfluid helium at a temperature of 2 K. SRF cavities designed for the BNL EIC create a standing electromagnetic wave, oscillating at a fundamental frequency of 647 MHz. Interaction of the charged particle beam with the EM field in the cavity creates higher order modes (HOM of oscillation which have adverse effects on the beam when allowed to propagate down the beam tube. HOM waveguides are thus designed to remove this excess energy which is then damped at room temperature. As a result, these waveguides provide a direct thermal link between room temperature and the superconducting cavities adding a static thermal load. The EM wave propagating through the warmer sections of the waveguide creates an additional dynamic thermal load. This study calculates these thermal loads, concluding that the dynamic load is small in comparison to the static load. Temperature distributions are mapped on the waveguide and the number of heat intercepts required to efficiently manage thermal loads have been determined. In addition, a thermal radiation study has been performed and it is found that this contribution is around three orders of magnitude smaller than the static conduction and dynamic loads.

  10. Thermal considerations in the cryogenic regime for the BNL double ridge higher order mode waveguide

    Science.gov (United States)

    Ravikumar, Dhananjay K.; Than, Yatming; Xu, Wencan; Longtin, Jon

    2017-09-01

    Brookhaven National Laboratory (BNL) has proposed to build an electron ion collider (EIC) as an upgrade to the existing Relativistic Heavy Ion Collider (RHIC). A part of the new design is to use superconducting radio frequency (SRF) cavities for acceleration, which sit in a bath of superfluid helium at a temperature of 2 K. SRF cavities designed for the BNL EIC create a standing electromagnetic wave, oscillating at a fundamental frequency of 647 MHz. Interaction of the charged particle beam with the EM field in the cavity creates higher order modes (HOM) of oscillation which have adverse effects on the beam when allowed to propagate down the beam tube. HOM waveguides are thus designed to remove this excess energy which is then damped at room temperature. As a result, these waveguides provide a direct thermal link between room temperature and the superconducting cavities adding a static thermal load. The EM wave propagating through the warmer sections of the waveguide creates an additional dynamic thermal load. This study calculates these thermal loads, concluding that the dynamic load is small in comparison to the static load. Temperature distributions are mapped on the waveguide and the number of heat intercepts required to efficiently manage thermal loads have been determined. In addition, a thermal radiation study has been performed and it is found that this contribution is around three orders of magnitude smaller than the static conduction and dynamic loads.

  11. Heuristic modelling of laser written mid-infrared LiNbO3 stressed-cladding waveguides.

    Science.gov (United States)

    Nguyen, Huu-Dat; Ródenas, Airán; Vázquez de Aldana, Javier R; Martínez, Javier; Chen, Feng; Aguiló, Magdalena; Pujol, Maria Cinta; Díaz, Francesc

    2016-04-04

    Mid-infrared lithium niobate cladding waveguides have great potential in low-loss on-chip non-linear optical instruments such as mid-infrared spectrometers and frequency converters, but their three-dimensional femtosecond-laser fabrication is currently not well understood due to the complex interplay between achievable depressed index values and the stress-optic refractive index changes arising as a function of both laser fabrication parameters, and cladding arrangement. Moreover, both the stress-field anisotropy and the asymmetric shape of low-index tracks yield highly birefringent waveguides not useful for most applications where controlling and manipulating the polarization state of a light beam is crucial. To achieve true high performance devices a fundamental understanding on how these waveguides behave and how they can be ultimately optimized is required. In this work we employ a heuristic modelling approach based on the use of standard optical characterization data along with standard computational numerical methods to obtain a satisfactory approximate solution to the problem of designing realistic laser-written circuit building-blocks, such as straight waveguides, bends and evanescent splitters. We infer basic waveguide design parameters such as the complex index of refraction of laser-written tracks at 3.68 µm mid-infrared wavelengths, as well as the cross-sectional stress-optic index maps, obtaining an overall waveguide simulation that closely matches the measured mid-infrared waveguide properties in terms of anisotropy, mode field distributions and propagation losses. We then explore experimentally feasible waveguide designs in the search of a single-mode low-loss behaviour for both ordinary and extraordinary polarizations. We evaluate the overall losses of s-bend components unveiling the expected radiation bend losses of this type of waveguides, and finally showcase a prototype design of a low-loss evanescent splitter. Developing a realistic waveguide

  12. Compensating for evanescent modes and estimating characteristic impedance in waveguide acoustic impedance measurements

    DEFF Research Database (Denmark)

    Nørgaard, Kren Rahbek; Fernandez Grande, Efren

    2017-01-01

    The ear-canal acoustic impedance and reflectance are useful for assessing conductive hearing disorders and calibrating stimulus levels in situ. However, such probe-based measurements are affected by errors due to the presence of evanescent modes and incorrect estimates or assumptions regarding...... characteristic impedance. This paper proposes a method to compensate for evanescent modes in measurements of acoustic impedance, reflectance, and sound pressure in waveguides, as well as estimating the characteristic impedance immediately in front of the probe. This is achieved by adjusting the characteristic...... impedance and subtracting an acoustic inertance from the measured impedance such that the non-causality in the reflectance is minimized in the frequency domain using the Hilbert transform. The method is thus capable of estimating plane-wave quantities of the sought-for parameters by supplying only...

  13. Semiconductor ring lasers coupled by a single waveguide

    Science.gov (United States)

    Coomans, W.; Gelens, L.; Van der Sande, G.; Mezosi, G.; Sorel, M.; Danckaert, J.; Verschaffelt, G.

    2012-06-01

    We experimentally and theoretically study the characteristics of semiconductor ring lasers bidirectionally coupled by a single bus waveguide. This configuration has, e.g., been suggested for use as an optical memory and as an optical neural network motif. The main results are that the coupling can destabilize the state in which both rings lase in the same direction, and it brings to life a state with equal powers at both outputs. These are both undesirable for optical memory operation. Although the coupling between the rings is bidirectional, the destabilization occurs due to behavior similar to an optically injected laser system.

  14. Floating dielectric slab optical interconnection between metal-dielectric interface surface plasmon polariton waveguides.

    Science.gov (United States)

    Kang, Minsu; Park, Junghyun; Lee, Il-Min; Lee, Byoungho

    2009-01-19

    A simple and effective optical interconnection which connects two distanced single metal-dielectric interface surface plasmon waveguides by a floating dielectric slab waveguide (slab bridge) is proposed. Transmission characteristics of the suggested structure are numerically studied using rigorous coupled wave analysis, and design rules based on the study are given. In the wave-guiding part, if the slab bridge can support more than the fundamental mode, then the transmission efficiency of the interconnection shows strong periodic dependency on the length of the bridge, due to the multi-mode interference (MMI) effect. Otherwise, only small fluctuation occurs due to the Fabry-Pérot effect. In addition, light beating happens when the slab bridge is relatively short. In the wave-coupling part, on the other hand, gap-assisted transmission occurs at each overlapping region as a consequence of mode hybridization. Periodic dependency on the length of the overlap region also appears due to the MMI effect. According to these results, we propose design principles for achieving both high transmission efficiency and stability with respect to the variation of the interconnection distance, and we show how to obtain the transmission efficiency of 68.3% for the 1mm-long interconnection.

  15. Laser generated soliton waveguides in photorefractive crystals

    International Nuclear Information System (INIS)

    Vlad, V.I.; Fazio, E.; Bertolotti, M.; Bosco, A.; Petris, A.

    2005-01-01

    Non-linear photo-excited processes using the photorefractive effect are revisited with emphasis on spatial soliton generation in special laser beam propagation conditions. The soliton beams can create reversible or irreversible single-mode waveguides in the propagating materials. The important features are the 3D orientation and graded index profile matched to the laser fundamental mode. Bright spatial solitons are theoretically demonstrated and experimentally observed for the propagation of c.w. and pulsed femtosecond laser beams in photorefractive materials such as Bi 12 SiO 20 (BSO) and lithium niobate crystals. Applications in high coupling efficiency, adaptive optical interconnections and photonic crystal production are possible

  16. Waveguide resonance mode response of stacked structures of metallic sub-wavelength slit arrays

    Science.gov (United States)

    Tokuda, Yasunori; Takano, Keisuke; Sakaguchi, Koichiro; Kato, Kosaku; Nakajima, Makoto; Akiyama, Koichi

    2018-05-01

    Detailed measurements of the optical properties of two-tier systems composed of metallic plates perforated with periodic sub-wavelength slit patterns were carried out using terahertz time-domain spectroscopy. We demonstrate that the transmission properties observed experimentally for various configurations can be reproduced successfully by simulations based on the finite-differential time-domain method. Fabry-Perot-like waveguide resonance mode behaviors specific to this quasi-dielectric system were then investigated. For structures with no lateral displacement between the slit-array plates, mode disappearance phenomena, which are caused by destructive interference between the odd-order mode and the blue- or red-shifted even-order modes, were observed experimentally. The uncommon behavior of the even-order modes was examined precisely to explain the slit-width dependence. For structures with half-pitched displacement between the plates, extraordinarily strong transmission was observed experimentally, even when the optical paths were shut off. This result was interpreted in terms of the propagation of surface plasmon polaritons through very thin and labyrinthine spacings that inevitably exist between the metallic plates. Furthermore, the optical mode disappearance phenomena are revealed to be characterized by anticrossing of the two mixing modes formed by even- and odd-order modes. These experimental observations that are supported theoretically are indispensable to the practical use of this type of artificial dielectric and are expected to encourage interest in optical mode behaviors that are not typically observed in conventional dielectric systems.

  17. Surface-Emitting Distributed Feedback Terahertz Quantum-Cascade Lasers in Metal-Metal Waveguides

    Science.gov (United States)

    Kumar, Sushil; Williams, Benjamin S.; Qin, Qi; Lee, Alan W. M.; Hu, Qing; Reno, John L.

    2007-01-01

    Single-mode surface-emitting distributed feedback terahertz quantumcascade lasers operating around 2.9 THz are developed in metal-metal waveguides. A combination of techniques including precise control of phase of reflection at the facets, and u e of metal on the sidewalls to eliminate higher-order lateral modes allow robust single-mode operation over a range of approximately 0.35 THz. Single-lobed far-field radiation pattern is obtained using a pi phase-shift in center of the second-order Bragg grating. A grating device operating at 2.93 THz lased up to 149 K in pulsed mode and a temperature tuning of 19 .7 GHz was observed from 5 K to 147 K. The same device lased up to 78 K in continuous-wave (cw) mode emitting more than 6 m W of cw power at 5 K. ln general, maximum temperature of pulsed operation for grating devices was within a few Kelvin of that of multi-mode Fabry-Perot ridge lasers

  18. Single Spatial-Mode Room-Temperature-Operated 3.0 to 3.4 micrometer Diode Lasers

    Science.gov (United States)

    Frez, Clifford F.; Soibel, Alexander; Belenky, Gregory; Shterengas, Leon; Kipshidze, Gela

    2010-01-01

    Compact, highly efficient, 3.0 to 3.4 m light emitters are in demand for spectroscopic analysis and identification of chemical substances (including methane and formaldehyde), infrared countermeasures technologies, and development of advanced infrared scene projectors. The need for these light emitters can be currently addressed either by bulky solid-state light emitters with limited power conversion efficiency, or cooled Interband Cascade (IC) semiconductor lasers. Researchers here have developed a breakthrough approach to fabrication of diode mid-IR lasers that have several advantages over IC lasers used for the Mars 2009 mission. This breakthrough is due to a novel design utilizing the strain-engineered quantum-well (QW) active region and quinternary barriers, and due to optimization of device material composition and growth conditions (growth temperatures and rates). However, in their present form, these GaSb-based laser diodes cannot be directly used as a part of sensor systems. The device spectrum is too broad to perform spectroscopic analysis of gas species, and operating currents and voltages are too high. In the current work, the emitters were fabricated as narrow-ridge waveguide index-guided lasers rather than broad stripe-gain guided multimode Fabry-Perot (FP) lasers as was done previously. These narrow-ridge waveguide mid-IR lasers exhibit much lower power consumptions, and can operate in a single spatial mode that is necessary for demonstration of single-mode distributed feedback (DBF) devices for spectroscopic applications. These lasers will enable a new generation of compact, tunable diode laser spectrometers with lower power consumption, reduced complexity, and significantly reduced development costs. These lasers can be used for the detection of HCN, C2H2, methane, and ethane.

  19. Analysis of a Waveguide-Fed Metasurface Antenna

    Science.gov (United States)

    Smith, David R.; Yurduseven, Okan; Mancera, Laura Pulido; Bowen, Patrick; Kundtz, Nathan B.

    2017-11-01

    The metasurface concept has emerged as an advantageous reconfigurable antenna architecture for beam forming and wave-front shaping, with applications that include satellite and terrestrial communications, radar, imaging, and wireless power transfer. The metasurface antenna consists of an array of metamaterial elements distributed over an electrically large structure, each subwavelength in dimension and with subwavelength separation between elements. In the antenna configuration we consider, the metasurface is excited by the fields from an attached waveguide. Each metamaterial element can be modeled as a polarizable dipole that couples the waveguide mode to radiation modes. Distinct from the phased array and electronically-scanned-antenna architectures, a dynamic metasurface antenna does not require active phase shifters and amplifiers but rather achieves reconfigurability by shifting the resonance frequency of each individual metamaterial element. We derive the basic properties of a one-dimensional waveguide-fed metasurface antenna in the approximation in which the metamaterial elements do not perturb the waveguide mode and are noninteracting. We derive analytical approximations for the array factors of the one-dimensional antenna, including the effective polarizabilities needed for amplitude-only, phase-only, and binary constraints. Using full-wave numerical simulations, we confirm the analysis, modeling waveguides with slots or complementary metamaterial elements patterned into one of the surfaces.

  20. Slow waves in microchannel metal waveguides and application to particle acceleration

    OpenAIRE

    L. C. Steinhauer; W. D. Kimura

    2003-01-01

    Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong ex...

  1. Experimental demonstration of a four-port photonic crystal cross-waveguide structure

    DEFF Research Database (Denmark)

    Yu, Yi; Heuck, Mikkel; Ek, Sara

    2012-01-01

    We report the design and fabrication of a four-port InP photonic crystal cavity-waveguide structure in which two crossing waveguides intersect in a cavity. Transmission measurements show that by exploiting mode-gap effects, high cross-talk suppression between the two waveguides can be obtained. I....... In addition, the waveguides couple to two distinct cavity resonances with different quality-factors as well as small mode volumes. This structure is promising for realizing ultra-fast, low-energy optical switches or memories....

  2. Single-mode distributed feedback laser operation with no dependence on the morphology of the gain medium

    Energy Technology Data Exchange (ETDEWEB)

    Umar, Muhammad [Department of Energy Systems Research, Ajou University, Suwon (Korea, Republic of); Min, Kyungtaek [Department of Energy Systems Research, Ajou University, Suwon (Korea, Republic of); Inter-university Semiconductor Research Center, Seoul National University (Korea, Republic of); Jeon, Heonsu [Department of Physics and Astronomy, Seoul National University (Korea, Republic of); Kim, Sunghwan [Department of Energy Systems Research, Ajou University, Suwon (Korea, Republic of); Department of Physics, Ajou University, Suwon (Korea, Republic of)

    2017-06-15

    Organic distributed feedback (DFB) lasers can be useful photonic tools for biological applications where the roles of organic materials are important, because highly coherent single mode emission with broad tuning range can be obtained. However, the formulaic structures of organic lasers, and the uses of gain media as resonators themselves, are not suitable for inducing laser emission from irregular shaped gain media, such as dye-staining cells and tissues. Here, we report a reusable photonic template comprising an exceedingly thin and discrete titanium dioxide (TiO{sub 2}) layer on a one-dimensional (1D) quartz grating to induce single mode DFB lasing from a variety of states of optical gain media. Using the same template, the external gain media of optically thick and thin casted film, liquid, and a free-standing thick film reveal single mode lasing with reliable performance. Numerical simulations demonstrate that the 25-nm thick TiO{sub 2} disconnected grating lines support a spatially confined DFB mode in the vertical direction, even under no index difference between superstrate and substrate. Additionally, not using the typical waveguide gain layer promises high sensitivity and detection limit in refractometric sensing. These results suggest that the photonic structure may serve as a versatile sensing platform for bioapplications. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Differential InP HEMT MMIC Amplifiers Embedded in Waveguides

    Science.gov (United States)

    Kangaslahti, Pekka; Schlecht, Erich; Samoska, Lorene

    2009-01-01

    prohibitively low impedances. Yet another advantage afforded by the virtual ground of the differential configuration is elimination of the need for a ground plane and, hence, elimination of the need for back-side metallization of the MMIC chip. In turn, elimination of the back-side metallization simplifies fabrication, reduces parasitic capacitances, and enables mounting of the MMIC in the electric-field plane ("E-plane") of a waveguide. E-plane mounting is consistent with (and essential for the utility of) the finline configuration, in which transmission lines lie on a dielectric sheet in the middle of a broad side of the waveguide. E-plane mounting offers a combination of low loss and ease of assembly because no millimeter-wave wire bonds or transition substrates are required. Moreover, because there is no ground plane behind the MMIC, the impedance for the detrimental even (single-ended) mode is high, suppressing coupling to that mode. Still another advantage of E-plane mounting is that the fundamental waveguide mode is inherently differential, eliminating the need for a balun to excite the differential mode.

  4. Device geometry considerations for ridge waveguide quantum dot mode-locked lasers

    International Nuclear Information System (INIS)

    Mee, J K; Raghunathan, R; Lester, L F; Wright, J B

    2014-01-01

    Quantum dot mode-locked lasers have emerged as a leading source for the efficient generation of high-quality optical pulses from a compact package, attracting considerable attention for support of multiple high-speed applications, owing to characteristics such as low noise operation and high pulse peak power, in addition to the ability to multiplex the output pulse train in temporal and frequency domains in order to obtain hundreds of GHz pulse repetition rates potentially operating at 1 Tbps. This topical review provides a detailed explanation into the primary advantages of quantum dots, identifying the key features that have made them superior to other material systems for passive mode-locking in semiconductor lasers. Following this account, the impact of the device's cavity geometry on the operational range of two-section, monolithic passively mode-locked lasers is investigated both experimentally and analytically. A model is described that predicts regimes of pulsed operation as a function of absorber length to gain length ratio. Experimental measurements of the pulse time-domain characteristics over a wide range of operating temperatures are found to be in excellent agreement with analytical predictions. The impact of ridge waveguide design on the operational range is also examined and the key dimensions that most strongly impact efficient operation are identified. (topical review)

  5. GRIN planar waveguide concentrator used with a single axis tracker.

    Science.gov (United States)

    Bouchard, Sébastien; Thibault, Simon

    2014-03-10

    It is generally accepted that small to medium level concentrators could be used as cost-competitive replacements for tracked solar panels. The objective is to design a system that can reach a good level of sun concentration with only one sun-tracking axis and is cheap to fabricate. As the most critical parameter for all concentrator designs, optical efficiency needed improvement to reduce the cost of power produced by our system. By using a graded-index planar waveguide with an index profile similar to SELFOC fiber, the ray's path can be controlled. Also, the concentrator can be fabricated in a single block, which reduces Fresnel reflections. Overall, the optical efficiency can be improved by as much as 33% compared to the same system made with a homogeneous waveguide. Furthermore, the ability to cost-effectively fabricate the concentrator by molding can be preserved, making it possible to reduce the cost of the solar power produced.

  6. Mode solvers for very thin long-range plasmonic waveguides

    Czech Academy of Sciences Publication Activity Database

    Francs, G. C.; Hugonin, J. P.; Čtyroký, Jiří

    2011-01-01

    Roč. 42, č. 8 (2011), s. 557-570 ISSN 0306-8919. [18th International Workshop on Optical Waveguide Theory and Numerical Modelling (OWTNM). Cambridge, 09.04.2010-10.04.2010] R&D Projects: GA MŠk OC09061 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical waveguide theory * integrated optics Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.822, year: 2011

  7. Freeform Phononic Waveguides

    Directory of Open Access Journals (Sweden)

    Georgios Gkantzounis

    2017-11-01

    Full Text Available We employ a recently introduced class of artificial structurally-disordered phononic structures that exhibit large and robust elastic frequency band gaps for efficient phonon guiding. Phononic crystals are periodic structures that prohibit the propagation of elastic waves through destructive interference and exhibit large band gaps and ballistic propagation of elastic waves in the permitted frequency ranges. In contrast, random-structured materials do not exhibit band gaps and favour localization or diffusive propagation. Here, we use structures with correlated disorder constructed from the so-called stealthy hyperuniform disordered point patterns, which can smoothly vary from completely random to periodic (full order by adjusting a single parameter. Such amorphous-like structures exhibit large band gaps (comparable to the periodic ones, both ballistic-like and diffusive propagation of elastic waves, and a large number of localized modes near the band edges. The presence of large elastic band gaps allows the creation of waveguides in hyperuniform materials, and we analyse various waveguide architectures displaying nearly 100% transmission in the GHz regime. Such phononic-circuit architectures are expected to have a direct impact on integrated micro-electro-mechanical filters and modulators for wireless communications and acousto-optical sensing applications.

  8. Planar Silicon Optical Waveguide Light Modulators

    DEFF Research Database (Denmark)

    Leistiko, Otto; Bak, H.

    1994-01-01

    that values in the nanosecond region should be possible, however, the measured values are high, 20 microseconds, due to the large area of the injector junctions, 1× 10¿2 cm2, and the limitations imposed by the detection circuit. The modulating properties of these devices are impressive, measurements......The results of an experimental investigation of a new type of optical waveguide based on planar technology in which the liglht guiding and modulation are achieved by exploiting free carrier effects in silicon are presented. Light is guided between the n+ substrate and two p+ regions, which also...... serve as carrier injectors for controling absorption. Light confinement of single mode devices is good, giving spot sizes of 9 ¿m FWHM. Insertion loss measurements indicate that the absorption losses for these waveguides are extremely low, less 1 dB/cm. Estimates of the switching speed indicate...

  9. Dispersion characteristics of plasmonic waveguides for THz waves

    Science.gov (United States)

    Markides, Christos; Viphavakit, Charusluk; Themistos, Christos; Komodromos, Michael; Kalli, Kyriacos; Quadir, Anita; Rahman, Azizur

    2013-05-01

    Today there is an increasing surge in Surface Plasmon based research and recent studies have shown that a wide range of plasmon-based optical elements and techniques have led to the development of a variety of active switches, passive waveguides, biosensors, lithography masks, to name just a few. The Terahertz (THz) frequency region of the electromagnetic spectrum is located between the traditional microwave spectrum and the optical frequencies, and offers a significant scientific and technological potential in many fields, such as in sensing, in imaging and in spectroscopy. Waveguiding in this intermediate spectral region is a major challenge. Amongst the various THz waveguides suggested, the metal-clad waveguides supporting surface plasmon modes waves and specifically hollow core structures, coated with insulating material are showing the greatest promise as low-loss waveguides for their use in active components and as well as passive waveguides. The H-field finite element method (FEM) based full-vector formulation is used to study the vectorial modal field properties and the complex propagation characteristics of Surface Plasmon modes of a hollow-core dielectric coated rectangular waveguide structure. Additionally, the finite difference time domain (FDTD) method is used to estimate the dispersion parameters and the propagation loss of the rectangular waveguide.

  10. 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.

  11. Terahertz cross-phase modulation of an optical mode

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Novitsky, Andrey; Zalkovskij, Maksim

    2013-01-01

    We discuss an optical scheme which facilitates modulation of an optical waveguide mode by metallic-nanoslit-enhanced THz radiation. The waveguide mode acquires an additional phase shift due to THz nonlinearity with fields reachable in experiments.......We discuss an optical scheme which facilitates modulation of an optical waveguide mode by metallic-nanoslit-enhanced THz radiation. The waveguide mode acquires an additional phase shift due to THz nonlinearity with fields reachable in experiments....

  12. 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.

  13. Slow-light enhancement of spontaneous emission in active photonic crystal waveguides

    DEFF Research Database (Denmark)

    Ek, Sara; Chen, Yaohui; Semenova, Elizaveta

    2012-01-01

    Photonic crystal defect waveguides with embedded active layers containing single or multiple quantum wells or quantum dots have been fabricated. Spontaneous emission spectra are enhanced close to the bandedge, consistently with the enhancement of gain by slow light effects. These are promising...... results for future compact devices for terabit/s communication, such as miniaturised semiconductor optical amplifiers and mode-locked lasers....

  14. Dispersion properties of Kolakoski-cladding hollow-core nanophotonic Bragg waveguide

    Directory of Open Access Journals (Sweden)

    Fesenko Volodymyr I.

    2016-09-01

    Full Text Available A comprehensive analysis of guided modes of a novel type of a planar Bragg reflection waveguide that consists of a low refractive index guiding layer sandwiched between two finite aperiodic mirrors is presented. The layers in the mirrors are aperiodically arranged according to the Kolakoski substitution rule. In such a waveguide, light is confined inside the core by Bragg reflection, while dispersion characteristics of guided modes strongly depend on aperiodicity of the cladding. Using the transfer matrix formalism bandgap conditions, dispersion characteristics and mode profiles of the guided modes of such a waveguide are studied on the GaAs/AlAs and Si/SiO2 epitaxial platforms, which are compatible with hybrid and heteroepitaxial frameworks of silicon photonics.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiu-Wen; Huang, Yong-Zhen, E-mail: yzhuang@semi.ac.cn; Yang, Yue-De; Xiao, Jin-Long; Weng, Hai-Zhong; Xiao, Zhi-Xiong [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100083 (China)

    2016-08-15

    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.

  16. Second-harmonic scanning optical microscopy of poled silica waveguides

    DEFF Research Database (Denmark)

    Pedersen, Kjeld; Bozhevolnyi, Sergey I.; Arentoft, Jesper

    2000-01-01

    Second-harmonic scanning optical microscopy (SHSOM) is performed on electric-field poled silica-based waveguides. Two operation modes of SHSOM are considered. Oblique transmission reflection and normal reflection modes are used to image the spatial distribution of nonlinear susceptibilities...... and limitations of the two operation modes when used for SHSOM studies of poled silica-based waveguides are discussed. The influence of surface defects on the resulting second-harmonic images is also considered. ©2000 American Institute of Physics....

  17. Ultrasonic Waveguide Sensor with a Layer-Structured Plate

    International Nuclear Information System (INIS)

    Joo, Young Sang; Bae, Jin Ho; Kim, Jong Bum

    2010-01-01

    In-vessel structures of a sodium-cooled fast reactor (SFR) are submerged in opaque liquid sodium in reactor vessel. The ultrasonic inspection techniques should be applied for observing the in-vessel structures under hot liquid sodium. Ultrasonic sensors such as immersion sensors and rod-type waveguide sensors had developed in order to apply under-sodium viewing of the in-vessel structures of SFR. Recently the novel plate-type ultrasonic waveguide sensor has been developed for the versatile application of under-sodium viewing in SFR. In the previous studies, the Ultrasonic waveguide sensor module had been designed and manufactured. And the feasibility study of the ultrasonic waveguide sensor has been performed. To Improve the performance of the ultrasonic waveguide sensor module in the under-sodium application, the dispersion effect due to the 10 m long distance propagation of the A 0 -mode Lamb wave should be minimized and the longitudinal leaky wave in a liquid sodium should be generated within the range of the effective radiation angle. In this study, a new concept of ultrasonic waveguide sensor with a layered-structured plate is suggested for the non-dispersive propagation of A 0 -mode Lamb wave in an ultrasonic waveguide sensor and the effective generation of leaky wave in a liquid sodium

  18. Fabrication of optical waveguides by imprinting: usage of positive tone resist as a mould for UV-curable polymer.

    Science.gov (United States)

    Hiltunen, Jussi; Hiltunen, Marianne; Puustinen, Jarkko; Lappalainen, Jyrki; Karioja, Pentti

    2009-12-07

    Optical ridge type waveguides based on UV-curable polymer were fabricated by imprinting method. Positive tone resist patterned on a silicon wafer was used as a mould. The characterization of waveguides was carried out by coupling TE-polarized light from a tapered fiber into a waveguide with 30 mm length and mapping the intensity distribution with another tapered fiber at the output facet of a waveguide. Proper single- or multimode operation was observed depending on the waveguide width being either 2 microm or 6 microm. Experimental observations on the mode profiles were also supported by the simulation results. Average power transmissions of 32% at 1530 nm wavelength and 45% at 1310 nm wavelength were characterized. The results suggest that the simple mould fabrication process might be a useful technique for device prototyping and that the performance of replicated waveguides can meet the requirements for certain applications.

  19. Scaling Fiber Lasers to Large Mode Area: An Investigation of Passive Mode-Locking Using a Multi-Mode Fiber.

    Science.gov (United States)

    Ding, Edwin; Lefrancois, Simon; Kutz, Jose Nathan; Wise, Frank W

    2011-01-01

    The mode-locking of dissipative soliton fiber lasers using large mode area fiber supporting multiple transverse modes is studied experimentally and theoretically. The averaged mode-locking dynamics in a multi-mode fiber are studied using a distributed model. The co-propagation of multiple transverse modes is governed by a system of coupled Ginzburg-Landau equations. Simulations show that stable and robust mode-locked pulses can be produced. However, the mode-locking can be destabilized by excessive higher-order mode content. Experiments using large core step-index fiber, photonic crystal fiber, and chirally-coupled core fiber show that mode-locking can be significantly disturbed in the presence of higher-order modes, resulting in lower maximum single-pulse energies. In practice, spatial mode content must be carefully controlled to achieve full pulse energy scaling. This paper demonstrates that mode-locking performance is very sensitive to the presence of multiple waveguide modes when compared to systems such as amplifiers and continuous-wave lasers.

  20. Energy transfer in coupled nonlinear phononic waveguides: transition from wandering breather to nonlinear self-trapping

    International Nuclear Information System (INIS)

    Kosevich, Y A; Manevitch, L I; Savin, A V

    2007-01-01

    We consider, both analytically and numerically, the dynamics of stationary and slowly-moving breathers (localized short-wavelength excitations) in two weakly coupled nonlinear oscillator chains (nonlinear phononic waveguides). We show that there are two qualitatively different dynamical regimes of the coupled breathers: the oscillatory exchange of the low-amplitude breather between the phononic waveguides (wandering breather), and one-waveguide-localization (nonlinear self-trapping) of the high-amplitude breather. We also show that phase-coherent dynamics of the coupled breathers in two weakly linked nonlinear phononic waveguides has a profound analogy, and is described by a similar pair of equations, to the tunnelling quantum dynamics of two weakly linked Bose-Einstein condensates in a symmetric double-well potential (single bosonic Josephson junction). The exchange of phonon energy and excitations between the coupled phononic waveguides takes on the role which the exchange of atoms via quantum tunnelling plays in the case of the coupled condensates. On the basis of this analogy, we predict a new tunnelling mode of the coupled Bose-Einstein condensates in a single bosonic Josephson junction in which their relative phase oscillates around π/2. The dynamics of relative phase of two weakly linked Bose-Einstein condensates can be studied by means of interference, while the dynamics of the exchange of lattice excitations in coupled nonlinear phononic waveguides can be observed by means of light scattering

  1. Polarization modulation based on the hybrid waveguide of graphene sandwiched structure

    Science.gov (United States)

    Yang, Junbo; Chen, Dingbo; Zhang, Jingjing; Zhang, Zhaojian; Huang, Jie

    2017-09-01

    Polarization beam splitter (PBS) plays an important role to realize beam control and modulation. A novel hybrid structure of graphene sandwiched waveguide is proposed to fulfill polarization manipulation and selection based on the refractive index engineering techniques. The fundamental mode of TM cannot be supported in this case. However, both TE and TM mode are excited and transmitting in the hybrid waveguide if the design parameters, including the waveguide width and the waveguide height, are changed. The incident wavelength largely affects the effective index, which results in supporting/not supporting the TM mode. The proposed design exhibits high extinction ratio, compact in size, flexible to control, compatible with CMOS process, and easy to be integrated with other optoelectronic devices, allowing it to be used in optical communication and optical information processing.

  2. Planar optical waveguide based sandwich assay sensors and processes for the detection of biological targets including protein markers, pathogens and cellular debris

    Science.gov (United States)

    Martinez, Jennifer S [Santa Fe, NM; Swanson, Basil I [Los Alamos, NM; Grace, Karen M [Los Alamos, NM; Grace, Wynne K [Los Alamos, NM; Shreve, Andrew P [Santa Fe, NM

    2009-06-02

    An assay element is described including recognition ligands bound to a film on a single mode planar optical waveguide, the film from the group of a membrane, a polymerized bilayer membrane, and a self-assembled monolayer containing polyethylene glycol or polypropylene glycol groups therein and an assay process for detecting the presence of a biological target is described including injecting a biological target-containing sample into a sensor cell including the assay element, with the recognition ligands adapted for binding to selected biological targets, maintaining the sample within the sensor cell for time sufficient for binding to occur between selected biological targets within the sample and the recognition ligands, injecting a solution including a reporter ligand into the sensor cell; and, interrogating the sample within the sensor cell with excitation light from the waveguide, the excitation light provided by an evanescent field of the single mode penetrating into the biological target-containing sample to a distance of less than about 200 nanometers from the waveguide thereby exciting the fluorescent-label in any bound reporter ligand within a distance of less than about 200 nanometers from the waveguide and resulting in a detectable signal.

  3. Dynamics of single photon transport in a one-dimensional waveguide two-point coupled with a Jaynes-Cummings system

    KAUST Repository

    Wang, Yuwen

    2016-09-22

    We study the dynamics of an ultrafast single photon pulse in a one-dimensional waveguide two-point coupled with a Jaynes-Cummings system. We find that for any single photon input the transmissivity depends periodically on the separation between the two coupling points. For a pulse containing many plane wave components it is almost impossible to suppress transmission, especially when the width of the pulse is less than 20 times the period. In contrast to plane wave input, the waveform of the pulse can be modified by controlling the coupling between the waveguide and Jaynes-Cummings system. Tailoring of the waveform is important for single photon manipulation in quantum informatics. © The Author(s) 2016.

  4. A unified approach for radiative losses and backscattering in optical waveguides

    International Nuclear Information System (INIS)

    Melati, D; Morichetti, F; Melloni, A

    2014-01-01

    Sidewall roughness in optical waveguides represents a severe impairment for the proper functionality of photonic integrated circuits. The interaction between the propagating mode and the roughness is responsible for both radiative losses and distributed backscattering. In this paper, a unified vision on these extrinsic loss phenomena is discussed, highlighting the fundamental role played by the sensitivity of the effective index n eff of the optical mode to waveguide width variations. The n w model presented applies to both 2D slab waveguides and 3D laterally confined waveguides and is in very good agreement with existing models that individually describe radiative loss or backscattering only. Experimental results are presented, demonstrating the validity of the n w model for arbitrary waveguide geometries and technologies. This approach enables an accurate description of realistic optical waveguides and provides simple design rules for optimization of the waveguide geometry in order to reduce the propagation losses generated by sidewall roughness. (paper)

  5. Integrating cell on chip—Novel waveguide platform employing ultra-long optical paths

    Directory of Open Access Journals (Sweden)

    Lena Simone Fohrmann

    2017-09-01

    Full Text Available Optical waveguides are the most fundamental building blocks of integrated optical circuits. They are extremely well understood, yet there is still room for surprises. Here, we introduce a novel 2D waveguide platform which affords a strong interaction of the evanescent tail of a guided optical wave with an external medium while only employing a very small geometrical footprint. The key feature of the platform is its ability to integrate the ultra-long path lengths by combining low propagation losses in a silicon slab with multiple reflections of the guided wave from photonic crystal (PhC mirrors. With a reflectivity of 99.1% of our tailored PhC-mirrors, we achieve interaction paths of 25 cm within an area of less than 10 mm2. This corresponds to 0.17 dB/cm effective propagation which is much lower than the state-of-the-art loss of approximately 1 dB/cm of single mode silicon channel waveguides. In contrast to conventional waveguides, our 2D-approach leads to a decay of the guided wave power only inversely proportional to the optical path length. This entirely different characteristic is the major advantage of the 2D integrating cell waveguide platform over the conventional channel waveguide concepts that obey the Beer-Lambert law.

  6. Integrating cell on chip—Novel waveguide platform employing ultra-long optical paths

    Science.gov (United States)

    Fohrmann, Lena Simone; Sommer, Gerrit; Pitruzzello, Giampaolo; Krauss, Thomas F.; Petrov, Alexander Yu.; Eich, Manfred

    2017-09-01

    Optical waveguides are the most fundamental building blocks of integrated optical circuits. They are extremely well understood, yet there is still room for surprises. Here, we introduce a novel 2D waveguide platform which affords a strong interaction of the evanescent tail of a guided optical wave with an external medium while only employing a very small geometrical footprint. The key feature of the platform is its ability to integrate the ultra-long path lengths by combining low propagation losses in a silicon slab with multiple reflections of the guided wave from photonic crystal (PhC) mirrors. With a reflectivity of 99.1% of our tailored PhC-mirrors, we achieve interaction paths of 25 cm within an area of less than 10 mm2. This corresponds to 0.17 dB/cm effective propagation which is much lower than the state-of-the-art loss of approximately 1 dB/cm of single mode silicon channel waveguides. In contrast to conventional waveguides, our 2D-approach leads to a decay of the guided wave power only inversely proportional to the optical path length. This entirely different characteristic is the major advantage of the 2D integrating cell waveguide platform over the conventional channel waveguide concepts that obey the Beer-Lambert law.

  7. Multilayered photonic integration on SOI platform using waveguide-based bridge structure

    Science.gov (United States)

    Majumder, Saikat; Chakraborty, Rajib

    2018-06-01

    A waveguide based structure on silicon on insulator platform is proposed for vertical integration in photonic integrated circuits. The structure consists of two multimode interference couplers connected by a single mode (SM) section which can act as a bridge over any other underlying device. Two more SM sections acts as input and output of the first and second multimode couplers respectively. Potential application of this structure is in multilayered photonic links. It is shown that the efficiency of the structure can be improved by making some design modifications. The entire simulation is done using effective-index based matrix method. The feature size chosen are comparable to waveguides fabricated previously so as to fabricate the proposed structure easily.

  8. Discrete mode lasers for communications applications

    Science.gov (United States)

    Barry, L. P.; Herbert, C.; Jones, D.; Kaszubowska-Anandarajah, A.; Kelly, B.; O'Carroll, J.; Phelan, R.; Anandarajah, P.; Shi, K.; O'Gorman, J.

    2009-02-01

    The wavelength spectra of ridge waveguide Fabry Perot lasers can be modified by perturbing the effective refractive index of the guided mode along very small sections of the laser cavity. One way of locally perturbing the effective index of the lasing mode is by etching features into the ridge waveguide such that each feature has a small overlap with the transverse field profile of the unperturbed mode, consequently most of the light in the laser cavity is unaffected by these perturbations. A proportion of the propagating light is however reflected at the boundaries between the perturbed and the unperturbed sections. Suitable positioning of these interfaces allows the mirror loss spectrum of a Fabry Perot laser to be manipulated. In order to achieve single longitudinal mode emission, the mirror loss of a specified mode must be reduced below that of the other cavity modes. Here we review the latest results obtained from devices containing such features. These results clearly demonstrate that these devices exceed the specifications required for a number of FTTH and Datacomms applications, such as GEPON, LX4 and CWDM. As well as this we will also present initial results on the linewidth of these devices.

  9. PLC-based LP₁₁ mode rotator for mode-division multiplexing transmission.

    Science.gov (United States)

    Saitoh, Kunimasa; Uematsu, Takui; Hanzawa, Nobutomo; Ishizaka, Yuhei; Masumoto, Kohei; Sakamoto, Taiji; Matsui, Takashi; Tsujikawa, Kyozo; Yamamoto, Fumihiko

    2014-08-11

    A PLC-based LP11 mode rotator is proposed. The proposed mode rotator is composed of a waveguide with a trench that provides asymmetry of the waveguide. Numerical simulations show that converting LP11a (LP11b) mode to LP11b (LP11a) mode can be achieved with high conversion efficiency (more than 90%) and little polarization dependence over a wide wavelength range from 1450 nm to 1650 nm. In addition, we fabricate the proposed LP11 mode rotator using silica-based PLC. It is confirmed that the fabricated mode rotator can convert LP11a mode to LP11b mode over a wide wavelength range.

  10. Integration of a photonic crystal polarization beam splitter and waveguide bend.

    Science.gov (United States)

    Zheng, Wanhua; Xing, Mingxin; Ren, Gang; Johnson, Steven G; Zhou, Wenjun; Chen, Wei; Chen, Lianghui

    2009-05-11

    In this work, we present the design of an integrated photonic-crystal polarization beam splitter (PC-PBS) and a low-loss photonic-crystal 60 degrees waveguide bend. Firstly, the modal properties of the PC-PBS and the mechanism of the low-loss waveguide bend are investigated by the two-dimensional finite-difference time-domain (FDTD) method, and then the integration of the two devices is studied. It shows that, although the individual devices perform well separately, the performance of the integrated circuit is poor due to the multi-mode property of the PC-PBS. By introducing deformed airhole structures, a single-mode PC-PBS is proposed, which significantly enhance the performance of the circuit with the extinction ratios remaining above 20 dB for both transverse-electric (TE) and transverse-magnetic (TM) polarizations. Both the specific result and the general idea of integration design are promising in the photonic crystal integrated circuits in the future.

  11. The waveguide Free-Electron Laser. 14

    International Nuclear Information System (INIS)

    Walsh, J.E.

    1990-01-01

    The general characteristics of free-electron lasers (FELs) which employ a waveguiding structure to confine electromagnetic fields and to couple them to the electron beam is discussed. The mode structure of the basic parallel plate waveguide and its adaptation via quasi-optical techniques to FEL resonator design are considered in detail. A summary of the theory of FEL systems which depend intrinsically on a guide structure (micro-undulator, Cerenkov and metal-grating FELs) and a review of progress on waveguide FEL experiments are also presented. (author). 44 refs.; 16 figs

  12. Strategies for waveguide coupling for SRF cavities

    International Nuclear Information System (INIS)

    Doolittle, L.R.

    1998-01-01

    Despite widespread use of coaxial couplers in SRF cavities, a single, simple waveguide coupling can be used both to transmit generator power to a cavity, and to remove a large class of Higher Order Modes (HOMs, produced by the beam). There are balances and tradeoffs to be made, such as the coupling strength of the various frequencies, the transverse component of the coupler fields on the beam axis, and the magnitude of the surface fields and currents. This paper describes those design constraints, categories of solutions, and examples from the CEBAF Energy Upgrade studies

  13. Modeling of Slot Waveguide Sensors Based on Polymeric Materials

    Science.gov (United States)

    Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

    2011-01-01

    Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

  14. Modeling of Slot Waveguide Sensors Based on Polymeric Materials

    Directory of Open Access Journals (Sweden)

    Lorenzo Pavesi

    2011-07-01

    Full Text Available Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies.

  15. Induced transparencies in metamaterial waveguides doped with quantum dots

    International Nuclear Information System (INIS)

    Singh, Mahi R; Brzozowski, Marek; Racknor, Chris

    2015-01-01

    The light-mater interaction in quantum dots doped artificial electromagnetic materials such as metamaterial waveguides has been studied. The effect of surface plasmon polaritons (SPPs) on the absorption coefficient of quantum dots in metamaterial waveguides is investigated. The waveguides are made by sandwiching a metamaterial slab between two dielectric material layers. An ensemble of quantum dots are deposited near the waveguide interfaces. The transfer matrix method is used to calculate the SSPs in the waveguide and the density matrix method and Schrödinger equation method are used to calculate the absorption spectrum. It is found that when the thickness of the metamaterial slab is greater than the SPP wavelength the SPP energy is degenerate. However when the thickness of the slab is smaller than that of the SPP wavelength the degeneracy of SPP state splits into odd and even SPP modes due the surface mode interaction (SMI) of the waveguide. We also found that the absorption spectrum has a minima (transparent state) which is due to strong coupling between excitons in quantum dots and SPPs in the waveguide. This transparent state is called the SPP induced transparency. However when the thickness of the slab is smaller than that of the SPP wavelength one transparent state in the absorption spectrum split into two transparent states due to the surface mode interaction. This type of transparency is called the SMI induced transparency. Transparent states can be achieved by applying pulse stress field or an intense laser pulse field. Hence present findings can be used to fabricate the metamaterial optical sensors and switches. (paper)

  16. Slow waves in microchannel metal waveguides and application to particle acceleration

    Directory of Open Access Journals (Sweden)

    L. C. Steinhauer

    2003-06-01

    Full Text Available Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO_{2} lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ∼0.6  mm. The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

  17. Slow waves in microchannel metal waveguides and application to particle acceleration

    Science.gov (United States)

    Steinhauer, L. C.; Kimura, W. D.

    2003-06-01

    Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO2 lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ˜0.6 mm). The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

  18. Single-bunch beam breakup in a dielectric-lined waveguide

    International Nuclear Information System (INIS)

    Ng, King-Yuen.

    1992-08-01

    We examine beam breakup of a 100 nC I mm-long (rms) source bunch inside a cylindrical dielectric waveguide, with dielectric ε = 2.65 filling the radius between 7.5 and 9.0 mm. Only ∼ 78% of the bunch with an initial offset of 0.3 mm survives the passage of the 3.75 m waveguide. The loss is mainly due to the large deflections of some particles that are slowed down to nearly zero velocity. As a result, quadrupole focussing of any sort will not help. However, if the waveguide is shortened to 3.3 m, the loss reduces to only 5.5%

  19. Bright Single InAsP Quantum Dots at Telecom Wavelengths in Position-Controlled InP Nanowires: The Role of the Photonic Waveguide.

    Science.gov (United States)

    Haffouz, Sofiane; Zeuner, Katharina D; Dalacu, Dan; Poole, Philip J; Lapointe, Jean; Poitras, Daniel; Mnaymneh, Khaled; Wu, Xiaohua; Couillard, Martin; Korkusinski, Marek; Schöll, Eva; Jöns, Klaus D; Zwiller, Valery; Williams, Robin L

    2018-05-09

    We report on the site-selected growth of bright single InAsP quantum dots embedded within InP photonic nanowire waveguides emitting at telecom wavelengths. We demonstrate a dramatic dependence of the emission rate on both the emission wavelength and the nanowire diameter. With an appropriately designed waveguide, tailored to the emission wavelength of the dot, an increase in the count rate by nearly 2 orders of magnitude (0.4 to 35 kcps) is obtained for quantum dots emitting in the telecom O-band, showing high single-photon purity with multiphoton emission probabilities down to 2%. Using emission-wavelength-optimized waveguides, we demonstrate bright, narrow-line-width emission from single InAsP quantum dots with an unprecedented tuning range of 880 to 1550 nm. These results pave the way toward efficient single-photon sources at telecom wavelengths using deterministically grown InAsP/InP nanowire quantum dots.

  20. Propagation properties of dielectric-lined hollow cylindrical metallic waveguides for THz waves

    International Nuclear Information System (INIS)

    Huang Binke; Zhao Chongfeng

    2013-01-01

    For the rigorous analysis of the propagation properties of dielectric-lined hollow cylindrical metallic waveguides operating in the THz range of frequencies, the characteristic equation for propagation constants is derived from the electromagnetic field equations and the boundary conditions of the dielectric-lined waveguides. The propagation constant of the dominant hybrid HE 11 mode can be obtained by solving the characteristic equation with the improved Muller method. The classical relaxation-effect model for the conductivity is adopted to describe the frequency dispersive behavior of normal metals for the metallic waveguide wall. For a 1.8 mm bore diameter silver waveguide with the inner surface coated with a 17 μm-thick layer of polystyrene(PS) film, the transmission losses of HE 11 mode can be reduced to the level below 1 dB/m at 1.5-3.0 THz, and the dispersion is relatively small for HE 11 mode. In addition, with the PS film thickness increasing, the transmission losses of HE 11 mode increase first and then decrease for a 2.2 mm bore diameter silver waveguide at 2.5 THz, and the minimum loss can be achieved by adopting the optimum dielectric layer thickness. (authors)

  1. A self-repairing polymer waveguide sensor

    International Nuclear Information System (INIS)

    Song, Young J; Peters, Kara J

    2011-01-01

    This paper presents experimental demonstrations of a self-repairing strain sensor waveguide created by self-writing in a photopolymerizable resin system. The sensor is fabricated between two multi-mode optical fibers via lightwaves in the ultraviolet (UV) wavelength range and operates as a sensor through interrogation of the power transmitted through the waveguide in the infrared (IR) wavelength range. After failure of the sensor occurs due to loading, the waveguide re-bridges the gap between the two optical fibers through the UV resin. The response of the original sensor and the self-repaired sensor to strain are measured and show similar behaviors

  2. Two mechanisms of disorder-induced localization in photonic-crystal waveguides

    Science.gov (United States)

    García, P. D.; KiršanskÄ--, G.; Javadi, A.; Stobbe, S.; Lodahl, P.

    2017-10-01

    Unintentional but unavoidable fabrication imperfections in state-of-the-art photonic-crystal waveguides lead to the spontaneous formation of Anderson-localized modes thereby limiting slow-light propagation and its potential applications. On the other hand, disorder-induced cavities offer an approach to cavity-quantum electrodynamics and random lasing at the nanoscale. The key statistical parameter governing the disorder effects is the localization length, which together with the waveguide length determines the statistical transport of light through the waveguide. In a disordered photonic-crystal waveguide, the localization length is highly dispersive, and therefore, by controlling the underlying lattice parameters, it is possible to tune the localization of the mode. In the present work, we study the localization length in a disordered photonic-crystal waveguide using numerical simulations. We demonstrate two different localization regimes in the dispersion diagram where the localization length is linked to the density of states and the photon effective mass, respectively. The two different localization regimes are identified in experiments by recording the photoluminescence from quantum dots embedded in photonic-crystal waveguides.

  3. Efficient fiber-coupled single-photon source based on quantum dots in a photonic-crystal waveguide

    DEFF Research Database (Denmark)

    Daveau, Raphaël S.; Balram, Krishna C.; Pregnolato, Tommaso

    2017-01-01

    Many photonic quantum information processing applications would benefit from a high brightness, fiber-coupled source of triggered single photons. Here, we present a fiber-coupled photonic-crystal waveguide (PCWG) singlephoton source relying on evanescent coupling of the light field from a tapered...

  4. Low-loss 3D-laser-written mid-infrared LiNbO3 depressed-index cladding waveguides for both TE and TM polarizations.

    Science.gov (United States)

    Nguyen, Huu-Dat; Ródenas, Airán; Vázquez de Aldana, Javier R; Martín, Guillermo; Martínez, Javier; Aguiló, Magdalena; Pujol, Maria Cinta; Díaz, Francesc

    2017-02-20

    We report mid-infrared LiNbO3 depressed-index microstructured cladding waveguides fabricated by three-dimensional laser writing showing low propagation losses (~1.5 dB/cm) at 3.68 µm wavelength for both the transverse electric and magnetic polarized modes, a feature previously unachieved due to the strong anisotropic properties of this type of laser microstructured waveguides and which is of fundamental importance for many photonic applications. Using a heuristic modeling-testing iteration design approach which takes into account cladding induced stress-optic index changes, the fabricated cladding microstructure provides low-loss single mode operation for the mid-IR for both orthogonal polarizations. The dependence of the localized refractive index changes within the cladding microstructure with post-fabrication thermal annealing processes was also investigated, revealing its complex dependence of the laser induced refractive index changes on laser fabrication conditions and thermal post-processing steps. The waveguide modes properties and their dependence on thermal post-processing were numerically modeled and fitted to the experimental values by systematically varying three fundamental parameters of this type of waveguides: depressed refractive index values at sub-micron laser-written tracks, track size changes, and piezo-optic induced refractive index changes.

  5. Laser performance and modeling of RE3+:YAG double-clad crystalline fiber waveguides

    Science.gov (United States)

    Li, Da; Lee, Huai-Chuan; Meissner, Stephanie K.; Meissner, Helmuth E.

    2018-02-01

    We report on laser performance of ceramic Yb:YAG and single crystal Tm:YAG double-clad crystalline fiber waveguide (CFW) lasers towards the goal of demonstrating the design and manufacturing strategy of scaling to high output power. The laser component is a double-clad CFW, with RE3+:YAG (RE = Yb, Tm respectively) core, un-doped YAG inner cladding, and ceramic spinel or sapphire outer cladding. Laser performance of the CFW has been demonstrated with 53.6% slope efficiency and 27.5-W stable output power at 1030-nm for Yb:YAG CFW, and 31.6% slope efficiency and 46.7-W stable output power at 2019-nm for Tm:YAG CFW, respectively. Adhesive-Free Bond (AFB®) technology enables a designable refractive index difference between core and inner cladding, and designable core and inner cladding sizes, which are essential for single transverse mode CFW propagation. To guide further development of CFW designs, we present thermal modeling, power scaling and design of single transverse mode operation of double-clad CFWs and redefine the single-mode operation criterion for the double-clad structure design. The power scaling modeling of double-clad CFW shows that in order to achieve the maximum possible output power limited by the physical properties, including diode brightness, thermal lens effect, and simulated Brillion scattering, the length of waveguide is in the range of 0.5 2 meters. The length of an individual CFW is limited by single crystal growth and doping uniformity to about 100 to 200 mm lengths, and also by availability of starting crystals and manufacturing complexity. To overcome the limitation of CFW lengths, end-to-end proximity-coupling of CFWs is introduced.

  6. Reverse-symmetry waveguides: Theory and fabrication

    DEFF Research Database (Denmark)

    Horvath, R.; Lindvold, Lars René; Larsen, N.B.

    2002-01-01

    We present an extensive theoretical analysis of reverse-symmetry waveguides with special focus on their potential application as sensor components in aqueous media and demonstrate a novel method for fabrication of such waveguides. The principle of reverse symmetry is based on making the refractive...... index of the waveguide substrate less than the refractive index of the medium covering the waveguiding film (n(water) = 1.33). This is opposed to the conventional waveguide geometry, where the substrate is usually glass or polymers with refractive indices of approximate to1.5. The reverse configuration...... are combined with air-grooved polymer supports to form freestanding single-material polymer waveguides of reverse symmetry capable of guiding light....

  7. Acoustic-gravity waves in atmospheric and oceanic waveguides.

    Science.gov (United States)

    Godin, Oleg A

    2012-08-01

    A theory of guided propagation of sound in layered, moving fluids is extended to include acoustic-gravity waves (AGWs) in waveguides with piecewise continuous parameters. The orthogonality of AGW normal modes is established in moving and motionless media. A perturbation theory is developed to quantify the relative significance of the gravity and fluid compressibility as well as sensitivity of the normal modes to variations in sound speed, flow velocity, and density profiles and in boundary conditions. Phase and group speeds of the normal modes are found to have certain universal properties which are valid for waveguides with arbitrary stratification. The Lamb wave is shown to be the only AGW normal mode that can propagate without dispersion in a layered medium.

  8. Mini-stop bands in single heterojunction photonic crystal waveguides

    KAUST Repository

    Shahid, N.; Amin, M.; Naureen, S.; Anand, S.

    2013-01-01

    Spectral characteristics of mini-stop bands (MSB) in line-defect photonic crystal (PhC) waveguides and in heterostructure PhC waveguides having one abrupt interface are investigated. Tunability of the MSB position by air-fill factor heterostructure PhC waveguides is utilized to demonstrate different filter functions, at optical communication wavelengths, ranging from resonance-like to wide band pass filters with high transmission. The narrowest filter realized has a resonance-like transmission peak with a full width at half maximum of 3.4 nm. These devices could be attractive for coarse wavelength selection (pass and drop) and for sensing applications. 2013 Copyright 2013 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License.

  9. Short-cavity DBR laser using an InP/InGaAsP deep-ridge waveguide with vertical-groove gratings

    NARCIS (Netherlands)

    Segawa, T.; Docter, B.; Kakitsuka, T.; Matsuo, S.; Ishii, T.; Kawaguchi, Y.; Kondo, Y.; Karouta, F.; Smit, M.K.; Suzuki, H.

    2007-01-01

    A compact distributed Bragg reflector (DBR) laser was fabricated using an InP/InGaAsP deep-ridge waveguide with vertical-groove gratings. We achieved stable single-mode laser operation with an active length of only 25-µm with low threshold current.

  10. FDTD modeling of anisotropic nonlinear optical phenomena in silicon waveguides.

    Science.gov (United States)

    Dissanayake, Chethiya M; Premaratne, Malin; Rukhlenko, Ivan D; Agrawal, Govind P

    2010-09-27

    A deep insight into the inherent anisotropic optical properties of silicon is required to improve the performance of silicon-waveguide-based photonic devices. It may also lead to novel device concepts and substantially extend the capabilities of silicon photonics in the future. In this paper, for the first time to the best of our knowledge, we present a three-dimensional finite-difference time-domain (FDTD) method for modeling optical phenomena in silicon waveguides, which takes into account fully the anisotropy of the third-order electronic and Raman susceptibilities. We show that, under certain realistic conditions that prevent generation of the longitudinal optical field inside the waveguide, this model is considerably simplified and can be represented by a computationally efficient algorithm, suitable for numerical analysis of complex polarization effects. To demonstrate the versatility of our model, we study polarization dependence for several nonlinear effects, including self-phase modulation, cross-phase modulation, and stimulated Raman scattering. Our FDTD model provides a basis for a full-blown numerical simulator that is restricted neither by the single-mode assumption nor by the slowly varying envelope approximation.

  11. Minimum wakefield achievable by waveguide damped cavity

    International Nuclear Information System (INIS)

    Lin, X.E.; Kroll, N.M.

    1995-01-01

    The authors use an equivalent circuit to model a waveguide damped cavity. Both exponentially damped and persistent (decay t -3/2 ) components of the wakefield are derived from this model. The result shows that for a cavity with resonant frequency a fixed interval above waveguide cutoff, the persistent wakefield amplitude is inversely proportional to the external Q value of the damped mode. The competition of the two terms results in an optimal Q value, which gives a minimum wakefield as a function of the distance behind the source particle. The minimum wakefield increases when the resonant frequency approaches the waveguide cutoff. The results agree very well with computer simulation on a real cavity-waveguide system

  12. Non-Markovian dynamics of a qubit due to single-photon scattering in a waveguide

    Science.gov (United States)

    Fang, Yao-Lung L.; Ciccarello, Francesco; Baranger, Harold U.

    2018-04-01

    We investigate the open dynamics of a qubit due to scattering of a single photon in an infinite or semi-infinite waveguide. Through an exact solution of the time-dependent multi-photon scattering problem, we find the qubit's dynamical map. Tools of open quantum systems theory allow us then to show the general features of this map, find the corresponding non-Linbladian master equation, and assess in a rigorous way its non-Markovian nature. The qubit dynamics has distinctive features that, in particular, do not occur in emission processes. Two fundamental sources of non-Markovianity are present: the finite width of the photon wavepacket and the time delay for propagation between the qubit and the end of the semi-infinite waveguide.

  13. Mechanics of inter-modal tunneling in nonlinear waveguides

    Science.gov (United States)

    Jiao, Weijian; Gonella, Stefano

    2018-02-01

    In this article, we investigate the mechanics of nonlinearly induced inter-modal energy tunneling between flexurally-dominated and axially-dominated modes in phononic waveguides. Special attention is devoted to elucidating the role played by the coupling between axial and flexural degrees of freedom in the determination of the available mode hopping conditions and the associated mechanisms of deformation. Waveguides offer an ideal test bed to investigate the mechanics of nonlinear energy tunneling, due to the fact that they naturally feature, even at low frequencies, families of modes (flexural and axial) that are intrinsically characterized by extreme complementarity. Moreover, thanks to their geometric simplicity, their behavior can be explained by resorting to intuitive structural mechanics models that effectively capture the dichotomy and interplay between flexural and axial mechanisms. After having delineated the fundamental mechanics of flexural-to-axial hopping using the benchmark example of a homogeneous structure, we adapt the analysis to the case of periodic waveguides, in which the complex dispersive behavior due to periodicity results in additional richness of mode hopping mechanisms. We finally extend the analysis to periodic waveguides with internal resonators, in which the availability of locally-resonant bandgaps implies the possibility to activate the resonators even at relatively low frequencies, thus increasing the degree of modal complementarity that is available in the acoustic range. In this context, inter-modal tunneling provides an unprecedented mechanism to transfer conspicuous packets of energy to the resonating microstructure.

  14. Photonic bandpass filter characteristics of multimode SOI waveguides integrated with submicron gratings.

    Science.gov (United States)

    Sah, Parimal; Das, Bijoy Krishna

    2018-03-20

    It has been shown that a fundamental mode adiabatically launched into a multimode SOI waveguide with submicron grating offers well-defined flat-top bandpass filter characteristics in transmission. The transmitted spectral bandwidth is controlled by adjusting both waveguide and grating design parameters. The bandwidth is further narrowed down by cascading two gratings with detuned parameters. A semi-analytical model is used to analyze the filter characteristics (1500  nm≤λ≤1650  nm) of the device operating in transverse-electric polarization. The proposed devices were fabricated with an optimized set of design parameters in a SOI substrate with a device layer thickness of 250 nm. The pass bandwidth of waveguide devices integrated with single-stage gratings are measured to be ∼24  nm, whereas the device with two cascaded gratings with slightly detuned periods (ΔΛ=2  nm) exhibits a pass bandwidth down to ∼10  nm.

  15. Wave propagation in plasma-filled wave-guide

    International Nuclear Information System (INIS)

    Leprince, Philippe

    1966-01-01

    This research thesis reports the study of wave propagation along a plasma column without external magnetic field. The author first present and comment various theoretical results, and dispersion curves plotted for the main modes (particularly, the bipolar mode). He tries to define fundamental magnitudes which characterise a plasma-filled wave-guide. He reports the comparison of some experimental results with the previous theoretical results. Based on the study of the bipolar mode, the author develops a method of measurement of plasma column density. In the last part, the author reports the study of the resonance of a plasma-containing cavity. Several resonances are highlighted and new dispersion curves are plotted by using a varying length cavity. He also addresses the coupling of plasma modes with guide modes, and thus indicates the shape of Brillouin diagrams for a plasma-filled wave-guide. Moreover, some phenomena highlighted during plasma column density measurements by using the cavity method could then be explained [fr

  16. Reciprocity principle for scattered fields from discontinuities in waveguides.

    Science.gov (United States)

    Pau, Annamaria; Capecchi, Danilo; Vestroni, Fabrizio

    2015-01-01

    This study investigates the scattering of guided waves from a discontinuity exploiting the principle of reciprocity in elastodynamics, written in a form that applies to waveguides. The coefficients of reflection and transmission for an arbitrary mode can be derived as long as the principle of reciprocity is satisfied at the discontinuity. Two elastodynamic states are related by the reciprocity. One is the response of the waveguide in the presence of the discontinuity, with the scattered fields expressed as a superposition of wave modes. The other state is the response of the waveguide in the absence of the discontinuity oscillating according to an arbitrary mode. The semi-analytical finite element method is applied to derive the needed dispersion relation and wave mode shapes. An application to a solid cylinder with a symmetric double change of cross-section is presented. This model is assumed to be representative of a damaged rod. The coefficients of reflection and transmission of longitudinal waves are investigated for selected values of notch length and varying depth. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Dynamically tunable slow light based on plasmon induced transparency in disk resonators coupled MDM waveguide system

    International Nuclear Information System (INIS)

    Han, Xu; Wang, Tao; Liu, Bo; He, Yu; Tang, Jian; Li, Xiaoming

    2015-01-01

    Ultrafast and low-power dynamically tunable single channel and multichannel slow light based on plasmon induced transparencies (PITs) in disk resonators coupled to a metal-dielectric-metal (MDM) waveguide system with a nonlinear optical Kerr medium is investigated both numerically and analytically. A coupled-mode theory (CMT) is introduced to analyze this dynamically tunable single channel slow light structure. Multichannel slow light is realized in this plasmonic waveguide structure based on a bright–dark mode coupling mechanism. In order to reduce the pump intensity and obtain ultrafast response time, the traditional nonlinear Kerr material is replaced by monolayer graphene. It is found that the magnitude of the single PIT window can be controlled between 0.08 and 0.48, while the corresponding group index is controlled between 14.5 and 2.0 by dynamically decreasing pump intensity from 11.7 to 4.4 MW cm −2 . Moreover, the phase shift multiplication effect is found in this structure. This work paves a new way towards the realization of highly integrated optical circuits and networks, especially for wavelength-selective, all-optical storage and nonlinear devices. (paper)

  18. A grating coupler with a trapezoidal hole array for perfectly vertical light coupling between optical fibers and waveguides

    Science.gov (United States)

    Mizutani, Akio; Eto, Yohei; Kikuta, Hisao

    2017-12-01

    A grating coupler with a trapezoidal hole array was designed and fabricated for perfectly vertical light coupling between a single-mode optical fiber and a silicon waveguide on a silicon-on-insulator (SOI) substrate. The grating coupler with an efficiency of 53% was computationally designed at a 1.1-µm-thick buried oxide (BOX) layer. The grating coupler and silicon waveguide were fabricated on the SOI substrate with a 3.0-µm-thick BOX layer by a single full-etch process. The measured coupling efficiency was 24% for TE-polarized light at 1528 nm wavelength, which was 0.69 times of the calculated coupling efficiency for the 3.0-µm-thick BOX layer.

  19. Direct imaging of optical interference in erbium-doped Al2O3 waveguides

    NARCIS (Netherlands)

    Hoven, van den G.N.; Polman, A.; Dam, van C.; Uffelen, van J.W.M.; Smit, M.K.

    1996-01-01

    Interference of 1.48-mu m light in multimode interference waveguides is made visible by imaging green and infrared upconversion luminescence from Er3+ ions dispersed in the waveguide. A two-dimensional mode density image can be derived from the data and agrees well with mode calculations for this

  20. Optical analogue of relativistic Dirac solitons in binary waveguide arrays

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Truong X., E-mail: truong.tran@mpl.mpg.de [Department of Physics, Le Quy Don University, 236 Hoang Quoc Viet str., 10000 Hanoi (Viet Nam); Max Planck Institute for the Science of Light, Günther-Scharowsky str. 1, 91058 Erlangen (Germany); Longhi, Stefano [Department of Physics, Politecnico di Milano and Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Piazza L. da Vinci 32, I-20133 Milano (Italy); Biancalana, Fabio [Max Planck Institute for the Science of Light, Günther-Scharowsky str. 1, 91058 Erlangen (Germany); School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS Edinburgh (United Kingdom)

    2014-01-15

    We study analytically and numerically an optical analogue of Dirac solitons in binary waveguide arrays in the presence of Kerr nonlinearity. Pseudo-relativistic soliton solutions of the coupled-mode equations describing dynamics in the array are analytically derived. We demonstrate that with the found soliton solutions, the coupled mode equations can be converted into the nonlinear relativistic 1D Dirac equation. This paves the way for using binary waveguide arrays as a classical simulator of quantum nonlinear effects arising from the Dirac equation, something that is thought to be impossible to achieve in conventional (i.e. linear) quantum field theory. -- Highlights: •An optical analogue of Dirac solitons in nonlinear binary waveguide arrays is suggested. •Analytical solutions to pseudo-relativistic solitons are presented. •A correspondence of optical coupled-mode equations with the nonlinear relativistic Dirac equation is established.

  1. Frustration of Bragg reflection by cooperative dual-mode interference: a new mode of optical propagation.

    Science.gov (United States)

    Yariv, A

    1998-12-01

    A new optical mode of propagation is described, which is the natural eigenmode (supermode) of a fiber (or any optical waveguide) with two cospatial periodic gratings. The mode frustrates the backward Bragg scattering from the grating by destructive interference of its two constituent submodes (which are eigenmodes of a uniform waveguide). It can be used in a new type of spatial mode conversion in optical guides.

  2. Calculation, normalization and perturbation of quasinormal modes in coupled cavity-waveguide systems

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; de Lasson, Jakob Rosenkrantz; Gregersen, Niels

    2014-01-01

    of divergent series to provide a framework for modeling of optical phenomena in such coupled cavity-waveguide systems. As an example, we apply the framework to study perturbative changes in the resonance frequency and Q value of a photonic crystal cavity coupled to a defect waveguide....

  3. Nonlinear optical model for strip plasmonic waveguides

    DEFF Research Database (Denmark)

    Lysenko, Oleg; Bache, Morten; Lavrinenko, Andrei

    2016-01-01

    This paper presents a theoretical model of nonlinear optical properties for strip plasmonic waveguides. The particular waveguides geometry that we investigate contains a gold core, adhesion layers, and silicon dioxide cladding. It is shown that the third-order susceptibility of the gold core...... significantly depends on the layer thickness and has the dominant contribution to the effective third-order susceptibility of the long-range plasmon polariton mode. This results in two nonlinear optical effects in plasmonic waveguides, which we experimentally observed and reported in [Opt. Lett. 41, 317 (2016...... approaches. (C) 2016 Optical Society of America...

  4. An on-chip polarization splitter based on the radiation loss in the bending hybrid plasmonic waveguide structure

    Science.gov (United States)

    Sun, Chengwei; Rong, Kexiu; Gan, Fengyuan; Chu, Saisai; Gong, Qihuang; Chen, Jianjun

    2017-09-01

    Polarization beam splitters (PBSs) are one of the key components in the integrated photonic circuits. To increase the integration density, various complex hybrid plasmonic structures have been numerically designed to shrink the footprints of the PBSs. Here, to decrease the complexity of the small hybrid structures and the difficulty of the hybrid micro-nano fabrications, the radiation losses are utilized to experimentally demonstrate an ultra-small, broadband, and efficient PBS in a simple bending hybrid plasmonic waveguide structure. The hybrid plasmonic waveguide comprising a dielectric strip on the metal surface supports both the transverse-magnetic (TM) and transverse-electric (TE) waveguide modes. Because of the different field confinements, the TE waveguide mode has larger radiation loss than the TM waveguide mode in the bending hybrid strip waveguide. Based on the different radiation losses, the two incident waveguide modes of orthogonal polarization states are efficiently split in the proposed structure with a footprint of only about 2.2 × 2.2 μm2 on chips. Since there is no resonance or interference in the splitting process, the operation bandwidth is as broad as Δλ = 70 nm. Moreover, the utilization of the strongly confined waveguide modes instead of the bulk free-space light (with the spot size of at least a few wavelengths) as the incident source considerably increases the coupling efficiency, resulting in a low insertion loss of <3 dB.

  5. Nonstationary behavior in a delayed feedback traveling wave tube folded waveguide oscillator

    International Nuclear Information System (INIS)

    Ryskin, N.M.; Titov, V.N.; Han, S.T.; So, J.K.; Jang, K.H.; Kang, Y.B.; Park, G.S.

    2004-01-01

    Folded waveguide traveling-wave tubes (FW TWT) are among the most promising candidates for powerful compact amplifiers and oscillators in millimeter and submillimeter wave bands. In this paper, the nonstationary behavior of a FW TWT oscillator with delayed feedback is investigated. Starting conditions of the oscillations are derived analytically. Results of numerical simulation of single-frequency, self-modulation (multifrequency) and chaotic generation regimes are presented. Mode competition phenomena, multistability and hysteresis are discussed

  6. Design of a Label-Free, Distributed Bragg Grating Resonator Based Dielectric Waveguide Biosensor

    Directory of Open Access Journals (Sweden)

    Florian Kehl

    2015-01-01

    Full Text Available In this work, we present a resonant, dielectric waveguide device based on distributed Bragg gratings for label-free biosensing applications. The refractive index sensitive optical transducer aims at improving the performance of planar waveguide grating sensor systems with limited Q-factor and dynamic range by combing the advantages of resonant cavities, such as a multitude of resonance peaks with high finesse, with the manageable complexity of waveguide grating couplers. The general sensor concept is introduced and supported by theoretical considerations as well as numerical simulations based on Coupled Mode Theory. In contrast to a single Bragg grating reflector, the presented Fabry-Pérot type distributed Bragg resonator exhibits an extended measurement range as well as relaxed fabrication tolerances. The resulting, relatively simple sensor structure can be fabricated with standard lithographic means and is independent of expensive light-sources and/or detectors, making an affordable but sensitive device, potentially suitable for point-of-care applications.

  7. Ultra-thin silicon/electro-optic polymer hybrid waveguide modulators

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Feng; Spring, Andrew M. [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Sato, Hiromu [Department of Molecular and Material Sciences, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Maeda, Daisuke; Ozawa, Masa-aki; Odoi, Keisuke [Nissan Chemical Industries, Ltd., 2-10-1 Tuboi Nishi, Funabashi, Chiba 274-8507 (Japan); Aoki, Isao; Otomo, Akira [National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe 651-2492 (Japan); Yokoyama, Shiyoshi, E-mail: s-yokoyama@cm.kyushu-u.ac.jp [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Department of Molecular and Material Sciences, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan)

    2015-09-21

    Ultra-thin silicon and electro-optic (EO) polymer hybrid waveguide modulators have been designed and fabricated. The waveguide consists of a silicon core with a thickness of 30 nm and a width of 2 μm. The cladding is an EO polymer. Optical mode calculation reveals that 55% of the optical field around the silicon extends into the EO polymer in the TE mode. A Mach-Zehnder interferometer (MZI) modulator was prepared using common coplanar electrodes. The measured half-wave voltage of the MZI with 7 μm spacing and 1.3 cm long electrodes is 4.6 V at 1550 nm. The evaluated EO coefficient is 70 pm/V, which is comparable to that of the bulk EO polymer film. Using ultra-thin silicon is beneficial in order to reduce the side-wall scattering loss, yielding a propagation loss of 4.0 dB/cm. We also investigated a mode converter which couples light from the hybrid EO waveguide into a strip silicon waveguide. The calculation indicates that the coupling loss between these two devices is small enough to exploit the potential fusion of a hybrid EO polymer modulator together with a silicon micro-photonics device.

  8. PREPARATION OF THE SINGLE MODE PLANAR OPTICAL SPLITTER MODULES AND THEIR CHARACTERIZATIONS

    Directory of Open Access Journals (Sweden)

    Vu Doan Mien

    2017-11-01

    Full Text Available Optical splitter modules have been prepared based on 1x8 single mode silica planar waveguide optical splitter chips with 250 µm spacing and v-groove fiber arrays for applications in fiber optic communications. We report the technology of precise optical coupling and packaging of the splitter modules and the measurements of the insertion loss (< 11 dB,  uniformity (< 0.80 dB and polarization dependence loss (PLD < 0.10 dB as well as the lateral profile and the image of the input and output lights for the wavelengths of 1310 nm and 1550 nm. The main characteristics of the prepared splitter modules are about the same for the commercial available products. The prepared modules have been tested for operation in the conditions of wide temperature range (5–80°C and humidity range (50–98% and no changes in the main characteristics were observed.

  9. Arrayed waveguide Sagnac interferometer.

    Science.gov (United States)

    Capmany, José; Muñoz, Pascual; Sales, Salvador; Pastor, Daniel; Ortega, Beatriz; Martinez, Alfonso

    2003-02-01

    We present a novel device, an arrayed waveguide Sagnac interferometer, that combines the flexibility of arrayed waveguides and the wide application range of fiber or integrated optics Sagnac loops. We form the device by closing an array of wavelength-selective light paths provided by two arrayed waveguides with a single 2 x 2 coupler in a Sagnac configuration. The equations that describe the device's operation in general conditions are derived. A preliminary experimental demonstration is provided of a fiber prototype in passive operation that shows good agreement with the expected theoretical performance. Potential applications of the device in nonlinear operation are outlined and discussed.

  10. Transverse wakefield of waveguide damped structures and beam dynamics

    International Nuclear Information System (INIS)

    Lin, X.

    1995-08-01

    In the design of new high energy particle colliders with higher luminosity one is naturally led to consider multi-bunch operation. However, the passage of a leading bunch through an accelerator cavity Generates a wakefield that may have a deleterious effect on the motion of the subsequent bunches. Therefore, the suppression of the wakefield is an essential requirement for beam stability. One solution to this problem, which has been studied extensively is to drain the wakefield energy out of the cavity by means of waveguides coupled with the cavity and fed into matched terminations. Waveguide dimensions are chosen to yield a cutoff frequency well above the frequency of the accelerating mode so that the latter is undamped. This paper presents a thorough investigation of the wakefield for this configuration. The effectiveness of waveguide damping has typically been assessed by evaluating the resultant Q ext of higher order cavity modes to determine their exponential damping rate. We have developed an efficient method to calculate Q ext of the damped modes from popular computer simulation codes such as MAFIA. This method has been successively applied to the B-factory RF cavity We have also found another type of wakefield, associated with waveguide cut-off, which decays as t -3/2 rather than in the well-known exponentially damped manner. Accordingly, we called it the persistent Wakefield. A similar phenomenon with essentially the same physical origin but occurring in the decay of unstable quantum states, has received extensive study. Then we have developed various methods of calculating this persistent wakefield, including mode matching and computer simulation. Based on a circuit model we estimate the limit that waveguide damping can reach to reduce the wakefield

  11. Spontaneous emission and gain in a waveguide free-electron laser

    International Nuclear Information System (INIS)

    Golightly, W.J.; Ride, S.K.

    1991-01-01

    A free-electron laser enclosed in a waveguide of narrowly spaced parallel plates has been proposed as a compact, coherent source of far-infrared radiation. In this paper, the spontaneous emission and small-signal gain of such a device are analyzed. Maxwell's equations are solved for the fields of a relativistic electron beam passing through a linearly polarized undulator in the presence of a parallel-plane waveguide. The radiation intensity is resolved into its component waveguide modes for the fundamental frequency and for all harmonics. The intensity profile in a given harmonic mode is altered significantly when a parameter involving the undulator period, beam energy, and transverse dimension of the guide is such that the radiation group velocity is close to the electrons' axial velocity. The small-signal gain in the waveguide free-electron laser is calculated and related to the spontaneous emission. Near zero slip, the gain curve is significantly different from that of a free-space free-electron laser with the same parameters

  12. Propagation losses in photonic crystal waveguides: Effects of band tail absorption and waveguide dispersion

    DEFF Research Database (Denmark)

    Rigal, F.; Joanesarson, Kristoffer Bitsch; Lyasota, A.

    2017-01-01

    Propagation losses in GaAs-based photonic crystal (PhC) waveguides are evaluated near the semiconductor band-edge by measuring the finesse of corresponding Ln cavities. This approach yields simultaneously the propagation losses and the mode reflectivity at the terminations of the cavities. We dem...

  13. Near-field imaging of light propagation in photonic crystal waveguides: Explicit role of Bloch harmonics

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Volkov, V.S.; Søndergaard, Thomas

    2002-01-01

    We employ a collection scanning near-field optical microscope (SNOM) to image the propagation of light at telecommunication wavelengths along straight and bent regions of silicon-on-insulator photonic crystal waveguides (PCWs) formed by removing a single row of holes in the triangular 410-nm...... the interference between a quasihomogeneous background field and Bloch harmonics of the PCW mode, we account for spatial frequency spectra of the intensity variations and determine the propagation constant of the PCW mode at 1520 nm. The possibilities and limitations of SNOM imaging for the characterization...

  14. Initial results for a 170 GHz high power ITER waveguide component test stand

    Science.gov (United States)

    Bigelow, Timothy; Barker, Alan; Dukes, Carl; Killough, Stephen; Kaufman, Michael; White, John; Bell, Gary; Hanson, Greg; Rasmussen, Dave

    2014-10-01

    A high power microwave test stand is being setup at ORNL to enable prototype testing of 170 GHz cw waveguide components being developed for the ITER ECH system. The ITER ECH system will utilize 63.5 mm diameter evacuated corrugated waveguide and will have 24 >150 m long runs. A 170 GHz 1 MW class gyrotron is being developed by Communications and Power Industries and is nearing completion. A HVDC power supply, water-cooling and control system has been partially tested in preparation for arrival of the gyrotron. The power supply and water-cooling system are being designed to operate for >3600 second pulses to simulate the operating conditions planned for the ITER ECH system. The gyrotron Gaussian beam output has a single mirror for focusing into a 63.5 mm corrugated waveguide in the vertical plane. The output beam and mirror are enclosed in an evacuated duct with absorber for stray radiation. Beam alignment with the waveguide is a critical task so a combination of mirror tilt adjustments and a bellows for offsets will be provided. Analysis of thermal patterns on thin witness plates will provide gyrotron mode purity and waveguide coupling efficiency data. Pre-prototype waveguide components and two dummy loads are available for initial operational testing of the gyrotron. ORNL is managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under Contract DE-AC-05-00OR22725.

  15. Waveguide based external cavity semiconductor lasers

    NARCIS (Netherlands)

    Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

    2012-01-01

    We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

  16. Vector pulsing soliton of self-induced transparency in waveguide

    International Nuclear Information System (INIS)

    Adamashvili, G.T.

    2015-01-01

    A theory of an optical resonance vector pulsing soliton in waveguide is developed. A thin transition layer containing semiconductor quantum dots forms the boundary between the waveguide and one of the connected media. Analytical and numerical solutions for the optical vector pulsing soliton in waveguide are obtained. The vector pulsing soliton in the presence of excitonic and bi-excitonic excitations is compared with the soliton for waveguide TM-modes with parameters that can be used in modern optical experiments. It is shown that these nonlinear waves have significantly different parameters and shapes. - Highlights: • An optical vector pulsing soliton in a planar waveguide is presented. • Explicit form of the optical vector pulsing soliton are obtained. • The vector pulsing soliton and the soliton have different parameters and profiles

  17. Modes in light wave propagating in semiconductor laser

    Science.gov (United States)

    Manko, Margarita A.

    1994-01-01

    The study of semiconductor laser based on an analogy of the Schrodinger equation and an equation describing light wave propagation in nonhomogeneous medium is developed. The active region of semiconductor laser is considered as optical waveguide confining the electromagnetic field in the cross-section (x,y) and allowing waveguide propagation along the laser resonator (z). The mode structure is investigated taking into account the transversal and what is the important part of the suggested consideration longitudinal nonhomogeneity of the optical waveguide. It is shown that the Gaussian modes in the case correspond to spatial squeezing and correlation. Spatially squeezed two-mode structure of nonhomogeneous optical waveguide is given explicitly. Distribution of light among the laser discrete modes is presented. Properties of the spatially squeezed two-mode field are described. The analog of Franck-Condon principle for finding the maxima of the distribution function and the analog of Ramsauer effect for control of spatial distribution of laser emission are discussed.

  18. Low-loss curved subwavelength grating waveguide based on index engineering

    Science.gov (United States)

    Wang, Zheng; Xu, Xiaochuan; Fan, D. L.; Wang, Yaoguo; Chen, Ray T.

    2016-03-01

    Subwavelength grating (SWG) waveguide is an intriguing alternative to conventional optical waveguides due to its freedom to tune a few important waveguide properties such as dispersion and refractive index. Devices based on SWG waveguide have demonstrated impressive performances compared to those of conventional waveguides. However, the large loss of SWG waveguide bends jeopardizes their applications in integrated photonics circuits. In this work, we propose that a predistorted refractive index distribution in SWG waveguide bends can effectively decrease the mode mismatch noise and radiation loss simultaneously, and thus significantly reduce the bend loss. Here, we achieved the pre-distortion refractive index distribution by using trapezoidal silicon pillars. This geometry tuning approach is numerically optimized and experimentally demonstrated. The average insertion loss of a 5 μm SWG waveguide bend can be reduced drastically from 5.58 dB to 1.37 dB per 90° bend for quasi-TE polarization. In the future, the proposed approach can be readily adopted to enhance performance of an array of SWG waveguide-based photonics devices.

  19. A half mode inkjet printed tunable ferrite isolator

    KAUST Repository

    Ghaffar, Farhan A.

    2017-10-24

    A novel half mode waveguide based ferrite isolator design is presented in this work. For the first time, tunability of the isolation band is demonstrated for a ferrite isolator. Instead of using the conventional antisymmetric bias the isolator requires a single direction of the magnetic bias field due to the half mode operation. Yttrium Iron Garnet (YIG) is used as the substrate for the device. The metallic walls of the waveguide are realized using inkjet printing. The magnetic biasing applied to the waveguide causes the RF waves to experience negative permeability in one direction of propagation hence providing isolation for this direction. For an applied bias of 3000 Oe, the device provides a maximum isolation figure of merit of 76.7 dB at 7.5 GHz. The isolation band can be controlled by changing the applied magnetostatic bias. As the bias is varied from 1500 Oe to 3500 Oe the center frequency of the isolation band varies from 4.45 GHz to 9 GHz. The measured response of the isolator shows that it can be integrated in any RF system requiring lower cost and good isolation.

  20. Dynamic diffraction-limited light-coupling of 3D-maneuvered wave-guided optical waveguides.

    Science.gov (United States)

    Villangca, Mark; Bañas, Andrew; Palima, Darwin; Glückstad, Jesper

    2014-07-28

    We have previously proposed and demonstrated the targeted-light delivery capability of wave-guided optical waveguides (WOWs). As the WOWs are maneuvered in 3D space, it is important to maintain efficient light coupling through the waveguides within their operating volume. We propose the use of dynamic diffractive techniques to create diffraction-limited spots that will track and couple to the WOWs during operation. This is done by using a spatial light modulator to encode the necessary diffractive phase patterns to generate the multiple and dynamic coupling spots. The method is initially tested for a single WOW and we have experimentally demonstrated dynamic tracking and coupling for both lateral and axial displacements.

  1. Dynamic diffraction-limited light-coupling of 3D-maneuvered wave-guided optical waveguides

    DEFF Research Database (Denmark)

    Villangca, Mark Jayson; Bañas, Andrew Rafael; Palima, Darwin

    2014-01-01

    We have previously proposed and demonstrated the targeted-light delivery capability of wave-guided optical waveguides (WOWs). As the WOWs are maneuvered in 3D space, it is important to maintain efficient light coupling through the waveguides within their operating volume. We propose the use...... of dynamic diffractive techniques to create diffraction-limited spots that will track and couple to the WOWs during operation. This is done by using a spatial light modulator to encode the necessary diffractive phase patterns to generate the multiple and dynamic coupling spots. The method is initially tested...... for a single WOW and we have experimentally demonstrated dynamic tracking and coupling for both lateral and axial displacements....

  2. Modal analysis and cut-off conditions of multichannel surface-acoustic-waveguide structures.

    Science.gov (United States)

    Griffel, G; Golan, G; Ruschin, S; Seidman, A; Croitoru, N

    1988-01-01

    Multichannel guides for surface acoustic waves can improve the efficiency of SAW (surface acoustic-wave) devices significantly. Focusing, steering, and modulating the propagating acoustical modes can be achieved similarly to optical waveguided devices. A general formulation is presented for the analysis of the lateral waveguiding properties of Rayleigh modes in surfaces loaded with deposited strips of different materials. General expressions are obtained for the number of modes and cutoff conditions in these structures. As examples of applications, a simple directional coupler and an electrically controlled coupler are proposed.

  3. Cost-effective, compact and high-speed integrable multi-mode interference modulator

    NARCIS (Netherlands)

    Lenstra, Daan; Yao, Weiming; Cardarelli, Simone; Mink, Jan

    2017-01-01

    Theoretical analysis of the modulation performance of this wave-guide device shows great potential when combined with a single-mode laser on a monolithic optical chip. On the basis of the reversed-bias electro-optic effect, modulation speeds surmounting 25 Gbit/s with 10 dB extinction ratio are

  4. Low-loss CMOS copper plasmonic waveguides at the nanoscale (Conference Presentation)

    Science.gov (United States)

    Fedyanin, Dmitry Y.; Yakubovsky, Dmitry I.; Kirtaev, Roman V.; Volkov, Valentyn S.

    2016-05-01

    Implementation of optical components in microprocessors can increase their performance by orders of magnitude. However, the size of optical elements is fundamentally limited by diffraction, while miniaturization is one of the essential concepts in the development of high-speed and energy-efficient electronic chips. Surface plasmon polaritons (SPPs) are widely considered to be promising candidates for the next generation of chip-scale technology thanks to the ability to break down the fundamental diffraction limit and manipulate optical signals at the truly nometer scale. In the past years, a variety of deep-subwavelength plasmonic structures have been proposed and investigated, including dielectric-loaded SPP waveguides, V-groove waveguides, hybrid plasmonic waveguides and metal nanowires. At the same time, for practical application, such waveguide structures must be integrated on a silicon chip and be fabricated using CMOS fabrication process. However, to date, acceptable characteristics have been demonstrated only with noble metals (gold and silver), which are not compatible with industry-standard manufacturing technologies. On the other hand, alternative materials introduce enormous propagation losses due absorption in the metal. This prevents plasmonic components from implementation in on-chip nanophotonic circuits. In this work, we experimentally demonstrate for the first time that copper plasmonic waveguides fabricated in a CMOS compatible process can outperform gold waveguides showing the same level of mode confinement and lower propagation losses. At telecommunication wavelengths, the fabricated ultralow-loss deep-subwavelength hybrid plasmonic waveguides ensure a relatively long propagation length of more than 50 um along with strong mode confinement with the mode size down to lambda^2/70, which is confirmed by direct scanning near-field optical microscopy (SNOM) measurements. These results create the backbone for design and development of high

  5. A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides

    Directory of Open Access Journals (Sweden)

    Wagner D.

    2015-01-01

    Full Text Available Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength. A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B, ABmm (MVNA 8-350 and Rohde&Schwarz (ZVA24 together with frequency multipliers. The

  6. Magnetosonic Waveguide Model of Solar Wind Flow Tubes A. K. ...

    Indian Academy of Sciences (India)

    of plasma velocity or due to sudden variation of Alfvén or sound speed. Surface mag- netosonic wave is evanescent both inside and outside of waveguide, while the body magnetosonic wave is oscillatory inside the waveguide and evanescent outside. Both the wave modes are localized and non-leaky. Nakariakov et al.

  7. 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....

  8. Conductance dips and spin precession in a nonuniform waveguide with spin–orbit coupling

    Energy Technology Data Exchange (ETDEWEB)

    Malyshev, A. I., E-mail: malyshev@phys.unn.ru; Kozulin, A. S. [Lobachevsky Nizhny Novgorod State University (Russian Federation)

    2015-07-15

    An infinite waveguide with a nonuniformity, a segment of finite length with spin–orbit coupling, is considered in the case when the Rashba and Dresselhaus parameters are identical. Analytical expressions have been derived in the single-mode approximation for the conductance of the system for an arbitrary initial spin state. Based on numerical calculations with several size quantization modes, we have detected and described the conductance dips arising when the waves are localized in the nonuniformity due to the formation of an effective potential well in it. We show that allowance for the evanescent modes under carrier spin precession in an effective magnetic field does not lead to a change in the direction of the average spin vector at the output of the system.

  9. Ultrafast Laser Fabrication of Bragg Waveguides in GLS Chalcogenide Glass

    Directory of Open Access Journals (Sweden)

    McMillen Ben

    2013-11-01

    Full Text Available We present work on the fabrication of Bragg waveguides in gallium-lanthanum-sulfide chalcogenide glass using an ultrafast laser. Waveguides were written with a single pass while modulating the writing beam. The spatial and temporal profile of the writing beam was ontrolled during waveguide fabrication in order to control the shape and size of the waveguide cross-section.

  10. Optimized-geometry ARROW waveguides using TiO{sub 2} as anti-resonant layer

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Daniel O.; Albertin, Katia F.; Alayo, Marco I. [PSI, University of Sao Paulo (Brazil)

    2010-04-15

    The simulation, fabrication and characterization of ARROW waveguides using dielectric films deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) and Sputtering techniques, are presented in this work. Amorphous titanium oxide (TiO{sub 2}) films were used as first cladding layer and silicon oxynitride (SiO{sub x}N{sub y}) films, as core layer. Furthermore, homemade routines based in two computational methods were used, for numerical simulations: Transfer Matrix Method (TMM) for the determination of the optimum thickness values of the Fabry-Perot layers, and the Finite Difference Method (FDM) for 2D design and determination of the maximum width that allows single-mode operation. The utilization of thermally grown silicon oxide as second anti-resonant layer, along with improvements in the Reactive Ion Etching conditions for the definition of sidewalls of the optical waveguides were responsible for diminishing optical attenuations. Optimization of the waveguide rib height was done both through FDM simulations and experimentally. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Influence of higher order modes on angled-facet amplifiers

    DEFF Research Database (Denmark)

    Wang, Z.; Mikkelsen, B.; Stubkjær, Kristian

    1991-01-01

    The influence of the first-order mode on the residual reflectivity of angled-facet amplifiers is analyzed. For a 7 degrees angled-facet ridge waveguide amplifier with a single-layer antireflective (AR) coating, a gain ripple lower than 1-dB at 25-dB gain can be obtained independent...... of the polarization, even in the presence of a first-order mode with a 15-dB gain. The tolerances for the thickness and refractive index of the AR coating are reduced by a factor of three compared to operation in the fundamental mode only. The influence of the higher order mode can virtually be suppressed...

  12. Enhanced Gain in Slow-Light Photonic Crystal Waveguides with Embedded Quantum Dots

    DEFF Research Database (Denmark)

    Ek, Sara; Hansen, Per Lunnemann; Semenova, Elizaveta

    2011-01-01

    We experimentally demonstrate enhanced gain in the slow-light regime of quantum dot photonic crystal waveguide slabs. These are promising results for future compact devices for terabit/s communication, such as compact optical amplifiers and mode-locked lasers.......We experimentally demonstrate enhanced gain in the slow-light regime of quantum dot photonic crystal waveguide slabs. These are promising results for future compact devices for terabit/s communication, such as compact optical amplifiers and mode-locked lasers....

  13. Mechanical Kerr nonlinearities due to bipolar optical forces between deformable silicon waveguides.

    Science.gov (United States)

    Ma, Jing; Povinelli, Michelle L

    2011-05-23

    We use an analytical method based on the perturbation of effective index at fixed frequency to calculate optical forces between silicon waveguides. We use the method to investigate the mechanical Kerr effect in a coupled-waveguide system with bipolar forces. We find that a positive mechanical Kerr coefficient results from either an attractive or repulsive force. An enhanced mechanical Kerr coefficient several orders of magnitude larger than the intrinsic Kerr coefficient is obtained in waveguides for which the optical mode approaches the air light line, given appropriate design of the waveguide dimensions.

  14. Ridge waveguide fabrication by combining ion implantation and precise dicing on a LiNbO{sub 3} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yu-Fan; Wang, Lei; Liu, Peng; Liu, Tao; Zhang, Lian; Huang, Dong-Ting; Wang, Xue-Lin, E-mail: xuelinwang@sdu.edu.cn

    2014-05-01

    A ridge waveguide structure was prepared on a z-cut LiNbO{sub 3} crystal wafer by a combined process of ion implantation and precise dicing. The single-crystal LiNbO{sub 3} was implanted at room temperature using 3 MeV oxygen ions at a fluence of 5 × 10{sup 14} ions/cm{sup 2}. After annealing to 200 °C, ridge structures were formed on the wafer surface by precise diamond blade dicing. Two different ridge widths, 8 and 10 μm, were chosen for comparison. The refractive index profile was reconstructed, and the near-field intensity distribution of the mode was recorded by a CCD camera using the end-face coupling method. FD-BPM was used to simulate the guided mode profile. Transmission and reflection optical microscopy were used to obtain micro-photograph images of the waveguide structure.

  15. Investigation and modelling of rare-earth activated waveguide structures

    International Nuclear Information System (INIS)

    Wolinski, W.; Malinowski, M.; Mossakowska-Wyszynska, A.; Piramidowicz, R.; Szczepanski, P.

    2005-01-01

    In this paper the overview of the recent study on the rare-earth activated waveguides performed in the Optoelectronic Department of IMiO is presented. We reported on the development of rare earth-doped fluorozirconate (ZBLAN) glass fibers that allow a construction of a new family of visible and ultraviolet fiber lasers pumped by upconversion. Especially the performance of holmium devices is presented. The properties of laser planar waveguides obtained by the LPE process and the growth conditions of rare earths doped YAG layers are presented. In this paper we present also the theoretical study of the nonlinear operation of planar waveguide laser, as an example the microdisk Nd:YAG structure is discussed. We derived an approximate formula which relates the small signal gain in the Nd:YAG active medium and the laser characteristics, obtained for whispering-gallery modes and radial modes, to the output power and real parameters of the laser structure (authors)

  16. Evolution of Eigenmodes of the Mhd-Waveguide in the Outer Magnetosphere

    Science.gov (United States)

    Chuiko, Daniil

    EVOLUTION OF EIGENMODES OF THE MHD-WAVEGUIDE IN THE OUTER MAGNETOSPHERE Mazur V.A., Chuiko D.A. Institute of Solar-Terrestrial Physics, Irkutsk, Russia. Geomagnetic field and plasma inhomogeneties in the outer equatorial part of the magnetosphere al-lows for existence of a channel with low Alfven speeds, which spans from the nose to the far flanks of the magnetosphere, in the morning as well as in the evening sectors. This channel plays a role of a waveguide for fast magnetosonic waves. When an eigenmode travels along the waveguide (i.e. in the azimuthal direction) it undergoes certain evolution. The parameters of the waveguide are changing along the way of wave’s propagation and the eigenmode “adapts” to these parameters. Conditions of the Kelvin-Helmholtz instability are changing due to the increment in the solar wind speed along the magnetopause. The conditions of the solar wind hydromagnetic waves penetration to the magnetosphere are changing due to the same increment. As such, the process of the penetration turns to overreflection regime, which abruptly increases the pump level of the magnetospheric waveguide. There is an Alfven resonance deep within the magnetosphere, which corresponds to the propagation of the fast mode along the waveguide. Oscillation energy dissipation takes place in the vicinity of the Alfven resonance. Alfven resonance is a standing Alfven wave along the magnetic field lines, so it reaches the ionosphere and the Earth surface, when the fast modes of the waveguide, localized in the low Alfven speed channel cannot be observed on Earth. The evolution of the waveguide oscillation propagating from the nose to the far tail is theoretically investigated in this work with consideration of all aforementioned effects. The spatial structure var-iation character, spectral composition and amplitude along the waveguide are found.

  17. Waveguides fabricated by femtosecond laser exploiting both depressed cladding and stress-induced guiding core.

    Science.gov (United States)

    Dong, Ming-Ming; Wang, Cheng-Wei; Wu, Zheng-Xiang; Zhang, Yang; Pan, Huai-Hai; Zhao, Quan-Zhong

    2013-07-01

    We report on the fabrication of stress-induced optical channel waveguides and waveguide splitters with laser-depressed cladding by femtosecond laser. The laser beam was focused into neodymium doped phosphate glass by an objective producing a destructive filament. By moving the sample along an enclosed routine in the horizontal plane followed by a minor descent less than the filament length in the vertical direction, a cylinder with rarified periphery and densified center region was fabricated. Lining up the segments in partially overlapping sequence enabled waveguiding therein. The refractive-index contrast, near- and far-field mode distribution and confocal microscope fluorescence image of the waveguide were obtained. 1-to-2, 1-to-3 and 1-to-4 splitters were also machined with adjustable splitting ratio. Compared with traditional femtosecond laser writing methods, waveguides prepared by this approach showed controllable mode conduction, strong field confinement, large numerical aperture, low propagation loss and intact core region.

  18. 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....

  19. Multiple temperature sensors embedded in an ultrasonic “spiral-like” waveguide

    Directory of Open Access Journals (Sweden)

    Suresh Periyannan

    2017-03-01

    Full Text Available This paper studies the propagation of ultrasound in spiral waveguides, towards distributed temperature measurements on a plane. Finite Element (FE approach was used for understanding the velocity behaviour and consequently designing the spiral waveguide. Temperature measurements were experimentally carried out on planar surface inside a hot chamber. Transduction was performed using a piezo-electric crystal that is attached to one end of the waveguide. Lower order axisymmetric guided ultrasonic modes L(0,1 and T(0,1 were employed. Notches were introduced along the waveguide to obtain ultrasonic wave reflections. Time of fight (TOF differences between the pre-defined reflectors (notches located on the waveguides were used to infer local temperatures. The ultrasonic temperature measurements were compared with commercially available thermocouples.

  20. Demonstration of slot-waveguide structures on silicon nitride / silicon oxide platform.

    Science.gov (United States)

    Barrios, C A; Sánchez, B; Gylfason, K B; Griol, A; Sohlström, H; Holgado, M; Casquel, R

    2007-05-28

    We report on the first demonstration of guiding light in vertical slot-waveguides on silicon nitride/silicon oxide material system. Integrated ring resonators and Fabry-Perot cavities have been fabricated and characterized in order to determine optical features of the slot-waveguides. Group index behavior evidences guiding and confinement in the low-index slot region at O-band (1260-1370nm) telecommunication wavelengths. Propagation losses of <20 dB/cm have been measured for the transverse-electric mode of the slot-waveguides.

  1. Flower-petal mode converter for NLC

    International Nuclear Information System (INIS)

    Hoag, H.A.; Tantawi, S.G.; Callin, R.; Deruyter, H.; Farkas, Z.D.; Ko, K.; Kroll, N.; Lavine, T.L.; Menegat, A.; Vlieks, A.E.

    1993-01-01

    It is important to minimize power loss in the waveguide system connecting klystron, pulse-compressor, and accelerator in an X-Band NLC. However, existing designs of klystron output cavity circuits and accelerator input couplers utilize rectangular waveguide which has relatively high transmission loss. It is therefore necessary to convert to and from the low-loss mode in circulator waveguide at each end of the system. A description is given of development work on high-power, high-vacuum open-quote flower-petal close-quote transducers, which convert the TE 10 mode in rectangular guide to the TE 01 mode in circular guide. A three-port modification of the flower petal device, which can be used as either a power combiner at the klystron or a power divider at the accelerator is also described

  2. Flower-petal mode converter for NLC

    International Nuclear Information System (INIS)

    Hoag, H.A.; Tantawi, S.G.; Callin, R.

    1993-04-01

    It is important to minimize power loss in the waveguide system connecting klystron, pulse-compressor, and accelerator in an X-Band NLC. However, existing designs of klystron output cavity circuits and accelerator input couplers utilize rectangular waveguide which has relatively high transmission loss. It is therefore necessary to convert to and from the low-loss mode in circular waveguide at each end of the system. A description is given of development work on high-power, high-vacuum 'flower-petal' transducers, which convert the TE 10 mode in rectangular guide to the TE 01 mode in circular guide. A three-port modification of the flower petal device, which can be used as either a power combiner at the klystron or a power divider at the accelerator is also described

  3. Ge22As20Se58 glass ultrafast laser inscribed waveguides for mid-IR integrated optics

    DEFF Research Database (Denmark)

    Morris, James M.; Mackenzie, Mark D.; Petersen, Christian Rosenberg

    2018-01-01

    Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mu m were measured along with the waveguide dispersion in the 1 to 4.5 mu m range, which is used to estimate the zero-dispersi...... ultrafast laser inscribed waveguide devices in GASIR-1 for mid-IR integrated optics applications. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.......Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mu m were measured along with the waveguide dispersion in the 1 to 4.5 mu m range, which is used to estimate the zero......-dispersion wavelength. Z-scan measurements of bulk samples have also been performed to determine the nonlinear refractive index. Finally, midIR supercontinuum generation has been shown when pumping the waveguides with femtosecond pulses centered at 4.6 mu m. Supercontinuum spanning approximately 4 mu m from 2.5 to 6...

  4. Dynamics of optical signals in a nematic waveguide

    Science.gov (United States)

    Reyes, J. Adrian

    2001-03-01

    We study the modes in a nonlinear nematic waveguide above the Frederickz transition and calculate each of the thresholds associated with different optical and orientational modes. Then, we exhibit the presence of kink-like solutions for the orientational equation under the action of optical fields and study its propagation. Finally, we analyse the dynamics of optical signal in the presence of orientational kinks for different modes and type of signals.

  5. Design of a compact and integrated TM-rotated/TE-through polarization beam splitter for silicon-based slot waveguides.

    Science.gov (United States)

    Xu, Yin; Xiao, Jinbiao

    2016-01-20

    A compact and integrated TM-rotated/TE-through polarization beam splitter for silicon-based slot waveguides is proposed and characterized. For the input TM mode, it is first transferred into the cross strip waveguide using a tapered directional coupler (DC), and then efficiently rotated to the corresponding TE mode using an L-shaped bending polarization rotator (PR). Finally, the TE mode for slot waveguide at the output end is obtained with the help of a strip-to-slot mode converter. By contrast, for the input TE mode, it almost passes through the slot waveguide directly and outputs at the bar end with nearly neglected coupling due to a large mode mismatch. Moreover, an additional S-bend connecting the tapered DC and bending PR is used to enhance the performance. Results show that a total device length of 19.6 μm is achieved, where the crosstalk (CT) and polarization conversion loss are, respectively -26.09 and 0.54 dB, for the TM mode, and the CT and insertion loss are, respectively, -22.21 and 0.41 dB, for the TE mode, both at 1.55 μm. The optical bandwidth is approximately 50 nm with a CT<-20  dB. In addition, fabrication tolerances and field evolution are also presented.

  6. Cross-correlated imaging of single-mode photonic crystal rod fiber with distributed mode filtering

    DEFF Research Database (Denmark)

    Laurila, Marko; Barankov, Roman; Jørgensen, Mette Marie

    2013-01-01

    Photonic crystal bandgap fibers employing distributed mode filtering design provide near diffraction-limited light outputs, a critical property of fiber-based high-power lasers. Microstructure of the fibers is tailored to achieve single-mode operation at specific wavelength by resonant mode...... identify regimes of resonant coupling between higher-order core modes and cladding band. We demonstrate a passive fiber design in which the higher-order modal content inside the single-mode guiding regime is suppressed by at least 20 dB even for significantly misaligned input-coupling configurations....

  7. Flexible multimode polymer waveguides for high-speed short-reach communication links

    Science.gov (United States)

    Bamiedakis, N.; Shi, F.; Chu, D.; Penty, R. V.; White, I. H.

    2018-02-01

    Multimode polymer waveguides have attracted great interest for use in high-speed short-reach communication links as they can be cost-effectively integrated onto standard PCBs using conventional methods of the electronics industry and provide low loss (30 GHz×m) interconnection. The formation of such waveguides on flexible substrates can further provide flexible low-weight low-thickness interconnects and offer additional freedom in the implementation of high-speed short-reach optical links. These attributes make these flexible waveguides particularly attractive for use in low-cost detachable chip-to-chip links and in environments where weight and shape conformity become important, such as in cars and aircraft. However, the highly-multimoded nature of these waveguides raises important questions about their performance under severe flex due to mode loss and mode coupling. In this work therefore, we investigate the loss, crosstalk and bandwidth performance of such waveguides under out-of plane bending and in-plane twisting under different launch conditions and carry out data transmission tests at 40 Gb/s on a 1 m long spiral flexible waveguide under flexure. Excellent optical transmission characteristics are obtained while robust loss, crosstalk and bandwidth performance are demonstrated under flexure. Error-free (BER<10-12) 40 Gb/s data transmission is achieved over the 1 m long spiral waveguide for a 180° bend with a 4 mm radius. The obtained results demonstrate the excellent optical and mechanical properties of this technology and highlight its potential for use in real-world systems.

  8. Dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating

    DEFF Research Database (Denmark)

    Guo, Kai; Christensen, Jesper B.; Christensen, Erik N.

    2017-01-01

    We numerically demonstrate dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating using a finite-difference mode solver. The proposed structure exhibits spectrally-flattened near-zero anomalous dispersion within the telecom wavelength range. We also numerica......We numerically demonstrate dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating using a finite-difference mode solver. The proposed structure exhibits spectrally-flattened near-zero anomalous dispersion within the telecom wavelength range. We also...

  9. ZnO - Wide Bandgap Semiconductor and Possibilities of Its Application in Optical Waveguide Structures

    Directory of Open Access Journals (Sweden)

    Struk Przemysław

    2014-08-01

    Full Text Available The paper presents the results of investigations concerning the application of zinc oxide - a wideband gap semiconductor in optical planar waveguide structures. ZnO is a promising semiconducting material thanks to its attractive optical properties. The investigations were focused on the determination of the technology of depositions and the annealing of ZnO layers concerning their optical properties. Special attention was paid to the determination of characteristics of the refractive index of ZnO layers and their coefficients of spectral transmission within the UV-VIS-NIR range. Besides that, also the mode characteristics and the attenuation coefficients of light in the obtained waveguide structures have been investigated. In the case of planar waveguides, in which the ZnO layers have not been annealed after their deposition, the values of the attenuation coefficient of light modes amount to a~ 30 dB/cm. The ZnO layers deposited on the heated substrate and annealed by rapid thermal annealing in an N2 and O2 atmosphere, are characterized by much lower values of the attenuation coefficients: a~ 3 dB/cm (TE0 and TM0 modes. The ZnO optical waveguides obtained according to our technology are characterized by the lowest values of the attenuation coefficients a encountered in world literature concerning the problem of optical waveguides based on ZnO. Studies have shown that ZnO layers elaborated by us can be used in integrated optic systems, waveguides, optical modulators and light sources.

  10. TM-pass polarizer based on multilayer graphene polymer waveguide

    Science.gov (United States)

    Cai, Ke-su; Li, Yue-e.; Wei, Wen-jing; Mu, Xi-jiao; Ma, A.-ning; Wang, Zhong; Song, Dan-ming

    2018-05-01

    A TM-pass polarizer based on multilayer graphene polymer waveguide is proposed and theoretically analyzed. The mode properties, the extinction ratio, the insertion loss and the bandwidth are also discussed. The results show that a TM-pass polarizer, which only guides the TM mode, can be achieved by multilayer graphene polymer waveguide. With length of 150 μm, the proposed polarizer can achieve extinction ratio of 33 dB and insertion loss of 0.5 dB at optical wavelength of 1.55 μm. This device has an excellent performance, including large extinction ratio and low insertion loss within the spectral range from 1.45 μm to 1.6 μm.

  11. A high gradient test of a single-cell superconducting radio frequency cavity with a feedback waveguide

    Science.gov (United States)

    Kostin, Roman; Avrakhov, Pavel; Kanareykin, Alexei; Solyak, Nikolay; Yakovlev, Vyacheslav; Kazakov, Sergey; Wu, Genfa; Khabiboulline, Timergali; Rowe, Allan; Rathke, John

    2015-09-01

    The most severe problem of the international linear collider (ILC-type) is its high cost, resulting in part from the enormous length of the collider. This length is determined mainly by the achievable accelerating gradient in the RF system of the collider. In current technology, the maximum acceleration gradient in superconducting (SC) structures is determined mainly by the value of the surface RF magnetic field. In order to increase the gradient, a superconducting traveling wave accelerating (STWA) structure is suggested. Utilization of STWA structure with small phase advance per cell for future high energy linear colliders such as ILCs may provide an accelerating gradient 1.2-1.4 times larger [1] than a standing wave structure. However, STWA structure requires a feedback waveguide for power redirecting from the end of the structure back to the front end of accelerating structure. Recent tests of a 1.3 GHz model of a single-cell cavity with waveguide feedback demonstrated an accelerating gradient comparable to the gradient of a single-cell ILC-type cavity from the same manufacturer [2]. In the present paper, high gradient test results are presented.

  12. Nanoantenna couplers for metal-insulator-metal waveguide interconnects

    Science.gov (United States)

    Onbasli, M. Cengiz; Okyay, Ali K.

    2010-08-01

    State-of-the-art copper interconnects suffer from increasing spatial power dissipation due to chip downscaling and RC delays reducing operation bandwidth. Wide bandwidth, minimized Ohmic loss, deep sub-wavelength confinement and high integration density are key features that make metal-insulator-metal waveguides (MIM) utilizing plasmonic modes attractive for applications in on-chip optical signal processing. Size-mismatch between two fundamental components (micron-size fibers and a few hundred nanometers wide waveguides) demands compact coupling methods for implementation of large scale on-chip optoelectronic device integration. Existing solutions use waveguide tapering, which requires more than 4λ-long taper distances. We demonstrate that nanoantennas can be integrated with MIM for enhancing coupling into MIM plasmonic modes. Two-dimensional finite-difference time domain simulations of antennawaveguide structures for TE and TM incident plane waves ranging from λ = 1300 to 1600 nm were done. The same MIM (100-nm-wide Ag/100-nm-wide SiO2/100-nm-wide Ag) was used for each case, while antenna dimensions were systematically varied. For nanoantennas disconnected from the MIM; field is strongly confined inside MIM-antenna gap region due to Fabry-Perot resonances. Major fraction of incident energy was not transferred into plasmonic modes. When the nanoantennas are connected to the MIM, stronger coupling is observed and E-field intensity at outer end of core is enhanced more than 70 times.

  13. Direct Observation of Bloch Harmonics and Negative Phase Velocity in Photonic Crystal Waveguides

    NARCIS (Netherlands)

    Gersen, H.; Karle, T.J.; Engelen, R.J.P.; Engelen, R.J.P.; Bogaerts, W.; Korterik, Jeroen P.; van Hulst, N.F.; Krauss, T.F.; Kuipers, L.

    2005-01-01

    The eigenfield distribution and the band structure of a photonic crystal waveguide have been measured with a phase-sensitive near-field scanning optical microscope. Bloch modes, which consist of more than one spatial frequency, are visualized in the waveguide. In the band structure, multiple

  14. Geometrical tuning art for entirely subwavelength grating waveguide based integrated photonics circuits.

    Science.gov (United States)

    Wang, Zheng; Xu, Xiaochuan; Fan, Donglei; Wang, Yaguo; Subbaraman, Harish; Chen, Ray T

    2016-05-05

    Subwavelength grating (SWG) waveguide is an intriguing alternative to conventional optical waveguides due to the extra degree of freedom it offers in tuning a few important waveguide properties, such as dispersion and refractive index. Devices based on SWG waveguides have demonstrated impressive performances compared to conventional waveguides. However, the high loss of SWG waveguide bends jeopardizes their applications in integrated photonic circuits. In this work, we propose a geometrical tuning art, which realizes a pre-distorted refractive index profile in SWG waveguide bends. The pre-distorted refractive index profile can effectively reduce the mode mismatch and radiation loss simultaneously, thus significantly reduce the bend loss. This geometry tuning art has been numerically optimized and experimentally demonstrated in present study. Through such tuning, the average insertion loss of a 5 μm SWG waveguide bend is reduced drastically from 5.43 dB to 1.10 dB per 90° bend for quasi-TE polarization. In the future, the proposed scheme will be utilized to enhance performance of a wide range of SWG waveguide based photonics devices.

  15. Break up of bound-N-spatial-soliton in a ramp waveguide

    NARCIS (Netherlands)

    Suryanto, A.; van Groesen, Embrecht W.C.

    2002-01-01

    We present an analytical and numerical investigation of the propagation of spatial solitons in a nonlinear waveguide with ramp linear refractive index profile (ramp waveguide). For the propagation of a single soliton beam in a ramp waveguide, the particle theory shows that the soliton beam follows a

  16. Leaky mode suppression in planar optical waveguides written in Er:TeO{sub 2}–WO{sub 3} glass and CaF{sub 2} crystal via double energy implantation with MeV N{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Bányász, I., E-mail: banyasz@sunserv.kfki.hu [Department of Crystal Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary); Zolnai, Z.; Fried, M. [Research Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O.B. 49, Budapest H-1525 (Hungary); Berneschi, S. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); “Enrico Fermi” Center for Study and Research, Piazza del Viminale 2, 00184 Roma (Italy); Pelli, S.; Nunzi-Conti, G. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2014-05-01

    Ion implantation proved to be an universal technique for producing waveguides in most optical materials. Tellurite glasses are good hosts of rare-earth elements for the development of fibre and integrated optical amplifiers and lasers covering all the main telecommunication bands. Er{sup 3+}-doped tellurite glasses are good candidates for the fabrication of broadband amplifiers in wavelength division multiplexing around 1.55 μm, as they exhibit large stimulated cross sections and broad emission bandwidth. Calcium fluoride is an excellent optical material, due to its perfect optical characteristics from UV wavelengths up to near IR. It has become a promising laser host material (doped with rare earth elements). Ion implantation was also applied to optical waveguide fabrication in CaF{sub 2} and other halide crystals. In the present work first single-energy implantations at 3.5 MeV at various fluences were applied. Waveguide operation up to 1.5 μm was observed in Er:Te glass, and up to 980 nm in CaF{sub 2}. Then double-energy implantations at a fixed upper energy of 3.5 MeV and lower energies between 2.5 and 3.2 MeV were performed to suppress leaky modes by increasing barrier width.

  17. Adiabatic Nanofocusing in Hybrid Gap Plasmon Waveguides on the Silicon-on-Insulator Platform.

    Science.gov (United States)

    Nielsen, Michael P; Lafone, Lucas; Rakovich, Aliaksandra; Sidiropoulos, Themistoklis P H; Rahmani, Mohsen; Maier, Stefan A; Oulton, Rupert F

    2016-02-10

    We present an experimental demonstration of a new class of hybrid gap plasmon waveguides on the silicon-on-insulator (SOI) platform. Created by the hybridization of the plasmonic mode of a gap in a thin metal sheet and the transverse-electric (TE) photonic mode of an SOI slab, this waveguide is designed for efficient adiabatic nanofocusing simply by varying the gap width. For gap widths greater than 100 nm, the mode is primarily photonic in character and propagation lengths can be many tens of micrometers. For gap widths below 100 nm, the mode becomes plasmonic in character with field confinement predominantly within the gap region and with propagation lengths of a few microns. We estimate the electric field intensity enhancement in hybrid gap plasmon waveguide tapers at 1550 nm by three-photon absorption of selectively deposited CdSe/ZnS quantum dots within the gap. Here, we show electric field intensity enhancements of up to 167 ± 26 for a 24 nm gap, proving the viability of low loss adiabatic nanofocusing on a commercially relevant photonics platform.

  18. Metasurface Waveguides Applied to Matched Feeds for Reflector Antennas

    DEFF Research Database (Denmark)

    Palvig, Michael Forum; Jorgensen, Erik; Meincke, Peter

    2017-01-01

    at different speeds than the fundamental mode in conventional waveguides, it is challenging to meet phase relationship requirements over a large band. We have found that traditional corrugated waveguides are poorly suited for matched feed applications. However, other surfaces that satisfy the balanced hybrid...... condition, but have a small capacitive longitudinal reactance and large inductive azimuthal reactance show very promising properties: In a large band, HE11 and HE21 have similar propagation characteristics....

  19. High-Power Microwave Transmission and Mode Conversion Program

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, Ronald J. [Univ. of Wisconsin, Madison, WI (United States)

    2015-08-14

    This is a final technical report for a long term project to develop improved designs and design tools for the microwave hardware and components associated with the DOE Plasma Fusion Program. We have developed basic theory, software, fabrication techniques, and low-power measurement techniques for the design of microwave hardware associated gyrotrons, microwave mode converters and high-power microwave transmission lines. Specifically, in this report we discuss our work on designing quasi-optical mode converters for single and multiple frequencies, a new method for the analysis of perturbed-wall waveguide mode converters, perturbed-wall launcher design for TE0n mode gyrotrons, quasi-optical traveling-wave resonator design for high-power testing of microwave components, and possible improvements to the HSX microwave transmission line.

  20. A hybrid waveguide cell for the dielectric properties of reservoir rocks

    International Nuclear Information System (INIS)

    Siggins, A F; Gunning, J; Josh, M

    2011-01-01

    A hybrid waveguide cell is described for broad-band measurements of the dielectric properties of hydrocarbon reservoir rocks. The cell is designed to operate in the radio frequency range of 1 MHz to 1 GHz. The waveguide consists of 50 Ω coaxial lines feeding into a central cylindrical section which contains the sample under test. The central portion of the waveguide acts as a circular waveguide and can accept solid core plugs of 38 mm diameter and lengths from 2 to 150 mm. The central section can also be used as a conventional coaxial waveguide when a central electrode with spring-loaded end collets is installed. In the latter mode the test samples are required to be in the form of hollow cylinders. An additional feature of the cell is that the central section is designed to telescope over a limited range of 1–2 mm with the application of an axial load. Effective pressures up to 35 MPa can be applied to the sample under the condition of uniaxial strain. The theoretical basis of the hybrid waveguide cell is discussed together with calibration results. Two reservoir rocks, a Donnybrook sandstone and a kaolin rich clay, are then tested in the cell, both as hollow cylinders in coaxial mode and in the form of solid core plugs. The complex dielectric properties of the two materials over the bandwidth of 1 MHz to 1 GHz are compared with the results of the two testing methods

  1. A hybrid waveguide cell for the dielectric properties of reservoir rocks

    Science.gov (United States)

    Siggins, A. F.; Gunning, J.; Josh, M.

    2011-02-01

    A hybrid waveguide cell is described for broad-band measurements of the dielectric properties of hydrocarbon reservoir rocks. The cell is designed to operate in the radio frequency range of 1 MHz to 1 GHz. The waveguide consists of 50 Ω coaxial lines feeding into a central cylindrical section which contains the sample under test. The central portion of the waveguide acts as a circular waveguide and can accept solid core plugs of 38 mm diameter and lengths from 2 to 150 mm. The central section can also be used as a conventional coaxial waveguide when a central electrode with spring-loaded end collets is installed. In the latter mode the test samples are required to be in the form of hollow cylinders. An additional feature of the cell is that the central section is designed to telescope over a limited range of 1-2 mm with the application of an axial load. Effective pressures up to 35 MPa can be applied to the sample under the condition of uniaxial strain. The theoretical basis of the hybrid waveguide cell is discussed together with calibration results. Two reservoir rocks, a Donnybrook sandstone and a kaolin rich clay, are then tested in the cell, both as hollow cylinders in coaxial mode and in the form of solid core plugs. The complex dielectric properties of the two materials over the bandwidth of 1 MHz to 1 GHz are compared with the results of the two testing methods.

  2. Adapting an optical nanoantenna for high E-field probing applications to a waveguided optical waveguide (WOW)

    Science.gov (United States)

    Rindorf, Lars; Glückstad, Jesper

    2013-03-01

    In the current work we intend to use the optical nano-antenna to include various functionalities for the recently demonstrated waveguided optical waveguide (WOW) by Palima et al. (Optics Express 2012). Specifically, we intend to study a WOW with an optical nano-antenna which can block the guiding light wavelength while admitting other wavelengths of light which address certain functionalities, e.g. drug release, in the WOW. In particular, we study a bow-tie optical nano-antenna to circular dielectric waveguides in aqueous environments. It is shown with finite element computer simulations that the nanoantenna can be made to operate in a bandstop mode around its resonant wavelength where there is a very high evanescent strong electrical probing field close to the antennas, and additionally the fluorescence or Raman excitations will be be unpolluted by stray light from the WOW due to the band-stop characteristic. We give geometrical parameters necessary for realizing functioning nanoantennas.

  3. Efficient Multiphoton Generation in Waveguide Quantum Electrodynamics

    Science.gov (United States)

    González-Tudela, A.; Paulisch, V.; Kimble, H. J.; Cirac, J. I.

    2017-05-01

    Engineering quantum states of light is at the basis of many quantum technologies such as quantum cryptography, teleportation, or metrology among others. Though, single photons can be generated in many scenarios, the efficient and reliable generation of complex single-mode multiphoton states is still a long-standing goal in the field, as current methods either suffer from low fidelities or small probabilities. Here we discuss several protocols which harness the strong and long-range atomic interactions induced by waveguide QED to efficiently load excitations in a collection of atoms, which can then be triggered to produce the desired multiphoton state. In order to boost the success probability and fidelity of each excitation process, atoms are used to both generate the excitations in the rest, as well as to herald the successful generation. Furthermore, to overcome the exponential scaling of the probability of success with the number of excitations, we design a protocol to merge excitations that are present in different internal atomic levels with a polynomial scaling.

  4. Influence of the flip-flop interaction on a single plasmon transport in 1D waveguide

    Science.gov (United States)

    Ko, Myong-Chol; Kim, Nam-Chol; Ho, Nam-Chol; Ryom, Ju-Song; Hao, Zhong-Hua; Li, Jian-Bo; Wang, Qu-Quan

    2017-12-01

    Transport of a single plasmon in the 1D waveguide coupled to two emitters with the flip-flop interaction is discussed theoretically via the real-space approach. We showed that the transmission and reflection of a single plasmon could be changeable by adjusting the flip-flop coupling strength of the QDs, the interaction of QDs with the metallic nanowaveguide, interparticle distance of the QDs and detuning. Setting the interparticle distances properly results in the switching between the complete transmission and the complete reflection. Especially, our results show that the QDs with the flip-flop interaction play important role in the transport of the propagating single plasmon, which is relevant to the Förster resonance energy transfer from donor QD to acceptor QD.

  5. Planned waveguide electric field breakdown studies

    International Nuclear Information System (INIS)

    Wang Faya; Li Zenghai

    2012-01-01

    This paper presents an experimental setup for X-band rf breakdown studies. The setup is composed of a section of WR90 waveguide with a tapered pin located at the middle of the waveguide E-plane. Another pin is used to rf match the waveguide so it operates in a travelling wave mode. By adjusting the penetration depth of the tapered pin, different surface electric field enhancements can be obtained. The setup will be used to study the rf breakdown rate dependence on power flow in the waveguide for a constant maximum surface electric field on the pin. Two groups of pins have been designed. The Q of one group is different and very low. The other has a similar Q. With the test of the two groups of pins, we should be able to discern how the net power flow and Q affect the breakdown. Furthermore, we will apply an electron beam treatment to the pins to study its effect on breakdown. Overall, these experiments should be very helpful in understanding rf breakdown phenomena and could significantly benefit the design of high gradient accelerator structures.

  6. Strong suppression of radiation states in a slab waveguide sandwiched between omnidirectional mirrors

    NARCIS (Netherlands)

    Hoekstra, Hugo; Yudistira, D.; Stoffer, Remco

    2005-01-01

    Structures in channel or slab waveguides, applied deliberately or due to imperfections, may lead to strong modal losses, corresponding to the excitation of radiation modes. As an example, losses are generally very large in slab photonic crystal (PhC) impurity waveguides (WGs) due to the combined

  7. Coherent ultra-violet to near-infrared generation in silica ridge waveguides.

    Science.gov (United States)

    Yoon Oh, Dong; Yang, Ki Youl; Fredrick, Connor; Ycas, Gabriel; Diddams, Scott A; Vahala, Kerry J

    2017-01-09

    Short duration, intense pulses of light can experience dramatic spectral broadening when propagating through lengths of optical fibre. This continuum generation process is caused by a combination of nonlinear optical effects including the formation of dispersive waves. Optical analogues of Cherenkov radiation, these waves allow a pulse to radiate power into a distant spectral region. In this work, efficient and coherent dispersive wave generation of visible to ultraviolet light is demonstrated in silica waveguides on a silicon chip. Unlike fibre broadeners, the arrays provide a wide range of emission wavelength choices on a single, compact chip. This new capability is used to simplify offset frequency measurements of a mode-locked frequency comb. The arrays can also enable mode-locked lasers to attain unprecedented tunable spectral reach for spectroscopy, bioimaging, tomography and metrology.

  8. 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....

  9. Ultra-low crosstalk, CMOS compatible waveguide crossings for densely integrated photonic interconnection networks.

    Science.gov (United States)

    Jones, Adam M; DeRose, Christopher T; Lentine, Anthony L; Trotter, Douglas C; Starbuck, Andrew L; Norwood, Robert A

    2013-05-20

    We explore the design space for optimizing CMOS compatible waveguide crossings on a silicon photonics platform. This paper presents simulated and experimental excess loss and crosstalk suppression data for vertically integrated silicon nitride over silicon-on-insulator waveguide crossings. Experimental results show crosstalk suppression exceeding -49/-44 dB with simulation results as low as -65/-60 dB for the TE/TM mode in a waveguide crossing with a 410 nm vertical gap.

  10. Hybrid plasmonic waveguide in a metal V-groove

    Directory of Open Access Journals (Sweden)

    Zhao-xian Chen

    2014-01-01

    Full Text Available We propose and investigate a type of hybrid plasmonic waveguide in a metal V-groove. A high-permittivity nanowire was placed in the metal channel covered with a dielectric film of lower permittivity. Deeper sub-wavelength confinement and much longer propagation distance were achieved in comparison with conventional channel plasmonic waveguides. The overall performance was improved as compared with the conventional hybrid plasmonic structure based on a flat metal surface. Finite element analysis showed that both the mode propagation and field profile can be adjusted by changing the nanowire radius and film thickness. Some benefits, such as a reduced scattering loss caused by the surface roughness, are also expected owing to the unique mode profile. The proposed approach has potential for application in high-level photonic integration.

  11. Proposal of highly sensitive optofluidic sensors based on dispersive photonic crystal waveguides

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Mortensen, Niels Asger

    2007-01-01

    Optofluidic sensors based on highly dispersive two-dimensional photonic crystal waveguides are studied theoretically. Results show that these structures are strongly sensitive to the refractive index of the infiltrated liquid (nl), which is used to tune dispersion of the photonic crystal waveguide....... The waveguide mode-gap edge shifts about 1.2 nm for δnl = 0.002. The shifts can be explained well by band structure theory combined with first-order perturbation theory. These devices are potentially interesting for chemical sensing applications....

  12. Single Nanowire Probe for Single Cell Endoscopy and Sensing

    Science.gov (United States)

    Yan, Ruoxue

    The ability to manipulate light in subwavelength photonic and plasmonic structures has shown great potentials in revolutionizing how information is generated, transformed and processed. Chemically synthesized nanowires, in particular, offers a unique toolbox not only for highly compact and integrated photonic modules and devices, including coherent and incoherent light sources, waveguides, photodetectors and photovoltaics, but also for new types of nanoscopic bio-probes for spot cargo delivery and in-situ single cell endoscopy and sensing. Such nanowire probes would enable us to carry out intracellular imaging and probing with high spatial resolution, monitor in-vivo biological processes within single living cells and greatly improve our fundamental understanding of cell functions, intracellular physiological processes, and cellular signal pathways. My work is aimed at developing a material and instrumental platform for such single nanowire probe. Successful optical integration of Ag nanowire plasmonic waveguides, which offers deep subwavelength mode confinement, and conventional photonic waveguides was demonstrated on a single nanowire level. The highest plasmonic-photonic coupling efficiency coupling was found at small coupling angles and low input frequencies. The frequency dependent propagation loss was observed in Ag nanowire and was confirmed by quantitative measurement and in agreement with theoretical expectations. Rational integration of dielectric and Ag nanowire waveguide components into hybrid optical-plasmonic routing devices has been demonstrated. This capability is essential for incorporating sub-100nm Ag nanowire waveguides into optical fiber based nanoprobes for single cell endoscopy. The nanoprobe system based on single nanowire waveguides was demonstrated by optically coupling semiconductor or metal nanowire with an optical fiber with tapered tip. This nanoprobe design requires minimal instrumentation which makes it cost efficient and readily

  13. Experimental demonstration of CMOS-compatible long-range dielectric-loaded surface plasmon-polariton waveguides (LR-DLSPPWs)

    DEFF Research Database (Denmark)

    Zektzer, Roy; Desiatov, Boris; Mazurski, Noa

    2015-01-01

    We demonstrate the design, fabrication and experimental characterization of long-range dielectric-loaded surface plasmon-polariton waveguides (LR-DLSPPWs) that are compatible with complementary metal-oxide semiconductor (CMOS) technology. The demonstrated waveguides feature good mode confinement...

  14. Optimize Etching Based Single Mode Fiber Optic Temperature Sensor

    OpenAIRE

    Ajay Kumar; Dr. Pramod Kumar

    2014-01-01

    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 th...

  15. A hybrid plasmonic waveguide terahertz quantum cascade laser

    Energy Technology Data Exchange (ETDEWEB)

    Degl' Innocenti, Riccardo, E-mail: rd448@cam.ac.uk; Shah, Yash D.; Wallis, Robert; Klimont, Adam; Ren, Yuan; Jessop, David S.; Beere, Harvey E.; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2015-02-23

    We present the realization of a quantum cascade laser emitting at around 2.85 THz, based on a hybrid plasmonic waveguide with a low refractive index dielectric cladding. This hybrid waveguide design allows the performance of a double-metal waveguide to be retained, while improving the emission far-field. A set of lasers based on the same active region material were fabricated with different metal layer thicknesses. A detailed characterization of the performance of these lasers revealed that there is an optimal trade-off that yields the best far-field emission and the maximum temperature of operation. By exploiting the pure plasmonic mode of these waveguides, the standard operation conditions of a double-metal quantum cascade laser were retrieved, such that the maximum operating temperature of these devices is not affected by the process. These results pave the way to realizing a class of integrated devices working in the terahertz range which could be further exploited to fabricate terahertz on-chip circuitry.

  16. Optical Forces on Non-Spherical Nanoparticles Trapped by Optical Waveguides

    Science.gov (United States)

    Hasan Ahmed, Dewan; Sung, Hyung Jin

    2011-07-01

    Numerical simulations of a solid-core polymer waveguide structure were performed to calculate the trapping efficiencies of particles with nanoscale dimensions smaller than the wavelength of the trapping beam. A three-dimensional (3-D) finite element method was employed to calculate the electromagnetic field. The inlet and outlet boundary conditions were obtained using an eigenvalue solver to determine the guided and evanescent mode profiles. The Maxwell stress tensor was considered for the calculation of the transverse and downward trapping efficiencies. A particle at the center of the waveguide showed minimal transverse trapping efficiency and maximal downward trapping efficiency. This trend gradually reversed as the particle moved away from the center of the waveguide. Particles with larger surface areas exhibited higher trapping efficiencies and tended to be trapped near the waveguide. Particles displaced from the wave input tended to be trapped at the waveguide surface. Simulation of an ellipsoidal particle showed that the orientation of the major axis along the waveguide's lateral z-coordinate significantly influenced the trapping efficiency. The particle dimensions along the z-coordinate were more critical than the gap distance (vertical displacement from the floor of the waveguide) between the ellipsoid particle and the waveguide. The present model was validated using the available results reported in the literature for different trapping efficiencies.

  17. Spectroelectrochemical sensing: planar waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Susan E.; Shi Yining; Seliskar, Carl J.; Heineman, William R

    2003-09-30

    The spectroelectrochemical sensor combines in a single device electrochemistry, spectroscopy, and selective partitioning into a film, giving improved selectivity for applications that involve complex samples. Sensing is based on the change in optical signal that accompanies electrochemical modulation of analyte that has partitioned into the film. Two classes of optical quality chemically-selective films based on two different host materials, namely, sol-gel processed silica and cross-linked poly(vinyl alcohol) have been developed. Films are typically 400-700 nm thick. Three types of sensor platforms are discussed: a multiple internal reflection (MIR) optic consisting of a bilayer of an indium tin oxide (ITO) optically transparent electrode deposited on a 1-mm thick glass substrate, a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide (5-9 {mu}m thick) was over-coated with a thin film of ITO, and a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide channel was formed and a pair of electrodes deposited along side the channel. These sensors were evaluated with ferrocyanide and a selective film of PDMDAAC-SiO{sub 2}, where PDMDAAC=poly(dimethyl diallylammonium chloride)

  18. Spectroelectrochemical sensing: planar waveguides

    International Nuclear Information System (INIS)

    Ross, Susan E.; Shi Yining; Seliskar, Carl J.; Heineman, William R.

    2003-01-01

    The spectroelectrochemical sensor combines in a single device electrochemistry, spectroscopy, and selective partitioning into a film, giving improved selectivity for applications that involve complex samples. Sensing is based on the change in optical signal that accompanies electrochemical modulation of analyte that has partitioned into the film. Two classes of optical quality chemically-selective films based on two different host materials, namely, sol-gel processed silica and cross-linked poly(vinyl alcohol) have been developed. Films are typically 400-700 nm thick. Three types of sensor platforms are discussed: a multiple internal reflection (MIR) optic consisting of a bilayer of an indium tin oxide (ITO) optically transparent electrode deposited on a 1-mm thick glass substrate, a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide (5-9 μm thick) was over-coated with a thin film of ITO, and a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide channel was formed and a pair of electrodes deposited along side the channel. These sensors were evaluated with ferrocyanide and a selective film of PDMDAAC-SiO 2 , where PDMDAAC=poly(dimethyl diallylammonium chloride)

  19. Integrated Sources of Polarization Entangled Photon Pair States via Spontaneous Four-Wave Mixing in AlGaAs Waveguides

    Science.gov (United States)

    Kultavewuti, Pisek

    Polarization-entangled photon pair states (PESs) are indispensable in several quantum protocols that should be implemented in an integrated photonic circuit for realizing a practical quantum technology. Preparing such states in integrated waveguides is in fact a challenge due to polarization mode dispersion. Unlike other conventional ways that are plagued with complications in fabrication or in state generation, in this thesis, the scheme based on parallel spontaneous four-wave mixing processes of two polarization waveguide modes is thoroughly studied in theory and experimentation for the polarization entanglement generation. The scheme in fact needs the modal dispersion, contradictory to the general perception, as revealed by a full quantum mechanical framework. The proper modal dispersion balances the effects of temporal walk-off and state factorizability. The study also shows that the popular standard platform such as a silicon-on-insulator wafer is far from suitable to implement the proposed simple generation technique. Proven by the quantum state tomography, the technique produces a highly-entangled state with a maximum concurrence of 0.97 +/- 0:01 from AlGaAs waveguides. In addition, the devices directly generated Bell states with an observed fidelity of 0.92 +/- 0:01 without any post-generation compensating steps. Novel suspended device structures, including their components, are then investigated numerically and experimentally characterized in pursuit of finding the geometry with the optimal dispersion property. The 700 nm x 1100 nm suspended rectangular waveguide is identified as the best geometry with a predicted maximum concurrence of 0.976 and a generation bandwidth of 3.3 THz. The suspended waveguide fabrication procedure adds about 15 dB/cm and 10 dB/cm of propagation loss to the TE and TM mode respectively, on top of the loss in corresponding full-cladding waveguides. Bridges, which structurally support the suspended waveguides, are optimized using

  20. Integrated nanoplasmonic quantum interfaces for room-temperature single-photon sources

    Science.gov (United States)

    Peyskens, Frédéric; Englund, Dirk; Chang, Darrick

    2017-12-01

    We describe a general analytical framework of a nanoplasmonic cavity-emitter system interacting with a dielectric photonic waveguide. Taking into account emitter quenching and dephasing, our model directly reveals the single-photon extraction efficiency η as well as the indistinguishability I of photons coupled into the waveguide mode. Rather than minimizing the cavity modal volume, our analysis predicts an optimum modal volume to maximize η that balances waveguide coupling and spontaneous emission rate enhancement. Surprisingly, our model predicts that near-unity indistinguishability is possible, but this requires a much smaller modal volume, implying a fundamental performance trade-off between high η and I at room temperature. Finally, we show that maximizing η I requires that the system has to be driven in the weak coupling regime because quenching effects and decreased waveguide coupling drastically reduce η in the strong coupling regime.

  1. Fabrication of planar waveguide in KNSBN crystal by swift heavy ion beam irradiation

    International Nuclear Information System (INIS)

    Guan, Jing; Wang, Lei; Qin, Xifeng

    2013-01-01

    We report on the fabrication of the planar waveguides in the KNSBN crystal by using 17 MeV C 5+ ions at a fluence of 2 × 10 14 ions/cm 2 . After implantation, near surface regions of the crystal, there has a positive extraordinary refractive index (n e ) change and the light inside the waveguides can propagate in a non-leaky manner. The two-dimensional modal profiles of the planar waveguides, measured by using the end-coupling arrangement, are in good agreement with the reconstructed modal distributions. The propagation loss for C 5+ irradiated waveguide is ∼0.8 dB/cm at 633 nm and ∼0.72 dB/cm at 1064 nm. The waveguide gives good confinement of waveguide modes, which exhibits acceptable guiding qualities for potential applications in integrated optics

  2. Fabrication of planar waveguide in KNSBN crystal by swift heavy ion beam irradiation

    Science.gov (United States)

    Guan, Jing; Wang, Lei; Qin, Xifeng

    2013-11-01

    We report on the fabrication of the planar waveguides in the KNSBN crystal by using 17 MeV C5+ ions at a fluence of 2 × 1014 ions/cm2. After implantation, near surface regions of the crystal, there has a positive extraordinary refractive index (ne) change and the light inside the waveguides can propagate in a non-leaky manner. The two-dimensional modal profiles of the planar waveguides, measured by using the end-coupling arrangement, are in good agreement with the reconstructed modal distributions. The propagation loss for C5+ irradiated waveguide is ∼0.8 dB/cm at 633 nm and ∼0.72 dB/cm at 1064 nm. The waveguide gives good confinement of waveguide modes, which exhibits acceptable guiding qualities for potential applications in integrated optics.

  3. A modal approach based on perfectly matched layers for the forced response of elastic open waveguides

    Science.gov (United States)

    Gallezot, M.; Treyssède, F.; Laguerre, L.

    2018-03-01

    This paper investigates the computation of the forced response of elastic open waveguides with a numerical modal approach based on perfectly matched layers (PML). With a PML of infinite thickness, the solution can theoretically be expanded as a discrete sum of trapped modes, a discrete sum of leaky modes and a continuous sum of radiation modes related to the PML branch cuts. Yet with numerical methods (e.g. finite elements), the waveguide cross-section is discretized and the PML must be truncated to a finite thickness. This truncation transforms the continuous sum into a discrete set of PML modes. To guarantee the uniqueness of the numerical solution of the forced response problem, an orthogonality relationship is proposed. This relationship is applicable to any type of modes (trapped, leaky and PML modes) and hence allows the numerical solution to be expanded on a discrete sum in a convenient manner. This also leads to an expression for the modal excitability valid for leaky modes. The physical relevance of each type of mode for the solution is clarified through two numerical test cases, a homogeneous medium and a circular bar waveguide example, excited by a point source. The former is favourably compared to a transient analytical solution, showing that PML modes reassemble the bulk wave contribution in a homogeneous medium. The latter shows that the PML mode contribution yields the long-term diffraction phenomenon whereas the leaky mode contribution prevails closer to the source. The leaky mode contribution is shown to remain accurate even with a relatively small PML thickness, hence reducing the computational cost. This is of particular interest for solving three-dimensional waveguide problems, involving two-dimensional cross-sections of arbitrary shapes. Such a problem is handled in a third numerical example by considering a buried square bar.

  4. Controllable scattering of photons in a one-dimensional resonator waveguide

    Science.gov (United States)

    Sun, C. P.; Zhou, L.; Gong, Z. R.; Liu, Y. X.; Nori, F.

    2009-03-01

    We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. [4pt] L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons in a 1D resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). URL: http://link.aps.org/abstract/PRL/v101/e100501

  5. Coupling of single quantum dots to a photonic crystal waveguide

    DEFF Research Database (Denmark)

    Lund-Hansen, Toke; Stobbe, Søren; Julsgaard, Brian

    Efficient and high quality single-photon sources is a key element in quantum information processing using photons. As a consequence, much current research is focused on realizing all-solid-state nanophotonic single-photon sources. Single photons can be harvested with high efficiency if the emitter...... is coupled efficiently to a single enhanced mode. One popular approach has been to couple single quantum dots to a nanocavity but a limiting factor in this configuration is that in order to apply the photon it should subsequently be coupled out of the cavity, reducing the overall efficiency significantly...

  6. 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...

  7. Terahertz particle-in-liquid sensing with spoof surface plasmon polariton waveguides

    Directory of Open Access Journals (Sweden)

    Zhijie Ma

    2017-11-01

    Full Text Available We present a highly sensitive microfluidic sensing technique for the terahertz (THz region of the electromagnetic spectrum based on spoof surface plasmon polaritons (SPPs. By integrating a microfluidic channel in a spoof SPP waveguide, we take advantage of these highly confined electromagnetic modes to create a platform for dielectric sensing of liquids. Our design consists of a domino waveguide, that is, a series of periodically arranged rectangular metal blocks on top of a metal surface that supports the propagation of spoof SPPs. Through numerical simulations, we demonstrate that the transmission of spoof SPPs along the waveguide is extremely sensitive to the refractive index of a liquid flowing through a microfluidic channel crossing the waveguide to give an interaction volume on the nanoliter scale. Furthermore, by taking advantage of the insensitivity of the domino waveguide’s fundamental spoof SPP mode to the lateral width of the metal blocks, we design a tapered waveguide able to achieve further confinement of the electromagnetic field. Using this approach, we demonstrate the highly sensitive detection of individual subwavelength micro-particles flowing in the liquid. These results are promising for the creation of spoof SPP based THz lab-on-a-chip microfluidic devices that are suitable for the analysis of biological liquids such as proteins and circulating tumour cells in buffer solution.

  8. Design, Fabrication, and Measurement of Two-Dimensional Photonic Crystal Slab Waveguides

    International Nuclear Information System (INIS)

    Chao, Zhang; Xuan, Tang; Xiao-Yu, Mao; Kai-Yu, Cui; Lei, Cao; Yi-Dong, Huang; Wei, Zhang; Jiang-De, Peng

    2008-01-01

    Two-dimensional photonic crystal slab waveguides on SOI wafer are designed and fabricated. Photonic band gap, band gap guided mode, and index guided mode are observed by measuring the transmission spectra. The experimental results are in good agreement with the theoretical ones

  9. Design of a GaP/Si composite waveguide for CW terahertz wave generation via difference frequency mixing.

    Science.gov (United States)

    Saito, Kyosuke; Tanabe, Tadao; Oyama, Yutaka

    2014-06-10

    We design a GaP/Si composite waveguide to achieve efficient terahertz (THz) wave generation under collinear phase-matched difference frequency mixing (DFM) between near-infrared light sources. This waveguide structure provides a strong mode confinement of both near-infrared sources and THz wave, resulting in an efficient mode overlapping. The numerical results show that the waveguide can produce guided THz wave (5.93 THz) with a power conversion efficiency of 6.6×10(-4)  W(-1). This value is larger than previously obtained with the bulk GaP crystal: 0.5×10(-9)  W(-1) [J. Lightwave Technol.27, 3057 (2009)]. Our proposed composite waveguide can be achieved by bridging the telecom wavelength and THz frequency region.

  10. Long-range plasmonic waveguides with hyperbolic cladding

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia E.; Shalaginov, Mikhail Y.; Ishii, Satoshi

    2015-01-01

    waveguides. We show that the proposed structures support long-range surface plasmon modes, which exist when the permittivity of the core matches the transverse effective permittivity component of the metamaterial cladding. In this regime, the surface plasmon polaritons of each cladding layer are strongly...

  11. Optical waveguide loop for planar trapping of blood cells and microspheres

    Science.gov (United States)

    Ahluwalia, Balpreet S.; Hellesø, Olav G.

    2013-09-01

    The evanescent field from a waveguide can be used to trap and propel a particle. An optical waveguide loop with an intentional gap at the center is used for planar transport and stable trapping of particles. The waveguide acts as a conveyor belt to trap and deliver spheres towards the gap. At the gap, the counter-diverging light fields hold the sphere at a fixed position. Numerical simulation based on the finite element method was performed in three dimensions using a computer cluster. The field distribution and optical forces for rib and strip waveguide designs are compared and discussed. The optical force on a single particle was computed for various positions of the particle in the gap. Simulation predicted stable trapping of particles in the gap. Depending on the gap separation (2-50 μm) a single or multiple spheres and red blood cells were trapped at the gap. Waveguides were made of tantalum pentaoxide material. The waveguides are only 180 nm thick and thus could be integrated with other functions on the chip.

  12. 2D MEMS electrostatic cantilever waveguide scanner for potential image display application

    Directory of Open Access Journals (Sweden)

    Gu Kebin

    2015-01-01

    Full Text Available This paper presents the current status of our micro-fabricated SU-8 2D electrostatic cantilever waveguide scanner. The current design utilizes a monolithically integrated electrostatic push-pull actuator. A 4.0 μm SU-8 rib waveguide design allows a relatively large core cross section (4μm in height and 20 μm in width to couple with existing optical fiber and a broad band single mode operation (λ= 0.7μm to 1.3μm with minimal transmission loss (85% to 87% output transmission efficiency with Gaussian beam profile input. A 2D scanning motion has been successfully demonstrated with two fundamental resonances found at 202 and 536 Hz in vertical and horizontal directions. A 130 μm and 19 μm, corresponding displacement and 0.062 and 0.009 rad field of view were observed at a +150V input. Beam divergence from the waveguide was corrected by a focusing GRIN lens and a 5μm beam diameter is observed at the focal plane. The transmission efficiency is low (~10% and cantilever is slightly under tensile residual stress due to inherent imperfection in the process and tooling in fabrication. However, 2D light scanning pattern was successfully demonstrated using 1-D push-pull actuation.

  13. Optical waveguides in LiTaO3 crystals fabricated by swift C5+ ion irradiation

    International Nuclear Information System (INIS)

    Liu, Guiyuan; He, Ruiyun; Akhmadaliev, Shavkat; Vázquez de Aldana, Javier R.; Zhou, Shengqiang; Chen, Feng

    2014-01-01

    We report on the optical waveguides, in both planar and ridge configurations, fabricated in LiTaO 3 crystal by using carbon (C 5+ ) ions irradiation at energy of 15 MeV. The planar waveguide was produced by direct irradiation of swift C 5+ ions, whilst the ridge waveguides were manufactured by using femtosecond laser ablation of the planar layer. The reconstructed refractive index profile of the planar waveguide has showed a barrier-shaped distribution, and the near-field waveguide mode intensity distribution was in good agreement with the calculated modal profile. After thermal annealing at 260 °C in air, the propagation losses of both the planar and ridge waveguides were reduced to 10 dB/cm

  14. Quantitative study of rectangular waveguide behavior in the THz.

    Energy Technology Data Exchange (ETDEWEB)

    Rowen, Adam M.; Nordquist, Christopher Daniel; Wanke, Michael Clement

    2009-10-01

    This report describes our efforts to quantify the behavior of micro-fabricated THz rectangular waveguides on a configurable, robust semiconductor-based platform. These waveguides are an enabling technology for coupling THz radiation directly from or to lasers, mixers, detectors, antennas, and other devices. Traditional waveguides fabricated on semiconductor platforms such as dielectric guides in the infrared or co-planar waveguides in the microwave regions, suffer high absorption and radiative losses in the THz. The former leads to very short propagation lengths, while the latter will lead to unwanted radiation modes and/or crosstalk in integrated devices. This project exploited the initial developments of THz micro-machined rectangular waveguides developed under the THz Grand Challenge Program, but instead of focusing on THz transceiver integration, this project focused on exploring the propagation loss and far-field radiation patterns of the waveguides. During the 9 month duration of this project we were able to reproduce the waveguide loss per unit of length in the waveguides and started to explore how the loss depended on wavelength. We also explored the far-field beam patterns emitted by H-plane horn antennas attached to the waveguides. In the process we learned that the method of measuring the beam patterns has a significant impact on what is actually measured, and this may have an effect on most of the beam patterns of THz that have been reported to date. The beam pattern measurements improved significantly throughout the project, but more refinements of the measurement are required before a definitive determination of the beam-pattern can be made.

  15. Compact Spectrometer based on a silicon multimode waveguide

    DEFF Research Database (Denmark)

    Piels, Molly; Zibar, Darko

    2017-01-01

    A multimode waveguide spectrometer with 4 GHz resolution, 250 GHz usable range, and a 1.6 mm × 2.1 mm footprint is demonstrated. The operating range is greatly extended by including distinct mode-exciting elements on chip....

  16. Observations of immuno-gold conjugates on influenza viruses using waveguide-mode sensors.

    Directory of Open Access Journals (Sweden)

    Subash C B Gopinath

    Full Text Available Gold nanoparticles were conjugated to an antibody (immuno-AuNP against A/Udorn/307/1972 (H3N2 influenza virus to detect viruses on a sensing plate designed for an evanescent field-coupled waveguide-mode sensor. Experiments were conducted using human influenza A/H3N2 strains, and immuno-AuNP could detect 8×10(5 PFU/ml (40 pg/µl intact A/Udorn/307/1972 and 120 pg/µl A/Brisbane/10/2007. Furthermore, increased signal magnitude was achieved in the presence of non-ionic detergent, as the virtual detection level was increased to 8×10(4 PFU/ml A/Udorn/307/1972. Immuno-AuNPs were then complexed with viruses to permit direct observation, and they formed a ring of confined nanodots on the membrane of both intact and detergent-treated viruses as directly visualized by scanning electron microscopy. With this complex the detection limit was improved further to 8×10(3 PFU/ml on anti-rabbit IgG immobilized sensing plate. These strategies introduce methods for observing trapped intact viruses on the sensing plates generated for optical systems.

  17. Photocatalytic oxidation of organic compounds via waveguide-supported titanium dioxide films

    Science.gov (United States)

    Miller, Lawrence W.

    A photochemical reactor based on titanium dioxide (TiO2)-coated silica optical fibers was constructed to explore the use of waveguide-supported TiO2 films for photocatalytic oxidation of organic compounds. The reactor was used for the photocatalytic oxidation of 4-chlorophenol in water. It was confirmed that TiO2 films could be securely attached to silica optical fibers. The 4-chlorophenol (100 mumol/L in water) was successfully oxidized on the TiO2 surface when UV light (310 nm--380 nm) was propagated through the fibers to the films. Rates of 4-chlorophenol oxidation and UV light flux to the fibers were measured. The quantum efficiency of 4-chlorophenol oxidation [defined as the change in 4-chlorophenol concentration divided by the UV light absorbed by the catalyst] was determined as a function of TiO2 catalyst film thickness and internal incident angle of propagating UV light. A maximum quantum efficiency of 2.8% was measured when TiO2 film thickness was ca. 80 nm and the maximum internal incident angle of propagating light was 84°. Quantum efficiency increased with increasing internal angle of incidence of propagating light and decreased with TiO2 film thickness. UV-Visible internal reflection spectroscopy was used to determine whether UV light propagated through TiO2-coated silica waveguides in an ATR mode. Propagation of UV light in an ATR mode was confirmed by the similarities between internal reflection spectra of phenolphthalein obtained with uncoated and TiO2-coated silica crystals. Planar silica waveguides coated with TiO2 were employed in a photocatalytic reactor for the oxidation of formic acid (833 mumol/L in water). It was shown that the quantum yield of formic acid oxidation [defined as the moles of formic acid oxidized divided by the moles of UV photons absorbed by the catalyst] on the waveguide-supported TiO2 surface is enhanced when UV light propagates through the waveguides in an ATR mode. A maximum quantum yield of 3.9% was found for formic

  18. Nanoscale Plasmonic V-Groove Waveguides for the Interrogation of Single Fluorescent Bacterial Cells

    DEFF Research Database (Denmark)

    Lotan, Oren; Bar-David, Jonathan; Smith, Cameron

    2017-01-01

    We experimentally demonstrate the interrogation of an individual Escherichia coli cell using a nanoscale plasmonic V-groove waveguide. Several different configurations were studied. The first involved the excitation of the cell in a liquid environment because it flows on top of the waveguide...

  19. Bloch-Surface-Polariton-Based Hybrid Nanowire Structure for Subwavelength, Low-Loss Waveguiding

    Directory of Open Access Journals (Sweden)

    Weijing Kong

    2018-03-01

    Full Text Available Surface plasmon polaritons (SPPs have been thoroughly studied in the past decades for not only sensing but also waveguiding applications. Various plasmonic device structures have been explored due to their ability to confine their optical mode to the subwavelength level. However, with the existence of metal, the large ohmic loss limits the propagation distance of the SPP and thus the scalability of such devices. Therefore, different hybrid waveguides have been proposed to overcome this shortcoming. Through fine tuning of the coupling between the SPP and a conventional waveguide mode, a hybrid mode could be excited with decent mode confinement and extended propagation distance. As an effective alternative of SPP, Bloch surface waves have been re-investigated more recently for their unique advantages. As is supported in all-dielectric structures, the optical loss for the Bloch surface wave is much lower, which stands for a much longer propagating distance. Yet, the confinement of the Bloch surface wave due to the reflections and refractions in the multilayer structure is not as tight as that of the SPP. In this work, by integrating a periodic multilayer structure that supports the Bloch surface wave with a metallic nanowire structure, a hybrid Bloch surface wave polariton could be excited. With the proposed hybrid nanowire structure, a hybrid mode is demonstrated with the deep subwavelength mode confinement and a propagation distance of tens of microns.

  20. Ultra-high speed all-optical signal processing using silicon waveguides and a carbon nanotubes based mode-locked laser

    DEFF Research Database (Denmark)

    Ji, Hua

    This thesis concerns the use of nano-engineered silicon waveguides for ultra-high speed optical serial data signal processing. The fundamental nonlinear properties of nano-engineered silicon waveguides are characterized. Utilizing the nonlinear effect in nano-engineered silicon waveguides for dem...

  1. Attenuation in Rectangular Waveguides with Finite Conductivity Walls

    Directory of Open Access Journals (Sweden)

    K. C. Yeong

    2011-06-01

    Full Text Available We present a fundamental and accurate approach to compute the attenuation of electromagnetic waves propagating in rectangular waveguides with finite conductivity walls. The wavenumbers kx and ky in the x and y directions respectively, are obtained as roots of a set of transcendental equations derived by matching the tangential component of the electric field (E and the magnetic field (H at the surface of the waveguide walls. The electrical properties of the wall material are determined by the complex permittivity ε, permeability μ, and conductivity σ. We have examined the validity of our model by carrying out measurements on the loss arising from the fundamental TE10 mode near the cutoff frequency. We also found good agreement between our results and those obtained by others including Papadopoulos’ perturbation method across a wide range of frequencies, in particular in the vicinity of cutoff. In the presence of degenerate modes however, our method gives higher losses, which we attribute to the coupling between modes as a result of dispersion.

  2. Direct mapping of light propagation in photonic crystal waveguides

    DEFF Research Database (Denmark)

    Bozhevolnyi, S.I.; Volkov, V.S.; Arentoft, J.

    2002-01-01

    Using near-field optical microscopy, we directly map the propagation of light in the wavelength range of 1510-1560 nm along bent photonic crystal waveguides formed by removing a single row of holes in the triangular 400-nm-period lattice and connected to access ridge waveguides, the structure being...

  3. Design and Measurement of Metallic Post-Wall Waveguide Components

    NARCIS (Netherlands)

    Coenen, T.J.; Bekers, D.J.; Tauritz, J.L.; Vliet, F.E. van

    2009-01-01

    Abstract—In this paper we discuss the design and measurement of a set of metallic post-wall waveguide components for antenna feed structures. The components are manufactured on a single layer printed circuit board and excited by a grounded coplanar waveguide. For a straight transmission line, a 90°

  4. Installation and calibration of a grating spectrometer for electron cyclotron emission measurements using circular waveguide

    International Nuclear Information System (INIS)

    Lohr, J.; Johns, G.; Moeller, C.; Prater, R.

    1986-01-01

    The grating spectrometer installation on the DIII-D tokamak is discussed. It uses fundamental circular waveguide propagating the TE 11 lowest order mode followed by oversized circular guide carrying the low loss TE 01 mode. The short section of fundamental guide permits use of an electronic chopper operating at 50 kHz for both calibration and plasma operation. By using a.c.-coupled amplifiers tuned to the chopping frequency, the background signal generated in the InSb detectors by neutrons and x-rays is automatically subtracted and the system noise bandwidth is reduced. Compared with a quasi-optical system, the much smaller fundamental horn and front end waveguide allow the entire waveguide system to be located outside a gate valve. With this configuration the entire waveguide run, including the actual horn and vacuum window used during plasma operations, can be included in the calibration set-up

  5. Propagation Characteristics of Multilayer Hybrid Insulator-Metal-Insulator and Metal-Insulator-Metal Plasmonic Waveguides

    Directory of Open Access Journals (Sweden)

    M. Talafi Noghani

    2014-02-01

    Full Text Available Propagation characteristics of symmetrical and asymmetrical multilayer hybrid insulator-metal-insulator (HIMI and metal-insulator-metal (HMIM plasmonic slab waveguides are investigated using the transfer matrix method. Propagation length (Lp and spatial length (Ls are used as two figures of merit to qualitate the plasmonic waveguides. Symmetrical structures are shown to be more performant (having higher Lp and lower Ls, nevertheless it is shown that usage of asymmetrical geometry could compensate for the performance degradation in practically realized HIMI waveguides with different substrate materials. It is found that HMIM slab waveguide could support almost long-range subdiffraction plasmonic modes at dimensions lower than the spatial length of the HIMI slab waveguide.

  6. An ITER-relevant evacuated waveguide transmission system for the JET-EP ECRH project

    International Nuclear Information System (INIS)

    Henderson, M.A.; Alberti, S.; Bird, J.

    2003-01-01

    An over-moded evacuated waveguide line was chosen for use in the transmission system for the proposed JET-enhanced performance project (JET-EP) electron cyclotron resonance heating (ECRH) system. A comparison between the quasi-optical, atmospheric waveguide and evacuated waveguide systems was performed for the project with a strong emphasis placed on the technical and financial aspects. The evacuated waveguide line was chosen as the optimal system in light of the above criteria. The system includes six lines of 63.5mm wave guide for transmitting 6.0 MW(10 s) at 113.3 GHz from the gyrotrons to the launching antenna. The designed lines are on average 72m in length and consist of nine mitre bends, for an estimated transmission efficiency of ∼90%. Each line is designed to include an evacuated switch leading to a calorimetric load, two dc breaks, two gate valves, one pump out tee, a power monitor mitre bend and a double-disc CVD window near the torus. The location of waveguide support is positioned to minimize the power converted to higher-order modes from waveguide sagging and misalignment. The two gate valves and CVD window are designed to be used as tritium barriers at the torus and between the J1T and J1D buildings. The last leg of the waveguide leading to the torus has to be designed to accommodate the torus movement during disruptions and thermal cycles. All lines are also designed to be compatible with the ITER ECRH system operating at 170 GHz. (author)

  7. Single-mode coherent synchrotron radiation instability

    Directory of Open Access Journals (Sweden)

    S. Heifets

    2003-06-01

    Full Text Available The microwave instability driven by the coherent synchrotron radiation (CSR has been previously studied [S. Heifets and G. V. Stupakov, Phys. Rev. ST Accel. Beams 5, 054402 (2002] neglecting effect of the shielding caused by the finite beam pipe aperture. In practice, the unstable mode can be close to the shielding threshold where the spectrum of the radiation in a toroidal beam pipe is discrete. In this paper, the CSR instability is studied in the case when it is driven by a single synchronous mode. A system of equations for the beam-wave interaction is derived and its similarity to the 1D free-electron laser theory is demonstrated. In the linear regime, the growth rate of the instability is obtained and a transition to the case of continuous spectrum is discussed. The nonlinear evolution of the single-mode instability, both with and without synchrotron damping and quantum diffusion, is also studied.

  8. Plasmon enhanced light amplification in metal–insulator–metal waveguides with gain

    International Nuclear Information System (INIS)

    Zhong, Xiao-Lan; Li, Zhi-Yuan

    2012-01-01

    In this paper we study the loss compensation and light amplification properties of metal–insulator–metal (MIM) waveguides that are doped with gain material in the dielectric core. An analytical approach based on Maxwell’s equations is developed to evaluate quantitatively the influence of the gain coefficient on the loss compensation and light amplification efficiencies of the waveguide under different values of the waveguide width and working wavelengths. The analytical results agree excellently with all-numerical calculations that directly solve Maxwell’s equations. The results show that the light amplification efficiency obeys a strict linear relationship with the gain coefficient, and MIM waveguides with narrower widths and under shorter wavelengths have better efficiencies. In addition, the MIM waveguides have higher light amplification efficiencies than usual dielectric waveguides, which suggests a very positive role of the plasmonic structure in enhancing the light amplification when gain is introduced. These loss and gain behaviors can be well explained by looking at the modal profile of each transport mode and the corresponding light energy confinement effect and slow light effect. (paper)

  9. 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....

  10. Electrically driven hybrid Si/III-V Fabry-Pérot lasers based on adiabatic mode transformers.

    Science.gov (United States)

    Ben Bakir, B; Descos, A; Olivier, N; Bordel, D; Grosse, P; Augendre, E; Fulbert, L; Fedeli, J M

    2011-05-23

    We report the first demonstration of an electrically driven hybrid silicon/III-V laser based on adiabatic mode transformers. The hybrid structure is formed by two vertically superimposed waveguides separated by a 100-nm-thick SiO2 layer. The top waveguide, fabricated in an InP/InGaAsP-based heterostructure, serves to provide optical gain. The bottom Si-waveguides system, which supports all optical functions, is constituted by two tapered rib-waveguides (mode transformers), two distributed Bragg reflectors (DBRs) and a surface-grating coupler. The supermodes of this hybrid structure are controlled by an appropriate design of the tapers located at the edges of the gain region. In the middle part of the device almost all the field resides in the III-V waveguide so that the optical mode experiences maximal gain, while in regions near the III-V facets, mode transformers ensure an efficient transfer of the power flow towards Si-waveguides. The investigated device operates under quasi-continuous wave regime. The room temperature threshold current is 100 mA, the side-mode suppression ratio is as high as 20 dB, and the fiber-coupled output power is ~7 mW.

  11. Optical Nano-antennae as Compact and Efficient Couplers from Free-space to Waveguide Modes

    DEFF Research Database (Denmark)

    Zenin, Vladimir A.; Malureanu, Radu; Volkov, Valentyn

    2015-01-01

    Optical nano-antennae are one of the possible solutions for coupling free-space radiation into subwavelength waveguides. Our efforts were concentrated on coupling between an optical fibre and a plasmonic slot waveguide. Such coupling is still an issue to be solved in order to advance the use...... of plasmonic waveguides for optical interconnects. During the talk, we will present our modelling optimisation, fabrication and measurement of the nano-antennae functionality. For the modelling part, we used CST Microwave studio for optimising the antenna geometry. Various antennae were modelled and fabricated....... The fabrication was based on electron beam lithography and lift-off processes. The measurements were performed with scattering scanning near-field microscope and allowed the retrieval of both amplitude and phase of the propagating plasmon. The obtained values agree very well with the theoretically predicted ones...

  12. Disorder-induced resonance shifts and mode edge broadening in photonic crystal waveguides

    DEFF Research Database (Denmark)

    Mann, N.; Javadi, Alisa; Garcia-Fernandez, Pedro David

    2014-01-01

    We present theory and measurements for systematically disordered slow-light photonic crystal waveguides and find a pronounced disorder-induced blueshift and broadening of the photon density of states....

  13. Ring cavity for a Raman capillary waveguide amplifier

    Science.gov (United States)

    Kurnit, N.A.

    1981-01-27

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  14. Ring cavity for a Raman capillary waveguide amplifir

    Science.gov (United States)

    Kurnit, N.A.

    1981-01-27

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  15. Nonlinear Dynamics of Ultrashort Long-Range Surface Plasmon Polariton Pulses in Gold Strip Waveguides

    DEFF Research Database (Denmark)

    Lysenko, Oleg; Bache, Morten; Olivier, Nicolas

    2016-01-01

    We study experimentally and theoretically nonlinear propagation of ultrashort long-range surface plasmon polaritons in gold strip waveguides. The nonlinear absorption of the plasmonic modes in the waveguides is measured with femtosecond pulses revealing a strong dependence of the third......-order nonlinear susceptibility of the gold core on the pulse duration and layer thickness. A comprehensive model for the pulse duration dependence of the third-order nonlinear susceptibility is developed on the basis of the nonlinear Schrödinger equation for plasmonic mode propagation in the waveguides....... The model accounts for the intrinsic delayed (noninstantaneous) nonlinearity of free electrons of gold as well as the thickness of the gold film and is experimentally verified. The obtained results are important for the development of active plasmonic and nanophotonic components....

  16. Anomalous dispersion properties of TM waves in subwavelength metallic waveguides loaded by uniaxial metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guanghui, E-mail: wanggh@scnu.edu.cn; Lei, Yuandong; Zhang, Weifeng

    2015-02-20

    Dispersion properties of transverse magnetic (TM) waves in a subwavelength metallic waveguide loaded by uniaxial metamaterials are investigated, based on two kinds of uniaxial metamaterials with different orientations of optical axis. The numerical results show that the existence of fundamental TM{sub 0} mode and high-order TM modes in the waveguide system is dependent on the orientation of optical axis. In addition, their anomalous dispersion properties are clarified. When the orientation of optical axis is selected properly, there are two branches of dispersion curves for each high-order mode—one is normal dispersion and another belongs to anomalous dispersion, showing a transition from a backward wave to a forward one with the increase of working frequency. Moreover, the group velocity and energy flow distribution for TM{sub 1} mode are also demonstrated. These properties may have potential applications in optical information storage, integrated optics and nanophotonic devices. - Highlights: • Two kinds of subwavelength uniaxial metamaterial waveguides are constructed. • We demonstrate anomalous dispersion properties of transverse magnetic (TM) guided modes. • There are two branches of dispersion curves for high-order TM modes, showing a transition from a backward wave to a forward one. • Group velocity can approach to zero, having potential application in optical information storage. • Negative group velocity and energy flow distribution for TM modes are shown.

  17. Heterogeneous integration of thin film compound semiconductor lasers and SU8 waveguides on SiO2/Si

    Science.gov (United States)

    Palit, Sabarni; Kirch, Jeremy; Mawst, Luke; Kuech, Thomas; Jokerst, Nan Marie

    2010-02-01

    We present the heterogeneous integration of a 3.8 μm thick InGaAs/GaAs edge emitting laser that was metal-metal bonded to SiO2/Si and end-fire coupled into a 2.8 μm thick tapered SU8 polymer waveguide integrated on the same substrate. The system was driven in pulsed mode and the waveguide output was captured on an IR imaging array to characterize the mode. The waveguide output was also coupled into a multimode fiber, and into an optical head and spectrum analyzer, indicating lasing at ~997 nm and a threshold current density of 250 A/cm2.

  18. Optical Intensity Modulation in an LiNbO3 Slab-Coupled Waveguide

    Directory of Open Access Journals (Sweden)

    Yalin Lu

    2008-01-01

    Full Text Available Optical intensity modulation has been demonstrated through switching the optical beam between the main core waveguide and a closely attached leaky slab waveguide by applying a low-voltage electrical field. Theory for simulating such an LiNbO3 slab-coupled waveguide structure was suggested, and the result indicates the possibility of making the spatial guiding mode large, circular and symmetric, which further allows the potential to significantly reduce the coupling losses with adjacent lasers and optical networks. Optical intensity modulation using electro-optic effect was experimentally demonstrated in a 5 cm long waveguide fabricated by using a procedure of soft proton exchange and then an overgrowth of thin LN film on top of a c-cut LiNbO3 wafer.

  19. Components for transmission of very high power mm-waves (200 kW at 28, 70 and 140 GHz) in overmoded circular waveguides

    International Nuclear Information System (INIS)

    Thumm, M.; Erckmann, V.; Kasparek, W.; Kumric, H.; Mueller, G.A.; Schueller, P.G.; Wilhelm, R.

    1986-03-01

    Optimized overmoded circular waveguide components of transmission lines developed for high-power (200 kW) millimeter wave applications at 28, 70 and 140 GHz, as e.g. electron cyclotron resonance heating (ECRH) of plasmas for thermonuclear fusion research with gyrotrons, are described. Axisymmetric, narrow, pencil-like beams with well-defined polarization (HE11 hybrid mode) are used at open-ended corrugated waveguide antennas. The HE11 mode is generated from TEsub(On) gyrotron modes by the two multi-step mode conversion processes: (1) TEsub(On)->TE 01 ->TE 11 ->HE 11 or (2) TEsub(On)->TE 01 ->TM 11 ->HE 11 . This paper reports computer-aided analyses and measurements on mode transducer systems of the first type at 28 and 70 GHz and of the second type at 140 GHz. In all cases the overall efficiency of the complete mode conversion sequence in the desired mode is approximately (92-95)%. The mode purity in the transmission lines is conserved by using corrugated gradual waveguide bends with optimized curvature distribution and diameter tapers with non-linear contours. Highly efficient corrugated-wall mode selective filters decouple the different waveguide sections. Mode content and reflected power are determined by a novel device (k-spectrometer). Absolute power calibration is done with newly developed calorimetric loads using an organic absorbing fluid. (orig.) [de

  20. Linear optical quantum computing in a single spatial mode.

    Science.gov (United States)

    Humphreys, Peter C; Metcalf, Benjamin J; Spring, Justin B; Moore, Merritt; Jin, Xian-Min; Barbieri, Marco; Kolthammer, W Steven; Walmsley, Ian A

    2013-10-11

    We present a scheme for linear optical quantum computing using time-bin-encoded qubits in a single spatial mode. We show methods for single-qubit operations and heralded controlled-phase (cphase) gates, providing a sufficient set of operations for universal quantum computing with the Knill-Laflamme-Milburn [Nature (London) 409, 46 (2001)] scheme. Our protocol is suited to currently available photonic devices and ideally allows arbitrary numbers of qubits to be encoded in the same spatial mode, demonstrating the potential for time-frequency modes to dramatically increase the quantum information capacity of fixed spatial resources. As a test of our scheme, we demonstrate the first entirely single spatial mode implementation of a two-qubit quantum gate and show its operation with an average fidelity of 0.84±0.07.

  1. Exact equivalent straight waveguide model for bent and twisted waveguides

    DEFF Research Database (Denmark)

    Shyroki, Dzmitry

    2008-01-01

    Exact equivalent straight waveguide representation is given for a waveguide of arbitrary curvature and torsion. No assumptions regarding refractive index contrast, isotropy of materials, or particular morphology in the waveguide cross section are made. This enables rigorous full-vector modeling...... of in-plane curved or helically wound waveguides with use of available simulators for straight waveguides without the restrictions of the known approximate equivalent-index formulas....

  2. Physics and technology of tunable pulsed single longitudinal mode ...

    Indian Academy of Sciences (India)

    Design and technology demonstration of compact, narrow bandwidth, high repetition rate, tunable SLM dye lasers in two different configurations, namely Littrow and grazing incidence grating (GIG), were carried out in our lab at BARC, India. The single longitudinal mode (SLM) dye laser generates single-mode laser beams ...

  3. Imaging of THz waves in 2D photonic crystal structures embedded in a slab waveguide

    International Nuclear Information System (INIS)

    Peier, P; Merbold, H; Feurer, T; Pahinin, V; Nelson, K A

    2010-01-01

    We present space- and time-resolved simulations and measurements of single-cycle terahertz (THz) waves propagating through two-dimensional (2D) photonic crystal structures embedded in a slab waveguide. Specifically, we use a plane wave expansion technique to calculate the band structure and a time-dependent finite-element method to simulate the temporal evolution of the THz waves. Experimentally, we measure the space-time evolution of the THz waves through a coherent time-resolved imaging method. Three different structures are laser machined in LiNbO 3 crystal slabs and analyzing the transmitted as well as the reflected THz waveforms allows determination of the bandgaps. Comparing the results with the calculated band diagrams and the time-dependent simulations shows that the experiments are consistent with 3D simulations, which include the slab waveguide geometry, the birefringence of the material, and a careful analysis of the excited modes within the band diagrams.

  4. Quality factor of a transmission line coupled coplanar waveguide resonator

    Energy Technology Data Exchange (ETDEWEB)

    Besedin, Ilya [National University for Science and Technology (MISiS), Moscow (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Menushenkov, Alexey P. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation)

    2018-12-15

    We investigate analytically the coupling of a coplanar waveguide resonator to a coplanar waveguide feedline. Using a conformal mapping technique we obtain an expression for the characteristic mode impedances and coupling coefficients of an asymmetric multi-conductor transmission line. Leading order terms for the external quality factor and frequency shift are calculated. The obtained analytical results are relevant for designing circuit-QED quantum systems and frequency division multiplexing of superconducting bolometers, detectors and similar microwave-range multi-pixel devices. (orig.)

  5. Hollow cylindrical plasma filament waveguide with discontinuous finite thickness cladding

    International Nuclear Information System (INIS)

    Alshershby, Mostafa; Hao Zuoqiang; Lin Jingquan

    2013-01-01

    We have explored here a hollow cylindrical laser plasma multifilament waveguide with discontinuous finite thickness cladding, in which the separation between individual filaments is in the range of several millimeters and the waveguide cladding thickness is in the order of the microwave penetration depth. Such parameters give a closer representation of a realistic laser filament waveguide sustained by a long stable propagation of femtosecond (fs) laser pulses. We report how the waveguide losses depend on structural parameters like normalized plasma filament spacing, filament to filament distance or pitch, normal spatial frequency, and radius of the plasma filament. We found that for typical plasma parameters, the proposed waveguide can support guided modes of microwaves in extremely high frequency even with a cladding consisting of only one ring of plasma filaments. The loss of the microwave radiation is mainly caused by tunneling through the discontinuous finite cladding, i.e., confinement loss, and is weakly dependent on the plasma absorption. In addition, the analysis indicates that the propagation loss is fairly large compared with the loss of a plasma waveguide with a continuous infinite thickness cladding, while they are comparable when using a cladding contains more than one ring. Compared to free space propagation, this waveguide still presents a superior microwave transmission to some distance in the order of the filamentation length; thus, the laser plasma filaments waveguide may be a potential channel for transporting pulsed-modulated microwaves if ensuring a long and stable propagation of fs laser pulses.

  6. Theoretical Analysis of Spectral Correlations Between Photon Pairs Generated in Nanoscale Silicon Waveguides

    International Nuclear Information System (INIS)

    Lu Liang-Liang; Xu Ping; Xu Jian-Ning; Zhu Shi-Ning; He Guang-Qiang

    2015-01-01

    Spontaneous four wave mixing in nonlinear waveguide is one of the excellent technique for generating photon pairs in well-defined guided modes. Here we present a comprehensive study of the frequency characteristic of correlated photon pairs generated in telecom C-band from a dispersion-engineered silicon wire waveguide. We have demonstrated that the waveguide configuration, shape of pump pulse, two-photon absorption as well as linear losses have significant influences on the biphoton spectral characteristics and the amount of frequency entanglement generated. The superior performance as well as the structural compactness and CMOS compatibility makes the silicon wire waveguide an ideal integrated platform for the implementation of on-chip quantum technologies. (paper)

  7. Improving the beam quality of high-power laser diodes by introducing lateral periodicity into waveguides

    Science.gov (United States)

    Sobczak, Grzegorz; DÄ browska, ElŻbieta; Teodorczyk, Marian; Kalbarczyk, Joanna; MalÄ g, Andrzej

    2013-01-01

    Low quality of the optical beam emitted by high-power laser diodes is the main disadvantage of these devices. The two most important reasons are highly non-Gaussian beam profile with relatively wide divergence in the junction plane and the filamentation effect. Designing laser diode as an array of narrow, close to each other single-mode waveguides is one of the solutions to this problem. In such devices called phase locked arrays (PLA) there is no room for filaments formation. The consequence of optical coupling of many single-mode waveguides is the device emission in the form of few almost diffraction limited beams. Because of losses in regions between active stripes the PLA devices have, however, somewhat higher threshold current and lower slope efficiencies compared to wide-stripe devices of similar geometry. In this work the concept of the high-power laser diode resonator consisted of joined PLA and wide stripe segments is proposed. Resulting changes of electro-optical characteristics of PLA are discussed. The devices are based on the asymmetric heterostructure designed for improvement of the catastrophic optical damage threshold as well as thermal and electrical resistances. Due to reduced distance from the active layer to surface in this heterostructure, better stability of current (and gain) distribution with changing drive level is expected. This could lead to better stability of optical field distribution and supermodes control. The beam divergence reduction in the direction perpendicular of the junction plane has been also achieved.

  8. Nanofabrication of Plasmonic Circuits Containing Single Photon Sources

    DEFF Research Database (Denmark)

    Siampour, Hamidreza; Kumar, Shailesh; Bozhevolnyi, Sergey I.

    2017-01-01

    Nanofabrication of photonic components based on dielectric loaded surface plasmon polariton waveguides (DLSPPWs) excited by single nitrogen vacancy (NV) centers in nanodiamonds is demonstrated. DLSPPW circuits are built around NV containing nanodiamonds, which are certified to be single-photon...... emitters, using electron-beam lithography of hydrogen silsesquioxane (HSQ) resist on silver-coated silicon substrates. A propagation length of 20 ± 5 μm for the NV single-photon emission is measured with DLSPPWs. A 5-fold enhancement in the total decay rate, and 58% coupling efficiency to the DLSPPW mode...

  9. Fully relativistic free-electron laser in a completely filled waveguide

    International Nuclear Information System (INIS)

    Farokhi, B.; Abdykian, A.

    2005-01-01

    An analysis of the azimuthally symmetrical, high frequency eigenmodes of a cylindrical metallic waveguide completely filled with a relativistic magnetized plasma is presented. A relativistic nonlinear wave equation is derived in a form which includes the coupling of EH and HE modes due to the finite axial magnetic field. Relativistic equations that permit calculation of the dispersion curves for four families of electromagnetic and electrostatic modes are derived. Numerical analysis is conducted to study the relativistic dispersion curves of various modes as a function of axial magnetic field B 0 . This treatment is shown that the dispersion curves dependent to γ in low frequency which is ignored in previous work. It is found that in drawn figures shown difference between relativistic and non-relativistic cases. The former each figure is treated for two orbit groups. This study is benefiting to facilities the development of devices for generation of high-power electromagnetic radiation, charged particle acceleration, and other applications of plasma waveguide. (author)

  10. Multiplexed Simultaneous High Sensitivity Sensors with High-Order Mode Based on the Integration of Photonic Crystal 1 × 3 Beam Splitter and Three Different Single-Slot PCNCs.

    Science.gov (United States)

    Zhou, Jian; Huang, Lijun; Fu, Zhongyuan; Sun, Fujun; Tian, Huiping

    2016-07-07

    We simulated an efficient method for the sensor array of high-sensitivity single-slot photonic crystal nanobeam cavities (PCNCs) on a silicon platform. With the combination of a well-designed photonic crystal waveguide (PhCW) filter and an elaborate single-slot PCNC, a specific high-order resonant mode was filtered for sensing. A 1 × 3 beam splitter carefully established was implemented to split channels and integrate three sensors to realize microarrays. By applying the three-dimensional finite-difference-time-domain (3D-FDTD) method, the sensitivities calculated were S₁ = 492 nm/RIU, S₂ = 244 nm/RIU, and S₃ = 552 nm/RIU, respectively. To the best of our knowledge, this is the first multiplexing design in which each sensor cite features such a high sensitivity simultaneously.

  11. Sourcewise represented green's function of the circular waveguide

    International Nuclear Information System (INIS)

    Prijmenko, S.D.; Bondarenko, L.A.

    2007-01-01

    Singular part of the Green's function of unbounded space is singled out in explicit form and contains all singularities, including a delta-shaped singularity. The problem of construction of Green's function for a field is solved, as a problem for diffraction of potential and rotational components electric field intensity of a point current source on the circular waveguide walls. The singling out of the electric field intensity singularity in an explicit form about a source enables to develop an effective algorithm of Green's function calculation at any distance between the source point and observation point in a circular waveguide

  12. Photonic Crystal Waveguides in Triangular Lattice of Nanopillars

    DEFF Research Database (Denmark)

    Chigrin, Dmitry N.; Lavrinenko, Andrei

    2004-01-01

    Photonic nanopillars waveguides have been analysed. Dielectric nanopillars are arranged in such way that they from a tringular lattice of 2D photonic crystal. Dispersion of the modes depends on the direction of the triangular lattice, Ã-J or Ã-X, in which nanopillars arrays are extended. Light fi....... Transmission spectra calculated by FDTD method completely reflect peculiarities of modes dispersion, showing up to 80% transmission for a realistic SOI nanopillar structure....

  13. Gratings in passive and active optical waveguides

    DEFF Research Database (Denmark)

    Berendt, Martin Ole

    1999-01-01

    will not only couple to the backward propagating fundamental mode, but also to cladding modes. Cladding modes are strongly bound, but slightly leaky, higher-order modes in the core-cladding-air index structure. If the waveguide is not surrounded by air, but by a recoating the cladding modes become highly...... attenuated. In either case the cladding mode coupling gives loss on the short wavelength side of the reflection band. The cladding mode coupling loss is a major problem for the utilization of fiber Bragg gratings in wavelength division multiplexed (WDM) system. In this project, a numerical model for cladding...... mode coupling has been developed. The model can predict the spectral location and size of coupling, for various fiber designs. By the aid of this modeling tool, a fiber has been optimized to give low cladding-mode losses. The optimized fiber has been produced and the predicted reduction of cladding...

  14. Planar waveguides and other confined geometries theory, technology, production, and novel applications

    CERN Document Server

    2015-01-01

    This book provides a comprehensive overview of the theoretical concepts and experimental applications of planar waveguides and other confined geometries, such as optical fibres. Covering a broad array of advanced topics, it begins with a sophisticated discussion of planar waveguide theory, and covers subjects including efficient production of planar waveguides, materials selection, nonlinear effects, and applications including species analytics down to single-molecule identification, and thermo-optical switching using planar waveguides. Written by specialists in the techniques and applications covered, this book will be a useful resource for advanced graduate students and researchers studying planar waveguides and optical fibers.

  15. Efficient frequency-domain numerical analysis of modified surface plasmon waveguides formed by a metallic sleeve and coaxial rod

    International Nuclear Information System (INIS)

    Tian Jinping; Xue Wenrui

    2012-01-01

    Some types of modified surface plasmonic waveguides formed by nanometric silver rods with triangular and square cross-section and a coaxial silver sleeve are proposed in this paper. The finite-difference frequency-domain method is used to study the propagation properties of the fundamental mode supported by these types of surface plasmonic waveguides. The field distribution of the fundamental mode and the dependences of the propagation properties on the geometrical parameters, working wavelength and gain media are discussed in detail. The results show that the above physical properties can be adjusted by choosing proper structure parameters, working wavelength and gain media. So the advantages of the properties of the modes render these waveguides promising optical components or photonic device integration and sensors that would benefit future plasmonic interconnects and circuits.

  16. Computation of mode eigenfunctions in graded-index optical fibers by the propagating beam method

    International Nuclear Information System (INIS)

    Feit, M.D.; Fleck, J.A. Jr.

    1980-01-01

    The propagating beam method utilizes discrete Fourier transforms for generating configuration-space solutions to optical waveguide problems without reference to modes. The propagating beam method can also give a complete description of the field in terms of modes by a Fourier analysis with respect to axial distance of the computed fields. Earlier work dealt with the accurate determination of mode propagation constants and group delays. In this paper the method is extended to the computation of mode eigenfunctions. The method is efficient, allowing generation of a large number of eigenfunctions from a single propagation run. Computations for parabolic-index profiles show excellent agreement between analytic and numerically generated eigenfunctions

  17. Broadband silicon polarization beam splitter with a high extinction ratio using a triple-bent-waveguide directional coupler.

    Science.gov (United States)

    Ong, Jun Rong; Ang, Thomas Y L; Sahin, Ezgi; Pawlina, Bryan; Chen, G F R; Tan, D T H; Lim, Soon Thor; Png, Ching Eng

    2017-11-01

    We report on the design and experimental demonstration of a broadband silicon polarization beam splitter (PBS) with a high extinction ratio (ER)≥30  dB. This was achieved using triple-bent-waveguide directional coupling in a single PBS, and cascaded PBS topology. For the single PBS, the bandwidths for an ER≥30  dB are 20 nm for the quasi-TE mode, and 70 nm for the quasi-TM mode when a broadband light source (1520-1610 nm) was employed. The insertion loss (IL) varies from 0.2 to 1 dB for the quasi-TE mode and 0.2-2 dB for the quasi-TM mode. The cascaded PBS improved the bandwidth of the quasi-TE mode for an ER≥30  dB to 90 nm, with a low IL of 0.2-2 dB. To the best of our knowledge, our PBS system is one of the best broadband PBSs with an ER as high as ∼42  dB and a low IL below 1 dB around the central wavelength, and experimentally demonstrated using edge-coupling.

  18. Analytical extraction of leaky modes in circular slab waveguides with arbitrary refractive index profile.

    Science.gov (United States)

    Sarrafi, P; Zareian, N; Mehrany, K

    2007-12-20

    Circular slab waveguides are conformally transformed into straight inhomogeneous waveguides, whereupon electromagnetic fields in the core are expanded in terms of Legendre polynomial basis functions. Thereafter, different analytical expression of electromagnetic fields in the cladding region, viz. Wentzel-Kramers-Brillouin solution, modified Airy function expansion, and the exact field solution for circular waveguides, i.e., Hankel function of complex order, are each matched to the polynomial expansion of the transverse electric field within the guide. This field matching process renders different boundary conditions to be satisfied by the set of orthogonal Legendre polynomial basis functions. In this fashion, the governing wave equation is converted into an algebraic and easy to solve eigenvalue problem, which is associated with a matrix whose elements are analytically given. Various numerical examples are presented and the accuracy of each of the abovementioned different boundary conditions is assessed. Furthermore, the computational efficiency and the convergence rate of the proposed method with increasing number of basis functions are briefly discussed.

  19. Investigation of single-mode and multi-mode hydromagnetic Rayleigh-Taylor instability in planar geometry

    International Nuclear Information System (INIS)

    Roderick, N.F.; Cochrane, K.; Douglas, M.R.

    1998-01-01

    Previous investigations carried out to study various methods of seeding the hydromagnetic Rayleigh-Taylor instability in magnetohydrodynamic simulations showed features similar to those seen in hydrodynamic calculations. For periodic single-mode initiations the results showed the appearance of harmonics as the single modes became nonlinear. For periodic multi-mode initiations new modes developed that indicated the presence of mode coupling. The MHD simulations used parameters of the high velocity large radius z-pinch experiments performed in the Z-accelerator at Sandia National Laboratories. The cylindrical convergent geometry and variable acceleration of these configurations made comparison with analytic, developed for planar geometry with constant acceleration, difficult. A set of calculations in planar geometry using constant current to produce acceleration and parameters characteristic of the cylindrical implosions has been performed to allow a better comparison. Results of these calculations, comparison with analytic theory, and comparison with the cylindrical configuration calculations will be discussed

  20. The passive optical properties of a silicon nanoparticle-embedded benzocyclobutene polymer waveguide

    International Nuclear Information System (INIS)

    Chiu, J.-J.; Perng, Tsong P

    2008-01-01

    The passive optical properties of a silicon nanoparticle-embedded benzocyclobutene (BCB) waveguide were investigated. The silicon nanoparticles, of a size varying from 6 to 25 nm, were prepared by vapor condensation. The transmission modes and losses were examined by the prism coupler and cut-back methods. A He-Ne laser beam with a wavelength of 6328 A was used to measure the effective index and thickness of the waveguide. Laser light could be efficiently coupled into the BCB waveguide when the embedded Si nanoparticles were smaller than 6 nm. The film thickness and effective index of the Si-embedded BCB waveguide were measured to be 1.825 μm and 1.565, respectively. The optical transmission losses of the pure BCB and Si-embedded ridge waveguides measured by the cut-back method were 0.85 and 1.63 dB cm -1 , respectively. Although the optical loss was increased by the embedded Si, the disturbance of the output contour was quite small. This result demonstrates that the nanoparticle-embedded polymer waveguide may be used for optoelectronic integrated circuits

  1. Vibro-acoustics of porous materials - waveguide modeling approach

    DEFF Research Database (Denmark)

    Darula, Radoslav; Sorokin, Sergey V.

    2016-01-01

    The porous material is considered as a compound multi-layered waveguide (i.e. a fluid layer surrounded with elastic layers) with traction free boundary conditions. The attenuation of the vibro-acoustic waves in such a material is assessed. This approach is compared with a conventional Biot's mode...

  2. Figures of merit for surface plasmon waveguides

    Science.gov (United States)

    Berini, Pierre

    2006-12-01

    Three figures of merit are proposed as quality measures for surface plasmon waveguides. They are defined as benefit-to-cost ratios where the benefit is confinement and the cost is attenuation. Three different ways of measuring confinement are considered, leading to three figures of merit. One of the figures of merit is connected to the quality factor. The figures of merit were then used to assess and compare the wavelength response of hree popular 1-D surface plasmon waveguides: the single metal-dielectric interface, the metal slab bounded by dielectric and the dielectric slab bounded by metal. Closed form expressions are given for the figures of merit of the single metal-dielectric interface.

  3. development of inhomogeneous disk-loaded accelerating waveguides and RF-coupling

    International Nuclear Information System (INIS)

    Ayzatsky, M.I.; Biller, E.Z.

    1996-01-01

    A description of different types of the accelerating structures that have been studied and constructed in NSC KIPT for electron linacs during last years is given in this paper. The accelerating structures consist of the inhomogeneous disk-loaded waveguides and input and output couplers. The disc-loaded waveguides operate at f = 2797 MHz in 2π/3 mode and have different laws of variation of the disk apertures. Before brazing cups were tuned with using special method. This method is discussed in this paper. (author)

  4. Wavelength interrogation of fiber Bragg grating sensors using tapered hollow Bragg waveguides.

    Science.gov (United States)

    Potts, C; Allen, T W; Azar, A; Melnyk, A; Dennison, C R; DeCorby, R G

    2014-10-15

    We describe an integrated system for wavelength interrogation, which uses tapered hollow Bragg waveguides coupled to an image sensor. Spectral shifts are extracted from the wavelength dependence of the light radiated at mode cutoff. Wavelength shifts as small as ~10  pm were resolved by employing a simple peak detection algorithm. Si/SiO₂-based cladding mirrors enable a potential operational range of several hundred nanometers in the 1550 nm wavelength region for a taper length of ~1  mm. Interrogation of a strain-tuned grating was accomplished using a broadband amplified spontaneous emission (ASE) source, and potential for single-chip interrogation of multiplexed sensor arrays is demonstrated.

  5. C-Scan Performance Test of Under-Sodium ultrasonic Waveguide Sensor in Sodium

    International Nuclear Information System (INIS)

    Joo, Young Sang; Bae, Jin Ho; Kim, Jong Bum

    2011-01-01

    Reactor core and in-vessel structures of a sodium-cooled fast (SFR) are submerged in opaque liquid sodium in the reactor vessel. The ultrasonic inspection techniques should be applied for observing the in-vessel structures under hot liquid sodium. Ultrasonic sensors such as immersion sensors and rod-type waveguide sensors have developed in order to apply under-sodium viewing of the in-vessel structures of SFR. Recently the novel plate-type ultrasonic waveguide sensor has been developed for the versatile application of under-sodium viewing in SFR. In previous studies, the ultrasonic waveguide sensor module was designed and manufactured, and the feasibility study of the ultrasonic waveguide sensor was performed. To improve the performance of the ultrasonic waveguide sensor in the under-sodium application, a new concept of ultrasonic waveguide sensors with a Be coated SS304 plate is suggested for the effective generation of a leaky wave in liquid sodium and the non-dispersive propagation of A 0 -mode Lamb wave in an ultrasonic waveguide sensor. In this study, the C-scan performance of the under-sodium ultrasonic waveguide sensor in sodium has been investigated by the experimental test in sodium. The under-sodium ultrasonic waveguide sensor and the sodium test facility with a glove box system and a sodium tank are designed and manufactured to carry out the performance test of under-sodium ultrasonic waveguide sensor in sodium environment condition

  6. Single-particle states vs. collective modes: friends or enemies ?

    Science.gov (United States)

    Otsuka, T.; Tsunoda, Y.; Togashi, T.; Shimizu, N.; Abe, T.

    2018-05-01

    The quantum self-organization is introduced as one of the major underlying mechanisms of the quantum many-body systems. In the case of atomic nuclei as an example, two types of the motion of nucleons, single-particle states and collective modes, dominate the structure of the nucleus. The collective mode arises as the balance between the effect of the mode-driving force (e.g., quadrupole force for the ellipsoidal deformation) and the resistance power against it. The single-particle energies are one of the sources to produce such resistance power: a coherent collective motion is more hindered by larger spacings between relevant single particle states. Thus, the single-particle state and the collective mode are "enemies" against each other. However, the nuclear forces are rich enough so as to enhance relevant collective mode by reducing the resistance power by changing single-particle energies for each eigenstate through monopole interactions. This will be verified with the concrete example taken from Zr isotopes. Thus, the quantum self-organization occurs: single-particle energies can be self-organized by (i) two quantum liquids, e.g., protons and neutrons, (ii) monopole interaction (to control resistance). In other words, atomic nuclei are not necessarily like simple rigid vases containing almost free nucleons, in contrast to the naïve Fermi liquid picture. Type II shell evolution is considered to be a simple visible case involving excitations across a (sub)magic gap. The quantum self-organization becomes more important in heavier nuclei where the number of active orbits and the number of active nucleons are larger.

  7. Multi-Mode Analysis of Dual Ridged Waveguide Systems for Material Characterization

    Science.gov (United States)

    2015-09-17

    analysis”. Instrumenta- tion and Measurement, IEEE Transactions on, 44(1):19–27, 1995. [26] Maode, Niu, Su Yong, Yan Jinkui, Fu Chenpeng, and Xu Deming ...waveguide method”. Instrumentation and Measurement, IEEE Transactions on, 46(2):519–522, 1997. [35] Wang, Shoujun, Maode Niu, and Deming Xu. “A frequency

  8. Towards the coupling of single photons from dye molecules to a photonic waveguide

    Science.gov (United States)

    Polisseni, Claudio; Kho, Kiang Wei; Major, Kyle; Grandi, Samuele; Boisser, Sebastien; Hwang, Jaesuk; Clark, Alex; Hinds, Edward

    Single photons are very attractive for quantum information processing given their long coherence time and their ability to carry information in many degrees of freedom. A current challenge is the efficient generation of single photons in a photonic chip in order to scale up the complexity of quantum operations. We have proposed that a dibenzoterrylene (DBT) molecule inside an anthracene (AC) crystal could couple lifetime-limited indistinguishable single photons into a photonic waveguide if deposited in its vicinity. In this talk I describe the recent progress towards the realization of this proposal. A new method has been developed for evaporating AC and DBT to produce crystals that are wide and thin. The crystals are typically several microns across and have remarkably uniform thickness, which we control between 20 and 150 nm. The crystal growth is carried out in a glove bag in order to exclude oxygen, which improves the photostability of the DBT molecules by orders of magnitude. We image the fluorescence of single DBT molecules using confocal microscopy and analyse the polarization of this light to determine the alignment of the molecules. I will report on our efforts to control the alignement of the molecules by aligning the host matrix with the substrate.

  9. An Integrative Biosensor Based on Contra-Directional Coupling Two-dimensional Photonic Crystal Waveguides

    International Nuclear Information System (INIS)

    Xiao-Yu, Mao; Di-Bi, Yao; Ling-Yun, Zhao; Yi-Dong, Huang; Wei, Zhang; Jiang-De, Peng

    2008-01-01

    We propose an integrative biochemical sensor utilizing the dip in the transmission spectrum of a normal single-line defect photonic crystal (PC) waveguide, which has a contra-directional coupling with another PC waveguide. When the air holes in the PC slab are filled with a liquid analyte with different refractive indices, the dip has a wavelength shift By detecting the output power variation at a certain fixed wavelength, a sensitivity of 1.2 × 10 −4 is feasible. This structure is easy for integration due to its plane waveguide structure and omissible pump source. In addition, high signal to noise ratio can be expected because signal transmits via a normal single-line defect PC waveguide instead of the PC hole area or analyte

  10. High accuracy electromagnetic field solvers for cylindrical waveguides and axisymmetric structures using the finite element method

    International Nuclear Information System (INIS)

    Nelson, E.M.

    1993-12-01

    Some two-dimensional finite element electromagnetic field solvers are described and tested. For TE and TM modes in homogeneous cylindrical waveguides and monopole modes in homogeneous axisymmetric structures, the solvers find approximate solutions to a weak formulation of the wave equation. Second-order isoparametric lagrangian triangular elements represent the field. For multipole modes in axisymmetric structures, the solver finds approximate solutions to a weak form of the curl-curl formulation of Maxwell's equations. Second-order triangular edge elements represent the radial (ρ) and axial (z) components of the field, while a second-order lagrangian basis represents the azimuthal (φ) component of the field weighted by the radius ρ. A reduced set of basis functions is employed for elements touching the axis. With this basis the spurious modes of the curl-curl formulation have zero frequency, so spurious modes are easily distinguished from non-static physical modes. Tests on an annular ring, a pillbox and a sphere indicate the solutions converge rapidly as the mesh is refined. Computed eigenvalues with relative errors of less than a few parts per million are obtained. Boundary conditions for symmetric, periodic and symmetric-periodic structures are discussed and included in the field solver. Boundary conditions for structures with inversion symmetry are also discussed. Special corner elements are described and employed to improve the accuracy of cylindrical waveguide and monopole modes with singular fields at sharp corners. The field solver is applied to three problems: (1) cross-field amplifier slow-wave circuits, (2) a detuned disk-loaded waveguide linear accelerator structure and (3) a 90 degrees overmoded waveguide bend. The detuned accelerator structure is a critical application of this high accuracy field solver. To maintain low long-range wakefields, tight design and manufacturing tolerances are required

  11. Proposal for efficient mode converter based on cavity quantum electrodynamics dark mode in a semiconductor quantum dot coupled to a bimodal microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiahua [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Key Laboratory of Fundamental Physical Quantities Measurement of Ministry of Education, Wuhan 430074 (China); Yu, Rong, E-mail: yurong321@126.com [School of Science, Hubei Province Key Laboratory of Intelligent Robot, Wuhan Institute of Technology, Wuhan 430073 (China); Ma, Jinyong; Wu, Ying, E-mail: yingwu2@163.com [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-10-28

    The ability to engineer and convert photons between different modes in a solid-state approach has extensive technological implications not only for classical communication systems but also for future quantum networks. In this paper, we put forward a scheme for coherent mode conversion of optical photons by utilizing the intermediate coupling between a single quantum dot and a bimodal photonic crystal microcavity via a waveguide. Here, one mode of the photonic crystal microcavity is coherently driven by an external single-frequency continuous-wave laser field and the two cavity modes are not coupled to each other due to their orthogonal polarizations. The undriven cavity mode is thus not directly coupled to the input driving laser and the only way it can get light is via the quantum dot. The influences of the system parameters on the photon-conversion efficiency are analyzed in detail in the limit of weak probe field and it is found that high photon-conversion efficiency can be achieved under appropriate conditions. It is shown that the cavity dark mode, which is a superposition of the two optical modes and is decoupled from the quantum dot, can appear in such a hybrid optical system. We discuss the properties of the dark mode and indicate that the formation of the dark mode enables the efficient transfer of optical fields between the two cavity modes.

  12. Guiding, bending, and splitting of coupled defect surface modes in a surface-wave photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhen; Gao, Fei [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore 637371 (Singapore); Zhang, Baile, E-mail: blzhang@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore 637371 (Singapore); Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, Singapore 637371 (Singapore)

    2016-01-25

    We experimentally demonstrate a type of waveguiding mechanism for coupled surface-wave defect modes in a surface-wave photonic crystal. Unlike conventional spoof surface plasmon waveguides, waveguiding of coupled surface-wave defect modes is achieved through weak coupling between tightly localized defect cavities in an otherwise gapped surface-wave photonic crystal, as a classical wave analogue of tight-binding electronic wavefunctions in solid state lattices. Wave patterns associated with the high transmission of coupled defect surface modes are directly mapped with a near-field microwave scanning probe for various structures including a straight waveguide, a sharp corner, and a T-shaped splitter. These results may find use in the design of integrated surface-wave devices with suppressed crosstalk.

  13. Guiding, bending, and splitting of coupled defect surface modes in a surface-wave photonic crystal

    International Nuclear Information System (INIS)

    Gao, Zhen; Gao, Fei; Zhang, Baile

    2016-01-01

    We experimentally demonstrate a type of waveguiding mechanism for coupled surface-wave defect modes in a surface-wave photonic crystal. Unlike conventional spoof surface plasmon waveguides, waveguiding of coupled surface-wave defect modes is achieved through weak coupling between tightly localized defect cavities in an otherwise gapped surface-wave photonic crystal, as a classical wave analogue of tight-binding electronic wavefunctions in solid state lattices. Wave patterns associated with the high transmission of coupled defect surface modes are directly mapped with a near-field microwave scanning probe for various structures including a straight waveguide, a sharp corner, and a T-shaped splitter. These results may find use in the design of integrated surface-wave devices with suppressed crosstalk

  14. Finite Ground Coplanar (FGC) Waveguide: Characteristics and Advantages Evaluated for Radiofrequency and Wireless Communication Circuits

    Science.gov (United States)

    Ponchak, George E.

    1999-01-01

    Researchers in NASA Lewis Research Center s Electron Device Technology Branch are developing transmission lines for radiofrequency and wireless circuits that are more efficient, smaller, and make lower cost circuits possible. Traditionally, radiofrequency and wireless circuits have employed a microstrip or coplanar waveguide to interconnect the various electrical elements that comprise a circuit. Although a coplanar waveguide (CPW) is widely viewed as better than a microstrip for most applications, it too has problems. To solve these problems, NASA Lewis and the University of Michigan developed a new version of a coplanar waveguide with electrically narrow ground planes. Through extensive numerical modeling and experimental measurements, we have characterized the propagation constant of the FGC waveguide, the lumped and distributed circuit elements integrated in the FGC waveguide, and the coupling between parallel transmission lines. Although the attenuation per unit length is higher for the FGC waveguide because of higher conductor loss, the attenuation is comparable when the ground plane width is twice the center conductor width as shown in the following graph. An upper limit to the line width is derived from observations that when the total line width is greater than ld/2, spurious resonances due to the parallel plate waveguide mode are established. Thus, the ground plane width must be less than ld/4 where ld is the wavelength in the dielectric. Since the center conductor width S is typically less than l/10 to maintain good transverse electromagnetic mode characteristics, it follows that a ground plane width of B = 2S would also be electrically narrow. Thus, we can now treat the ground strips of the FGC waveguide the same way that the center conductor is treated.

  15. Wave-guided optical waveguides

    DEFF Research Database (Denmark)

    Palima, Darwin; Bañas, Andrew Rafael; Vizsnyiczai, George

    2012-01-01

    This work primarily aims to fabricate and use two photon polymerization (2PP) microstructures capable of being optically manipulated into any arbitrary orientation. We have integrated optical waveguides into the structures and therefore have freestanding waveguides, which can be positioned anywhe...... bridge the diffraction barrier. This structure-mediated paradigm may be carried forward to open new possibilities for exploiting beams from far-field optics down to the subwavelength domain....

  16. High-temperature superconducting coplanar-waveguide quarter-wavelength resonator with odd- and even-mode resonant frequencies for dual-band bandpass filter

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Kei; Takagi, Yuta; Narahashi, Shoichi [Research Laboratories, NTT DOCOMO, INC., 3-6 Hikari-no-oka Yokosuka, Kanagawa 239-8536 Japan (Japan); Nojima, Toshio, E-mail: satokei@nttdocomo.co.j [Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0814 Japan (Japan)

    2010-06-01

    This paper presents a high-temperature superconducting coplanar-waveguide quarter-wavelength resonator that has two different resonant modes for use in a dual-band bandpass filter (DBPF). An RF filter with multiple passbands such as the DBPF is a basic element that is expected to achieve broadband transmission by using separated frequency bands aggregately and simultaneously in future mobile communication systems. The proposed resonator has a folded center conductor and two open stubs that are aligned close to it. The odd- and even-mode resonant frequencies are configured using the space between the folded center conductor and the open stubs. It is easy to configure the odd- and even-mode coupling coefficients independently because the two resonant modes have different current density distributions. Consequently, a DBPF with two different bandwidths can be easily designed. This paper presents three design examples for a four-pole Chebyshev DBPF with different combinations of fractional bandwidths in order to investigate the validity of the proposed resonator. This paper also presents measured results of the DBPF based on the design examples from the standpoint of experimental investigation. The designed and measured frequency responses confirm that the proposed resonator is effective in achieving DBPFs not only with two of the same bandwidths but also with two different bandwidths.

  17. Maximum likelihood estimation of the position of a radiating source in a waveguide

    International Nuclear Information System (INIS)

    Hinich, M.J.

    1979-01-01

    An array of sensors is receiving radiation from a source of interest. The source and the array are in a one- or two-dimensional waveguide. The maximum-likelihood estimators of the coordinates of the source are analyzed under the assumptions that the noise field is Gaussian. The Cramer-Rao lower bound is of the order of the number of modes which define the source excitation function. The results show that the accuracy of the maximum likelihood estimator of source depth using a vertical array in a infinite horizontal waveguide (such as the ocean) is limited by the number of modes detected by the array regardless of the array size

  18. Phase radiation characteristics of an open-ended circular waveguide

    DEFF Research Database (Denmark)

    Shishkova, Anna; Pivnenko, Sergey; Kim, Oleksiy S.

    2007-01-01

    General analytical expressions are derived for the far-field amplitude and phase radiation patterns of an open-ended circular waveguide (OE-CWG) regardless of its radius or the operation frequency for the dominant and symmetric higher-order excitation modes. The derivation is based on the rigorous...... solution to the problem of diffraction at an open end of a waveguide proposed by Weinstein. The near-field amplitude and phase patterns of an OE-CWG are then calculated using the spherical wave expansion technique. The measurement of the radiation pattern of an OE-CWG was carried out to verify the validity...

  19. Optical waveguides in Nd:GdVO4 crystals fabricated by swift N3+ ion irradiation

    Science.gov (United States)

    Dong, Ningning; Yao, Yicun; Chen, Feng

    2012-12-01

    Optical planar waveguides have been manufactured in Nd:GdVO4 crystal by swift N3+ ions irradiation at fluence of 1.5 × 1014 ions/cm2. A typical "barrier"-style refractive index profile was formed and the light can be well confined in the waveguide region. The modal distribution of the guided modes obtained from numerical calculation has a good agreement with the experimental modal distribution. The measured photoluminescence spectra revealed that the fluorescence properties of the Nd3+ ions have been modified to some extent in the waveguide's volume. The propagation loss of the planar waveguide can decrease to lower than 1 dB/cm after adequate annealing.

  20. Optical waveguides in LiTaO{sub 3} crystals fabricated by swift C{sup 5+} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guiyuan [School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle Physics and Particle Irradiation (Ministry of Education), Shandong University, Jinan 250100 (China); School of Science, Shandong Jianzhu University, Jinan 250101 (China); He, Ruiyun [School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle Physics and Particle Irradiation (Ministry of Education), Shandong University, Jinan 250100 (China); Akhmadaliev, Shavkat [Institute of Ion Beam and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01314 (Germany); Vázquez de Aldana, Javier R. [Laser Microprocessing Group, Universidad de Salamanca, Salamanca 37008 (Spain); Zhou, Shengqiang [Institute of Ion Beam and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01314 (Germany); Chen, Feng [School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle Physics and Particle Irradiation (Ministry of Education), Shandong University, Jinan 250100 (China)

    2014-04-01

    We report on the optical waveguides, in both planar and ridge configurations, fabricated in LiTaO{sub 3} crystal by using carbon (C{sup 5+}) ions irradiation at energy of 15 MeV. The planar waveguide was produced by direct irradiation of swift C{sup 5+} ions, whilst the ridge waveguides were manufactured by using femtosecond laser ablation of the planar layer. The reconstructed refractive index profile of the planar waveguide has showed a barrier-shaped distribution, and the near-field waveguide mode intensity distribution was in good agreement with the calculated modal profile. After thermal annealing at 260 °C in air, the propagation losses of both the planar and ridge waveguides were reduced to 10 dB/cm.