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Sample records for crystal sapphire fibers

  1. Single-Crystal Sapphire Optical Fiber Sensor Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Pickrell, Gary [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Scott, Brian [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Wang, Anbo [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Yu, Zhihao [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States)

    2013-12-31

    This report summarizes technical progress on the program “Single-Crystal Sapphire Optical Fiber Sensor Instrumentation,” funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. This project was completed in three phases, each with a separate focus. Phase I of the program, from October 1999 to April 2002, was devoted to development of sensing schema for use in high temperature, harsh environments. Different sensing designs were proposed and tested in the laboratory. Phase II of the program, from April 2002 to April 2009, focused on bringing the sensor technologies, which had already been successfully demonstrated in the laboratory, to a level where the sensors could be deployed in harsh industrial environments and eventually become commercially viable through a series of field tests. Also, a new sensing scheme was developed and tested with numerous advantages over all previous ones in Phase II. Phase III of the program, September 2009 to December 2013, focused on development of the new sensing scheme for field testing in conjunction with materials engineering of the improved sensor packaging lifetimes. In Phase I, three different sensing principles were studied: sapphire air-gap extrinsic Fabry-Perot sensors; intensity-based polarimetric sensors; and broadband polarimetric sensors. Black body radiation tests and corrosion tests were also performed in this phase. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. At the beginning of Phase II, in June 2004, the BPDI sensor was tested at the Wabash River coal gasifier

  2. SINGLE-CRYSTAL SAPPHIRE OPTICAL FIBER SENSOR INSTRUMENTATION

    Energy Technology Data Exchange (ETDEWEB)

    A. Wang; G. Pickrell; R. May

    2002-09-10

    material were thoroughly investigated to determine an optimal approach for on-line, real-time, reliable, long-term monitoring of temperatures inside the coal gasification environment. Among these were a sapphire fiber extrinsic Fabry-Perot interferometric (EFPI) sensor; an intensity-measurement based polarimetric sapphire sensor and a broadband polarimetric differential interferometric (BPDI) sapphire sensor. Based on the current evaluation and analysis of the experimental results, the broadband polarimetric differential interferometric (BPDI) sensor system was chosen for further prototype instrumentation development because of it's superior performance compared to the other systems. This approach is based on the self-calibrating measurement of the optical path length differences in a single-crystal sapphire disk, which is a function of both the temperature dependent birefringence and the temperature dependent dimensional changes.

  3. Ultrahigh resolution optical coherence tomography with femtosecond Ti:sapphire laser and photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    XUE Ping; James G FUJIMOTO

    2008-01-01

    Optical coherence tomography (OCT) with ultrahigh axial resolution was achieved by the super-contin- uum generated by coupling femtosecond pulses from a commercial Ti :sapphire laser into an air-silica microstructure fiber. The visible spectrum of the super-continuum from 450 to 700 nm centered at 540 nm can be generated. A free-space axial OCT resolution of 0.64 IJm was achieved. The sensitivity of OCT system was 108 dB with incident light power 3 mW at sample, only 7dB below the theoretical limit. Subcellular OCT imaging was also demonstrated, showing great potential for biomedical application.

  4. Preparation, properties and application of sapphire single-crystal fibers grown by the EFG method

    Directory of Open Access Journals (Sweden)

    Kubát J.

    2013-05-01

    Full Text Available Sapphire – the single crystal of aluminum oxide (Al2O3 – is one of the most important artificially produced materials. The sapphire fibres studied were grown in Crytur using the “edge-defined film-fed growth” (EFG technique. Their unique physical and chemical properties can be employed in various applications. Due to their high refractive index and a broad transmission band spanning the ultraviolet, visible and infrared bands, sapphire fibres are perfect waveguides in harsh environments. The current major applications are Er:YAG laser beam delivery and pyrometric and spectrometric measurements in furnaces, combustion engines, etc. In this paper we summarize an adjustment of the EFG method to grow thin filaments by giving possible molybdenum die designs. We investigated the fibres using an optical microscope and measured their transmission of an Er:YAG laser beam (2.94 μm. The attenuation of the tested samples is approximately 0.1 dB/cm.

  5. Neutron Transmission through Sapphire Crystals

    DEFF Research Database (Denmark)

    Sapphire crystals are excellent filters of fast neutrons, while at the same time exhibit moderate to very little absorption at smaller energies. We have performed an extensive series of measurements in order to quantify the above effect. Alongside our experiments, we have performed a series...... of simulations, in order to reproduce the transmission of cold neutrons through sapphire crystals. Those simulations were part of the effort of validating and improving the newly developed interface between the Monte-Carlo neutron transport code MCNP and the Monte Carlo ray-tracing code McStas....

  6. Secondary particle emission from sapphire single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Minnebaev, K.F., E-mail: minnebaev@mail.ru [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Khvostov, V.V.; Zykova, E.Yu.; Tolpin, K.A. [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Colligon, J.S. [Manchester Metropolitan University, Chester Street, Manchester M1 5GD (United Kingdom); Yurasova, V.E. [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation)

    2015-07-01

    Secondary ion emission from sapphire single crystal has been studied experimentally and by means of computer simulation. The particular oscillations of secondary ion energy spectra and two specific maxima of O{sup +} and Al{sup +} ions were observed under irradiation of (0001) sapphire face by 1 and 10 keV Ar{sup +} ions. We have explained this by the interplay of the charge exchange processes between moving particles and solids. The existence of two maxima in energy spectra of O{sup +} and Al{sup +} secondary ions can be also connected with special features of single-crystal sputtering: the low-energy peak can be formed by random sputtering and the high-energy peak from focusing collisions. In addition some similarity was found between the positions of low-energy maximum in energy spectra of Al{sup +} ions emitted from sapphire and the principal maxima of Al{sup +} ions ejected from the aluminum single crystal. This indicates a possibility to explain the presence of low-energy maximum in energy spectra of secondary ions ejecting from sapphire by emission of Al{sup +} ions from aluminum islands appearing in a number of cases on the sapphire surface due to preferential sputtering of oxygen. These different mechanisms of creating the energy spectra of ions emitted from sapphire should be taken in account.

  7. The growth of sapphire single crystals

    Directory of Open Access Journals (Sweden)

    STEVAN DJURIC

    2001-06-01

    Full Text Available Sapphire (Al2O3 single crystals were grown by the Czochralski technique both in air and argon atmospheres. The conditions for growing sapphire single crystals were calculated by using a combination of Reynolds and Grashof numbers. Acritical crystal diameter dc = 20 mm and the critical rate of rotation wc = 20 rpm were calculated from the hydrodynamics of the melt. The value of the rate of crystal growth was experimentally found to be 3.5 mm/h. According to our previous experiments, it was confirmed that three hours exposures to conc. H3PO4 at 593 K was suitable for chemical polishing. Also, three hours exposure to conc.H3PO4 at 523 K was found to be a suitable etching solution. The lattice parameters a = 0.47573 nm and c = 1.29893 nm were determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.

  8. A peek into the history of sapphire crystal growth

    Science.gov (United States)

    Harris, Daniel C.

    2003-09-01

    After the chemical compositions of sapphire and ruby were unraveled in the middle of the 19th century, chemists set out to grow artificial crystals of these valuable gemstones. In 1885 a dealer in Geneva began to sell ruby that is now believed to have been created by flame fusion. Gemnologists rapidly concluded that the stones were artificial, but the Geneva ruby stimulated A. V. L. Verneuil in Paris to develop a flame fusion process to produce higher quality ruby and sapphire. By 1900 there was brisk demand for ruby manufactured by Verneuil's method, even though Verneuil did not publicly announce his work until 1902 and did not publish details until 1904. The Verneuil process was used with little alteration for the next 50 years. From 1932-1953, S. K. Popov in the Soviet Union established a capability for manufacturing high quality sapphire by the Verneuil process. In the U.S., under government contract, Linde Air Products Co. implemented the Verneuil process for ruby and sapphire when European sources were cut off during World War II. These materials were essential to the war effort for jewel bearings in precision instruments. In the 1960s and 1970s, the Czochralski process was implemented by Linde and its successor, Union Carbide, to make higher crystal quality material for ruby lasers. Stimulated by a government contract for structural fibers in 1966, H. LaBelle invented edge-defined film-fed growth (EFG). The Saphikon company, which is currently owned by Saint-Gobain, evolved from this effort. Independently and simultaneously, Stepanov developed edge-defined film-fed growth in the Soviet Union. In 1967 F. Schmid and D. Viechnicki at the Army Materials Research Lab grew sapphire by the heat exchanger method (HEM). Schmid went on to establish Crystal Systems, Inc. around this technology. Rotem Industries, founded in Israel in 1969, perfected the growth of sapphire hemispheres and near-net-shape domes by gradient solidification. In the U.S., growth of near

  9. Nanostructured sapphire optical fiber for sensing in harsh environments

    Science.gov (United States)

    Chen, Hui; Liu, Kai; Ma, Yiwei; Tian, Fei; Du, Henry

    2017-05-01

    We describe an innovative and scalable strategy of transforming a commercial unclad sapphire optical fiber to an allalumina nanostructured sapphire optical fiber (NSOF) that overcomes decades-long challenges faced in the field of sapphire fiber optics. The strategy entails fiber coating with metal Al followed by subsequent anodization to form anodized alumina oxide (AAO) cladding of highly organized pore channel structure. We show that Ag nanoparticles entrapped in AAO show excellent structural and morphological stability and less susceptibility to oxidation for potential high-temperature surface-enhanced Raman Scattering (SERS). We reveal, with aid of numerical simulations, that the AAO cladding greatly increases the evanescent-field overlap both in power and extent and that lower porosity of AAO results in higher evanescent-field overlap. This work has opened the door to new sapphire fiber-based sensor design and sensor architecture.

  10. Fiber-laser-pumped Ti:sapphire laser

    CERN Document Server

    Samanta, G K; Devi, Kavita; Ebrahim-Zadeh, M

    2010-01-01

    We report the first experimental demonstration of efficient and high-power operation of a Ti:sapphire laser pumped by a simple, compact, continuous-wave (cw) fiber-laser-based green source. The pump radiation is obtained by direct single-pass second-harmonic-generation (SHG) of a 33-W, cw Yb-fiber laser in 30-mm-long MgO:sPPLT crystal, providing 11 W of single-frequency green power at 532 nm in TEM00 spatial profile with power and frequency stability better than 3.3% and 32 MHz, respectively, over one hour. The Ti:sapphire laser is continuously tunable across 743-970 nm and can deliver an output power up to 2.7 W with a slope efficiency as high as 32.8% under optimum output coupling of 20%. The laser output has a TEM00 spatial profile with M2<1.44 across the tuning range and exhibits a peak-to-peak power fluctuation below 5.1% over 1 hour.

  11. Neutron Transmission through Sapphire Crystals: Experiments and Simulations

    OpenAIRE

    Rantsiou, Emmanouela; Filges, Uwe; Panzner, Tobias; Klinkby, Esben Bryndt

    2013-01-01

    Sapphire crystals are excellent filters of fast neutrons, while at the same time exhibit moderate to very little absorption at smaller energies. We have performed an extensive series of measurements in order to quantify the above effect. Alongside our experiments, we have performed a series of simulations, in order to reproduce the transmission of cold neutrons through sapphire crystals. Thosesimulations were part of the effort of validating and improving the newly developed interface between...

  12. Blocks and residual stresses in shaped sapphire single crystals

    Science.gov (United States)

    Krymov, V. M.; Nosov, Yu. G.; Bakholdin, S. I.; Maslov, V. N.; Shul‧pina, I. L.; Nikolaev, V. I.

    2017-01-01

    The formation of blocks and residual stresses in shaped sapphire crystals grown from the melt by the Stepanov method (EFG) has been studied. The probability of block formation is higher for the growth along the c axis compared to that grown in the a-axis direction. The distribution of residual stress in sapphire crystals of tubular, rectangular and round cross section was measured by the conoscopy method. It was found that the magnitude of the residual stress increases from the center to the periphery of the crystal and reaches up to about 20 MPa. Residual stress tensor components for solid round rod and tubular single crystals were determined by numerical integration.

  13. Neurosurgery contact handheld probe based on sapphire shaped crystal

    Science.gov (United States)

    Shikunova, I. A.; Stryukov, D. O.; Rossolenko, S. N.; Kiselev, A. M.; Kurlov, V. N.

    2017-01-01

    A handheld contact probe based on sapphire shaped crystal is developed for intraoperative spectrally-resolved optical diagnostics, laser coagulation and aspiration of malignant brain tissue. The technology was integrated into the neurosurgical workflow for intraoperative real-time identification and removing of invasive brain cancer.

  14. A Century of Sapphire Crystal Growth

    Science.gov (United States)

    2004-05-17

    Crystal growth storage cabinet from Frémy’s lab.5,6 Flame Fusion and the Verneuil Process In 1885 rubies selling for $1000-2500...1891: Working with his student, M. Pacquier, Verneuil had developed most of what we now call Verneuil flame-fusion crystal growth . Verneuil ... Verneuil ) Crystal Growth Nassau, Gems Made by Man 11 • 1892: Verneuil eliminated crystal cracking by making contact area between ruby crystal

  15. Parametric sensitivity and temporal dynamics of sapphire crystal growth via the micro-pulling-down method

    Science.gov (United States)

    Samanta, Gaurab; Yeckel, Andrew; Bourret-Courchesne, Edith D.; Derby, Jeffrey J.

    2012-11-01

    The micro-pulling-down (μ-PD) crystal growth of sapphire fibers, whose steady-state limits were the focus of our prior study [Samanta et al., Journal of Crystal Growth 335 (2011) 148-159], is further examined using a parametric sensitivity computation derived by linearizing the nonlinear model around a quasi-steady-state (QSS). In addition, transient analyses are performed to assess inherent stability and dynamic responses in this μ-PD system. Information from these two approaches enlarges our understanding of this particular process, and the approaches themselves are put forth as valuable complements to classical QSS analysis.

  16. High-temperature sapphire optical sensor fiber coatings

    Science.gov (United States)

    Desu, Seshu B.; Claus, Richard O.; Raheem, Ruby; Murphy, Kent A.

    1990-10-01

    the filter. These modes may be attributed to a number of material degradation mechanisms, such as thermal shock, oxidation corrosion of the material, mechanical loads, or phase changes in the filter material. Development of high temperature optical fiber (sapphire) sensors embedded in the CXF filters would be very valuable for both monitoring the integrity of the filter during its use and understanding the mechanisms of degradation such that durable filter development will be facilitated. Since the filter operating environment is very harsh, the high temperature sapphire optical fibers need to be protected and for some sensing techniques the fiber must also be coated with low refractive index film (cladding). The objective of the present study is to identify materials and develop process technologies for the application of claddings and protective coatings that are stable and compatible with sapphire fibers at both high temperatures and pressures.

  17. Photonic crystal fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Hansen, K P; Nielsen, M D;

    2003-01-01

    Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications...... of photonic crystal fibers with particular emphasis on recent advances in the field....

  18. Photonic Crystal Fiber Attenuator

    Institute of Scientific and Technical Information of China (English)

    Joo; Beom; Eom; Hokyung; Kim; Jinchae; Kim; Un-Chul; Paek; Byeong; Ha; Lee

    2003-01-01

    We propose a novel fiber attenuator based on photonic crystal fibers. The difference in the modal field diameters of a conventional single mode fiber and a photonic crystal fiber was used. A variable optical attenuator was also achieved by applying macro-bending on the PCF part of the proposed attenuator

  19. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    Despite the general recession in the global economy and the collapse of the optical telecommunication market, research within specialty fibers is thriving. This is, more than anything else, due to the technology transition from standard all-glass fibers to photonic crystal fibers, which, instead...... of doping, use a microstructure of air and glass to obtain a refractive index difference between the core and the cladding. This air/glass microstructure lends the photonic crystal fibers a range of unique and highly usable properties, which are very different from those found in solid standard fibers....... The freedom to design the dispersion profile of the fibers is much larger and it is possible to create fibers, which support only a single spatial mode, regardless of wavelength. In comparison, the standard dispersion-shifted fibers are limited by a much lower index-contrast between the core and the cladding...

  20. Numerical computation of sapphire crystal growth using heat exchanger method

    Science.gov (United States)

    Lu, Chung-Wei; Chen, Jyh-Chen

    2001-05-01

    The finite element software FIDAP is employed to study the temperature and velocity distribution and the interface shape during a large sapphire crystal growth process using a heat exchanger method (HEM). In the present study, the energy input to the crucible by the radiation and convection inside the furnace and the energy output through the heat exchanger is modeled by the convection boundary conditions. The effects of the various growth parameters are studied. It is found that the contact angle is obtuse before the solid-melt interface touches the sidewall of the crucible. Therefore, hot spots always appear in this process. The maximum convexity decreases significantly when the cooling-zone radius (RC) increases. The maximum convexity also decreases significantly as the combined convection coefficient inside the furnace (hI) decreases.

  1. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    , leading to reduced mode confinement and dispersion flexibility. In this thesis, we treat the nonlinear photonic crystal fiber – a special sub-class of photonic crystal fibers, the core of which has a diameter comparable to the wavelength of the light guided in the fiber. The small core results in a large...... nonlinear coefficient and in various applications, it is therefore possible to reduce the required fiber lengths quite dramatically, leading to increased stability and efficiency. Furthermore, it is possible to design these fibers with zero-dispersion at previously unreachable wavelengths, paving the way...... for completely new applications, especially in and near the visible wavelength region. One such application is supercontinuum generation. Supercontinuum generation is extreme broadening of pulses in a nonlinear medium (in this case a small-core fiber), and depending on the dispersion of the fiber, it is possible...

  2. Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High-T and Dynamic Gas Pressure in Harsh Environments

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hai [Clemson Univ., SC (United States); Tsai, Hai-Lung [Missouri Univ. of Science and Technology, Rolla, MO (United States); Dong, Junhang [Univ. of Cincinnati, OH (United States)

    2014-09-30

    This is the final report for the program “Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High Temperature and Dynamic Gas Pressure in Harsh Environments”, funded by NETL, and performed by Missouri University of Science and Technology, Clemson University and University of Cincinnati from October 1, 2009 to September 30, 2014. Securing a sustainable energy economy by developing affordable and clean energy from coal and other fossil fuels is a central element to the mission of The U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL). To further this mission, NETL funds research and development of novel sensor technologies that can function under the extreme operating conditions often found in advanced power systems. The main objective of this research program is to conduct fundamental and applied research that will lead to successful development and demonstration of robust, multiplexed, microstructured silica and single-crystal sapphire fiber sensors to be deployed into the hot zones of advanced power and fuel systems for simultaneous measurements of high temperature and gas pressure. The specific objectives of this research program include: 1) Design, fabrication and demonstration of multiplexed, robust silica and sapphire fiber temperature and dynamic gas pressure sensors that can survive and maintain fully operational in high-temperature harsh environments. 2) Development and demonstration of a novel method to demodulate the multiplexed interferograms for simultaneous measurements of temperature and gas pressure in harsh environments. 3) Development and demonstration of novel sapphire fiber cladding and low numerical aperture (NA) excitation techniques to assure high signal integrity and sensor robustness.

  3. Sapphire: Relation between luminescence of starting materials and luminescence of single crystals

    Science.gov (United States)

    Mogilevsky, R.; Nedilko, S.; Sharafutdinova, L.; Burlay, S.; Sherbatskii, V.; Boyko, V.; Mittl, S.

    2009-10-01

    A relation between photoluminescence (PL) characteristics of different starting materials used for crystal growth and un-doped sapphire single crystals manufactured using various methods of crystal growth (Kyropolus, HEM, Czochralski, and EFG) was found. The crystals grown using the Verneuil starting material exhibited significant PL when any method of crystal growth was used. On the contrary, sapphire samples grown by the same technologies wherein the starting material was EMT HPDA R revealed very low PL. (HPDA R is produced by EMT, Inc., with proprietary and patented technology.)

  4. Dislocation Analysis for Large-sized Sapphire Single Crystal Grown by SAPMAC Method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, large-sized sapphire (Φ230×210 mm, 27.5 kg) was grown by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at the cooled center). Dislocation peculiarity in large sapphire boule (0001) basal plane was investigated by chemical etching, scanning electron microscopy and X-ray topography method. The triangular dislocation etch pit measured is 7.6×101~8.0×102 cm-2, in which relative high-density dislocations were generated at both initial and final stages of crystal growth. The analysis of single-crystal X-ray topography shows that there are no apparent sub-grain boundaries; the dislocation lines are isolated and straight. Finally, the origins of low-density dislocation in sapphire crystal are discussed by numerical analysis method.

  5. Temperature and thermal stress evolutions in sapphire crystal during the cooling process by heat exchanger method

    Science.gov (United States)

    Ma, Wencheng; Zhao, Wenhan; Wu, Ming; Ding, Guoqiang; Liu, Lijun

    2017-09-01

    Transient numerical calculations were carried out to predict the evolutions of temperature and thermal stress in sapphire single crystal during the cooling process by heat exchanger method (HEM). Internal radiation in the semitransparent sapphire crystal was taken into account using the finite volume method (FVM) in the global heat transfer model. The numerical results seem to indicate that the narrow bottom region of the sapphire crystal is subjected to high thermal stress during the cooling process, which could be responsible for the seed cracking of the as-grown crystal, while the thermal stress is relatively small in the central main body of the crystal, and is less than 10 MPa during the whole cooling process. The fast decrease of the thermal stress in the bottom region of the crystal during the initial stage of cooling process is dominated by the reduction of the cooling helium gas in the heat exchanger shaft, and is not significantly affected by the heating power reduction rate.

  6. The effect of crystal orientation on the cryogenic strength of hydroxide catalysis bonded sapphire

    Science.gov (United States)

    Haughian, K.; Douglas, R.; van Veggel, A. A.; Hough, J.; Khalaidovski, A.; Rowan, S.; Suzuki, T.; Yamamoto, K.

    2015-04-01

    Hydroxide catalysis bonding has been used in gravitational wave detectors to precisely and securely join components of quasi-monolithic silica suspensions. Plans to operate future detectors at cryogenic temperatures has created the need for a change in the test mass and suspension material. Mono-crystalline sapphire is one candidate material for use at cryogenic temperatures and is being investigated for use in the KAGRA detector. The crystalline structure of sapphire may influence the properties of the hydroxide catalysis bond formed. Here, results are presented of studies of the potential influence of the crystal orientation of sapphire on the shear strength of the hydroxide catalysis bonds formed between sapphire samples. The strength was tested at approximately 8 K; this is the first measurement of the strength of such bonds between sapphire at such reduced temperatures. Our results suggest that all orientation combinations investigated produce bonds of sufficient strength for use in typical mirror suspension designs, with average strengths >23 MPa.

  7. Supersmooth and modified surface of sapphire crystals: Formation, characterization, and applications in nanotechnologies

    Science.gov (United States)

    Muslimov, A. E.; Asadchikov, V. E.; Butashin, A. V.; Vlasov, V. P.; Deryabin, A. N.; Roshchin, B. S.; Sulyanov, S. N.; Kanevsky, V. M.

    2016-09-01

    The results of studying the state of the surface of sapphire crystals by a complex of methods in different stages of crystal treatment are considered by an example of preparing sapphire substrates with a supersmooth surface. The possibility of purposefully forming regular micro- and nanoreliefs and thin transition layers using thermal and thermochemical impacts are considered. The advantages of sapphire substrates with a modified surface for forming heteroepitaxial CdTe and ZnO semiconductor films and ordered ensembles of gold nanoparticles are described. The results of the experiments on the application of crystalline sapphire as a material for X-ray optical elements are reported. These elements include total external reflection mirrors and substrates for multilayer mirrors, output windows for synchrotron radiation, and monochromators working in the reflection geometry in X-ray spectrometers. In the latter case, the problems of the defect structure of bulk crystals sapphire and the choice of a method for growing sapphire crystals of the highest structural quality are considered.

  8. High Temperature Testing with Sapphire Fiber White-Light Michelson Interferometers

    Science.gov (United States)

    Barnes, A.; Pedrazzani, J.; May, R.; Murphy, K.; Tran, T.; Coate, J.

    1996-01-01

    In the design of new aerospace materials, developmental testing is conducted to characterize the behavior of the material under severe environmental conditions of high stress, temperature, and vibration. But to test these materials under extreme conditions requires sensors that can perform in harsh environments. Current sensors can only monitor high temperature test samples using long throw instrumentation, but this is inherently less accurate than a surface mounted sensor, and provides no means for fabrication process monitoring. A promising alternative is the use of sapphire optical fiber sensors. Sapphire is an incredibly rugged material, being extremely hard (9 mhos), chemically inert, and having a melting temperature (over 2000 C). Additionally, there is a extensive background of optical fiber sensors upon which to draw for sapphire sensor configurations.

  9. Crystal front shape control by use of an additional heater in a Czochralski sapphire single crystal growth system

    Science.gov (United States)

    Hur, Min-Jae; Han, Xue-Feng; Choi, Ho-Gil; Yi, Kyung-Woo

    2017-09-01

    The quality of sapphire single crystals used as substrates for LED production is largely influenced by two defects: dislocation density and bubbles trapped in the crystal. In particular, the dislocation density has a higher value in sapphire grown by the Czochralski (CZ) method than by other methods. In the present study, we predict a decreased value for the convexity and thermal gradient at the crystal front (CF) through the use of an additional heater in an induction-heated CZ system. In addition, we develop a solute concentration model by which the location of bubble formation in CZ growth is calculated, and the results are compared with experimental results. We further calculate the location of bubble entrapment corresponding with the use of an additional heater. We find that sapphire crystal growth with an additional heater yields a decreased thermal gradient at the CF, together with decreased CF convexity, improved energy efficiency, and improvements in terms of bubble formation location.

  10. Intracavity frequency doubling of CW Ti:Sapphire laser utilising BiBO nonlinear crystal

    DEFF Research Database (Denmark)

    Thorhauge, Morten; Mortensen, Jesper Liltorp; Tidemand-Lichtenberg, Peter

    Utilising BiBO nonlinear crystal frequency doubling a Ti:Sapphire CW laser gave 100 mW at 405 nm and 53 mW at 392 nm. Stability proved excellent without servo control. Broad tunability was shown around 392 nm.......Utilising BiBO nonlinear crystal frequency doubling a Ti:Sapphire CW laser gave 100 mW at 405 nm and 53 mW at 392 nm. Stability proved excellent without servo control. Broad tunability was shown around 392 nm....

  11. Photonic-crystal fibers gyroscope

    Directory of Open Access Journals (Sweden)

    Ali Muse Haider

    2015-01-01

    Full Text Available In this paper we proposed to use of a photonic crystal fiber with an inner hollow defect. The use of such fibers is not affected by a material medium on the propagation of optical radiation. Photonic crystal fibers present special properties and capabilities that lead to an outstanding potential for sensing applications

  12. A higher-order-mode fiber delivery for Ti:Sapphire femtosecond lasers

    DEFF Research Database (Denmark)

    Jespersen, Kim Giessmann; Le, Tuan; Grüner-Nielsen, Lars Erik

    2010-01-01

    We report the first higher-order-mode fiber with anomalous dispersion at 800nm and demonstrate its potential in femtosecond pulse delivery for Ti:Sapphire femtosecond lasers. We obtain 125fs pulses after propagating a distance of 3.6 meters in solid-silica fiber. The pulses could be further...... compressed in a quartz rod to nearly chirp-free 110fs pulses. Femtosecond pulse delivery is achieved by launching the laser output directly into the delivery fiber without any pre-chirping of the input pulse. The demonstrated pulse delivery scheme suggests scaling to >20meters for pulse delivery in harsh...

  13. Evaluation of the Quality of Sapphire Using X-Ray Rocking Curves and Double-Crystal X-Ray Topography

    Science.gov (United States)

    1994-05-01

    hard, high-strength, chemically resistant optical windows; and sub- srates for the growth of epitaxial films. The quality of a sapphire crystal can... crystal diffractometer. Single- crystal sapphire may be grown by a variety of different methods, of which the more common are Verneuil (flame fusion...Linear features (L), which may represent slight variations in lattice parameter along the crystal growth front, or dislocation networks, ad small

  14. Multimode interference and a white light scanning Michelson interferometer with a 400-mm sapphire fiber sensing head

    Science.gov (United States)

    Li, Tianchu; May, Russell G.; Wang, Anbo; Claus, Richard O.

    1998-08-01

    In this paper we present the analysis of multimode (MM) interference induced by MM fiber interferometers and report the development of a white light scanning fiber Michelson interferometer with a sapphire fiber sensing head for the measurement of position-distance at high temperatures. The 'mode fading' effect in standard graded 50/125 micrometers fiber and independent 'inter-mode interference' in 100 micrometers step index profile fiber are discussed. By means of the 'mode selecting' technique, proposed and developed in this work, we demonstrated white light fringes with signal to noise ratios of more than 12 with a sensing head composed of a 400 mm long lead sapphire fiber and an uncoated sapphire target fiber.

  15. Coherent anti-Stokes Raman scattering microscopy with a photonic crystal fiber based light source

    DEFF Research Database (Denmark)

    Paulsen, H.N.; Hilligsøe, Karen Marie; Thøgersen, J.

    2003-01-01

    A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup is demonstra...... is demonstrated by imaging of micrometer-sized polystyrene beads....

  16. Study on Inclusions in Large Sapphire Optical Crystal Grown by SAPMAC Method

    Institute of Scientific and Technical Information of China (English)

    WANG Gui-gen; ZHANG Ming-fu; ZUO Hong-bo; HE Xiao-dong; HAN Jie-cai

    2006-01-01

    The sapphire (Al2O3) single crystal is a kind of excellent infrared transmission window materials. A large-sized sapphire (Φ225 mm×205 mm, 27.5 kg) was grown by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at cooled center). Several kinds of inclusion in the large sapphire crystal were investigated by means of an optical microscopy (OM), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The experimental results show that most inclusions are consisted of solid metallic and non-metallic particles as well as gas pores caused by the impurity of alumina as the raw material, the thermal dissociation of aluminum oxide melt and the reaction of the melt to the crucible material (Mo) at high temperatures. It is also found that in different crystal regions the inclusions are of varied sizes, morphology and chemical compositions. Finally, the measures to reduce and eliminate the inclusions are proposed to improve the crystal quality.

  17. Photonic crystal fibers in biophotonics

    Science.gov (United States)

    Tuchin, Valery V.; Skibina, Julia S.; Malinin, Anton V.

    2011-12-01

    We observed recent experimental results in area of photonic crystal fibers appliance. Possibility of creation of fiberbased broadband light sources for high resolution optical coherence tomography is discussed. Using of femtosecond pulse laser allows for generation of optical radiation with large spectral width in highly nonlinear solid core photonic crystal fibers. Concept of exploitation of hollow core photonic crystal fibers in optical sensing is demonstrated. The use of photonic crystal fibers as "smart cuvette" gives rise to efficiency of modern optical biomedical analysis methods.

  18. Demonstrating the feasibility of heat extraction through sapphire fibers for the GW observatory KAGRA

    CERN Document Server

    Khalaidovski, Alexander; Chen, Dan; Komma, Julius; Schwarz, Christian; Tokoku, Chihiro; Kimura, Nobuhiro; Suzuki, Toshikazu; Scheie, Alan O; Majorana, Ettore; Nawrodt, Ronny; Yamamoto, Kazuhiro

    2014-01-01

    Currently, the Japanese gravitational wave laser interferometer KAGRA is under construction in the Kamioka observatory. As one main feature, it will employ sapphire mirrors operated at a temperature of 20K to reduce the impact from thermal noise and suspended from multi-stage pendulums to reduce seismic noise. Thus the heat load deposited in the mirrors by absorption of the circulating laser light as well as originating from thermal radiation will need to be extracted through the last suspension stage. This stage will consist of four thin sapphire fibers with larger heads necessary to connect the fibers to both the mirror and the upper stage. In this paper, we discuss heat conductivity measurements on different fiber candidates. While all fibers had a diameter of 1.6mm, different surface treatments and approaches to attach the heads were analyzed. Our measurements show that fibers fulfilling the basic KAGRA heat conductivity requirement of $\\kappa\\geq\\,$5000 W/m/K at 20K are technologically feasible.

  19. Low Temperature Rhombohedral Single Crystal SiGe Epitaxy on c-plane Sapphire

    Science.gov (United States)

    Duzik, Adam J.; Choi, Sang H.

    2016-01-01

    Current best practice in epitaxial growth of rhombohedral SiGe onto (0001) sapphire (Al2O3) substrate surfaces requires extreme conditions to grow a single crystal SiGe film. Previous models described the sapphire surface reconstruction as the overriding factor in rhombohedral epitaxy, requiring a high temperature Al-terminated surface for high quality films. Temperatures in the 850-1100 C range were thought to be necessary to get SiGe to form coherent atomic matching between the (111) SiGe plane and the (0001) sapphire surface. Such fabrication conditions are difficult and uneconomical, hindering widespread application. This work proposes an alternative model that considers the bulk sapphire structure and determines how the SiGe film nucleates and grows. Accounting for thermal expansion effects, calculations using this new model show that both pure Ge and SiGe can form single crystal films in the 450-550 C temperature range. Experimental results confirm these predictions, where x-ray diffraction and atomic force microscopy show the films fabricated at low temperature rival the high temperature films in crystallographic and surface quality. Finally, an explanation is provided for why films of comparable high quality can be produced in either temperature range.

  20. A century of sapphire crystal growth: origin of the EFG method

    Science.gov (United States)

    Harris, Daniel C.

    2009-08-01

    A. Verneuil developed flame fusion to grow sapphire and ruby on a commercial scale around 1890. Flame fusion was further perfected by Popov in the Soviet Union in the 1930s and by Linde Air Products Co. in the U.S. during World War II. Union Carbide Corp., the successor to Linde, developed Czochralski crystal growth for sapphire laser materials in the 1960s. Edge-Defined Film-Fed Growth (EFG) was invented by H. Labelle in the 1960s and the Heat Exchanger Method (HEM) was invented by F. Schmid and D. Viechnicki in 1967. Both methods were commercialized in the 1970s. Gradient solidification was invented in Israel in the 1970s by J. Makovsky. The Horizontal Directional Solidification Method (HDSM) was invented by Kh. S. Bagdasorov in the Soviet Union in the 1960s. Kyropoulos growth of sapphire, known as GOI crystal growth in the Soviet Union, was developed by M. Musatov at the State Optical Institute in St. Petersburg in the 1970s. Today, half of the world's sapphire is produced by the GOI method.

  1. A scalable pathway to nanostructured sapphire optical fiber for evanescent-field sensing and beyond

    Science.gov (United States)

    Chen, Hui; Tian, Fei; Kanka, Jiri; Du, Henry

    2015-03-01

    We here report an innovative and scalable strategy of transforming a commercial unclad sapphire optical fiber to an all-alumina nanostructured sapphire optical fiber (NSOF). The strategy entails fiber coating with metal aluminum followed by anodization to form alumina cladding of highly organized pore channel structure. Through experiments and numerical simulation, we demonstrate the utility and benefit of NSOF, analogous to all-silica microstructured optical fiber, for evanescent-field surface-enhanced Raman scattering (SERS) measurements. We experimentally reveal the feasibility of Ag nanoparticles (NPs)-enabled NSOF SERS sensing of 10-6 M Rhodamine 6G (R6G) after thermal treatment at 500 °C for 6 h by taking advantage of porous anodic aluminum oxide (AAO) structure to stabilize the Ag NPs. We show, via numerical simulations, that AAO cladding significantly increases the evanescent-field overlap, lower porosity of AAO results in higher evanescent-field overlap, and optimized AAO nanostructure yields greater SERS enhancement.

  2. High energy terahertz pulses from organic crystals: DAST and DSTMS pumped at Ti:sapphire wavelength

    CERN Document Server

    Monoszlai, B; Jazbinsek, M; Hauri, C P

    2013-01-01

    High energy terahertz pulses are produced by optical rectification (OR) in organic crystals DAST and DSTMS by a Ti:sapphire amplifier system centered at 0.8 microns. The simple scheme provides broadband spectra between 1 and 5 THz, when pumped by collimated 60 fs near-infrared pump pulse and it is scalable in energy. Fluence-dependent conversion efficiency and damage threshold are reported as well as optimized OR at visible wavelength.

  3. Photonic crystal fibers -

    DEFF Research Database (Denmark)

    Libori, Stig E. Barkou

    2002-01-01

    During this ph.d. work, attention has been focused on understanding and analyzing the modal behavior of micro-structured fibers. Micro-structured fibers are fibers with a complex dielectric toplogy, and offer a number of novel possibilities, compared to standard silica based optical fibers. The t...

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

    Science.gov (United States)

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

    2014-08-27

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

  5. Modelling of Verneuil process for the sapphire crystal growth

    Science.gov (United States)

    Barvinschi, Floricica; Santailler, Jean-Louis; Duffar, Thierry; Le Gal, Hervé

    1999-03-01

    The finite element software FIDAP was used to simulate the Verneuil crystal growth process. The turbulent combustion between hydrogen and oxygen, giving water, the hydrodynamics of the gas phase, the inlet and outlet chemical species flow resulting from the combustion and the heat transfer in the furnace (including internal wall-to-wall radiation) are taken into account. A problem with 10 degrees of freedom per node is generated, solved and the results of the axisymmetric model have shown that the coupling of all these phenomena can be achieved in one numerical model. The effects of transparency of the crystal is discussed. A qualitative agreement between some experimental observations and the model is found, so that modelling may be a good tool for studying the Verneuil process. Nevertheless, some improvements of the model in conjunction with other experimental validations appear necessary.

  6. Broadband multiplex coherent anti-Stokes Raman scattering microscopy employing photonic-crystal fibers

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn; Paulsen, Henrik Nørgaard; Birkedal, Victoria;

    2006-01-01

    We demonstrate spectral multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy and microscopy based on a single Ti:sapphire oscillator and a nonlinear photonic-crystal fiber (PCF). The Stokes pulse is generated by spectral conversion of the laser pulse in a PCF. The pump pulse...

  7. Protons and deuterons in magnesium-doped sapphire crystals

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, R.; Gonzalez, R.; Colera, I. [Univ. Carlos III de Madrid, Leganes (Spain). Dept. de Fisica; Vila, R. [CIEMAT, Madrid (Spain). Inst. de Investigacion Basica

    1997-04-01

    Of great importance to the use of ceramics in fusion reactors are the problems associated with the presence of a high level of transmutation products induced by high-energy neutrons. For aluminum oxide, the four major products are magnesium, hydrogen, carbon, and helium. The solubility and diffusivity of hydrogen isotopes strongly depend on the concentration of specific impurities, which results in a change in the position and full-width-at-half-maximum of the OH{sup {minus}} and OD{sup {minus}} bands. The OH{sup {minus}} and OD{sup {minus}} stretching frequencies in magnesium-doped aluminum oxide crystals were determined by infrared absorption measurements. Two very broad bands centered at {approximately}3,005 and 2,228 cm{sup {minus}1} were observed for OH{sup {minus}} and OD{sup {minus}}, respectively. Polarization experiment results were compatible with OH{sup {minus}} (OD{sup {minus}}) ions lying in the basal plane, as is the case in undoped crystals. The threshold temperature for the in-diffusion of deuterons was obtained by annealing the samples in flowing D{sub 2}O vapor; the resulting value was {approximately}1,050 K. At 1223 K, the diffusion coefficient was {approximately}3 {times} 10{sup {minus}7} cm{sup 2}/s, and the activation energy was 1.6 eV.

  8. Analysis of liquid crystal properties for photonic crystal fiber devices

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Wei, Lei

    2009-01-01

    We analyze the bandgap structure of Liquid Crystal infiltrated Photonic Crystal Fibers depending on the parameters of the Liquid Crystals by means of finite element simulations. For a biased Liquid Crystal Photonic Crystal Fiber, we show how the tunability of the bandgap position depends...... on the Liquid Crystal parameters....

  9. Heat Treatment of the Photonic Crystal Fiber

    Institute of Scientific and Technical Information of China (English)

    Joo; Beom; Eom; Seongwoo; Yoo; Jinchae; Kim; Hokyung; Kim; Un-Chul; Paek; Byeong; Ha; Lee

    2003-01-01

    We report heat treatment of the photonic crystal fiber. As the temperature was increased, the transmission of the photonic crystal fiber was increased, unlike conventional single mode fiber. The transmission increase at short wavelength region was larger than long wavelength region for the various temperatures. After crystallization of the silica glass, the spectra of the photonic crystal fiber were just decreased at all wavelength regions, but, in case of the single mode fiber, the absorption in visibl...

  10. Development of Sensors Using Evanescent Wave Interactions in Sapphire Optical Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Michael W. Renfro; Eric H. Jordan

    2006-12-31

    The development of tunable diode laser absorption sensors for measurements in industrial boilers, both through direct absorption and evanescent wave absorption have been performed in the work presented here. These sensors use both direct and indirect absorption through the use of evanescent interactions within a coal firing combustion environment. For the direct absorption sensor, wavelength modulation absorption spectroscopy with second-harmonic detection was implemented within a physical probe designed to be placed with the flue stack of a power plant. Measurements were taken of carbon dioxide and water vapor concentration during operation at a local industrial facility. The design of this sensor probe overcomes problems of beam steering and permits a reference gas measurement. Extracted concentration data and design elements from the direct absorption measurements are presented. In addition, development of a sapphire fiber-based sensor using evanescent wave absorption along the outside of the fiber is presented. Evanescent absorption allows for the laser transmission to be maintained in the fiber at all times and may alleviate problems of background emission, beam steering, and especially scattering of the laser beam from solid particles experienced through free path direct absorption measurements in particulated flows. Laboratory measurements using evanescent fiber detection are presented.

  11. Analysis of liquid crystal properties for photonic crystal fiber devices

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Wei, Lei;

    2009-01-01

    We analyze the bandgap structure of Liquid Crystal infiltrated Photonic Crystal Fibers depending on the parameters of the Liquid Crystals by means of finite element simulations. For a biased Liquid Crystal Photonic Crystal Fiber, we show how the tunability of the bandgap position depends on the L...

  12. Single-crystal sapphire resonator at millikelvin temperatures: Observation of thermal bistability in high- Q factor whispering gallery modes

    Science.gov (United States)

    Creedon, Daniel L.; Tobar, Michael E.; Le Floch, Jean-Michel; Reshitnyk, Yarema; Duty, Timothy

    2010-09-01

    Resonance modes in single crystal sapphire (α-Al2O3) exhibit extremely high electrical and mechanical Q factors ( ≈109 at 4 K), which are important characteristics for electromechanical experiments at the quantum limit. We report the cool down of a bulk sapphire sample below superfluid liquid-helium temperature (1.6 K) to as low as 25 mK. The electromagnetic properties were characterized at microwave frequencies, and we report the observation of electromagnetically induced thermal bistability in whispering gallery modes due to the material T3 dependence on thermal conductivity and the ultralow dielectric loss tangent. We identify “magic temperatures” between 80 and 2100 mK, the lowest ever measured, at which the onset of bistability is suppressed and the frequency-temperature dependence is annulled. These phenomena at low temperatures make sapphire suitable for quantum metrology and ultrastable clock applications, including the possible realization of the quantum-limited sapphire clock.

  13. Tunable integrated optical filters based on sapphire microspheres and liquid crystals

    Science.gov (United States)

    Gilardi, Giovanni; Yilmaz, Hasan; Sharif Murib, Mohammed; Asquini, Rita; d'Alessandro, Antonio; Serpengüzel, Ali; Beccherelli, Romeo

    2010-05-01

    We present an integrated optical narrowband electrically tunable filter based on the whispering gallery modes of sapphire microspheres and double ion-exchanged channel BK7 glass waveguides. Tuning is provided by a liquid crystal infiltrated between the spheres and the glass substrate. By suitably choosing the radii of the spheres and of the circular apertures, upon which the spheres are positioned, arrays of different filters can be realized on the same substrate with a low cost industrial process. We evaluate the performance in terms of quality factor, mode spacing, and tuning range by comparing the numerical results obtained by the numerical finite element modeling approach and with the analytical approach of the Generalized Lorenz-Mie Theory for various design parameters. By reorienting the LC in an external electrical field, we demonstrate the tuning of the spectral response of the sapphire microsphere based filter. We find that the value of the mode spacing remains nearly unchanged for the different values of the applied electric field. An increase of the applied electric field strength, changes the refractive index of the liquid crystal, so that for a fixed geometry the mode spacing remains unchanged.

  14. Photonic crystal fiber modelling and applications

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Libori, Stig E. Barkou

    2001-01-01

    Photonic crystal fibers having a microstructured air-silica cross section offer new optical properties compared to conventional fibers for telecommunication, sensor, and other applications. Recent advances within research and development of these fibers are presented.......Photonic crystal fibers having a microstructured air-silica cross section offer new optical properties compared to conventional fibers for telecommunication, sensor, and other applications. Recent advances within research and development of these fibers are presented....

  15. Photonic crystal fibers: fundamentals to emerging applications

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard

    2005-01-01

    A review of the fundamental properties of photonic crystal fibers is presented. Special focus is held on the emerging fields of application within areas such as actively controlled fiber devices and high-power fiber lasers.......A review of the fundamental properties of photonic crystal fibers is presented. Special focus is held on the emerging fields of application within areas such as actively controlled fiber devices and high-power fiber lasers....

  16. High-birefringent photonic crystal fiber

    DEFF Research Database (Denmark)

    Libori, Stig E. Barkou; Broeng, Jes; Knudsen, Erik

    2001-01-01

    A highly birefringent photonic crystal fiber design is analysed. Birefringence up to 10-3 is found. Random fluctuations in the cladding design are analysed, and the fiber is found to be a feasible polarization maintaining fiber.......A highly birefringent photonic crystal fiber design is analysed. Birefringence up to 10-3 is found. Random fluctuations in the cladding design are analysed, and the fiber is found to be a feasible polarization maintaining fiber....

  17. All-solid-state narrow-linewidth 455-nm blue laser based on Ti: sapphire crystal

    Institute of Scientific and Technical Information of China (English)

    Shankui Rong; Xiaolei Zhu; Weibiao Chen

    2009-01-01

    A compact, all-solid-state, narrow-linewidth, pulsed 455-nm blue laser based on Ti:sapphire crystal is developed. Pumped by a 10-Hz, frequency-doubled all-solid-state Nd:YAG laser and injection-seeded by an external cavity laser diode, the narrow-linewidth 910-nm laser with pulse width of 20 ns is obtained from a Tirsapphire laser. 3.43-mJ blue laser can be obtained from the laser system by frequency-doubling with BBO crystal. This research is very useful to determine the roadmap of developing the practical, high power blue laser. This kind of laser will have potential application for underwater communication.

  18. Influence of Cr and W alloying on the fiber-matrix interfacial shear strength in cast and directionally solidified sapphire NiAl composites

    Science.gov (United States)

    Asthana, R.; Tiwari, R.; Tewari, S. N.

    1995-01-01

    Sapphire-reinforced NiAl matrix composites with chromium or tungsten as alloying additions were synthesized using casting and zone directional solidification (DS) techniques and characterized by a fiber pushout test as well as by microhardness measurements. The sapphire-NiAl(Cr) specimens exhibited an interlayer of Cr rich eutectic at the fiber-matrix interface and a higher interfacial shear strength compared to unalloyed sapphire-NiAl specimens processed under identical conditions. In contrast, the sapphire-NiAl(W) specimens did not show interfacial excess of tungsten rich phases, although the interfacial shear strength was high and comparable to that of sapphire-NiAl(Cr). The postdebond sliding stress was higher in sapphire-NiAl(Cr) than in sapphire-NiAl(W) due to interface enrichment with chromium particles. The matrix microhardness progressively decreased with increasing distance from the interface in both DS NiAl and NiAl(Cr) specimens. The study highlights the potential of casting and DS techniques to improve the toughness and strength of NiAl by designing dual-phase microstructures in NiAl alloys reinforced with sapphire fibers.

  19. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2003-04-01

    This report summarizes technical progress over the first six months of the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Research efforts were focused on analyzing and testing factors that impact performance degradation of the initially designed sensor prototype, including sensing element movement within the sensing probe and optical signal quality degradation. Based these results, a new version of the sensing system was designed by combining the sapphire disk sensing element and the single crystal zirconia right angle light reflector into one novel single crystal sapphire right angle prism. The new sensor prototype was tested up to 1650 C.

  20. The study on the nanomachining property and cutting model of single-crystal sapphire by atomic force microscopy.

    Science.gov (United States)

    Huang, Jen-Ching; Weng, Yung-Jin

    2014-01-01

    This study focused on the nanomachining property and cutting model of single-crystal sapphire during nanomachining. The coated diamond probe is used to as a tool, and the atomic force microscopy (AFM) is as an experimental platform for nanomachining. To understand the effect of normal force on single-crystal sapphire machining, this study tested nano-line machining and nano-rectangular pattern machining at different normal force. In nano-line machining test, the experimental results showed that the normal force increased, the groove depth from nano-line machining also increased. And the trend is logarithmic type. In nano-rectangular pattern machining test, it is found when the normal force increases, the groove depth also increased, but rather the accumulation of small chips. This paper combined the blew by air blower, the cleaning by ultrasonic cleaning machine and using contact mode probe to scan the surface topology after nanomaching, and proposed the "criterion of nanomachining cutting model," in order to determine the cutting model of single-crystal sapphire in the nanomachining is ductile regime cutting model or brittle regime cutting model. After analysis, the single-crystal sapphire substrate is processed in small normal force during nano-linear machining; its cutting modes are ductile regime cutting model. In the nano-rectangular pattern machining, due to the impact of machined zones overlap, the cutting mode is converted into a brittle regime cutting model.

  1. Intracavity doubling of CW Ti:sapphire laser to 392.5 nm using BiBO-crystal

    DEFF Research Database (Denmark)

    Mortensen, Jesper Liltorp; Thorhauge, Morten; Tidemand-Lichtenberg, Peter

    2005-01-01

    In this work we present results obtained for intra-cavity frequency-doubling of a 785 nm CW Ti:sapphire laser utilising BiBO as the non-linear crystal. Intracavity doubling offers several advantages compared to extra-cavity doubling, such as no need to couple to an external resonance cavity...

  2. Single-crystal Sapphire Based Optical Polarimetric Sensor for High Temperature Measurement

    Directory of Open Access Journals (Sweden)

    Anbo Wang

    2006-08-01

    Full Text Available Optical sensors have been investigated and widely deployed in industrial andscientific measurement and control processes, mainly due to their accuracy, high sensitivityand immunity to electromagnetic interference and other unique characteristics. They areespecially suited for harsh environments applications, where no commercial electricalsensors are available for long-term stable operations. This paper reports a novel contactoptical high temperature sensor targeting at harsh environments. Utilizing birefringentsingle crystal sapphire as the sensing element and white light interferometric signalprocessing techniques, an optical birefringence based temperature sensor was developed.With a simple mechanically structured sensing probe, and an optical spectrum-codedinterferometric signal processor, it has been tested to measure temperature up to 1600 °Cwith high accuracy, high resolution, and long-term measurement stability.

  3. Studies on Crystal Orientation of ZnO Film on Sapphire Using High-throughout X-ray Diffraction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The orientation of the nano-columnar ZnO films grown on sapphire using the technique of metal-organic chemical vapor deposition (MOCVD) exhibits deviation because of the mismatch between the crystal lattices of the films and the sapphire substrate. A high-throughout X-ray diffraction method was employed to determine the crystal orientation of the ZnO films at a time scale of the order of minutes based on the general area detection diffraction system (GADDS). This rapid, effective, and ready method, adapted for characterizing the orientation of the nano-columnar crystals is used to directly explain the results of observation of the X-ray diffraction images, by the measurements of the orientations of the crystal columns of the ZnO films along c-axis and in parallel to ab plane.

  4. Cladded single crystal fibers for high power fiber lasers

    Science.gov (United States)

    Kim, W.; Shaw, B.; Bayya, S.; Askins, C.; Peele, J.; Rhonehouse, D.; Meyers, J.; Thapa, R.; Gibson, D.; Sanghera, J.

    2016-09-01

    We report on the recent progress in the development of cladded single crystal fibers for high power single frequency lasers. Various rare earth doped single crystal YAG fibers with diameters down to 17 μm with length > 1 m have been successfully drawn using a state-of-the-art Laser Heated Pedestal Growth system. Single and double cladding on rare earth doped YAG fibers have been developed using glasses where optical and physical properties were precisely matched to doped YAG core single crystal fiber. The double clad Yb:YAG fiber structures have dimensions analogous to large mode area (LMA) silica fiber. We also report successful fabrications of all crystalline core/clad fibers where thermal and optical properties are superior over glass cladded YAG fibers. Various fabrication methods, optical characterization and gain measurements on these cladded YAG fibers are reported.

  5. Photonic crystal fibers, devices, and applications

    Institute of Scientific and Technical Information of China (English)

    Wei JIN; Jian JU; Hoi Lut HO; Yeuk Lai HOO; Ailing ZHANG

    2013-01-01

    This paper reviews different types of air-silica photonic crystal fibers (PCFs), discusses their novel properties, and reports recent advances in PCF components and sensors as well as techniques for splicing PCFs to standard telecomm fibers.

  6. Recent Progress of Photonic Crystal Fibers

    Institute of Scientific and Technical Information of China (English)

    Katsusuke; Tajima

    2003-01-01

    Photonic crystal fibers are attractive since we can realize a wide variety of unique features in the PCFs, which cannot be realized in conventional single-mode fibers. We describe recent progress in the PCF.

  7. Numerical investigation of factors affecting the shape of the crystal-melt interface in edge-defined film-fed growth of sapphire crystals

    Science.gov (United States)

    Stelian, C.; Barthalay, N.; Duffar, T.

    2017-07-01

    Numerical modeling is used to investigate the shape of the crystal-melt interface in edge-defined film-fed growth (EFG) of large size sapphire rods and sheets. The present analysis shows that the temperature distribution in the meniscus is significantly affected by the internal radiative exchanges in the sapphire crystal. 2D axisymmetric computations performed in the case of sapphire rods, show a concave shape of the interface for opaque crystals, and a convex shaped interface for semi-transparent crystals. The temperature gradient across the meniscus increases significantly in the case which accounts for the internal radiative effect in the crystal. Large temperature differences along the free surface of the meniscus generate intense Marangoni flow, which can influence the shape of the growth interface. In this case, the meniscus height increases, producing instabilities in the growth process. The effect of die geometry on the interface shape is analyzed by increasing the angle between the working edges of the die. Computations shows that the interface curvature decreases as this angle increases, but the solidification isotherm moves up, leading to an increased meniscus height. 3D modeling is applied to investigate the EFG growth of large size sapphire sheets. Numerical results show a non-uniform temperature distribution in the meniscus, and a complex 3D flow pattern. However, the intensity of the flow is low in this case, having no influence on the temperature field and interface shape.

  8. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate

    Science.gov (United States)

    Sun, Haiding; Wu, Feng; tahtamouni, T. M. Al; Alfaraj, Nasir; Li, Kuang-Hui; Detchprohm, Theeradetch; Dupuis, Russell D.; Li, Xiaohang

    2017-10-01

    The growth of high quality AlN epitaxial films relies on precise control of the initial growth stages. In this work, we examined the influence of the trimethylaluminum (TMAl) pretreatment of sapphire substrates on the structural properties, crystal quality and growth modes of heteroepitaxial AlN films on (0 0 0 1) sapphire substrates. Without the pretreatment, the AlN films nucleated on the smooth surface but exhibited mixed crystallographic Al- (N-) polarity, resulting in rough AlN film surfaces. With increasing the pretreatment time from 1 to 5 s, the N-polarity started to be impeded. However, small islands were formed on sapphire surface due to the decompostion of TMAl. As a result, small voids became noticeable at the nucleation layer (NL) because the growth started as quasi three-dimensional (3D) but transformed to 2D mode as the film grew thicker and got coalesced, leading to smoother and Al-polar films. On the other hand, longer pretreatment time of 40 s formed large 3D islands on sapphire, and thus initiated a 3D-growth mode of the AlN film, generating Al-polar AlN nanocolumns with different facets, which resulted into rougher film surfaces. The epitaxial growth modes and their correlation with the AlN film crystal quality under different TMAl pretreatments are also discussed.

  9. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate

    KAUST Repository

    Sun, Haiding

    2017-08-08

    The growth of high quality AlN epitaxial films relies on precise control of the initial growth stages. In this work, we examined the influence of the trimethylaluminum (TMAl) pretreatment of sapphire substrates on the structural properties, crystal quality and growth modes of heteroepitaxial AlN films on (0001) sapphire substrates. Without the pretreatment, the AlN films nucleated on the smooth surface but exhibited mixed crystallographic Al- (N-) polarity, resulting in rough AlN film surfaces. With increasing the pretreatment time from 1 to 5 s, the N-polarity started to be impeded. However, small islands were formed on sapphire surface due to the decompostion of TMAl. As a result, small voids became noticeable at the nucleation layer (NL) because the growth started as quasi three-dimensional (3D) but transformed to 2D mode as the film grew thicker and got coalesced, leading to smoother and Al-polar films. On the other hand, longer pretreatment time of 40 s formed large 3D islands on sapphire, and thus initiated a 3D-growth mode of the AlN film, generating Al-polar AlN nanocolumns with different facets, which resulted into rougher film surfaces. The epitaxial growth modes and their correlation with the AlN film crystal quality under different TMAl pretreatments are also discussed.

  10. Biased liquid crystal photonic bandgap fiber

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2008-01-01

    We simulate the director structure of all capillaries in a biased photonic crystal fiber infiltrated with liquid crystals. Various mode simulations for different capillaries show the necessity to consider the entire structure.......We simulate the director structure of all capillaries in a biased photonic crystal fiber infiltrated with liquid crystals. Various mode simulations for different capillaries show the necessity to consider the entire structure....

  11. Laser-induced microexplosion confined in the bulk of a sapphire crystal: evidence of multimegabar pressures.

    Science.gov (United States)

    Juodkazis, S; Nishimura, K; Tanaka, S; Misawa, H; Gamaly, E G; Luther-Davies, B; Hallo, L; Nicolai, P; Tikhonchuk, V T

    2006-04-28

    Extremely high pressures (approximately 10 TPa) and temperatures (5 x 10(5) K) have been produced using a single laser pulse (100 nJ, 800 nm, 200 fs) focused inside a sapphire crystal. The laser pulse creates an intensity over 10(14) W/cm2 converting material within the absorbing volume of approximately 0.2 microm3 into plasma in a few fs. A pressure of approximately 10 TPa, far exceeding the strength of any material, is created generating strong shock and rarefaction waves. This results in the formation of a nanovoid surrounded by a shell of shock-affected material inside undamaged crystal. Analysis of the size of the void and the shock-affected zone versus the deposited energy shows that the experimental results can be understood on the basis of conservation laws and be modeled by plasma hydrodynamics. Matter subjected to record heating and cooling rates of 10(18) K/s can, thus, be studied in a well-controlled laboratory environment.

  12. Photonics crystal fiber Raman sensors

    Science.gov (United States)

    Yang, Xuan; Bond, Tiziana C.; Zhang, Jin Z.; Li, Yat; Gu, Claire

    2012-11-01

    Hollow core photonic crystal fiber (HCPCF) employs a guiding mechanism fundamentally different from that in conventional index guiding fibers. In an HCPCF, periodic air channels in a glass matrix act as reflectors to confine light in an empty core. As a result, the interaction between light and glass can be very small. Therefore, HCPCF has been used in applications that require extremely low non-linearity, high breakdown threshold, and zero dispersion. However, their applications in optical sensing, especially in chemical and biological sensing, have only been extensively explored recently. Besides their well-recognized optical properties the hollow cores of the fibers can be easily filled with liquid or gas, providing an ideal sampling mechanism in sensors. Recently, we have demonstrated that by filling up a HCPCF with gas or liquid samples, it is possible to significantly increase the sensitivity of the sensors in either regular Raman or surface enhanced Raman scattering (SERS) applications. This is because the confinement of both light and sample inside the hollow core enables direct interaction between the propagating wave and the analyte. In this paper, we report our recent work on using HCPCF as a platform for Raman or SERS in the detection of low concentration greenhouse gas (ambient CO2), biomedically significant molecules (e.g., glucose), and bacteria. We have demonstrated that by filling up a HCPCF with gas or liquid samples, it is possible to significantly increase the sensitivity of the sensors in either regular Raman or SERS applications.

  13. Influence of Thermal Conductivity on Interface Shape during Growth of Sapphire Crystal Using a Heat-Exchanger-Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The internal radiative contributed on heat transfer will enhance the heat transport inside the crystalline phase during growth the transparent sapphire crystal using a heat-exchanger-method (HEM). The artificially enhanced thermal conductivity of the solid to include the internal radiation effect was used in the present study. Numerical simulations using FIDAP were performed to investigate the effects of the thermal conductivity on the shape of the melt-crystal interface, the temperature distribution, and the velocity distribution. Heat transfer (including radiation) from the furnace to the crucible and heat extraction from the heat exchanger can be modeled by the convection boundary conditions. In the present study, we focus on the influence of the conductivity on the shape of the melt-crystal interface. Therefore, the effect of the others growth parameters during the HEM crystal growth was neglected. For the homogenous conductivity (km=kS=k), the maximum convexity decreases as k increases and the rate of maximum convexity increases for a higher conductivity is less abrupt than for a lower conductivity. For the no homogenous conductivity (km≠kS), the higher solid's kS generates lower maximum convexity and the variation in maximum convexity was less abrupt for the different melt's km. The maximum convexity decreases slightly as the enhance conductivity of the sapphire crystal increases. The effects of the anisotropic conductivity of the sapphire crystal were also addressed. The maximum convexity of the melt-crystal interface decreases when the radial conductivity (ksr) of the crystal increases. The maximum convexity increases as the axial conductivity (ksz) of the crucible increases.

  14. 蓝宝石晶体的双面研磨加工%Dual-lapping process for sapphire crystal

    Institute of Scientific and Technical Information of China (English)

    文东辉; 洪滔; 张克华; 鲁聪达

    2009-01-01

    In order to achieve high efficiency and low damaged layers during a sapphire crystal lapping process,an experimental research on the rougness,lapping uniformity and sub-surface damaged layer were studied in this paper.The sapphire with (0001) orientation was lapped by 280 mesh boron carbide abrasive grits.The effects of lapping time on the material removal rates and surface roughness were investigated,and the processing remainders by the dual-lapping were determined in accordance with the surface states of the sapphire.Then micro-surface uniformity of the sapphire was also presented by using WYKO laser equipment.Finally,a nano-indentation test was carried out to measure the depth of damaged layer according to the hardness or modulus variances.Experimental results show that the sapphire crystal can offer the R,in 0.523 μm,R,<6.0 μm,the depth of heavy damaged layer of 460 nm,and the depth of sub-surface damaged layer no more than 1 μm,after it is lapped by the abrasive with 280 mesh boron carbide grits in 120 min.%为了实现对蓝宝石晶体的高效低损伤研磨加工,对蓝宝石晶体的双面研磨加工表面粗糙度、研磨均匀性和亚表面损伤层的深度进行实验研究.采用280min的双面研磨加工后可以获得Ra为0.523 μm,Rt<6.0 μm的表面;其深度损伤层约为460 nm,亚表面损伤层<1 μm.

  15. Photonic crystal fiber based antibody detection

    OpenAIRE

    Duval, A.; Lhoutellier, M; Jensen, J. B.; Hoiby, P E; Missier, V; Pedersen, L. H.; Hansen, Theis Peter; Bjarklev, Anders Overgaard; Bang, Ole

    2004-01-01

    An original approach for detecting labeled antibodies based on strong penetration photonic crystal fibers is introduced. The target antibody is immobilized inside the air-holes of a photonic crystal fiber and the detection is realized by the means of evanescent-wave fluorescence spectroscopy and the use of a transversal illumination setup.

  16. Photonic crystal fiber based antibody detection

    DEFF Research Database (Denmark)

    Duval, A; Lhoutellier, M; Jensen, J B

    2004-01-01

    An original approach for detecting labeled antibodies based on strong penetration photonic crystal fibers is introduced. The target antibody is immobilized inside the air-holes of a photonic crystal fiber and the detection is realized by the means of evanescent-wave fluorescence spectroscopy and ...

  17. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2003-11-01

    This report summarizes technical progress over the second six month period of the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Research efforts were focused on evaluating corrosion effects in single crystal sapphire at temperatures up to 1400 C, and designing the sensor mechanical packaging with input from Wabash River Power Plant. Upcoming meetings will establish details for the gasifier field test.

  18. Thermal Conductance through Sapphire-Sapphire Bonding

    Science.gov (United States)

    Suzuki, T.; Tomaru, T.; Haruyama, T.; Shintomi, T.; Uchinyama, T.; Miyoki, S.; Ohashi, M.; Kuroda, K.

    2003-07-01

    Thermal conductance on sapphire-sapphire bonded interface has been investigated. Two pieces of single crystal sapphire bar with square cross section were bonded together by adhesion free bonding. In two sections of the bar, thermal conductivity was measured between 5 K to 300K. One section contains a bonded interface and the other section measured a thermal conductivity of the sapphire as a reference. No significant thermal resistance due to bonded interface was found from this measurement. Obtained thermal conductivity reaches κ 1 × 104 [W/m·K] in temperature range of T = 20 ˜ 30 K which is a planned operating temperature of a cryogenic mirror of the Large scale Cryogenic Gravitational wave telescope. It looks promising for sapphire bonding technique to improve a heat transfer from a large cryogenic mirror to susp ension wires.

  19. Sapphire ball lensed fiber probe for common-path optical coherence tomography in ocular imaging and sensing

    Science.gov (United States)

    Zhao, Mingtao; Huang, Yong; Kang, Jin U.

    2013-03-01

    We describe a novel common-path optical coherence tomography (CP-OCT) fiber probe design using a sapphire ball lens for cross-sectional imaging and sensing in retina vitrectomy surgery. Single mode Gaussian beam (TEM00) simulation was used to optimize lateral resolution and working distance (WD) of the common-path probe. A theoretical sensitivity model for CP-OCT was prosed to assess its optimal performance based an unbalanced photodetector configuration. Two probe designs with working distances (WD) 415μm and 1221μm and lateral resolution 11μm and 18μm, respectively were implemented with sensitivity up to 88dB. The designs are also fully compatible with conventional Michelson interferometer based OCT configurations. The reference plane of the probe, located at the distal beam exit interface of the single mode fiber (SMF), was encased within a 25-gauge hypodermic needle by the sapphire ball lens facilitates its applications in bloody and harsh environments. The performances of the fiber probe with 11μm of lateral resolution and 19μm of axial resolution were demonstrated by cross-sectional imaging of a cow cornea and retina in vitro with a 1310nm swept source OCT system. This probe was also attached to a piezoelectric motor for active compensation of physiological tremor for handheld retinal surgical tools.

  20. Erbium doped tellurite photonic crystal optical fiber

    Science.gov (United States)

    Osorio, Sergio P.; Fernandez, Enver; Rodriguez, Eugenio; Cesar, Carlos L.; Barbosa, Luiz C.

    2005-04-01

    In this work we present the fabrication of tellurite glass photonic crystal fiber doped with a very large erbium concentration. Tellurite glasses are important hosts for rare earth ions due to its very high solubility, which allows up to 10,000 ppm Er3+ concentrations. The photonic crystal optical fibers and tellurite glasses can be, therefore, combined in an efficient way to produce doped fibers for large bandwidth optical amplifiers. The preform was made of a 10 mm external diameter tellurite tube filled with an array of non-periodic tellurite capillaries and an erbium-doped telluride rod that constitute the fiber core. The preform was drawn in a Heathway Drawing Tower, producing fibers with diameters between 120 - 140 μm. We show optical microscope photography of the fiber"s transverse section. The ASE spectra obtained with a spectra analyzer show a red shift as the length of the optical fiber increases.

  1. Biased liquid crystal infiltrated photonic bandgap fiber

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Scolari, Lara

    2009-01-01

    A simulation scheme for the transmission spectrum of a photonic crystal fiber infiltrated with a nematic liquid crystal and subject to an external bias is presented. The alignment of the biased liquid crystal is simulated using the finite element method to solve the relevant system of coupled...... partial differential equations. From the liquid crystal alignment the full tensorial dielectric permittivity in the capillaries is derived. The transmission spectrum for the photonic crystal fiber is obtained by solving the generalized eigenvalue problem deriving from Maxwell’s equations using a vector...... element based finite element method. We demonstrate results for a splay aligned liquid crystal infiltrated into the capillaries of a four-ring photonic crystal fiber and compare them to corresponding experiments....

  2. Crystal Quality and Light Output Power of GaN-Based LEDs Grown on Concave Patterned Sapphire Substrate.

    Science.gov (United States)

    Wu, YewChung Sermon; Isabel, A Panimaya Selvi; Zheng, Jian-Hsuan; Lin, Bo-Wen; Li, Jhen-Hong; Lin, Chia-Chen

    2015-04-22

    The crystal quality and light output power of GaN-based light-emitting diodes (LEDs) grown on concave patterned sapphire substrate (CPSS) were investigated. It was found that the crystal quality of GaN-based LEDs grown on CPSS improved with the decrease of the pattern space (percentage of c-plane). However, when the pattern space decreased to 0.41 μm (S0.41-GaN), the GaN crystallinity dropped. On the other hand, the light output power of GaN-based LEDs was increased with the decrease of the pattern space due to the change of the light extraction efficiency.

  3. Liquid Crystal photonic Bandgap Fiber Devices

    DEFF Research Database (Denmark)

    Wei, Lei

    In this Ph.D. thesis, an experimental investigation of liquid crystal photonic bandgap (LCPBG) fiber devices and applications is presented. Photonic crystal fibers (PCFs) consist of a cladding microstructure with periodic index variations and a core defined by a defect of the structure....... The presence of liquid crystals (LCs) in the air-holes of the PCF transforms the fiber from a total internal reflection (TIR) guiding type into a photonic bandgap (PBG) guiding type. The light is confined to the silica core by coherent scattering from the LC-filled air-holes and the transmission spectrum...... of each LCPBG fiber. Finally, the applications for LCPBG fiber devices based on the on-chip platform design have been demonstrated in realizing microwave true-time delay and creating an electrically tunable fiber laser. Referatet mailes...

  4. Liquid Crystal photonic Bandgap Fiber Devices

    DEFF Research Database (Denmark)

    Wei, Lei

    In this Ph.D. thesis, an experimental investigation of liquid crystal photonic bandgap (LCPBG) fiber devices and applications is presented. Photonic crystal fibers (PCFs) consist of a cladding microstructure with periodic index variations and a core defined by a defect of the structure....... The presence of liquid crystals (LCs) in the air-holes of the PCF transforms the fiber from a total internal reflection (TIR) guiding type into a photonic bandgap (PBG) guiding type. The light is confined to the silica core by coherent scattering from the LC-filled air-holes and the transmission spectrum...... of each LCPBG fiber. Finally, the applications for LCPBG fiber devices based on the on-chip platform design have been demonstrated in realizing microwave true-time delay and creating an electrically tunable fiber laser. Referatet mailes...

  5. First Single-Crystal Mullite Fibers

    Science.gov (United States)

    1997-01-01

    Ceramic-matrix composites strengthened by suitable fiber additions are being developed for high-temperature use, particularly for aerospace applications. New oxide-based fibers, such as mullite, are particularly desirable because of their resistance to high-temperature oxidative environments. Mullite is a candidate material in both fiber and matrix form. The primary objective of this work was to determine the growth characteristics of single-crystal mullite fibers produced by the laser-heated floating zone method. Directionally solidified fibers with nominal mullite compositions of 3Al2O3 2SiO2 were grown by the laser-heated floating zone method at the NASA Lewis Research Center. SEM analysis revealed that the single-crystal fibers grown in this study were strongly faceted and that the facets act as critical flaws, limiting fiber strength. The average fiber tensile strength is 1.15 GPa at room temperature. The mullite fibers exhibit superior strength retention (80 percent of their room temperature tensile strength at 1450 C). Examined by transmission electron microscopy, these mullite single crystals are free of dislocations, low-angle boundaries, and voids. In addition, they show a high degree of oxygen vacancy ordering. High-resolution digital images from an optical microscope furnish evidence of the formation of a liquid-liquid miscibility gap during crystal growth. These images represent the first experimental evidence of liquid immiscibility for these compositions and temperatures. Continuing investigation with controlled seeding of mullite single crystals is planned.

  6. On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Anbo Wang

    2007-03-31

    This report summarizes technical progress October 2006 - March 2007 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. During the second phase, an alternative high temperature sensing system based on Fabry-Perot interferometry was developed that offers a number of advantages over the BPDI solution. The objective of this program is to bring the sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. The sapphire wafer-based interferometric sensing system that was installed at TECO's Polk Power Station remained in operation for seven months. Our efforts have been focused on monitoring and analyzing the real-time data collected, and preparing for a second field test.

  7. On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Anbo Wang

    2007-03-31

    This report summarizes technical progress October 2006 - March 2007 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. During the second phase, an alternative high temperature sensing system based on Fabry-Perot interferometry was developed that offers a number of advantages over the BPDI solution. The objective of this program is to bring the sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. The sapphire wafer-based interferometric sensing system that was installed at TECO's Polk Power Station remained in operation for seven months. Our efforts have been focused on monitoring and analyzing the real-time data collected, and preparing for a second field test.

  8. 单晶蓝宝石的延性研磨加工%Ductile lapping of single crystal sapphire

    Institute of Scientific and Technical Information of China (English)

    戴欣平; 赵萍; 文东辉

    2012-01-01

    To achieve the ductile lapping of a single crystal sapphire, micro/nano mechanic characteristics of the sapphire (0001) plane were measured by nanoindentation and nanoscratch methods. The indentation model of single cone abrasive grain was proposed and then critical force conditions were deduced during ductile lapping process. Experimental studies were conducted for the single crystal sapphire based on the diamond abrasive grain charging into a synthetic tin plate, and characteristics of ductile lapped surface were measured by a NT9800 white light interferometer, a Scan Emission Microscopy (SEM) and a Transmission Electron Microscopy (TEM). Experimental results show that nanoindentation and nanoscratch methods can provide processing parameters for the ductile lapping of single crystal sapphires, and its critical depth of pile-up is around 100 nm for sapphire nanoindenta-tion. The ductile lapping of the single crystal sapphire can be implemented by charging into diamond abrasive grains and selecting proper loads and the optimal load for ductile lapping is 21 kPa. After ductile lapping, the surface scratch depth of single crystal sapphire shows a smaller dispersion and the dislocation and slip are formed on the lapped surface.%为实现单晶蓝宝石的延性研磨加工,采用纳米压痕和划痕法测试并分析了单晶蓝宝石(0001)面的微纳力学特性,建立了单颗圆锥状磨粒的压入模型并计算了延性研磨加工的受力临界条件,分析了金刚石磨粒嵌入合成锡研磨盘表面的效果.对单晶蓝宝石进行了延性研磨加工试验,采用NT9800白光干涉仪、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等方法分析了单晶蓝宝石的延性研磨表面特征.试验结果表明:采用纳米压痕和划痕法可以为单晶蓝宝石的延性研磨加工提供工艺参数,单晶蓝宝石的延性堆积的极限深度为100 nm,金刚石磨粒的嵌入及在适当载荷下可以实现蓝宝石的延性研磨加

  9. Large Mode Area Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Nielsen, Martin Dybendal

    2004-01-01

    The photonic crystal fiber (PCF) is a novel single-material optical waveguide realized by an arrangement of air-holes running along the full length of the fiber. Since the proposal of the PCF in 1996, the technology has developed into being a well-established area of research and commercialisation......-mode area fiber optimised for visible light applications. The second is a fiber optimised for the telecommunication band realizing a nonlinear effective area 5 times larger than state of the art conventional fibers. Two examples of alternative designs are demonstrated addressing the core and the cladding...

  10. Anomalous bending effect in photonic crystal fibers.

    Science.gov (United States)

    Tu, Haohua; Jiang, Zhi; Marks, Daniel L; Boppart, Stephen A

    2008-04-14

    An unexpected transmission loss up to 50% occurs to intense femtosecond pulses propagating along an endlessly single-mode photonic crystal fiber over a length of 1 m. A specific leaky-fiber mode gains amplification along the fiber at the expense of the fundamental fiber mode through stimulated four-wave mixing and Raman scattering, leading to this transmission loss. Bending near the fiber entrance dissipates the propagating seed of this leaky mode, preventing the leaky mode amplification and therefore enhancing the transmission of these pulses.

  11. Growth and Crystal Orientation of ZnTe on m-Plane Sapphire with Nanofaceted Structure

    Science.gov (United States)

    Nakasu, Taizo; Sun, Wei-Che; Kobayashi, Masakazu; Asahi, Toshiaki

    2016-11-01

    ZnTe thin films on sapphire substrate with nanofaceted structure have been studied. The nanofaceted structure of the m-plane (10-10) sapphire was obtained by heating the substrate at above 1100°C in air, and the r-plane (10-12) and S-plane (1-101) were confirmed. ZnTe layers were prepared on the nanofaceted m-plane sapphire substrates by molecular beam epitaxy (MBE). The effect of the nanofaceted structure on the orientation of the thin films was examined based on x-ray diffraction (XRD) pole figures. Transmission electron microscopy (TEM) was also employed to characterize the interface structures. The ZnTe layer on the nanofaceted m-plane sapphire substrate exhibited (331)-plane orientation, compared with (211)-plane without the nanofaceted structure. After thermal treatment, the m-plane surface vanished and (211) layer could not be formed because of the lack of surface lattice matching. On the other hand, (331)-plane thin film was formed on the nanofaceted m-plane sapphire substrate, since the (111) ZnTe domains were oriented on the S-facet. The orientation of the ZnTe epilayer depended on the atomic ordering on the surface and the influence of the S-plane.

  12. 100 mW of blue light at 405 nm from intracavity doubling of CW Ti:Sapphire laser utilising BiBO-crystal

    DEFF Research Database (Denmark)

    Thorhauge, Morten; Mortensen, Jesper Liltorp; Tidemand-Lichtenberg, Peter

    2006-01-01

    100 mW of coherent blue light with a wavelength of 405 nm was generated utilising a BiB3O6 (BiBO) nonlinear crystal to frequency double a Ti:Sapphire laser. Phase match curves as well as sensitivity to angular misalignment was calculated. The BiBO crystal was found to be excellent for this applic...

  13. Birefringence measurements in single crystal sapphire and calcite shocked along the a axis

    Science.gov (United States)

    Tear, Gareth R.; Chapman, David J.; Eakins, Daniel E.; Proud, William G.

    2017-01-01

    Calcite and sapphire were shock compressed along the direction (a axis) in a plate impact configuration. Polarimetery and Photonic Doppler Velocimetery (PDV) were used to measure the change in birefringence with particle velocity in the shock direction. Results for sapphire agree well with linear photoelastic theory and current literature showing a linear relationship between birefringence and particle velocity up to 310 m s-1. A maximum change in birefringence of 5% was observed. Calcite however showed anomolous behaviour with no detectable change in birefringence (less than 0.1%) over the range of particle velocities studied (up to 75 m s-1).

  14. Evaluation of heat extraction through sapphire fibers for the GW observatory KAGRA

    OpenAIRE

    Khalaidovski, Alexander; Hofmann, Gerd; CHEN, DAN; Komma, Julius; Schwarz, Christian; Tokoku, Chihiro; Kimura, Nobuhiro; Suzuki, Toshikazu; Scheie, Allen O.; Majorana, Ettore; Nawrodt, Ronny; Yamamoto, Kazuhiro

    2014-01-01

    Currently, the Japanese gravitational wave laser interferometer KAGRA is under construction in the Kamioka mine. As one main feature, it will employ sapphire mirrors operated at a temperature of 20K to reduce the impact from thermal noise. To reduce seismic noise, the mirrors will also be suspended from multi-stage pendulums. Thus the heat load deposited in the mirrors by absorption of the circulating laser light as well as heat load from thermal radiation will need to be extracted through th...

  15. Liquid Crystals and Photonic Bandgap Fiber Components

    DEFF Research Database (Denmark)

    Weirich, Johannes; Wei, Lei; Scolari, Lara

    Liquid Crystal(LC)filled Photonic Crystal Fibers(PCFs) represent a promising platform for the design and the fabrication of tunable all-in fiber devices. Tunability is achieved by varying the refractive index of the LC thermally, optically or electrically. In this contribution we present important...... parts of the LC theory as well as an application of a LC infiltrated PCF subject to an external electrostatic field. The fiber is placed between two electrodes and the voltage is increased step by step leading to the reorientation of the LC in the fiber capillaries. This mechanism can be used to produce...... a swichable polarizer, and an on chip LC photonic bandgap fiber polarimeter is presented, which admits strong attenuation of one polarization direction while the other one is nearly unaffected....

  16. Electrically tunable liquid crystal photonic bandgap fiber laser

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin; Scolari, Lara; Wei, Lei;

    2010-01-01

    We demonstrate electrical tunability of a fiber laser by using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate an al...

  17. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang; Zhengyu Huang; Yizheng Zhu

    2005-04-01

    This report summarizes technical progress October 2004-March 2005 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Due to the difficulties described on the last report, field testing of the BPDI system has not continued to date. However, we have developed an alternative high temperature sensing solution, which is described in this report.

  18. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang; Zhengyu Huang

    2004-04-01

    This report summarizes technical progress over the third six month period of the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Research efforts were focused on sensor probe design and machining, sensor electronics design, software algorithm design, sensor field installation procedures, and sensor remote data access and control. Field testing will begin in the next several weeks.

  19. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang; Zhengyu Huang; Yizheng Zhu

    2005-04-01

    This report summarizes technical progress October 2004-March 2005 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Due to the difficulties described on the last report, field testing of the BPDI system has not continued to date. However, we have developed an alternative high temperature sensing solution, which is described in this report.

  20. Subwavelength engineered fiber-to-chip silicon-on-sapphire interconnects for mid-infrared applications (Conference Presentation)

    Science.gov (United States)

    Alonso-Ramos, Carlos; Han, Zhaohong; Le Roux, Xavier; Lin, Hongtao; Singh, Vivek; Lin, Pao Tai; Tan, Dawn; Cassan, Eric; Marris-Morini, Delphine; Vivien, Laurent; Wada, Kazumi; Hu, Juejun; Agarwal, Anuradha; Kimerling, Lionel C.

    2016-05-01

    The mid-Infrared wavelength range (2-20 µm), so-called fingerprint region, contains the very sharp vibrational and rotational resonances of many chemical and biological substances. Thereby, on-chip absorption-spectrometry-based sensors operating in the mid-Infrared (mid-IR) have the potential to perform high-precision, label-free, real-time detection of multiple target molecules within a single sensor, which makes them an ideal technology for the implementation of lab-on-a-chip devices. Benefiting from the great development realized in the telecom field, silicon photonics is poised to deliver ultra-compact efficient and cost-effective devices fabricated at mass scale. In addition, Si is transparent up to 8 µm wavelength, making it an ideal material for the implementation of high-performance mid-IR photonic circuits. The silicon-on-insulator (SOI) technology, typically used in telecom applications, relies on silicon dioxide as bottom insulator. Unfortunately, silicon dioxide absorbs light beyond 3.6 µm, limiting the usability range of the SOI platform for the mid-IR. Silicon-on-sapphire (SOS) has been proposed as an alternative solution that extends the operability region up to 6 µm (sapphire absorption), while providing a high-index contrast. In this context, surface grating couplers have been proved as an efficient means of injecting and extracting light from mid-IR SOS circuits that obviate the need of cleaving sapphire. However, grating couplers typically have a reduced bandwidth, compared with facet coupling solutions such as inverse or sub-wavelength tapers. This feature limits their feasibility for absorption spectroscopy applications that may require monitoring wide wavelength ranges. Interestingly, sub-wavelength engineering can be used to substantially improve grating coupler bandwidth, as demonstrated in devices operating at telecom wavelengths. Here, we report on the development of fiber-to-chip interconnects to ZrF4 optical fibers and integrated SOS

  1. Effect of Shouldering Angle on Distribution of Thermal Stress in Sapphire Single Crystal Growth Using Improved Kyropoulos

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A two-dimensional model was established in the rectangular co-ordinate to study the thermal stress in the sapphire single crystal grown by the improved Kyropoulos. In the simulation, the distribution, the maximum and minimum values of the thermal stress were calculated. In addition, the relationship between the thermal stress and the shouldering angles was obtained that for lower shouldering angles, the maximum of the thermal stress value is lower and the minimum value is higher. It indicates that the distribution of the thermal stress can be improved by decreasing the shouldering angles of the crystal during the growth process. To evaluate the model, the experiment was carried out and the results are in good agreement with the calculation.

  2. Distributed optical fibre devices based on liquid crystal infiltrated photonic crystal fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Broeng, Jes; Hermann, D.S.

    2004-01-01

    We describe a new class of hybrid photonic crystal fibers, which are liquid crystal infiltrated fibers. Using these fibers, we demonstrate 'distributed' tunable filter and switching functionalities operating by the photonic bandgap effect....

  3. REINFORCEMENT OF NICKEL CHROMIUM ALLOYS WITH SAPPHIRE WHISKERS.

    Science.gov (United States)

    SAPPHIRE, COMPOSITE MATERIALS, CERAMIC FIBERS , CERAMIC FIBERS , TITANIUM COMPOUNDS, ZIRCONIUM COMPOUNDS, HYDRIDES, ADDITIVES, CHROMIUM ALLOYS, FIBER METALLURGY, IRON COMPOUNDS, ENCAPSULATION, DENSITY, SURFACE TENSION.

  4. Broadband multiplex coherent anti-Stokes Raman scattering microscopy employing photonic-crystal fibers

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn; Paulsen, Henrik Nørgaard; Birkedal, Victoria

    2006-01-01

    We demonstrate spectral multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy and microscopy based on a single Ti:sapphire oscillator and a nonlinear photonic-crystal fiber (PCF). The Stokes pulse is generated by spectral conversion of the laser pulse in a PCF. The pump pulse...... is either a highly chirped pulse or a pulse spectrally compressed in a PCF. A region of the Raman spectrum from 800 to 4000 cm(-1) is accessible with two different PCFs. Spectral resolution improvement by 1 order of magnitude over a transform-limited pump pulse utilizing a chirped or spectrally compressed...

  5. Chalcogenide glass hollow core photonic crystal fibers

    Science.gov (United States)

    Désévédavy, Frédéric; Renversez, Gilles; Troles, Johann; Houizot, Patrick; Brilland, Laurent; Vasilief, Ion; Coulombier, Quentin; Traynor, Nicholas; Smektala, Frédéric; Adam, Jean-Luc

    2010-09-01

    We report the first hollow core photonic crystal fibers (HC PCF) in chalcogenide glass. To design the required HC PCF profiles for such high index glass, we use both band diagram analysis to define the required photonic bandgap and numerical simulations of finite size HC PCFs to compute the guiding losses. The material losses have also been taken into account to compute the overall losses of the HC PCF profiles. These fibers were fabricated by the stack and draw technique from TeAsSe (TAS) glass. The fibers we drew in this work are composed of six rings of holes and regular microstructures. Two profiles are presented, one is known as a kagome lattice and the other one corresponds to a triangular lattice. Geometrical parameters are compared to the expected parameters obtained by computation. Applications of such fibers include power delivery or fiber sensors among others.

  6. Growth of ruby and sapphire crystals by the flux method; Crescimento de cristais de rubi e safira pelo metodo do fluxo

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Gislene da Silva [Universidade Federal de Mato Grosso (DRM/UFMT), Cuiaba, MT (Brazil). Dept. de Recuros Minerais; Prado, Rogerio Junqueira, E-mail: rjprado@ufmt.b [Universidade Federal de Mato Grosso (IF/UFMT), Cuiaba, MT (Brazil). Inst. de Fisica

    2010-07-01

    This work reports the growth of corundum crystals by the flux method. The main objective was the evaluation of versatility, effectiveness and real possibilities of the flux method to the synthesis and doping of monocrystals with impurities of particular interest. In this work the chosen impurities were 1) Cr and 2) Fe and Ti, aiming the synthesis of rubies and sapphires, respectively. The crystals were grown by heating a mixture of Al{sub 2}O{sub 3}:Cr or Al{sub 2}O{sub 3}:Fe:Ti and flux (MoO{sub 3}). The maximum crystal size obtained was 1.0 mm, all transparent, presenting well developed faces, bipyramidal hexagonal shape, and showing a typical red (ruby) and/or light blue (sapphire) color. EDX and XPD experiments were performed in order to characterize some of the synthesized crystals. All crystallized specimens presented the a-alumina atomic structure. (author)

  7. Crescimento de cristais de rubi e safira pelo método do fluxo Growth of ruby and sapphire crystals by the flux method

    Directory of Open Access Journals (Sweden)

    Gislene da Silva Ribeiro

    2010-01-01

    Full Text Available This work reports the growth of corundum crystals by the flux method. The main objective was the evaluation of versatility, effectiveness and real possibilities of the flux method to the synthesis and doping of monocrystals with impurities of particular interest. In this work the chosen impurities were i Cr and ii Fe and Ti, aiming the synthesis of rubies and sapphires, respectively. The crystals were grown by heating a mixture of Al2O3:Cr or Al2O3:Fe:Ti and flux (MoO3. The maximum crystal size obtained was 1.0 mm, all transparent, presenting well developed faces, bipiramidal hexagonal shape, and showing a typical red (ruby and/or light blue (sapphire color. EDX and XPD experiments were performed in order to characterize some of the synthesized crystals. All crystallized specimens presented the α-alumina atomic structure.

  8. Electrically tunable liquid crystal photonic bandgap fiber laser

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin; Scolari, Lara; Wei, Lei

    2010-01-01

    We demonstrate electrical tunability of a fiber laser by using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate an all......-spliced laser cavity based on a liquid crystal photonic bandgap fiber mounted on a silicon assembly, a pump/signal combiner with single-mode signal feed-through and an ytterbium-doped photonic crystal fiber. The laser cavity produces a single-mode output and is tuned in the range 1040-1065nm by applying...

  9. Coupling to photonic crystal fibers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.; Bjarklev, Anders Overgaard; Knudsen, Erik;

    2002-01-01

    In this work we have analyzed the correspondence between the fundamental mode of PCFs and Gaussian modes as a function of frequency, pitch, and air hole size. Such analysis provides insight into design space regions of PCFs, where low-loss coupling to standard fibers may be obtained....

  10. Supercontinuum noise in tapered photonic crystal fibers

    DEFF Research Database (Denmark)

    Møller, Uffe; Sørensen, Simon Toft; Moselund, Peter Morten;

    Supercontinuum generation (SCG) in highly nonlinear photonic crystal fibers (PCF) has drawn a lot of attention for the last decade. Pumping such PCFs with high-power picosecond laser pulses enables the creation of broadband and intense light. Picosecond SCG is initiated by modulation instability...

  11. A photonic crystal fiber with zero dispersion at 1064 nm

    DEFF Research Database (Denmark)

    Andersen, Peter Andreas

    2002-01-01

    We report on the dispersion properties of a single mode, large core photonic crystal fiber. Using white light interferometry the fiber is found to have zero dispersion at 1064 nm......We report on the dispersion properties of a single mode, large core photonic crystal fiber. Using white light interferometry the fiber is found to have zero dispersion at 1064 nm...

  12. Development of Auto-Seeding System Using Image Processing Technology in the Sapphire Crystal Growth Process via the Kyropoulos Method

    Directory of Open Access Journals (Sweden)

    Churl Min Kim

    2017-04-01

    Full Text Available The Kyropoulos (Ky and Czochralski (Cz methods of crystal growth are used for large-diameter single crystals. The seeding process in these methods must induce initial crystallization by initiating contact between the seed crystals and the surface of the melted material. In the Ky and Cz methods, the seeding process lays the foundation for ingot growth during the entire growth process. When any defect occurs in this process, it is likely to spread to the entire ingot. In this paper, a vision system was constructed for auto seeding and for observing the surface of the melt in the Ky method. An algorithm was developed to detect the time when the internal convection of the melt is stabilized by observing the shape of the spoke pattern on the melt material surface. Then, the vision system and algorithm were applied to the growth furnace, and the possibility of process automation was examined for sapphire growth. To confirm that the convection of the melt was stabilized, the position of the island (i.e., the center of a spoke pattern was detected using the vision system and image processing. When the observed coordinates for the center of the island were compared with the coordinates detected from the image processing algorithm, there was an average error of 1.87 mm (based on an image with 1024 × 768 pixels.

  13. Supercontinuum Generation Using a Polarization-Maintaining Photonic Crystal Fibre by a Regeneratively Amplified Ti:Sapphire Laser

    Institute of Scientific and Technical Information of China (English)

    YU Yong-Qin; RUAN Shuang-Chen; DU Chen-Lin; YAO Jian-Quan

    2005-01-01

    @@ Supercontinuum with an ultra-broad bandwidth in the range from 380nm to 1750nm was generated by injecting 250 kHz 200 fs optical pulses produced by a regeneratively amplified Ti:sapphire laser into a 2.5-m-long polarization-maintaining photonic crystal fibre (PCF). It is indicated that the mechanism for the supercontinuum generation in the anomalous dispersion region of the PCF are directly related to the Raman effect, the fission of higher-order solitons, nonsolitonic radiation, and the coinstantaneous effect of four-wave mixing. The frequency components beyond 1.4 μm were also observed. It is interpreted that the energy of solitons is shifted beyond the OH absorption with a higher input power.

  14. Influence of gas flow on thermal field and stress during growth of sapphire single crystal using Kyropoulos method

    Institute of Scientific and Technical Information of China (English)

    LI Jinquan; SU Xiaoping; NA Mujilatu; YANG Hai; LI Jianmin; YU Yunqi; MI Jianjun

    2006-01-01

    The professional modeling software package CrysVUn was employed to study the process of a large sapphire single crystal growth using Kyropoulos method.The influence of gas pressure on thermal field, solid-liquid interface shape, gas velocity field and von Mises stress were studied for the first time.It is found that the root of the seed melt when gas pressure equals to one atmosphere or more than one atmosphere, especially during the seeding period, this result is consistent with the experimental observation, and this paper presents three ways to solve this problem.The temperature gradient and stress decreases significantly as the gas pressure increases.The convexity of the solid-liquid interface slightly increases when the gas pressure increases.Numerical analysis was used to optimize the hot zone design.

  15. Tunable intra-cavity SHG of CW Ti:Sapphire lasers around 785 nm and 810 nm in BiBO-crystals

    DEFF Research Database (Denmark)

    Thorhauge, Morten; Mortensen, Jesper Liltorp; Tidemand-Lichtenberg, Peter

    2006-01-01

    Phasematch curves as well as sensitivity to angular and wavelength misalignment for generation of second-harmonic of 785 nm and 810 nm in Bi3BO6 crystal was calculated. Measurements were done for intra-cavity CW SHG in a Ti:Sapphire laser. The BiBO crystal was found to be excellent for this appli......Phasematch curves as well as sensitivity to angular and wavelength misalignment for generation of second-harmonic of 785 nm and 810 nm in Bi3BO6 crystal was calculated. Measurements were done for intra-cavity CW SHG in a Ti:Sapphire laser. The BiBO crystal was found to be excellent...

  16. On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2005-11-01

    This report summarizes technical progress April-September 2005 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Due to the difficulties described on the last report, field testing of the BPDI system has not continued to date. However, we have developed an alternative high temperature sensing solution, which is described in this report. The sensing system will be installed and tested at TECO's Polk Power Station. Following a site visit in June 2005, our efforts have been focused on preparing for that field test, including he design of the sensor mechanical packaging, sensor electronics, the data transfer module, and the necessary software codes to accommodate this application.. We are currently ready to start sensor fabrication.

  17. On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2005-11-01

    This report summarizes technical progress April-September 2005 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Due to the difficulties described on the last report, field testing of the BPDI system has not continued to date. However, we have developed an alternative high temperature sensing solution, which is described in this report. The sensing system will be installed and tested at TECO's Polk Power Station. Following a site visit in June 2005, our efforts have been focused on preparing for that field test, including he design of the sensor mechanical packaging, sensor electronics, the data transfer module, and the necessary software codes to accommodate this application.. We are currently ready to start sensor fabrication.

  18. Recent advances in liquid-crystal fiber optics and photonics

    Science.gov (United States)

    Woliński, T. R.; Siarkowska, A.; Budaszewski, D.; Chychłowski, M.; Czapla, A.; Ertman, S.; Lesiak, P.; Rutkowska, K. A.; Orzechowski, K.; Sala-Tefelska, M.; Sierakowski, M.; DÄ browski, R.; Bartosewicz, B.; Jankiewicz, B.; Nowinowski-Kruszelnicki, E.; Mergo, P.

    2017-02-01

    Liquid crystals over the last two decades have been successfully used to infiltrate fiber-optic and photonic structures initially including hollow-core fibers and recently micro-structured photonic crystal fibers (PCFs). As a result photonic liquid crystal fibers (PLCFs) have been created as a new type of micro-structured fibers that benefit from a merge of "passive" PCF host structures with "active" LC guest materials and are responsible for diversity of new and uncommon spectral, propagation, and polarization properties. This combination has simultaneously boosted research activities in both fields of Liquid Crystals Photonics and Fiber Optics by demonstrating that optical fibers can be more "special" than previously thought. Simultaneously, photonic liquid crystal fibers create a new class of fiber-optic devices that utilize unique properties of the photonic crystal fibers and tunable properties of LCs. Compared to "classical" photonic crystal fibers, PLCFs can demonstrate greatly improved control over their optical properties. The paper discusses the latest advances in this field comprising PLCFs that are based on nanoparticles-doped LCs. Doping of LCs with nanoparticles has recently become a common method of improving their optical, magnetic, electrical, and physical properties. Such a combination of nanoparticles-based liquid crystals and photonic crystal fibers can be considered as a next milestone in developing a new class of fiber-based optofluidic systems.

  19. Soliton blueshift in tapered photonic crystal fibers.

    Science.gov (United States)

    Stark, S P; Podlipensky, A; Russell, P St J

    2011-02-25

    We show that solitons undergo a strong blueshift in fibers with a dispersion landscape that varies along the direction of propagation. The experiments are based on a small-core photonic crystal fiber, tapered to have a core diameter that varies continuously along its length, resulting in a zero-dispersion wavelength that moves from 731 nm to 640 nm over the transition. The central wavelength of a soliton translates over 400 nm towards a shorter wavelength. This is accompanied by strong emission of radiation into the UV and IR spectral regions. The experimental results are confirmed by numerical simulation.

  20. Polarization squeezing with photonic crystal fibers

    DEFF Research Database (Denmark)

    Milanovic, J.; Huck, Alexander; Heersink, J.

    2007-01-01

    We report on the generation of polarization squeezing by employing intense, ultrashort light pulses in a single pass method in photonic crystal fibers. We investigated the squeezing behavior near the zero-dispersion wavelength and in the anomalous dispersion regime by using two distinct fibers. We...... observed a maximal squeezing at 810 nm of -3.3 +/- 0.3 dB with an excess noise of +16.8 +/- 0.3 dB in the anomalous regime. Correcting for linear and interference losses between the polarization modes, this corresponds to -6 +/- 1 dB. The ratio of squeezing to excess noise indicates the creation of a much...

  1. Electrically tunable Yb-doped fiber laser based on a liquid crystal photonic bandgap fiber device

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin; Scolari, Lara; Wei, Lei

    2010-01-01

    We demonstrate electrical tunability of a fiber laser using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a tunable liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate...... an all-spliced laser cavity based on the liquid crystal photonic bandgap fiber mounted on a silicon assembly, a pump/signal combiner with single-mode signal feed-through and an ytterbium-doped photonic crystal fiber. The laser cavity produces a single-mode output and is tuned in the range 1040-1065 nm...

  2. Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors

    Directory of Open Access Journals (Sweden)

    Keisuke Iwano

    2016-10-01

    Full Text Available We investigate the optical transmittances of ion-irradiated sapphire crystals as potential vacuum ultraviolet (VUV to near-infrared (NIR window materials of fusion reactors. Under potential conditions in fusion reactors, sapphire crystals are irradiated with hydrogen (H, deuterium (D, and helium (He ions with 1-keV energy and ∼ 1020-m-2 s-1 flux. Ion irradiation decreases the transmittances from 140 to 260 nm but hardly affects the transmittances from 300 to 1500 nm. H-ion and D-ion irradiation causes optical absorptions near 210 and 260 nm associated with an F-center and an F+-center, respectively. These F-type centers are classified as Schottky defects that can be removed through annealing above 1000 K. In contrast, He-ion irradiation does not cause optical absorptions above 200 nm because He-ions cannot be incorporated in the crystal lattice due to the large ionic radius of He-ions. Moreover, the significant decrease in transmittance of the ion-irradiated sapphire crystals from 140 to 180 nm is related to the light scattering on the crystal surface. Similar to diamond polishing, ion irradiation modifies the crystal surface thereby affecting the optical properties especially at shorter wavelengths. Although the transmittances in the VUV wavelengths decrease after ion irradiation, the transmittances can be improved through annealing above 1000 K. With an optical transmittance in the VUV region that can recover through simple annealing and with a high transparency from the ultraviolet (UV to the NIR region, sapphire crystals can therefore be used as good optical windows inside modern fusion power reactors in terms of light particle loadings of hydrogen isotopes and helium.

  3. Photonic Crystal Fiber Interferometer for Dew Detection

    OpenAIRE

    Mathew, Jinesh; Semenova, Yuliya; Farrell, Gerald

    2012-01-01

    A novel method for dew detection based on photonic crystal fiber (PCF) interferometer that operates in reflection mode is presented in this paper. The fabrication of the sensor head is simple since it only involves cleaving and fusion splicing. The sensor shows good sensitivity to dew formation with a large wavelength peak shift of the interference pattern at the onset of dew formation. The device’s response to ambient humidity and temperature are also studied and reported in this paper. From...

  4. Influence of the crucible geometry on the shape of the melt crystal interface during growth of sapphire crystal using a heat exchanger method

    Science.gov (United States)

    Chen, Jyh-Chen; Lu, Chung-Wei

    2004-05-01

    Computer simulations using the commercial code FIDAP, which is based on finite element techniques, were performed to investigate the effect of the shape of the crucible on the temperature distribution, velocity distribution and shape of the melt-crystal interface, during the application of the heat exchanger method (HEM) of growing sapphire crystals. Heat transfer from the furnace to the crucible and heat extraction from the heat exchanger can be modeled by the convection boundary conditions. Cylindrical crucibles with differently curved corners at their base are considered. The curved base of the crucible decreases the convexity of the melt-crystal interface and suppresses the appearance of "hot spots". A hemispherically shaped crucible base yields the lowest maximum convexity. The variation in convexity of the melt-crystal interface is less abrupt for a cylindrical crucible with curved corners at the base than one without curved corners. The effects of the thickness and the conductivity of the crucible are also addressed. The convexity of the melt-crystal interface decreases as the thickness of the crucible wall increases. The convexity also declines as the conductivity of the crucible increases.

  5. Titanium distribution in Ti-sapphire single crystals grown by Czochralski and Verneuil technique

    Science.gov (United States)

    Alombert-Goget, G.; Li, H.; Faria, J.; Labor, S.; Guignier, D.; Lebbou, K.

    2016-01-01

    The distributions of Ti3+ and Ti4+ ions were evaluated by photoluminescence measurement in the wafers cut from different positions of the ingots grown by Czochralski and Verneuil techniques. Particular radial distributions of Ti4+ as function of the position in the ingot were observed in the crystals grown by Verneuil technique different than the crystals grown by Czochralski method.

  6. Modeling of dopant segregation in sapphire single crystal fibre growth by Micro-Pulling-Down method

    Science.gov (United States)

    Wenjia, Su; Duffar, Thierry; Nehari, Abdeljelil; Kononets, Valerii; Lebbou, Kheirreddine

    2017-09-01

    Experiments and numerical simulations are conducted in order to study the causes and solutions for the Ti inhomogeneity problem in Ti doped sapphire Micro-Pulling-Down (μ-PD) growth. The measurement and modeling of the thermal and flow fields, electromagnetic field, Ti concentration in the molten zone and along the fibre axis are compared. For the mean Ti concentration along the fibre and temperature along the iridium crucible, the modeling results are consistent with experiments. Results showed that for high pulling rate, the mass transfer in the capillary is dominated by convection. Marangoni convection is strong in the meniscus due to the large temperature gradient, which has great impact on the Ti distribution for different fibre radii. For high pulling rate, Ti concentration increases quickly from the seed along the fibre axis, and reaches a constant value after about 0.5-2 mm. Radial segregation is high for large diameter fibres. The constant Ti concentration along the fibre axis is increasing when increasing the fibre radius from 0.2 to 0.6 mm. For 0.8 mm, it decreases due to the change of the vortex. At low growth rate, the transport in the capillary is diffusive, back to the crucible, which leads to a Scheil-like Ti distribution, in full agreement with the experimental results.

  7. Hydrogen effect on the properties of sapphire

    Science.gov (United States)

    Mogilevsky, Radion N.; Sharafutdinova, Liudmila G.; Nedilko, Sergiy; Gavrilov, Valeriy; Verbilo, Dmitriy; Mittl, Scott D.

    2009-05-01

    Sapphire is a widely used material for optical, electronic and semiconductor applications due to its excellent optical properties and very high durability. Optical and mechanical properties of sapphire depend on many factors such as the starting materials that are used to grow crystals, methods to grow sapphire crystals, etc. Demand for highest purity and quality of sapphire crystals increased ten fold for the last several years due to new applications for this material. In this work we studied the effect of starting materials and crystal growth methods on the optical and mechanical properties of sapphire, especially concentrating on the effect of hydrogen on the properties of sapphire. It was found that the infrared (IR) absorption which is traditionally used to measure the hydrogen content in sapphire crystals cannot be reliably used and the data obtained by this method provides a much lower hydrogen concentration than actual. We have shown for the first time that Nuclear Magnetic Resonance techniques can be successfully used to determine hydrogen concentration in sapphire crystals. We have shown that hydrogen concentration in sapphire can reach thousands of ppm if these crystals are grown from Verneuil starting material or aluminum oxide powder. Alternatively, the hydrogen concentration is very low if sapphire crystals are grown from High Purity Densified Alumina (HPDA®) as a starting material. HPDA® is produced by EMT, Inc through their proprietary patented technology. It was found that optical and mechanical properties of sapphire crystals grown using EMT HPDA® starting material are much better than those sapphire crystals grown using a starting material of Verneuil crystals or aluminum oxide powder.

  8. Photonic crystal fiber with novel dispersion properties

    Institute of Scientific and Technical Information of China (English)

    Shuqin LOU; Shujie LOU; Tieying GUO; Liwen WANG; Weiguo CHEN; Honglei LI; Shuisheng JIAN

    2009-01-01

    Our recent research on designing microstruc-tured fiber with novel dispersion properties is reported in this paper. Two kinds ofphotonic crystal fibers (PCFs) are introduced first. One is the highly nonlinear PCF with broadband nearly zero flatten dispersion. With introducing the germanium-doped (Ge-doped) core into highly non-linear PCF and optimizing the diameters of the first two inner rings of air holes, a new structure of highly non-linear PCF was designed with the nonlinear coefficient up to 47 W-1·km-1 at the wavelength 1.55 μm and nearly zero flattened dispersion of ±0.5 ps/(km·nm) in telecom-munication window (1460-1625nm). Another is the highly negative PCF with a ring of fluorin-doped (F-doped) rods to form its outer ring core while pure silica rods to form its inner core. The peak dispersion - 1064 ps/(km·nm) in 8 nm full width at half maximum (FWHM) wavelength range and -365ps/(km·nm) in 20nm (FWHM) wavelength range can be reached by adjusting the structure parameters. Then, our recent research on the fabrication of PCFs is reported. Effects of draw parameters such as drawing temperature, feed speed, and furnace temperature on the geometry of the final photonic crystal fiber are investigated.

  9. Tunable Photonic Band Gaps In Photonic Crystal Fibers Filled With a Cholesteric Liquid Crystal

    Institute of Scientific and Technical Information of China (English)

    Thomas; Tanggaard; Larsen; David; Sparre; Hermann; Anders; Bjarklev

    2003-01-01

    A photonic crystal fiber has been filled with a cholesteric liquid crystal. A temperature sensitive photonic band gap effect was observed, which was especially pronounced around the liquid crystal phase transition temperature.

  10. Fiber and Crystals Dual Readout calorimeters

    CERN Document Server

    Cascella, Michele; Lee, Sehwook

    2016-01-01

    The RD52 (DREAM) collaboration is performing R\\&D on dual readout calorimetry techniques with the aim of improving hadronic energy resolution for future high energy physics experiments. The simultaneous detection of Cherenkov and scintillation light enables us to measure the electromagnetic fraction of hadron shower event-by-event. As a result, we could eliminate the main fluctuation which prevented from achieving precision energy measurement for hadrons. We have tested the performance of the lead and copper fiber prototypes calorimeters with various energies of electromagnetic particles and hadrons. During the beam test, we investigated the energy resolutions for electrons and pions as well as the identification of those particles in a longitudinally unsegmented calorimeter. Measurements were also performed on pure and doped PbWO$_{4}$ crystals, as well as BGO and BSO, with the aim of realising a crystal based dual readout detector. We will describe our results, focusing on the more promising properties ...

  11. Crystal-free Formation of Non-Oxide Optical Fiber

    Science.gov (United States)

    Nabors, Sammy A.

    2015-01-01

    Researchers at NASA Marshall Space Flight Center have devised a method for the creation of crystal-free nonoxide optical fiber preforms. Non-oxide fiber optics are extensively used in infrared transmitting applications such as communication systems, chemical sensors, and laser fiber guides for cutting, welding and medical surgery. However, some of these glasses are very susceptible to crystallization. Even small crystals can lead to light scatter and a high attenuation coefficient, limiting their usefulness. NASA has developed a new method of non-oxide fiber formation that uses axial magnetic fields to suppress crystallization. The resulting non-oxide fibers are crystal free and have lower signal attenuation rates than silica based optical fibers.

  12. Liquid crystal parameter analysis for tunable photonic bandgap fiber devices

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Wei, Lei;

    2010-01-01

    We investigate the tunability of splay-aligned liquid crystals for the use in solid core photonic crystal fibers. Finite element simulations are used to obtain the alignment of the liquid crystals subject to an external electric field. By means of the liquid crystal director field the optical per...

  13. Photonic crystal fiber design for broadband directional coupling

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Bang, Ole; Bjarklev, Anders Overgaard

    2004-01-01

    A novel design for a broadband directional coupler based on a photonic crystal fiber is investigated numerically. It is shown that suitable index-depressing doping of the core regions in an index-guiding twin-core photonic crystal fiber can stabilize the coupling coefficient between the cores over...

  14. Photonic crystal fiber design for broadband directional coupling

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Bang, Ole; Bjarklev, Anders Overgaard

    2004-01-01

    A novel design for a broadband directional coupler based on a photonic crystal fiber is investigated numerically. It is shown that suitable index-depressing doping of the core regions in an index-guiding twin-core photonic crystal fiber can stabilize the coupling coefficient between the cores over...

  15. Research on interferometric photonic crystal fiber hydrophone

    Science.gov (United States)

    Luo, Hong; Zhang, Zhen-hui; Wang, Fu-yin; Xiong, Shui-dong

    2013-08-01

    Current research on photonic crystal fiber (PCF) for acoustic sensing was focused on the PCF's pressure sensitivity enhancement. However, whether the enhancement of the PCF's pressure sensitivity can be actually realized is still controversial. Practical hydrophone, utilizing PCFs, to manifest its superior sensitivity to normal single mode fibers (SMFs) for acoustic sensing, should be made. Account to this point of view, actual hydrophone was fabricated. Index guiding PCF was used, the fiber core is solid silicon dioxide (SiO2), and the cladding is SiO2 filled with lots of periodical transverse circular air hollows. The PCF, mounted on an air-backed mandrel for structural sensitivity enhancement, was used as a sensing arm of the fiber Michelson interferometer. The other arm, so called reference arm, was made of SMF. Faraday rotator mirrors (FRM) were spliced in the end of each interferometric arm account for polarization induced phase fading, which is a common scheme in fiber interferometric sensing systems. A similar hydrophone, with all the same structure except that the PCF was exchanged into SMF, was also fabrication to make the contrast. The narrowlinewidth and frequency-tunable optical fiber laser was used to achieve high accuracy optical interferometric measurement. Meanwhile, the phase generated carrier (PGC) modulation-demodulation scheme was adopted to interrogate the measurand signal. Experiment was done by using acoustic standing-wave test apparatus. Linearity characteristics of the two hydrophones were measured at frequency 100Hz, 500Hz, and 1000Hz, experimental results showed that the maximum error of the linearity was 10%, a little larger than the theoretical results. Pressure sensitivities of the PCF hydrophone and the SMF hydrophone were measured using a reference standard PZT hydrophone in the frequency range from 20 Hz to 1600 Hz, the measurement data showed that the sensitivity of the PCF hydrophone was about -162.8 dB re. rad/μPa, with a

  16. Fiber and crystals dual readout calorimeters

    Science.gov (United States)

    Cascella, Michele; Franchino, Silvia; Lee, Sehwook

    2016-11-01

    The RD52 (DREAM) collaboration is performing R&D on dual readout calorimetry techniques with the aim of improving hadronic energy resolution for future high energy physics experiments. The simultaneous detection of Cherenkov and scintillation light enables us to measure the electromagnetic fraction of hadron shower event-by-event. As a result, we could eliminate the main fluctuation which prevented from achieving precision energy measurement for hadrons. We have tested the performance of the lead and copper fiber prototypes calorimeters with various energies of electromagnetic particles and hadrons. During the beam test, we investigated the energy resolutions for electrons and pions as well as the identification of those particles in a longitudinally unsegmented calorimeter. Measurements were also performed on pure and doped PbWO4 crystals, as well as BGO and BSO, with the aim of realizing a crystal based dual readout detector. We will describe our results, focusing on the more promising properties of homogeneous media for the technique. Guidelines for additional developments on crystals will be also given. Finally we discuss the construction techniques that we have used to assemble our prototypes and give an overview of the ones that could be industrialized for the construction of a full hermetic calorimeter.

  17. Optical fiber tips functionalized with semiconductor photonic crystal cavities

    CERN Document Server

    Shambat, Gary; Rivoire, Kelley; Sarmiento, Tomas; Harris, James; Vuckovic, Jelena

    2011-01-01

    We demonstrate a simple and rapid epoxy-based method for transferring photonic crystal cavities to the facets of optical fibers. Passive Si cavities were measured via fiber taper coupling as well as direct transmission from the fiber facet. Active quantum dot containing GaAs cavities showed photoluminescence that was collected both in free space and back through the original fiber. Cavities maintain a high quality factor (2000-4000) in both material systems. This new design architecture provides a practical mechanically stable platform for the integration of photonic crystal cavities with macroscale optics and opens the door for novel research on fiber-coupled cavity devices.

  18. Frequency-doubled diode laser for direct pumping of Ti:sapphire lasers

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2012-01-01

    A single-pass frequency doubled high-power tapered diode laser emitting nearly 1.3 W of green light suitable for direct pumping of Ti:sapphire lasers generating ultrashort pulses is demonstrated. The pump efficiencies reached 75 % of the values achieved with a commercial solid-state pump laser....... However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20...... fs are measured. These results open the opportunity of establishing diode laser pumped Ti:sapphire lasers for e.g. biophotonic applications like retinal optical coherence tomography or pumping of photonic crystal fibers for CARS microscopy....

  19. Fiber field-effect device via in situ channel crystallization.

    Science.gov (United States)

    Danto, Sylvain; Sorin, Fabien; Orf, Nicholas D; Wang, Zheng; Speakman, Scott A; Joannopoulos, John D; Fink, Yoel

    2010-10-01

    The in situ crystallization of the incorporated amorphous semiconductor within the multimaterial fiber device yields a large decrease in defect density and a concomitant five-order-of-magnitude decrease in resistivity of the novel metal-insulator-crystalline semiconductor structure. Using a post-drawing crystallization process, the first tens-of-meters-long single-fiber field-effect device is demonstrated. This work opens significant opportunities for incorporating higher functionality in functional fibers and fabrics.

  20. Polarization modulation instability in photonic crystal fibers.

    Science.gov (United States)

    Kruhlak, R J; Wong, G K; Chen, J S; Murdoch, S G; Leonhardt, R; Harvey, J D; Joly, N Y; Knight, J C

    2006-05-15

    Polarization modulation instability (PMI) in birefringent photonic crystal fibers has been observed in the normal dispersion regime with a frequency shift of 64 THz between the generated frequencies and the pump frequency. The generated sidebands are orthogonally polarized to the pump. From the observed PMI frequency shift and the measured dispersion, we determined the phase birefringence to be 5.3 x 10(-5) at a pump wavelength of 647.1 nm. This birefringence was used to estimate the PMI gain as a function of pump wavelength. Four-wave mixing experiments in both the normal and the anomalous dispersion regimes generated PMI frequency shifts that show good agreement with the predicted values over a 70 THz range. These results could lead to amplifiers and oscillators based on PMI.

  1. Electrially tunable photonic bandgap guidance in a liquid crystal filled photonic crystal fiber

    DEFF Research Database (Denmark)

    Haakestad, Magnus W.; Alkeskjold, Thomas Tanggaard; Nielsen, Martin Dybendal;

    2005-01-01

    Tunable bandgap guidance is obtained by filling the holes of a solid core photonic crystal fiber with a nematic liquid crystal and applying an electric field. The response times are measured and found to be in the millisecond range.......Tunable bandgap guidance is obtained by filling the holes of a solid core photonic crystal fiber with a nematic liquid crystal and applying an electric field. The response times are measured and found to be in the millisecond range....

  2. Growth of single-crystal YAG fiber optics.

    Science.gov (United States)

    Nie, Craig D; Bera, Subhabrata; Harrington, James A

    2016-07-11

    Single-crystal YAG (Y3Al5O12) fibers have been grown by the laser heated pedestal growth technique with losses as low as 0.3 dB/m at 1.06 μm. These YAG fibers are as long as about 60 cm with diameters around 330 μm. The early fibers were grown from unoriented YAG seed fibers and these fibers exhibited facet steps or ridges on the surface of the fiber. However, recently we have grown fibers using an oriented seed to grow step-free fibers. Scattering losses made on the fibers indicate that the scattering losses are equal to about 30% of the total loss.

  3. Photonic crystal fibers for supercontinuum generation pumped by a gain-switched CW fiber laser

    DEFF Research Database (Denmark)

    Larsen, Casper; Noordegraaf, Danny; Hansen, Kim P.

    2012-01-01

    Supercontinuum generation in photonics crystal fibers (PCFs) pumped by CW lasers yields high spectral power density and average power. However, such systems require very high pump power and long nonlinear fibers. By on/off modulating the pump diodes of the fiber laser, the relaxation oscillations...

  4. Fabrication of fiber-embedded multi-core photonic crystal fibers

    Institute of Scientific and Technical Information of China (English)

    Weimin Sun; Xiaoqi Liu; Fenghua Fu; Jianzhong Zhang

    2008-01-01

    @@ A novel fabrication method of multi-core photonic crystal fibers is proposed on the basis of a fiberembedded technique. A taper tower is used to modify the structures of the fiber preform, and four steps of fiber fabrication and different structures of fiber samples are given. The mode structures and beating characteristics of a photonic crystal fiber sample with two successive cores are investigated in detail with the help of a supercontinuum light source, a charge-coupled device (CCD) camera, and an optical spectrum analyzer. The test results show a clear beating phenomenon between two orthotropic polarization modes with a 2.8-nm peak interval in wavelength.

  5. Crystal structure of fiber structured pentacene thin films

    OpenAIRE

    2007-01-01

    This PhD thesis presents a technique based on the grazing incidence crystal truncation rod (GI-CTR) X-ray diffraction method used to solve the crystal structure of substrate induced fiber structured organic thin films. The crystal structures of pentacene thin films grown on technologically relevant gate dielectric substrates are reported. It is widely recognized, that the intrinsic charge transport properties in organic thin film transistors (OTFTs) depend strongly on the crystal structur...

  6. Optical tuning of photonic bandgaps in dye-doped nematic liquid crystal photonic crystal fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard; Hermann, David Sparre;

    2005-01-01

    An all-optical modulator is demonstrated, which utilizes a pulsed 532 nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal. In order to investigate the time response of the LCPBG fiber device, a low-power CW probe...

  7. Tunable nonlinear beam defocusing in infiltrated photonic crystal fibers

    DEFF Research Database (Denmark)

    Rosberg, Christian Romer; Bennet, Francis H; Neshev, Dragomir N.;

    2007-01-01

    We demonstrate a novel experimental platform for discrete nonlinear optics based on infiltrated photonic crystal fibers. We observe tunable discrete diffraction and nonlinear self-defocusing, and apply the effects to realize a compact all-optical power limiter....

  8. Highly efficient fluorescence sensing with hollow core photonic crystal fibers

    OpenAIRE

    Smolka, Stephan; Barth, Michael; Benson, Oliver

    2008-01-01

    We investigate hollow core photonic crystal fibers for ultra-sensitive fluorescence detection by selectively infiltrating the central hole with fluorophores. Dye concentrations down to 10(-9) M can be detected using only nanoliter sample volumes.

  9. Highly efficient fluorescence sensing with hollow core photonic crystal fibers

    DEFF Research Database (Denmark)

    Smolka, Stephan; Barth, Michael; Benson, Oliver

    2008-01-01

    We investigate hollow core photonic crystal fibers for ultra-sensitive fluorescence detection by selectively infiltrating the central hole with fluorophores. Dye concentrations down to 10(-9) M can be detected using only nanoliter sample volumes.......We investigate hollow core photonic crystal fibers for ultra-sensitive fluorescence detection by selectively infiltrating the central hole with fluorophores. Dye concentrations down to 10(-9) M can be detected using only nanoliter sample volumes....

  10. Rigorous modeling of cladding modes in photonic crystal fibers

    DEFF Research Database (Denmark)

    Rindorf, Lars Henning; Bang, Ole

    We study the cladding modes of a photonic crystal fiber (PCF) with a finite size cladding using a finite element method. The cladding consists of seven rings of air holes with bulk silica outside.......We study the cladding modes of a photonic crystal fiber (PCF) with a finite size cladding using a finite element method. The cladding consists of seven rings of air holes with bulk silica outside....

  11. Narrow-linewidth chirped frequency comb from a frequency-shifted feedback Ti:sapphire laser seeded by a phase-modulated single-frequency fiber laser.

    Science.gov (United States)

    Brandl, Matthias F; Mücke, Oliver D

    2010-12-15

    Frequency-shifted feedback (FSF) lasers have emerged as powerful tools for precision distance metrology. At the output of a Michelson interferometer, the detected rf spectra of the FSF laser light contain a length-dependent heterodyne beat signal whose linewidth ultimately limits the achievable accuracy of length measurements. Here, we demonstrate a narrow-linewidth chirped frequency comb from an FSF Ti:sapphire ring laser seeded by a phase-modulated, ultra-low-phase-noise, single-frequency fiber laser. We experimentally investigate the influence of the seed laser linewidth on the resulting width and shape of the length-dependent rf beat signal. An ultranarrow heterodyne beat linewidth of <20 Hz is observed.

  12. Spatial and spectral imaging of LMA photonic crystal fiber amplifiers

    DEFF Research Database (Denmark)

    Laurila, Marko; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2011-01-01

    We demonstrate modal characterization using spatial and spectral resolved (S2) imaging, on an Ytterbium-doped large-mode-area photonic crystal fiber (PCF) amplifier and compare results with conventional cut-off methods. We apply numerical simulations and step-index fiber experiments to calibrate...

  13. Mode-coupling in photonic crystal fibers with multiple cores

    DEFF Research Database (Denmark)

    Kristensen, Martin

    2000-01-01

    Summary form only given. We have fabricated a photonic crystal fiber (PCF) with multiple cores by drawing a fiber preform from stacked glass tubes. Transmission is high through each core despite many unintentional defects in the cladding indicating that the guidance is determined by the holes near...

  14. Highly Birefringent Photonic Crystal Fibers BUsing Asymmetric Core Design

    Institute of Scientific and Technical Information of China (English)

    Zhao Chun-Liu; Lu Chao; Yan Min; Wang Xiaoyan; Lou Junjun; Li Qin; Zhou Xiaoqun; Cai Qing; P.R.Chaudhuri

    2003-01-01

    We demonstrate a highly birefringent photonic crystal fiber by utilizing the asymmetric core design. Based on spectral measurements of the polarization mode interfering, we estimate that the fiber has a beat length of about 0.33 mm at 1545 nm.

  15. Soft-glass hollow-core photonic crystal fibers

    Science.gov (United States)

    Melnikov, Leonid; Khromova, Irina; Scherbakov, Andrey; Nikishin, Nikolay

    2005-09-01

    The results of numerical modeling and experimental investigations of manufactured diamond-shaped and large area hollow core photonic crystal fibers with periodical cladding (kagome-lattice and closely packed tubes) are presented. The use of soft glasses allows to fabricate high-quality structures with moderate losses. Numerical methods, designing strategies and fabrication issues of these promising fiber structures are discussed.

  16. High dno/dT liquid crystals and their applications in a thermally tunable liquid crystal photonic crystal fiber

    DEFF Research Database (Denmark)

    Li, J.; Gauza, S.; Wu, S.-T.

    2006-01-01

    crystal mixtures, designated as UCF-1 and UCF-2. The dn(o)/dT of UCF-1 is similar to 4x higher than that of 5CB at room temperature. By infiltrating UCF-1 into the air holes of a three-rod core photonic crystal fiber, we demonstrate a thermally tunable photonic bandgap fiber with tuning sensitivity of 27...

  17. Inhibited coupling hollow-core photonic crystal fiber

    Science.gov (United States)

    Benabid, F.; Gérôme, F.; Vincetti, L.; Debord, B.; Alharbi, M.; Bradley, T.

    2014-02-01

    We review the recent progress on the enhanced inhibited coupling in kagome hollow-core photonic crystal fiber by introducing negative curvature in the fiber-core shape. We show that increasing the hypocycloid contour curvature leads to a dramatic decrease in transmission loss and optical overlap with the silica surround and to a single modedness. Fabricated hypocycloid-core hollow-core photonic crystal fibers with a transmission loss in the range of 20-40 dB/km and for a spectral range of 700 nm-2000 nm have now become typical.

  18. Chromatic dispersion of liquid crystal infiltrated capillary tubes and photonic crystal fibers

    DEFF Research Database (Denmark)

    Rasmussen, Per Dalgaard; Lægsgaard, Jesper; Bang, Ole

    2006-01-01

    We consider chromatic dispersion of capillary tubes and photonic crystal fibers infiltrated with liquid crystals. A perturbative scheme for inclusion of material dispersion of both liquid crystal and the surrounding waveguide material is derived. The method is used to calculate the chromatic disp...

  19. Mg-ion indiffusion of lithium niobate single crystal fiber

    Institute of Scientific and Technical Information of China (English)

    阙文修; 姚熹; 霍玉晶

    1995-01-01

    A core-cladding waveguide structure of lithium niobate single crystal fiber with different refractive index profiles has been obtained by using an Mg-ion indiffusion process. The propagation loss of the dadded crystal fiber is measured to be 14 times as low as that of the undadded crystal fibers. Mechanisms of Mg-ion indiffusion and reasons of lattice distortion are analyzed and discussed. It is found by X-ray diffraction analysis as well as scanning electron microscopy that MgO-rich layer in the magnesium diffused surface exhibits the crystal structure of a new compound from the Li-Mg-Nb-O ternary system. It is proposed, for the first time, that this new compound in MgO-rich layer is the real source of Mg-ion indiffusion lithium niobate.

  20. High-resolution wavefront shaping with a photonic crystal fiber for multimode fiber imaging

    NARCIS (Netherlands)

    Amitonova, L. V.; Descloux, A.; Petschulat, J.; Frosz, M. H.; Ahmed, G.; Babic, F.; Jiang, X.; Mosk, A. P.; Russell, P. S. J.; Pinkse, P.W.H.

    2016-01-01

    We demonstrate that a high-numerical-aperture photonic crystal fiber allows lensless focusing at an unparalleled res- olution by complex wavefront shaping. This paves the way toward high-resolution imaging exceeding the capabilities of imaging with multi-core single-mode optical fibers. We analyze t

  1. Tunable All-in-Fiber Waveplates Based on Negative Dielectric Liquid Crystal Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Eskildsen, Lars; Weirich, Johannes;

    2008-01-01

    Tunable all-in-fiber waveplates based on negative dielectric liquid crystal photonic bandgap fibers are presented. The birefringence can be tuned electrically and thermally to work as a quarter-wave or a half-wave plate in the range 1520 nm-1580 nm....

  2. High-resolution wavefront shaping with a photonic crystal fiber for multimode fiber imaging

    NARCIS (Netherlands)

    Amitonova, L. V.; Descloux, A.; Petschulat, J.; Frosz, M. H.; Ahmed, G.; Babic, F.; Jiang, X.; Mosk, A. P.; Russell, P. S. J.; Pinkse, P.W.H.

    2016-01-01

    We demonstrate that a high-numerical-aperture photonic crystal fiber allows lensless focusing at an unparalleled res- olution by complex wavefront shaping. This paves the way toward high-resolution imaging exceeding the capabilities of imaging with multi-core single-mode optical fibers. We analyze t

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

  4. Fiber Bragg Gratings in Small-Core Ge-Doped Photonic Crystal Fibers

    Institute of Scientific and Technical Information of China (English)

    Yiping Wang; Hartmut Bartelt; Wolfgang Ecke; Reinhardt Willsch; Jens Kobelke; Michael Kautz; Sven Brueckner; Manfred Rothhardt

    2008-01-01

    This paper reports fiber Bragg gratings (FBGs) inscribed in a small-core Ge-doped photonic crystal fibers with a UV laser and a Talbot inter-ferometer. The responses of such FBGs to temper-ature, strain, bending, and transverse-loading were systematically investigated. The Bragg wavelength of the FBGs shifts toward longer wavelengths with increasing temperature, tensile strain, and trans-verse-loading. The bending and transverse- loading properties of the FBGs are sensitive to the fiber orientations.

  5. FIBER LASER CONSTRUCTION AND THEORY INCLUDING FIBER BRAGG GRATINGS Photonic Crystal Fibers (PCFs) and applications of gas filled PCFs

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Jacob O. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-08

    The principles used in fiber lasers have been around for a while but it is only within the past few years that fiber lasers have become commercially available and used in high power laser applications. This paper will focus on the basic design principles of fiber lasers, including fiber Bragg gratings, principles of operation, and forms of non-linear effects. It will describe the type and associated doping of the fiber used and difficult designs used to guide energy from the pump to the active medium. Topics covered include fiber laser design, fiber Bragg gratings, materials used, differences in quantum energy loss, thermo-optical effects, stimulated Raman scattering, Brillouin scattering, photonic crystal fibers and applications of gas filled Photonic Crystal Fibers (PCFs). Thanks to fiber lasers, the energy required to produce high power lasers has greatly dropped and as such we can now produce kW power using a standard 120V 15A circuit. High power laser applications are always requiring more power. The fiber laser can now deliver the greater power that these applications demand. Future applications requiring more power than can be combined using standard materials or configurations will need to be developed to overcome the high energy density and high non-linear optical scattering effects present during high power operations.

  6. Dispersion Properties in Total Internal Reflective Photonic Crystal Fiber

    Institute of Scientific and Technical Information of China (English)

    WEN Hua; HAO Dong-shan

    2004-01-01

    The dispersion properties in the short wavelength region of total internal reflective photonic crystal fiber have been studied by using the models of the equivalent twin waveguide soliton coupling,effective refractive index, effective normalized frequency and dispersion management solitons. It is shown that the dispersion in the cladding waveguide of the total internal reflective photonic crystal fiber is a positive dispersion,and the dispersion of its core waveguide is a negative dispersion. The method of the compensated probing laser diffraction by the phase hole induced by the stationary pumping laser in the cladding waveguide enables the average dispersion value of the total internal reflective photonic crystal fiber to be close to zero and the zero dispersion point to shift to the short wavelength region.

  7. Photonic crystal fiber long-period gratings for biochemical sensing.

    Science.gov (United States)

    Rindorf, Lars; Jensen, Jesper B; Dufva, Martin; Pedersen, Lars Hagsholm; Høiby, Poul Erik; Bang, Ole

    2006-09-04

    We present experimental results showing that long-period gratings in photonic crystal fibers can be used as sensitive biochemical sensors. A layer of biomolecules was immobilized on the sides of the holes of the photonic crystal fiber and by observing the shift in the resonant wavelength of a long-period grating it was possible to measure the thickness of the layer. The long-period gratings were inscribed in a large-mode area silica photonic crystal fiber with a CO2 laser. The thicknesses of a monolayer of poly-L-lysine and double-stranded DNA was measured using the device. We find that the grating has a sensitivity of approximately 1.4nm/1nm in terms of the shift in resonance wavelength in nm per nm thickness of biomolecule layer.

  8. Optical devices based on liquid crystal photonic bandgap fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard

    2005-01-01

    In this ph.d. work, an experimental and theoretical study on Liquid Crystal (LC) infiltrated Photonic Crystal Fibers (PCFs) has been carried out. PCFs usually, consists of an air/silica microstructure of air holes arranged in a triangular lattice surrounding a core defect defined by a missing air...... hole. The presence of a LC in the holes of the PCF transforms the fiber from a Total Internal Reflection (TIR) guiding type into a Photonic BandGap (PBG) guiding type, where light is confined to the silica core by coherent scattering from the LC-billed holes. The high dielectric and optical anisotropy...... of LCs combined with the unique waveguiding features of PBG fibers gives the LC filled PCFs unique tunable properties. PBG guidance has been demonstrated for different mesophases of LCs and various functional compact fibers has been demonstrated, which utilitzes the high thermo-optical and electro...

  9. Radiation trapping inside a hollow-core photonic crystal fiber

    CERN Document Server

    Jen, H H; Lee, Kevin C J; Chen, Yi-Hsin; Yu, Ite A

    2014-01-01

    We report the radiation trapping effect inside a hollow-core photonic crystal fiber (PCF). An optical dipole trap was used to load and confine the atoms in the PCF without contacting the wall of the fiber. The transmission of a probe light propagating through the PCF was studied experimentally and theoretically. With the experimental results and theoretical predictions, we conclude that the radiation trapping can play a significant role and should be taken into account in the spectroscopic measurements inside the PCF.

  10. Eliminating Crystals in Non-Oxide Optical Fiber Preforms and Optical Fibers

    Science.gov (United States)

    Tucker, Dennis S.; LaPointe, Michael R.

    2012-01-01

    Non ]oxide fiber optics such as heavy metal fluoride and chalcogenide glasses are extensively used in infrared transmitting applications such as communication systems, chemical sensors, and laser fiber guides for cutting, welding and medical surgery. The addition of rare earths such as erbium, enable these materials to be used as fiber laser and amplifiers. Some of these glasses however are very susceptible to crystallization. Even small crystals can lead to light scatter and a high attenuation coefficient, limiting their usefulness. Previously two research teams found that microgravity suppressed crystallization in heavy metal fluoride glasses. Looking for a less expensive method to suppress crystallization, ground based research was performed utilizing an axial magnetic field. The experiments revealed identical results to those obtained via microgravity processing. This research then led to a patented process for eliminating crystals in optical fiber preforms and the resulting optical fibers. In this paper, the microgravity results will be reviewed as well as patents and papers relating to the use of magnetic fields in various material and glass processing applications. Finally our patent to eliminate crystals in non ]oxide glasses utilizing a magnetic field will be detailed.

  11. Compact electrically controlled broadband liquid crystal photonic bandgap fiber polarizer

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2009-01-01

    An electrically controlled liquid crystal photonic-bandgap fiber polarizer is experimentally demonstrated. A maximum 21.3dB electrically tunable polarization extinction ratio is achieved with 45° rotatable transmission axis as well as switched on and off in 1300nm–1600nm.......An electrically controlled liquid crystal photonic-bandgap fiber polarizer is experimentally demonstrated. A maximum 21.3dB electrically tunable polarization extinction ratio is achieved with 45° rotatable transmission axis as well as switched on and off in 1300nm–1600nm....

  12. Fiber-to-fiber nonlinear coupling via a nematic liquid crystal

    Science.gov (United States)

    Nyushkov, B. N.; Trashkeev, S. I.; Ivanenko, A. V.; Kolker, D. B.; Purtov, P. A.

    2017-01-01

    Nonlinear optical coupling between two single-mode fibers terminated coaxially in a nematic liquid crystal (NLC) was explored for the first time. Light-induced reorientation of nematic molecules can result in the stable self-collimation of light transmitted through the gap between fibers. Thus, high coupling efficiency can be achieved despite large fiber spacing. We demonstrated a coupling efficiency of up to ∼0.7, achieved with spacing equal to four diffraction lengths. This feature opens up possibilities for the development of novel in-line fiber-optic elements based on NLCs. For instance, a polarization controller was proposed and considered.

  13. Design of photonic crystal fibers with anomalous dispersion

    Institute of Scientific and Technical Information of China (English)

    CHI Hao; ZHANG Xian-min; SHEN Lin-fang

    2006-01-01

    Photonic crystal fibers (PCFs) with anomalous dispersion in short wavelength region are significant for some applications, such as short wavelength soliton propagation, super continuum generation and short pulse fiber lasing.In this paper,a systematic method for designing PCFs with required anomalous dispersion region is proposed by using a finite difference solver and the scaling transformation of the waveguide dispersion of PCFs.Designed PCF can be anomalously dispersive in the region less than 1.3 μm,which is very difficult to realize in the traditional standard single-mode fibers.The effectiveness of the proposed method is approved by numerical results.

  14. Direct pumping of ultrashort Ti:sapphire lasers by a frequency doubled diode laser

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2011-01-01

    electro-optical efficiency of the diode laser. Autocorrelation measurements show that pulse widths of less than 20 fs can be expected with an average power of 52 mW when using our laser. These results indicate the high potential of direct diode laser pumped Ti: sapphire lasers to be used in applications...... like retinal optical coherence tomography (OCT) or pumping of photonic crystal fibers for CARS (coherent anti-stokes Raman spectroscopy) microscopy....

  15. Generation of femtosecond anti-stokes pulses through phase-matched parametric four-wave mixing in a photonic crystal fiber.

    Science.gov (United States)

    Konorov, S O; Serebryannikov, E E; Zheltikov, A M; Zhou, Ping; Tarasevitch, A P; von der Linde, D

    2004-07-01

    Phase-matched parametric four-wave mixing in higher-order guided modes of a photonic crystal fiber is shown to result in an efficient decay of 40-fs 800-nm Ti:sapphire laser pump pulses into an anti-Stokes signal with a central wavelength around 590-600 nm and a Stokes signal centered at 1.25 microm. The photonic crystal fiber is designed in such a way as to minimize the group-velocity dispersion at the pump wavelength, phase match the parametric four-wave-mixing process, and reduce the group delay between the pump and the anti-Stokes pulses. The duration of the anti-Stokes pulse under these conditions, as shown by cross-correlation frequency-resolved optical gating measurements, is less than 200 fs.

  16. On-chip tunable long-period gratings in liquid crystal infiltrated photonic crystal fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Weirich, Johannes; Alkeskjold, Thomas Tanggaard;

    2009-01-01

    An on-chip tunable long-period grating device in a liquid crystal infiltrated photonic crystal fiber is experimentally demonstrated. The depth and position of the notch are tuned electrically and thermally. The transmission axis can be electrically controlled as well as switched on and off....

  17. Theoretical analysis of a biased photonic crystal fiber infiltrated with a negative dielectric anisotropy liquid crystal

    DEFF Research Database (Denmark)

    Weirich, Johannes; Wei, Lei; Lægsgaard, Jesper;

    2009-01-01

    We simulate the PBG mode of a biased Photonic Crystal Fiber (PCF) infiltrated with a Liquid Crystal (LC) with negative dielectric anisotropy. We analyse the voltage induced change of the transmission spectrum, dispersion and losses and compare them to the experimental values....

  18. Supercontinuum generation using a selectively water-filled photonic crystal fiber for enhancement in the visible spectral region

    Science.gov (United States)

    Yoshida, Eiichi; Wada, Akira; Karasawa, Naoki

    2016-07-01

    We generated a supercontinuum from a selectively water-filled photonic crystal fiber (PCF) for enhancement in the visible spectral region using an optical pulse from a Ti:sapphire oscillator at 804 nm. We prepared a 7-cm-long fused silica PCF, where the holes adjacent to the central core were filled with water, using a UV-curable adhesive to close holes selectively before filling holes with water by capillary force. Compared with that of the PCF without water, the group velocity dispersion curve of the selectively water-filled PCF became flatter near 800 nm and the intensity in the visible spectral region of the supercontinuum became higher and more uniform. The spectra simulated using the calculated dispersion properties of the selectively water-filled PCF showed good agreement with the experimental spectra.

  19. Electrically tunable bandpass filter using solid-core photonic crystal fibers filled with multiple liquid crystals

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2010-01-01

    An electrically tunable bandpass filter is designed and fabricated by integrating two solid-core photonic crystal fibers filled with different liquid crystals in a double silicon v-groove assembly. By separately controlling the driving voltage of each liquid-crystal-filled section, both the short......-wavelength edge and the long-wavelength edge of the bandpass filter are tuned individually or simultaneously with the response time in the millisecond range....

  20. Photonic crystal fiber modal interferometer based on thin-core-fiber mode exciter.

    Science.gov (United States)

    Miao, Yinping; Ma, Xixi; Wu, Jixuan; Song, Binbin; Zhang, Hao; Liu, Bo; Yao, Jianquan

    2015-11-10

    A thin-core-fiber excited photonic crystal fiber modal interferometer has been proposed and experimentally demonstrated. By employing a thin-core fiber as the mode exciter, both of the core and cladding modes propagate in the photonic crystal fiber and interfere with each other. The experimental results show that the transmission dips corresponding to different-order modes have various strain responses with opposite shift directions. The strain sensitivity could be improved to 58.57  pm/με for the applied strain from 0 to 491 με by utilizing the wavelength interval between the dips with opposite shift directions. Moreover, due to the pure silica property of the employed photonic crystal fiber, the proposed fiber modal interferometer exhibits a low-temperature sensitivity of about 0.56  pm/°C within a temperature range from 26.4°C (room temperature) to 70°C. Additionally, the proposed fiber modal interferometer has several advantages, such as good stability, compact structure, and simple fabrication. Therefore, it is more applicable for strain measurement with reducing temperature cross-sensitivity.

  1. Infiltration liquid crystal in microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Wei, Lei; Bang, Ole

    2009-01-01

    POF is butt-coupled to a conventional single mode fiber (SMF) with the broadband light from a supercontinuum source. It is clear to see the colour of the guided modes is red, since some wavelengths are attenuated by the material loss of PMMA in visible region. A positive dielectric anisotropy liquid crystal E...

  2. Supercontinuum Generation in Uniform and Tapered Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Sørensen, Simon Toft; Møller, Uffe Visbech; Larsen, Casper;

    Supercontinuum generation (SCG) is a striking phenomenon of extreme spectral broadening involving a wealth of beautiful nonlinear physics. The study of SCG and development of today’s commercial sources really took off with the invention of the photonic crystal fiber (PCF), in which light can...

  3. Liquid Crystal Photonic bandgap Fibers: Modeling and Devices

    DEFF Research Database (Denmark)

    Weirich, Johannes

    In this PhD thesis an experimental and numerical investigation of liquid crystal infiltrated photonic bandgap fibers (LCPBGs) is presented. A simulation scheme for modeling LCPBG devices including electrical tunability is presented. New experimental techniques, boundary coating and the applicatio...

  4. Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms

    DEFF Research Database (Denmark)

    Markos, Christos; Kubat, Irnis; Bang, Ole

    2014-01-01

    The combination of chalcogenide glasses with polymer photonic crystal fibers (PCFs) is a difficult and challenging task due to their different thermo-mechanical material properties. Here we report the first experimental realization of a hybrid polymer-chalcogenide PCF with integrated As2S3 glass ...

  5. Birefringent Bragg Gratings in Highly-Nonlinear Photonic Crystal Fiber

    Institute of Scientific and Technical Information of China (English)

    Kevin Cook; John Canning; John Holdsworth

    2008-01-01

    Efficient writing of Bragg gratings in 12-ring highly-nonlinear photonic crystal fibers is described. Experimental and numerical investigations are performed to reveal the optimum angle for coupling UV writing light to the core. Furthermore, we show that the formation of a strongly briefringent grating is at a particular angle of orientation.

  6. Widely tunable femtosecond solitonic radiation in photonic crystal fiber cladding

    DEFF Research Database (Denmark)

    Peng, J. H.; Sokolov, A. V.; Benabid, F.

    2010-01-01

    We report on a means to generate tunable ultrashort optical pulses. We demonstrate that dispersive waves generated by solitons within the small-core features of a photonic crystal fiber cladding can be used to obtain femtosecond pulses tunable over an octave-wide spectral range. The generation...

  7. Fiber Drawn 2D Polymeric Photonic Crystal THz Filters

    DEFF Research Database (Denmark)

    Stecher, Matthias; Jansen, Christian; Ahmadi-Boroujeni, Mehdi

    2012-01-01

    In this paper, we report on different polymeric 2D photonic crystal filters for THz frequencies which are fabricated by a standard fiber drawing technique. The bandstop filters were simulated and designed by the generalized multipole technique (GMT). The frequency and angle dependent transmission...

  8. Estimating modal instability threshold for photonic crystal rod fiber amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Hansen, Kristian Rymann; Laurila, Marko;

    2013-01-01

    We present a semi-analytic numerical model to estimate the transverse modal instability (TMI) threshold for photonic crystal rod amplifiers. The model includes thermally induced waveguide perturbations in the fiber cross section modeled with finite element simulations, and the relative intensity...

  9. Coupling of two defect modes in photonic crystal fibers

    Institute of Scientific and Technical Information of China (English)

    Yuntuan Fang; Tinggen Shen

    2005-01-01

    The coupling characteristics of two defect modes in photonic crystal fibers are investigated theoretically by the finite-difference time-domain (FDTD) method. The transmission spectrum and eigenmodes of optical wave are found to be very sensitive to the geometrical and physical parameters of the structure, as well as to the relative position of the two defects.

  10. Photonic Crystal Fiber Based Entangled Photon Sources

    Science.gov (United States)

    2014-03-01

    new entanglement source is to make sure the source can provide an efficient and scalable quantum information processor . They are usually generated...multiple scattering on the telecom wavelength photon-pair. Our findings show that quantum correlation of polarization-entangled photon-pairs is...Fiber, Quantum communication, Keyed Communication in Quantum Noise (KCQ) 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18

  11. Ultraviolet laser crystallized ZnO:Al films on sapphire with high Hall mobility for simultaneous enhancement of conductivity and transparency

    Energy Technology Data Exchange (ETDEWEB)

    Nian, Qiong; Zhang, Martin Y. [School of Industrial Engineering, Purdue University, 315N. Grant St, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, 1205W State St, West Lafayette, Indiana 47907 (United States); Schwartz, Bradley D. [Goodrich Corporation, UTC Aerospace Systems, 100 Wooster Heights Road, Danbury, Connecticut 06810 (United States); Cheng, Gary J., E-mail: gjcheng@purdue.edu [School of Industrial Engineering, Purdue University, 315N. Grant St, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, 1205W State St, West Lafayette, Indiana 47907 (United States); School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907 (United States)

    2014-05-19

    One of the most challenging issues in transparent conductive oxides (TCOs) is to improve their conductivity without compromising transparency. High conductivity in TCO films often comes from a high carrier concentration, which is detrimental to transparency due to free carrier absorption. Here we show that UV laser crystallization (UVLC) of aluminum-doped ZnO (AZO) films prepared by pulsed laser deposition on sapphire results in much higher Hall mobility, allowing relaxation of the constraints of the conductivity/transparency trade-off. X-ray diffraction patterns and morphological characterizations show grain growth and crystallinity enhancement during UVLC, resulting in less film internal imperfections. Optoelectronic measurements show that UVLC dramatically improves the electron mobility, while the carrier concentration decreases which in turn simultaneously increases conductivity and transparency. AZO films under optimized UVLC achieve the highest electron mobility of 79 cm{sup 2}/V s at a low carrier concentration of 7.9 × 10{sup +19} cm{sup −3}. This is realized by a laser crystallization induced decrease of both grain boundary density and electron trap density at grain boundaries. The infrared (IR) to mid-IR range transmittance spectrum shows UVLC significantly enhances the AZO film transparency without compromising conductivity.

  12. Magnetic Field Measurements Based on Terfenol Coated Photonic Crystal Fibers

    Directory of Open Access Journals (Sweden)

    Carla C. Kato

    2011-11-01

    Full Text Available A magnetic field sensor based on the integration of a high birefringence photonic crystal fiber and a composite material made of Terfenol particles and an epoxy resin is proposed. An in-fiber modal interferometer is assembled by evenly exciting both eigenemodes of the HiBi fiber. Changes in the cavity length as well as the effective refractive index are induced by exposing the sensor head to magnetic fields. The magnetic field sensor has a sensitivity of 0.006 (nm/mT over a range from 0 to 300 mT with a resolution about ±1 mT. A fiber Bragg grating magnetic field sensor is also fabricated and employed to characterize the response of Terfenol composite to the magnetic field.

  13. Magnetic field measurements based on Terfenol coated photonic crystal fibers.

    Science.gov (United States)

    Quintero, Sully M M; Martelli, Cicero; Braga, Arthur M B; Valente, Luiz C G; Kato, Carla C

    2011-01-01

    A magnetic field sensor based on the integration of a high birefringence photonic crystal fiber and a composite material made of Terfenol particles and an epoxy resin is proposed. An in-fiber modal interferometer is assembled by evenly exciting both eigenemodes of the HiBi fiber. Changes in the cavity length as well as the effective refractive index are induced by exposing the sensor head to magnetic fields. The magnetic field sensor has a sensitivity of 0.006 (nm/mT) over a range from 0 to 300 mT with a resolution about ±1 mT. A fiber Bragg grating magnetic field sensor is also fabricated and employed to characterize the response of Terfenol composite to the magnetic field.

  14. SU-8 process optimization for high fiber coupling efficiency of liquid crystal filled photonic bandgap fiber components

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2009-01-01

    SU-8 structures are built up to increase the fiber coupling efficiency of liquid crystal photonic bandgap fiber components. The resolution reduction of UV exposure is minimized to 4%, and insertion loss is reduced to 2.7dB.......SU-8 structures are built up to increase the fiber coupling efficiency of liquid crystal photonic bandgap fiber components. The resolution reduction of UV exposure is minimized to 4%, and insertion loss is reduced to 2.7dB....

  15. Hundred-Watt-Level, All-Fiber-Integrated Supercontinuum Generation from Photonic Crystal Fiber

    Science.gov (United States)

    Chen, Hongwei; Chen, Zilun; Chen, Shengping; Hou, Jing; Lu, Qisheng

    2013-03-01

    A photonic crystal fiber (PCF) based supercontinuum source with hundred-watt-level average power output is presented in this paper. The output delivery fiber of a 120 W picosecond master-oscillator power-amplifier (MOPA) laser with a 15 µm fiber core is directly spliced with a 2.6-m-long PCF to form the all-fiber-integrated SC source. Using the controlled air-hole collapse technique to expand the core diameter of the PCF, a super-low splice loss (˜0.2 dB) between the delivery fiber and the PCF has been demonstrated. A 92.5 W SC spanning from about 700 nm to beyond 1700 nm is obtained.

  16. High power supercontinuum generation in tapered photonic crystal fibers

    DEFF Research Database (Denmark)

    Møller, Uffe; Sørensen, Simon Toft; Larsen, Casper;

    2012-01-01

    Tapering of photonic crystal fibers has proven to be an effective way of blueshifting the dispersive wavelength edge of a supercontinuum spectrum down in the deep-blue. In this contribution we will discuss the underlying mechanisms of supercontinuum generation in tapers. We show, by introducing...... the concept of a group-acceleration mismatch, that for a given taper length, the downtapering section should be as long as possible to enhance the amount of blueshifted light. We also discuss the noise properties of supercontinuum in uniform and tapered fibers and we demonstrate that the amplitude noise...

  17. Hybrid squeezing of solitonic resonant radiation in photonic crystal fibers

    CERN Document Server

    Tran, Truong X; Soeller, Christoph; Blow, Keith J; Biancalana, Fabio

    2011-01-01

    We report on the existence of a novel kind of squeezing in photonic crystal fibers which is conceptually intermediate between the four-wave mixing induced squeezing, in which all the participant waves are monochromatic waves, and the self-phase modulation induced squeezing for a single pulse in a coherent state. This hybrid squeezing occurs when an arbitrary short soliton emits quasi-monochromatic resonant radiation near a zero group velocity dispersion point of the fiber. Photons around the resonant frequency become strongly correlated due to the presence of the classical soliton, and a reduction of the quantum noise below the shot noise level is predicted.

  18. Chromatic Dispersion Compensation Using Photonic Crystal Fibers with Hexagonal Distribution

    Directory of Open Access Journals (Sweden)

    Erick E. Reyes-Vera

    2013-11-01

    Full Text Available In this paper we show various configurations of photonic crystal fiber with hexagonal holes distribution for compensation of chromatic dispersion in optical communications links. The vectorial finite element method with scattering boundary condition was used for the analysis of the fibers. From these results it was estimated variation of the dispersion and the dispersion slope with respect to change in the diameter of the holes in the microstructure. With the above was possible to obtain values of dispersion in the C and L bands of telecommunications close to -850 ps / nm * km, with confinement losses 10-3 dB / km

  19. Refractometry based on a photonic crystal fiber interferometer.

    Science.gov (United States)

    Jha, Rajan; Villatoro, Joel; Badenes, Gonçal; Pruneri, Valerio

    2009-03-01

    We report a simple and compact modal interferometer for applications in refractometry. The device consists of a stub of large-mode-area photonic crystal fiber (PCF) spliced between standard single-mode fibers. In the splice regions the voids of the PCF are fully collapsed, thus allowing the coupling and recombination of PCF core and cladding modes. The device is highly stable over time, has low temperature sensitivity, and is suitable for measuring indices in the 1.330-1.440 range. The measure of the refractive index is carried out by monitoring the shift of the interference pattern.

  20. Soliton blue-shift in tapered photonic crystal fiber

    CERN Document Server

    Stark, S P; Russell, P St J

    2010-01-01

    We show that solitons undergo a strong blue shift in fibers with a dispersion landscape that varies along the direction of propagation. The experiments are based on a small-core photonic crystal fiber, tapered to have a core diameter that varies continuously along its length, resulting in a zero-dispersion wavelength that moves from 731 nm to 640 nm over the transition. The central wavelength of a soliton translates over 400 nm towards shorter wavelength. This accompanied by strong emission of radiation into the UV and IR spectral region. The experimental results are confirmed by numerical simulation.

  1. High-Visibility Photonic Crystal Fiber Interferometer as Multifunctional Sensor

    Directory of Open Access Journals (Sweden)

    Joel Villatoro

    2013-02-01

    Full Text Available A photonic crystal fiber (PCF interferometer that exhibits record fringe contrast (~40 dB is demonstrated along with its sensing applications. The device operates in reflection mode and consists of a centimeter-long segment of properly selected PCF fusion spliced to single mode optical fibers. Two identical collapsed zones in the PCF combined with its modal properties allow high-visibility interference patterns. The interferometer is suitable for refractometric and liquid level sensing. The measuring refractive index range goes from 1.33 to 1.43 and the maximum resolution is ~1.6 × 10−5.

  2. Photonic detection and characterization of DNA using sapphire microspheres

    OpenAIRE

    Serpengüzel, Ali; Murib, Mohammed Sharif; Yeap, Weng-Siang; Martens, Daan; Bienstman, Peter; De Ceuninck, Ward; van Grinsven, Bart; Schoening, Michael J.; Michiels, Luc; Haenen, Ken; Ameloot, Marcel; Wagner, Patrick

    2014-01-01

    A microcavity-based deoxyribonucleic acid (DNA) optical biosensor is demonstrated for the first time using synthetic sapphire for the optical cavity. Transmitted and elastic scattering intensity at 1510 nm are analyzed from a sapphire microsphere (radius 500 mu m, refractive index 1.77) on an optical fiber half coupler. The 0.43 nm angular mode spacing of the resonances correlates well with the optical size of the sapphire sphere. Probe DNA consisting of a 36-mer fragment was covalently immob...

  3. Holographic polymer-dispersed liquid crystal Bragg grating integrated inside a solid core photonic crystal fiber

    CERN Document Server

    Zito, Gianluigi

    2013-01-01

    A polymer/liquid crystal-based fiber Bragg grating (PLC-FBG) is fabricated with visible two-beam holography by photo-induced modulation of a pre-polymer/LC solution infiltrated into the hollow channels of a solid core photonic crystal fiber (PCF). The fabrication process and effects related to the photonic bandgap guidance into the infiltrated PCF, and characterization of the PLC-FBG are discussed. Experimental data here presented, demonstrate that the liquid crystal inclusions of the PLC-FBG lead to high thermal and bending sensitivities. The microscopic behavior of the polymer/liquid crystal phase separation inside the PCF capillaries is examined using scanning electron microscopy, while further discussed.

  4. High Performance Large Mode-Area Ytterbium-doped Photonic Crystal Fiber for Fiber Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wei; Lu Peixiang [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074 (China); Li Shiyu; Wang Dongxiang, E-mail: chenwei@fiberhome.com.cn [State Key Laboratory of Optical Communication Technologies and Networks, Fiberhome Telecommunication Technologies Co. Ltd, 430074 (China)

    2011-02-01

    In this letter, large-mode-area double-cladding ytterbium-doped photonic crystal fiber was designed in theory and fabricated in practice. This fiber we have fabricated successfully has endless single mode operation performance and large inner-cladding numerical aperture of more than 0.75. The struts width between large air-holes in the outer-cladding is about 0.22 {mu}m. The photonic crystal fiber has a mode-area about 1465.7{mu}m{sup 2}. Due to the material being pure silica and air, such structures have excellent capacity to with-stand high temperature. The laser light can have very good beam quality, even diffraction-limited beam quality because of the single-mode core. This fabrication technical breakthrough of novelty high performance double-cladding ytterbium-doped photonic crystal fibers will give contributions to the high power fiber lasers and promote the progress of technology in the fields of high power lasers.

  5. Enhanced electrophoretic DNA separation in photonic crystal fiber.

    Science.gov (United States)

    Sun, Yi; Nguyen, Nam-Trung; Kwok, Yien Chian

    2009-07-01

    Joule heating generated by the electrical current in capillary electrophoresis leads to a temperature gradient along the separation channel and consequently affects the separation quality. We describe a method of reducing the Joule heating effect by incorporating photonic crystal fiber into a micro capillary electrophoresis chip. The photonic crystal fiber consists of a bundle of extremely narrow hollow channels, which ideally work as separation columns. Electrophoretic separation of DNA fragments was simultaneously but independently carried out in 54 narrow capillaries with a diameter of 3.7 microm each. The capillary bundle offers more efficient heat dissipation owing to the high surface-to-volume ratio. Under the same electrical field strength, notable improvement in resolution was obtained in the capillary bundle chip.

  6. Photon Polarization in Photonic Crystal Fibers under Compton Scattering

    Institute of Scientific and Technical Information of China (English)

    HAO Dong-shan; ZHANG Xiao-fu

    2007-01-01

    Using the quantum invariant theory and unitary transformation means, we study the influences of multi-photon nonlinear Compton scattering on the photon polarization in photonic crystal fibers(PCF). The results show that the photon polarization of the incident photon changes a lot due to scattered optical, and its general geometric phase factor, Hamiton number and evolution operator are definited both by the incident and scattered optical.

  7. Coherent and incoherent spectral broadening in a photonic crystal fiber.

    Science.gov (United States)

    Gross, C; Best, Th; van Oosten, D; Bloch, I

    2007-07-01

    The coherence of the spectral broadening process is the key requisite for the application of supercontinua in frequency combs. We investigate the coherence of two subsequent supercontinuum pulses created in a photonic crystal fiber pumped by a femtosecond laser. We measure Young interference fringes from a Michelson-type interferometer at different wavelengths of the output spectrum and analyze their dependence on pump intensity and polarization. The visibility of these fringes is a direct measure of the coherence of the spectral broadening processes.

  8. Supermode analysis of the 18-core photonic crystal fiber laser

    Institute of Scientific and Technical Information of China (English)

    王远; 姚建铨; 郑一博; 温午麒; 陆颖; 王鹏

    2012-01-01

    The modal of 18-core photonic crystal fiber laser is discussed and calculated.And corresponding far-field distribution of the supermodes is given by Fresnel diffraction integral.For improving beam quality,the mode selection method based on the Talbot effect is introduced.The reflection coefficients are calculated,and the result shows that an in-phase supermode can be locked better at a large propagation distance.

  9. Optimized photonic crystal fibers supporting efficient capillary electrophoresis

    Science.gov (United States)

    Calcerrada, M.; García-Ruiz, C.; Roy, P.; Gonzalez-Herraez, M.

    2013-05-01

    In this paper we present preliminary results on the use of Photonic Crystal Fibers (PCFs) in a conventional capillary electrophoresis system to separate and detect fluorescent species. PCFs show interesting advantages over conventional capillaries for this application, including larger surface-to-volume ratio and potential for higher resolution with comparable sensitivity. Our results illustrate some of these advantages, and we point out the need for stringent tolerances in the fabrication of specific PCFs for this application.

  10. Nanoengineering of photonic crystal fibers for supercontinuum spectral shaping

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch; Sørensen, Thorkild; Bang, Ole

    2006-01-01

    Supercontinuum generation using picosecond pulses pumped into cobweb photonic crystal fibers is investigated. Dispersion profiles are calculated for several fiber designs and used to analytically investigate the influence of the fiber structural parameters (core size and wall thickness......) on the location of the Stokes and anti-Stokes bands and gain bandwidth. An analysis shows that the Raman effect is responsible for reducing the four-wave mixing gain and a slight reduction in the corresponding frequency shift from the pump, when the frequency shift is much larger than the Raman shift. Using...... numerical simulations we find that four-wave mixing is the dominant physical mechanism for the pumping scheme considered, and that there is a trade-off between the spectral width and the spectral flatness of the supercontinuum. The balance of this trade-off is determined by nanometer-scale design...

  11. Confinement loss in adiabatic photonic crystal fiber tapers

    Science.gov (United States)

    Kuhlmey, Boris T.; Nguyen, Hong C.; Steel, M. J.; Eggleton, Benjamin J.

    2006-09-01

    We numerically study confinement loss in photonic crystal fiber (PCF) tapers and compare our results with previously published experimental data. Agreement between theory and experiment requires taking into account hole shrinkage during the tapering process, which we measure by using a noninvasive technique. We show that losses are fully explained within the adiabatic approximation and that they are closely linked to the existence of a fundamental core-mode cutoff. This cutoff is equivalent to the core-mode cutoff in depressed-cladding fibers, so that losses in PCF tapers can be obtained semiquantitatively from an equivalent depressed-cladding fiber model. Finally, we discuss the definition of adiabaticity in this open boundary problem.

  12. Different supercontinuum generation processes in photonic crystal fibers pumped with a 1064-nm picosecond pulse

    Science.gov (United States)

    Chen, Hong-Wei; Jin, Ai-Jun; Chen, Sheng-Ping; Hou, Jing; Lu, Qi-Sheng

    2013-08-01

    Picosecond pulse pumped supercontinuum generation in photonic crystal fiber is investigated by performing a series of comparative experiments. The main purpose is to investigate the supercontinuum generation processes excited by a given pump source through the experimental study of some specific fibers. A 20-W all-fiber picosecond master oscillator-power amplifier (MOPA) laser is used to pump three different kinds of photonic crystal fibers for supercontinuum generation. Three diverse supercontinuum formation processes are observed to correspond to photonic crystal fibers with distinct dispersion properties. The experimental results are consistent with the relevant theoretical results. Based on the above analyses, a watt-level broadband white light supercontinuum source spanning from 500 nm to beyond 1700 nm is demonstrated by using a picosecond fiber laser in combination with the matched photonic crystal fiber. The limitation of the group velocity matching curve of the photonic crystal fiber is also discussed in the paper.

  13. Different supercontinuum generation processes in photonic crystal fibers pumped with a 1064-nm picosecond pulse

    Institute of Scientific and Technical Information of China (English)

    Chen Hong-Wei; Jin Ai-Jun; Chen Sheng-Ping; Hou Jing; Lu Qi-Sheng

    2013-01-01

    Picosecond pulse pumped supercontinuum generation in photonic crystal fiber is investigated by performing a series of comparative experiments.The main purpose is to investigate the supercontinuum generation processes excited by a given pump source through the experimental study of some specific fibers.A 20-W all-fiber picosecond master oscillator-power amplifier (MOPA) laser is used to pump three different kinds of photonic crystal fibers for supercontinuum generation.Three diverse supercontinuum formation processes are observed to correspond to photonic crystal fibers with distinct dispersion properties.The experimental results are consistent with the relevant theoretical results.Based on the above analyses,a watt-level broadband white light supercontinuum source spanning from 500 nm to beyond 1700 nm is demonstrated by using a picosecond fiber laser in combination with the matched photonic crystal fiber.The limitation of the group velocity matching curve of the photonic crystal fiber is also discussed in the paper.

  14. Optical frequency standard using acetylene-filled hollow-core photonic crystal fibers

    DEFF Research Database (Denmark)

    Triches, Marco; Michieletto, Mattia; Hald, Jan

    2015-01-01

    Gas-filled hollow-core photonic crystal fibers are used to stabilize a fiber laser to the 13C2H2 P(16) (ν1+ν3) transition at 1542 nm using saturated absorption. Four hollow-core fibers with different crystal structure are compared in terms of long term lock-point repeatability and fractional...

  15. Liquid crystals in micron-scale droplets, shells and fibers

    Science.gov (United States)

    Urbanski, Martin; Reyes, Catherine G.; Noh, JungHyun; Sharma, Anshul; Geng, Yong; Subba Rao Jampani, Venkata; Lagerwall, Jan P. F.

    2017-04-01

    The extraordinary responsiveness and large diversity of self-assembled structures of liquid crystals are well documented and they have been extensively used in devices like displays. For long, this application route strongly influenced academic research, which frequently focused on the performance of liquid crystals in display-like geometries, typically between flat, rigid substrates of glass or similar solids. Today a new trend is clearly visible, where liquid crystals confined within curved, often soft and flexible, interfaces are in focus. Innovation in microfluidic technology has opened for high-throughput production of liquid crystal droplets or shells with exquisite monodispersity, and modern characterization methods allow detailed analysis of complex director arrangements. The introduction of electrospinning in liquid crystal research has enabled encapsulation in optically transparent polymeric cylinders with very small radius, allowing studies of confinement effects that were not easily accessible before. It also opened the prospect of functionalizing textile fibers with liquid crystals in the core, triggering activities that target wearable devices with true textile form factor for seamless integration in clothing. Together, these developments have brought issues center stage that might previously have been considered esoteric, like the interaction of topological defects on spherical surfaces, saddle-splay curvature-induced spontaneous chiral symmetry breaking, or the non-trivial shape changes of curved liquid crystal elastomers with non-uniform director fields that undergo a phase transition to an isotropic state. The new research thrusts are motivated equally by the intriguing soft matter physics showcased by liquid crystals in these unconventional geometries, and by the many novel application opportunities that arise when we can reproducibly manufacture these systems on a commercial scale. This review attempts to summarize the current understanding of

  16. A novel fiber-optic temperature sensor based on high temperature-dependent optical properties of ZnO film on sapphire fiber-ending

    Energy Technology Data Exchange (ETDEWEB)

    Cai Pinggen; Zhen Dong; Xu Xiaojun; Liu Yulin [Department of Applied Physics, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, Zhejiang Province (China); Chen Naibo [Department of Science, Zhijiang College of Zhejiang University of Technology, Hangzhou 310024 (China); Wei Gaorao [Department of Applied Physics, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, Zhejiang Province (China); Sui Chenghua, E-mail: suich@zjut.edu.cn [Department of Applied Physics, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, Zhejiang Province (China)

    2010-07-25

    We report the growth of high-quality thin films of ZnO via an electron-beam evaporation technique. Studies of the transmittance spectra have revealed a sharp optical absorption edge and a significant redshift. After annealing at 673 K, the ZnO films again demonstrated a sharp absorption edge in a manner similar to the as-deposited samples. This illustrates the excellent thermal stability of the thin films and, as such, demonstrates their potential as fiber-optic temperature sensors. Utilizing the influence of optical absorption spectra at different temperatures, a novel fiber-optic temperature sensor based on this material has been designed and tested. This technique could offer a simple, robust and cost-effective method to be used in high temperature sensing applications.

  17. PbS Quantum Dots Filled Photonic Crystal Fiber for All-fiber Amplifier

    Science.gov (United States)

    Wang, Zhanbing; Shang, Yana; Pang, Fufei; Liu, Huanhuan; Chen, Na; Wu, Yan; Kang, Yanan

    2017-06-01

    In this paper, we have proposed a novel type of fiber amplifier by filling the PbS semiconductor quantum dots into the holes of photonic crystal fibers (PCFs) for the first time. Based on simulation results, we have found that the loss of PCF filled with PbS is slightly increased compared with the one without PbS at wavelength of 1310 nm. Furthermore, we have successfully fabricated the PbS-filled PCF with selective air-hole cladding by a new perfusion technique that can optimize the overall loss.

  18. Erbium-doped photonic crystal fiber chaotic laser

    Science.gov (United States)

    Martín, Juan C.; Used, Javier; Sánchez-Martín, José A.; Berdejo, Víctor; Vallés, Juan A.; Álvarez, José M.; Rebolledo, Miguel A.

    2011-09-01

    An erbium-doped photonic crystal fiber laser has been designed, constructed and characterized in order to examine the feasibility of this kind of devices for secure communications applications based on two identical chaotic lasers. Inclusion of a tailored photonic crystal fiber as active medium improves considerably the security of the device because it allows customization of the mode transversal profile, very influential on the laser dynamics and virtually impossible to be cloned by undesired listeners. The laser design has been facilitated by the combination of characterization procedures and models developed by us, which allow prediction of the most suitable laser features (losses, length of active fiber, etc.) to a given purpose (in our case, a laser that emits chaotically for a wide assortment of pump modulation conditions). The chaotic signals obtained have been characterized by means of topological analysis techniques. The underlying chaotic attractors found present topological structures belonging to classes of which very scarce experimental results have been reported. This fact is interesting from the point of view of the study of nonlinear systems and, besides, it is promising for secure communications: the stranger the signals, the more difficult for an eavesdropper to synthesize another system with similar dynamics.

  19. Continuous preparation of polymer coated drug crystals by solid hollow fiber membrane-based cooling crystallization.

    Science.gov (United States)

    Chen, Dengyue; Singh, Dhananjay; Sirkar, Kamalesh K; Pfeffer, Robert

    2016-02-29

    A facile way to continuously coat drug crystals with a polymer is needed in controlled drug release. Conventional polymer coating methods have disadvantages: high energy consumption, low productivity, batch processing. A novel method for continuous polymer coating of drug crystals based on solid hollow fiber cooling crystallization (SHFCC) is introduced here. The drug acting as the host particle and the polymer for coating are Griseofulvin (GF) and Eudragit RL100, respectively. The polymer's cloud point temperature in its acetone solution was determined by UV spectrophotometry. An acetone solution of the polymer containing the drug in solution as well as undissolved drug crystals in suspension were pumped through the tube side of the SHFCC device; a cold liquid was circulated in the shell side to rapidly cool down the feed solution-suspension in the hollow-fiber lumen. The polymer precipitated from the solution and coated the suspended crystals due to rapid temperature reduction and heterogeneous nucleation; crystals formed from the solution were also coated by the polymer. Characterizations by scanning electron microscopy, thermogravimetric analysis, laser diffraction spectroscopy, X-ray diffraction, Raman spectroscopy, and dissolution tests show that a uniformly coated, free-flowing drug/product can be obtained under appropriate operating conditions without losing the drug's pharmaceutical properties and controlled release characteristics.

  20. Frequency conversion through spontaneous degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2014-01-01

    Frequency conversion through spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers. Different FWM processes are observed, phasematching between fiber modes of orthogonal polarization, intermodal phasematching across bandgaps, and intramodal...

  1. Dispersion engineered cob-web photonic crystal fibers for efficient supercontinuum generation

    OpenAIRE

    Sørensen, Niels Thorkild; Nikolov, N. I.; Bang, Ole; Bjarklev, Anders Overgaard; Hougaard, Kristian G.; Hansen, Kim Per

    2004-01-01

    Highly nonlinear cob-web photonic crystal fibers are engineered to have dispersion profiles for efficient direct degenerate four-wave mixing and optimized supercontinuum generation with low-power picosecond pulses. This process is robust to fiber irregularities.

  2. Dispersion engineered cob-web photonic crystal fibers for efficient supercontinuum generation

    DEFF Research Database (Denmark)

    Sørensen, Niels Thorkild; Nikolov, N.I.; Bang, Ole;

    2004-01-01

    Highly nonlinear cob-web photonic crystal fibers are engineered to have dispersion profiles for efficient direct degenerate four-wave mixing and optimized supercontinuum generation with low-power picosecond pulses. This process is robust to fiber irregularities.......Highly nonlinear cob-web photonic crystal fibers are engineered to have dispersion profiles for efficient direct degenerate four-wave mixing and optimized supercontinuum generation with low-power picosecond pulses. This process is robust to fiber irregularities....

  3. Dispersion-tailored, low-loss photonic crystal fibers for the THz range

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Adam, Aurèle J.L.;

    2009-01-01

    We have fabricated a new type of photonic crystal fibers based on a cyclic olefin copolymer, transparent in the THz range. We characterize the propagation loss, dispersion, and spatial beam profile in fibers designed for low and high dispersion.......We have fabricated a new type of photonic crystal fibers based on a cyclic olefin copolymer, transparent in the THz range. We characterize the propagation loss, dispersion, and spatial beam profile in fibers designed for low and high dispersion....

  4. Guided mode gain competition in Yb-doped rod-type photonic crystal fibers

    DEFF Research Database (Denmark)

    Poli, Federica; Passaro, Davide; Cucinotta, Annamaria

    2009-01-01

    The gain competition among the guided modes in Yb-doped rod-type photonic crystal fibers with a low refractive index core is investigated with a spatial model to demonstrate the fiber effective single-mode behaviour.......The gain competition among the guided modes in Yb-doped rod-type photonic crystal fibers with a low refractive index core is investigated with a spatial model to demonstrate the fiber effective single-mode behaviour....

  5. Selective detection of labeled DNA using an air-clad photonic crystal fiber

    DEFF Research Database (Denmark)

    Jensen, Jesper Bo Damm; Hoiby, P.E.; Pedersen, L.H.

    2004-01-01

    Demonstration of selective detection of fluorophore labeled DNA by hybridization inside the air holes of a photonic crystal fiber A laser exposes the fiber from the side and the emitted fluorescence tunnels into the core.......Demonstration of selective detection of fluorophore labeled DNA by hybridization inside the air holes of a photonic crystal fiber A laser exposes the fiber from the side and the emitted fluorescence tunnels into the core....

  6. Fabrication of sisal fibers/epoxy composites with liquid crystals polymer grafted on sisal fibers

    Science.gov (United States)

    Luo, Q. Y.; Lu, S. R.; Song, L. F.; Li, Y. Q.

    2016-07-01

    In this word, microcrystalline cellulose fibers (MCFs), extracted from sisal fibers, were treated with function end-group hyperbranched liquid crystals (HLP). This work brought some insights into the successful surface modification in epoxy composite with HLP. The HLP-MCFs/epoxy composites are studied systematically. The HLP - MCFs/epoxy composites were studied by Fourier transform infrared spectroscopy (FT-IR), polarizing microscope (POM), X-ray photoelectron spectroscopy (XPS) and mechanical properties analysis. The results reveal that the reinforcement of EP composites was carried out by adding HLP-MCFs. In particular, with 1.0 wt% filler loading, the flexural strength, tensile strength, impact strength and flexural modulus of the HLP-MCFs/EP composites were increased by 60%, 69%, 130%, and 192%, respectively. It anticipates that our current work exploits more efficient methods to overcome the few nature fiber/polymer (NPC) adhesion in the interface region and provides implications for the engineering applications of the development of NPC.

  7. 20 W all fiber supercontinuum generation from picosecond MOPA pumped photonic crystal fiber

    Science.gov (United States)

    Chen, S.-P.; Wang, J.-H.; Chen, H.-W.; Chen, Z.-L.; Hou, J.; Xu, X.-J.; Chen, J.-B.; Liu, Z.-J.

    2011-03-01

    An all fiber high power supercontinuum (SC) source is demonstrated by pumping a section of photonic crystal fiber (PCF) with a picosecond MOPA laser. The core of the PCF is enlarged at the input end through a serious of PCF post processing method to match the output fiber of the picosecond laser, to ensure low loss splicing, hence high power operation of the whole system. The supercontinuum output spectrum covers the wavelength range from 650 nm to beyond 1700 nm. Limited by available pump power, 20 W super-continuum output power is obtained under 29.5 W picosecond pump power, giving a high optical to optical conversion efficiency of 67.8%.

  8. Highly-stable monolithic femtosecond Yb-fiber laser system based on photonic crystal fibers

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

    2010-01-01

    of around 297 fs duration. Our laser shows exceptional stability. No Q-switched modelocking events were detected during 4-days long observation. An average fluctuation of only 7.85 · 10−4 over the mean output power was determined as a result of more than 6-hours long measurement. The laser is stable towards......A self-starting, passively stabilized, monolithic all polarizationmaintaining femtosecond Yb-fiber master oscillator / power amplifier with very high operational and environmental stability is demonstrated. The system is based on the use of two different photonic crystal fibers. One is used...... in the oscillator cavity for dispersion balancing and nonlinear optical limiting, and another one is used for low nonlinearity final pulse recompression. The chirped-pulse amplification and recompression of the 232-fs, 45-pJ/pulse oscillator output yields a final direct fiber-end delivery of 7.3-nJ energy pulses...

  9. Numerical study on pulse trapping in birefringent photonic crystal fibers

    Institute of Scientific and Technical Information of China (English)

    YAO Yan-yan; LI Shu-guang; FU Bo; ZHANG Lei; ZHANG Mei-yan

    2011-01-01

    Using an adaptive split-step Fourier method, the coupled nonlinear Schrodinger equations have been numerically solved in this paper. The nonlinear propagation of an ultrashort optical pulse in the birefringent photonic crystal fibers is investigated numerically. It is found that the phenomenon of pulse trapping occurs when the incident pulse is deviating from the principal axis of the fiber with some angle. Owing to the bireffingence effect, the incident pulse can be regarded as twoorthogonal polarized pulses. The phenomenon of pulse trapping occurs because of the cross phase modulation (XPM) between the two components. As a result, the bandwidth of the supercontinuum (SC) decreases compared with the case that the incident pulse is input along the principal axis. When the polarization direction of the incident pulse is parallel to the fast axis, the bandwidth of the supercontinuum is maximaL

  10. Temporal nonlinear beam dynamics in infiltrated photonic crystal fibers

    DEFF Research Database (Denmark)

    Bennet, Francis; Rosberg, Christian Romer; Neshev, Dragomir N.

    of nonlinear beam reshaping occurring on a short time scale before the establishment of a steady state regime. In experiment, a 532nm laser beam can be injected into a single hole of an infiltrated PCF cladding structure, and the temporal dynamics of the nonlinear response is measured by monitoring......Liquid-infiltrated photonic crystal fibers (PCFs) offer a new way of studying light propagation in periodic and discrete systems. A wide range of available fiber structures combined with the ease of infiltration opens up a range of novel experimental opportunities for optical detection and bio......-sensing as well as active devices for all-optical switching at low (mW) laser powers. Commercially available PCFs infiltrated with liquids also provide a versatile and compact tool for exploration of the fundamentals of nonlinear beam propagation in periodic photonic structures. To explore the full scientific...

  11. Low loss and broadband hollow-core photonic crystal fibers

    Science.gov (United States)

    Wang, Y. Y.; Gerome, F.; Humbert, G.; Blondy, J. M.; Benabid, F.

    2011-03-01

    We report on recent developments on fabrication and optical guidance of Kagome-lattice hollow-core photonic crystal fiber (HC-PCF). These include the design and fabrication of a hypocycloid-shaped core Kagome HC-PCF that combines a record optical attenuation with a baseline exhibiting ~180 dB/km over a transmission bandwidth larger than 200 THz. These results are corroborated with theoretical simulations which show that both the core-shape and the cladding ring number play role in inhibited coupling, inducing core-mode confinement for the fundamental transmission band. We also show that the inhibited coupling is weaker for the first higher-order transmission band by theoretically and experimentally comparing Kagome HC-PCF with a single anti-resonant ring hollow-core fiber.

  12. Faceted ceramic fibers, tapes or ribbons and epitaxial devices therefrom

    Science.gov (United States)

    Goyal, Amit

    2013-07-09

    A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.

  13. Faceted ceramic fibers, tapes or ribbons and epitaxial devices therefrom

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Amit (Knoxville, TN)

    2012-07-24

    A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.

  14. Growth of new borate crystals with fiber shape by the micro-pulling down technique

    Science.gov (United States)

    Assi, Farah; Ferriol, Michel; Aillerie, Michel; Cochez, Marianne

    2017-07-01

    Borate-based materials are of high interest to generate an UV laser light from a crystal. Fiber-shaped crystals combining the advantages of fiber lasers and crystalline lasers, we have investigated the growing conditions required to obtain usable fibers of Bi2ZnB2O7 (BZBO) and LaBGeO5 (LBGO). For BZBO, the major drawback was the pronounced color of the fibers and for LBGO, it was the high viscosity of its melt leading to use a flux. This paper presents our state of the art to obtain good quality BZBO and LBGO crystal fibers.

  15. Initial steps of supercontinuum generation in photonic crystal fibers

    DEFF Research Database (Denmark)

    Hilligsøe, Karen Marie; Paulsen, H.N.; Thøgersen, J.;

    2003-01-01

    The onset of supercontinuum generation in a photonic crystal fiber is investigated experimentally and numerically as a function of pump wavelength and intensity with 100-fs pulses. Soliton formation is found to be the determining factor in the initial step. The formation and behavior of a blueshi...... of a blueshifted, nonsolitonic component, emitted as the soliton evolves towards the stable regime, is investigated and the role of phase matching through higher-order dispersion is highlighted. Good agreement between experiments and simulations is obtained....

  16. Photonic crystal fiber long-period gratings for biochemical sensing

    DEFF Research Database (Denmark)

    Rindorf, Lars Henning; Jensen, Jesper Bo; Dufva, Hans Martin

    2006-01-01

    -period grating it was possible to measure the thickness of the layer. The long-period gratings were inscribed in a large-mode area silica photonic crystal fiber with a CO2 laser. The thicknesses of a monolayer of poly-L-lysine and double-stranded DNA was measured using the device. We find that the grating has...... a sensitivity of approximately 1.4nm/1nm in terms of the shift in resonance wavelength in nm per nm thickness of biomolecule layer....

  17. Analyses of cladding modes in photonic crystal fiber.

    Science.gov (United States)

    Park, Hyun Chul; Hwang, In Kag; Yeom, Dong Il; Kim, Byoung Yoon

    2007-11-12

    Characteristics of cladding modes in a photonic crystal fiber (PCF) are numerically analyzed using the plane wave expansion method. The presence of the outer silica ring in the PCF tends to push the optical fields of the cladding modes toward the rim of the PCF, which creates 'ring modes' whose fields are tightly confined in the outer ring. The dispersion of the cladding modes are determined mainly by the dispersive property of the holey cladding structure. The optical field patterns of the cladding modes and the beatlengths between the fundamental mode and the cladding modes are also investigated.

  18. Active Photonic crystal fibers for high power applications

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin

    . This plays an important role in high power lasers and ampliers with respect to efficiency, packaging, and thermal handling. The third part of the work has involved developing tools for characterizing the mode quality and stability of large core bers. Stable, single-mode bers with larger cores are essential......The photonic crystal ber technology provides means to realize bers optimized for high power operation, due to the large single-mode cores and the unique design exibility of the microstructure. The work presented in this thesis focuses on improving the properties of active photonic crystal bers...... for high power ber lasers and ampliers, and on adding new functionality to the fibers - all with the purpose of pushing the technology towards high powers. The first part of the work has been to investigate photo darkening, the mitigation of which is crucial in the quest for higher powers. The work has...

  19. Nd3+ Doped Silicate Glass Photonic Crystal Fiber with Random Hole Distributions

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The fabrication of one kind of large core area Nd3+ doped silicate glass photonic crystal fiber, and demonstration of the fiber's waveguidence properties were reported. This fiber owns a random air hole distribution in the cladding. The measured minimum loss of this kind of fiber is 10 dB·m-1 at 660 nm. These fibers can sustain only a single mode at least over wavelength ranging from 660 nm to 980 nm.

  20. Photonic crystal fiber based chloride chemical sensors for corrosion monitoring

    Science.gov (United States)

    Wei, Heming; Tao, Chuanyi; Krishnaswamy, Sridhar

    2016-04-01

    Corrosion of steel is one of the most important durability issues in reinforced concrete (RC) structures because aggressive ions such as chloride ions permeate concrete and corrode steel, consequently accelerating the destruction of structures, especially in marine environments. There are many practical methods for corrosion monitoring in RC structures, mostly focusing on electrochemical-based sensors for monitoring the chloride ion which is thought as one of the most important factors resulting in steel corrosion. In this work, we report a fiber-optic chloride chemical sensor based on long period gratings inscribed in a photonic crystal fiber (PCF) with a chloride sensitive thin film. Numerical simulation is performed to determine the characteristics and resonance spectral response versus the refractive indices of the analyte solution flowing through into the holes in the PCF. The effective refractive index of the cladding mode of the LPGs changes with variations of the analyte solution concentration, resulting in a shift of the resonance wavelength, hence providing the sensor signal. This fiber-optic chemical sensor has a fast response, is easy to prepare and is not susceptible to electromagnetic environment, and can therefore be of use for structural health monitoring of RC structures subjected to such aggressive environments.

  1. Measurement of gas viscosity using photonic crystal fiber

    Science.gov (United States)

    Gao, R.-K.; Sheehe, S. L.; Kurtz, J.; O'Byrne, S.

    2016-11-01

    A new measurement technique for gas viscosity coefficient is designed and demonstrated using the technique of tunable diode laser absorption spectroscopy (TDLAS). Gas flow is driven by a pressure gradient between two gas cells, through a photonic crystal fiber (PCF) surrounded by a furnace for temperature adjustment. PCF with 20-micron diameter affords physical space for gas-light interaction and provides a basis for gas viscosity measurement by determining the time for flow to exit a capillary tube under the influence of a pressure gradient. Infrared radiation from a diode laser is coupled into the fiber to be guided through the gas, and the light attenuation due to absorption from the molecular absorbing species is measured by a photo detector placed at the exit of the fiber. A numerical model from Sharipov and Graur describing local number density distribution in a unsteady state is applied for the determination of gas viscosity, based on the number density of gas measured by the absorption of the laser light, using the Beer-Lambert law. The measurement system is confirmed by measuring the viscosity of CO2 as a reference gas.

  2. Double Sided Si(Ge)/Sapphire/III-Nitride Hybrid Structure

    Science.gov (United States)

    Park, Yeonjoon (Inventor); Choi, Sang Hyouk (Inventor)

    2016-01-01

    One aspect of the present invention is a double sided hybrid crystal structure including a trigonal Sapphire wafer containing a (0001) C-plane and having front and rear sides. The Sapphire wafer is substantially transparent to light in the visible and infrared spectra, and also provides insulation with respect to electromagnetic radio frequency noise. A layer of crystalline Si material having a cubic diamond structure aligned with the cubic direction on the (0001) C-plane and strained as rhombohedron to thereby enable continuous integration of a selected (SiGe) device onto the rear side of the Sapphire wafer. The double sided hybrid crystal structure further includes an integrated III-Nitride crystalline layer on the front side of the Sapphire wafer that enables continuous integration of a selected III-Nitride device on the front side of the Sapphire wafer.

  3. Second-order polarization-mode dispersion in photonic crystal fibers

    DEFF Research Database (Denmark)

    Larsen, T; Bjarklev, Anders Overgaard; Peterson, A

    2003-01-01

    We report the first experimental measurements of second-order polarization-mode dispersion in two successive 900 meter pulls of a silica photonic crystal fiber.......We report the first experimental measurements of second-order polarization-mode dispersion in two successive 900 meter pulls of a silica photonic crystal fiber....

  4. A Dual-Function All-in-Fiber Device Based on Negative Dielectric Liquid Crystal Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Eskildsen, Lars; Weirich, Johannes;

    2008-01-01

    A dual-function all-in-fiber device based on negative dielectric liquid crystal photonic bandgap fibers is presented. This device can work both as an electrically tunable waveplate in the range 1520nm-1580nm, and as a polarimeter at 1310nm....

  5. Study on the Anisotropy of Meniscus in the Growing Sapphire

    Institute of Scientific and Technical Information of China (English)

    YAO Tai; ZUO Hong-bo; HAN Jie-cai; MENG Song-he; ZHANG Ming-fu; LI Chang-qing; Grigoryan Benik

    2006-01-01

    This study is aimed at predicting the relationship between the meniscus and the quality of the sapphire crystals produced by the micro-pulling and shoulder at cooled center (SAPMIC) technique. As with different orientations, the shapes of the meniscus vary, so an investigation into the anisotropy of the meniscus shapes is very important for the final quality of the sapphire crystal. An effective model to describe meniscus shapes and their formation process has been presented. The model has been applied to a sapphire crystal of 200 mm diameter in order to check its reliability. The results show that the model proves to be useful for forecasting the final shapes of the sapphire crystal made by the SAPMIC technique.

  6. Dynamic control of higher-order modes in hollow-core photonic crystal fibers.

    Science.gov (United States)

    Euser, T G; Whyte, G; Scharrer, M; Chen, J S Y; Abdolvand, A; Nold, J; Kaminski, C F; Russell, P St J

    2008-10-27

    We present a versatile method for selective mode coupling into higher-order modes of photonic crystal fibers, using holograms electronically generated by a spatial light modulator. The method enables non-mechanical and completely repeatable changes in the coupling conditions. We have excited higher order modes up to LP(31) in hollow-core photonic crystal fibers. The reproducibility of the coupling allows direct comparison of the losses of different guided modes in both hollow-core bandgap and kagome-lattice photonic crystal fibers. Our results are also relevant to applications in which the intensity distribution of the light inside the fiber is important, such as particle- or atom-guidance.

  7. Harmonic Mode-Locked Fiber Laser based on Photonic Crystal Fiber Filled with Topological Insulator Solution

    Directory of Open Access Journals (Sweden)

    Yu-Shan Chen

    2015-04-01

    Full Text Available We reported that the photonic crystal fiber (PCF filled with TI:Bi2Te3 nanosheets solution could act as an effective saturable absorber (SA. Employing this TI-PCF SA device; we constructed an ytterbium-doped all-fiber laser oscillator and achieved the evanescent wave mode-locking operation. Due to the large cavity dispersion; the fundamental mode-locking pulse had the large full width at half maximum (FWHM of 2.33 ns with the repetition rate of ~1.11 MHz; and the radio frequency (RF spectrum with signal-to-noise ratio (SNR of 61 dB. In addition; the transition dynamics from a bunched state of pulses to harmonic mode-locking (HML was also observed; which was up to 26th order.

  8. Supercontinuum generation from dispersion-flattened photonic crystal fiber using picosecond pulses

    Institute of Scientific and Technical Information of China (English)

    Li He; Bojun Yang; Xiaoguang Zhang; Li Yu

    2006-01-01

    We present the all-fiber system for supercontiuum (SC) generation with picosecond pulses. By launching1.6-ps pulses from pulsed erbium-doped fiber laser (EDFL) into a section of photonic crystal fiber (PCF),the spectral broadening is observed. The bandwidth of 237 nm (at 20 dB level) is achieved.

  9. Hollow-core photonic crystal fiber-optic probes for Raman spectroscopy.

    Science.gov (United States)

    Konorov, Stanislav O; Addison, Christopher J; Schulze, H Georg; Turner, Robin F B; Blades, Michael W

    2006-06-15

    We have implemented a new Raman fiber-optic probe design based on a hollow-core photonic-crystal excitation fiber surrounded by silica-core collection fibers. The photonic-crystal fiber offers low attenuation at the pump radiation wavelength, mechanical flexibility, high radiation stability, and low background noise. Because the excitation beam is transmitted through air inside the hollow-core fiber, silica Raman scattering is much reduced, improving the quality of the spectra obtained using probes of this design. Preliminary results show that the new probe design decreases the Raman background from the silica by approximately an order of magnitude compared to solid-core silica Raman probes.

  10. Micro-displacement sensor based on a hollow-core photonic crystal fiber.

    Science.gov (United States)

    Rodrigues Pinto, Ana Margarida; Baptista, José Manuel; Santos, José Luís; Lopez-Amo, Manuel; Frazão, Orlando

    2012-12-17

    A sensing head based on a hollow-core photonic crystal fiber for in-reflection measurement of micro-displacements is presented. The sensing structure takes advantage of the multimodal behavior of a short segment of hollow-core photonic crystal fiber in-reflection, being spliced to a single mode fiber at its other end. A modal interferometer is obtained when the sensing head is close to a mirror, through which displacement is measured.

  11. Stabilized soliton self-frequency shift and 0.1- PHz sideband generation in a photonic-crystal fiber with an air-hole-modified core.

    Science.gov (United States)

    Liu, Bo-Wen; Hu, Ming-Lie; Fang, Xiao-Hui; Li, Yan-Feng; Chai, Lu; Wang, Ching-Yue; Tong, Weijun; Luo, Jie; Voronin, Aleksandr A; Zheltikov, Aleksei M

    2008-09-15

    Fiber dispersion and nonlinearity management strategy based on a modification of a photonic-crystal fiber (PCF) core with an air hole is shown to facilitate optimization of PCF components for a stable soliton frequency shift and subpetahertz sideband generation through four-wave mixing. Spectral recoil of an optical soliton by a red-shifted dispersive wave, generated through a soliton instability induced by high-order fiber dispersion, is shown to stabilize the soliton self-frequency shift in a highly nonlinear PCF with an air-hole-modified core relative to pump power variations. A fiber with a 2.3-microm-diameter core modified with a 0.9-microm-diameter air hole is used to demonstrate a robust soliton self-frequency shift of unamplified 50-fs Ti: sapphire laser pulses to a central wavelength of about 960 nm, which remains insensitive to variations in the pump pulse energy within the range from 60 to at least 100 pJ. In this regime of frequency shifting, intense high- and low-frequency branches of dispersive wave radiation are simultaneously observed in the spectrum of PCF output. An air-hole-modified-core PCF with appropriate dispersion and nonlinearity parameters is shown to provide efficient four-wave mixing, giving rise to Stokes and anti-Stokes sidebands whose frequency shift relative to the pump wavelength falls within the subpetahertz range, thus offering an attractive source for nonlinear Raman microspectroscopy.

  12. An 8-channel wavelength demultiplexer based on photonic crystal fiber

    Science.gov (United States)

    Malka, Dror

    2017-05-01

    We propose a novel 8-channel wavelength demultiplexer based on photonic crystal fiber (PCF) structures that operate at 1530nm, 1535nm, 1540nm, 1545nm, 1550nm, 1555nm, 1560nm and 1565nm wavelengths. The new design is based on replacing some air-holes zones with silicon nitride and lithium niobate materials along the PCF axis with optimization of the PCF size. The reason of using these materials is because that each wavelength has a different value of coupling length. Numerical investigations were carried out on the geometrical parameters by using a beam propagation method (BPM). Simulation results show that the proposed device can transmit 8-channel that works in the whole C-band (1530- 1565nm) with low crosstalk ((-16.88)-(-15.93) dB) and bandwidth (4.02-4.69nm). Thus, the device can be very useful in optical networking systems that work on dense wavelength division multiplexing (DWDM) technology.

  13. Highly Nonlinear and Birefringent Spiral Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    S. Revathi

    2014-01-01

    Full Text Available We propose and design a spiral photonic crystal fiber with elliptical air holes for achieving high birefringence, large nonlinearity, and negative dispersion. The structure is designed using chalcogenide glass (As2S3 for different ellipticity ratios of air holes in the cladding and the effect on various properties is observed. The proposed structure has birefringence of the order 10−2, nonlinearity of 26739.42 W−1 m−1, and dispersion of −1136.69 at 0.85 μm. An accurate numerical approach based on finite element method is used for the design and simulation of the structure. Due to high birefringence and negative dispersion, the proposed structure can be used for polarization control and dispersion compensation, respectively.

  14. Emerging Applications of Photonic Crystal Fibers (Conference Presentation)

    Science.gov (United States)

    Russell, Philip S. J.

    2016-03-01

    The well-controlled guided modes and long path-lengths offered by both solid and hollow core photonic crystal fibres (PCFs) permit remarkable enhancements (and in some cases reductions) in many kinds of light-matter interaction. Recent examples include: Ultrafast spectrally bright deep and vacuum UV sources based on gas-filled hollow core PCF (pressure-tunable dispersion is a unique feature); generation of stable bright deep UV supercontinuum light in PCF drawn from the fluorozirconate glass ZBLAN; OAM-birefringent helically twisted PCF that preserves the sign of orbital angular momentum; and light-driven optoacoustic devices that permit stable high harmonic mode-locking of fiber ring lasers at GHz repetition rates.

  15. Tunable and rotatable polarization controller using photonic crystal fiber filled with liquid crystal

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2010-01-01

    We design and fabricate a compact tunable and rotatable polarization controller using liquid crystal photonic band gap fibers. The electrically and thermally induced phase shift in the Poincaré sphere and corresponding birefringence change are measured. The direction of the electric field...... is managed by connecting four electrodes in different electrode configurations, and the thermal tunability is controlled by on-chip heaters. According to the results, a quarter-wave plate and a half-wave plate working in the wavelength range of 1520–1600 nm are experimentally demonstrated....

  16. Method of surface treatment on sapphire substrate

    Institute of Scientific and Technical Information of China (English)

    NIU Xin-huan; LIU Yu-ling; TAN Bai-mei; HAN Li-ying; ZHANG Jian-xin

    2006-01-01

    Sapphire single crystals are widely used in many areas because of the special physic properties and important application value. As an important substrate material,stringent surface quality requirements,i.e. surface finish and flatness,are required. The use of CMP technique can produce high quality surface finishes at low cost and with fast material removal rates. The sapphire substrate surface is treated by using CMP method. According to sapphire substrate and its product properties,SiO2 sol is chosen as abrasive. The particle size is 15-25 nm and the concentration is 40%. According to the experiment results,pH value is 10.5-11.5. After polishing and cleaning the sapphire surface,the surface roughness was measured by using AFM method and the lowest value of Ra 0.1 nm was obtained. From the results,it can be seen that using such method,the optimal sapphire surface can be gotten,which is advantageous for epitaxial growth and device making-up.

  17. Silica-air photonic crystal fiber design that permits waveguiding by a true photonic bandgap effect

    DEFF Research Database (Denmark)

    Barkou, Stig Eigil; Broeng, Jes; Bjarklev, Anders Overgaard

    1999-01-01

    A theoretical investigation of a novel type of optical fiber is presented. The operation of the fiber relies entirely on wave guidance through the photonic bandgap effect and not on total internal reflection, thereby distinguishing that fiber from all other known fibers, including recently studied...... photonic crystal fibers. The novel fiber has a central low-index core region and a cladding consisting of a silica background material with air holes situated within a honeycomb lattice structure. We show the existence of photonic bandgaps for the silica–air cladding structure and demonstrate how light can...

  18. Electrically controllable liquid crystal photonic bandgap fiber with dual-frequency control

    DEFF Research Database (Denmark)

    Scolari, Lara; Alkeskjold, Thomas Tanggaard; Riishede, Jesper

    2005-01-01

    We present an electrically tunable liquid crystal photonic bandgap fiber device based on a dual frequency liquid crystal with pre-tilted molecules that allows the bandgaps to be continuously tuned. The frequency dependent behavior of the liquid crystal enables active shifting of the bandgaps toward...

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  20. Structure of shaped sapphire grown from multicapillary dies

    Science.gov (United States)

    Dobrovinskaya, E. R.; Litvinov, L. A.; Pischik, V. V.

    1990-07-01

    Peculiarities in grain structure development have been studied in sapphire crystals grown with multicapillary channels in the die to feed melt to the crystallization zone. A new mechanism of grain boundary formation based on gas-bubble collapse at the crystal-melt interface is proposed.

  1. Photonic crystal distributed feedback fiber lasers with Bragg gratings

    DEFF Research Database (Denmark)

    Søndergaard, Thomas

    2000-01-01

    Two new types of optical fibers, where air-holes are running down their length, are considered for making fiber lasers with Bragg gratings. The mode areas for pump and signal in these fiber lasers may be either larger or smaller compared to the corresponding mode areas for fiber lasers based on s...... on standard step index fibers. This makes possible realization of fiber lasers with a low pump threshold (small mode area), and fiber lasers suitable for high-power applications (large mode area)......Two new types of optical fibers, where air-holes are running down their length, are considered for making fiber lasers with Bragg gratings. The mode areas for pump and signal in these fiber lasers may be either larger or smaller compared to the corresponding mode areas for fiber lasers based...

  2. A test resonator for Kagome Hollow-core Photonic Crystal Fibers for resonant rotation sensing

    Science.gov (United States)

    Fsaifes, Ihsan; Feugnet, Gilles; Ravaille, Alexia; Debord, Benoït; Gérôme, Frédéric; Baz, Assaad; Humbert, Georges; Benabid, Fetah; Schwartz, Sylvain; Bretenaker, Fabien

    2017-01-01

    We build ring resonators to assess the potentialities of Kagome Hollow-Core Photonic Crystal Fibers for future applications to resonant rotation sensing. The large mode diameter of Kagome fibers permits to reduce the free space fiber-to-fiber coupling losses, leading to cavities with finesses of about 30 for a diameter equal to 15 cm. Resonance linewidths of 3.2 MHz with contrasts as large as 89% are obtained. Comparison with 7-cell photonic band gap (PBG) fiber leads to better finesse and contrast with Kagome fiber. Resonators based on such fibers are compatible with the angular random walk required for medium to high performance rotation sensing. The small amount of light propagating in silica should also permit to further reduce the Kerr-induced non-reciprocity by at least three orders of magnitudes in 7-cell Kagome fiber compared with 7-cell PBG fiber.

  3. Triple-wavelength switchable multiwavelength erbium-doped fiber laser based on a highly nonlinear photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Han, Young-Geun [Hanyang University, Seoul (Korea, Republic of)

    2010-04-15

    We propose and experimentally investigate a novel scheme for a triple-wavelength switchable multiwavelength erbium-doped fiber laser based on a highly nonlinear photonic crystal fiber incorporating a multiply-phase-shifted fiber Bragg grating. A nonlinear optical loop mirror based on a highly nonlinear photonic crystal fiber is exploited to suppress the homogeneous line broadening of an erbium-doped fiber amplifier and to provide the triple lasing wavelength switchability. A multiply phase-shifted fiber Bragg grating with three channels, depending on the number of phase-shifted segments, is implemented to establish a multichannel filter and to generate the multiwavelength output. A high-quality multiwavelength output with a high extinction ratio of {approx}45 dB and a high output flatness of {approx}0.3 dB is realized. The switching performance to provide lasing-wavelength selectivity can be realized by using a nonlinear polarization rotation based on a nonlinear optical loop mirror. The lasing wavelength can be switched individually by controlling both the polarization controller within the nonlinear optical loop mirror and the cavity loss. The proposed multiwavelength fiber laser can be operated in the single-, dual-, and triple-lasing wavelength states. Based on the bending technique, the lasing wavelength of the proposed multiwavelength erbium-doped fiber laser can be readily controlled, and its tunability was measured to be {approx}7.2 nm/m{sup -1}.

  4. Influence on photonic crystal fiber dispersion of the size of air holes in different rings within the cladding

    Institute of Scientific and Technical Information of China (English)

    Yanfeng Li(栗岩锋); Bowen Liu(刘博文); zhihang Wang(王子涵); Minglie Hu(胡明列); Qingyue Wang(王清月)

    2004-01-01

    @@ The influence on photonic crystal fiber dispersion of the size of air holes in different rings within thecladding is investigated using a semivectorial finite difference method.Numerical results reveal that thephotonic crystal fiber dispersion is more sensitive to the variation of the air hole size in the first and secondrings,indicating that design of photonic crystal fibers with desirable dispersion properties requires moreprecise control of the paxameters of the air holes in the vicinity of the fiber core.

  5. Fiber Sagnac interferometer based on a liquid-filled photonic crystal fiber for temperature sensing

    Science.gov (United States)

    Liu, Qiang; Li, Shu-Guang; Shi, Min

    2016-12-01

    A fiber Sagnac interferometer based on the square-lattice photonic crystal fiber (PCF) for temperature sensing is designed. All the air holes are assumed to be filled with temperature sensitive liquid. The temperature sensing characteristics are analyzed by finite element method (FEM). The phase birefringence B, the group birefringence Bg, and the sensitivity dependence on the operable wavelength λ are studied, and the temperature varies from 25 °C to 85 °C. The birefringence sensitive coefficient of ∂ B / ∂ T is -10-7 / ° C. The sensitivity could reach to -11.9 nm/°C (-29 750 nm/RIU) at 1.8 μm as the temperature is 25 °C. The sensitivity is also studied by the transmission spectrum, and the wavelength spacing between the resonance wavelengths at 85 °C can reach to 492 nm. The average sensitivity could reach to -7.54 nm/°C (-18 850 nm/RIU). The diameter d1 on the sensing characteristics of the temperature sensor is also analyzed. The temperature sensor shows high sensitivity and broad detecting window.

  6. Intermodal parametric gain of degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    OpenAIRE

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process.

  7. Study on Dispersion Properties of Photonic Crystal Fiber by Effective-Index Model

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The group-velocity-dispersion properties of photonic crystal fiber (PCF) were investigated by effective-index model. The relationship between waveguide dispersion and structure parameters: the pitch A and the relative hole size/was studied.

  8. Study on Dispersion Properties of Photonic Crystal Fiber by Effective-Index Model

    Institute of Scientific and Technical Information of China (English)

    Ren Guobin; Wang Zhi; Lou Shuqin; Jian Shuisheng

    2003-01-01

    The group-velocity-dispersion properties of photonic crystal fiber (PCF) were investigated by effective-index model. The relationship between waveguide dispersion and structure parameters: the pitch and the relative hole size f was studied.

  9. Experimental study on all Yb-doped photonic crystal fiber laser

    Science.gov (United States)

    Fu, Jian; Hou, Zhiyun; Zhou, Guiyao; Zhao, Jingde; Zhang, Wei; Xia, Changming; Cang, Xuelong; Liu, Jiantao

    2017-02-01

    In this paper, we demonstrated an experiment of the all Yb-doped photonic crystal fiber laser using free space optical paths method. The experimental setup of all Yb-doped photonic crystal fiber laser is composed of the seed laser and the amplifier. The laser gain medium of the seed laser and the amplifier are the same Yb-doped photonic crystal fibers that are fabricated by non-chemical vapor deposition (Non-CVD) technology. The seed laser cavity is a Fabry-Perot cavity. The amplifier is pumped by back-end method. They are coupled each other by lens and dichroic mirrors on the optical table. The experimental results have a good reference value for the photonic crystal fiber laser research in the future.

  10. Fiber-optic Michelson interferometer with high sensitivity based on a liquid-filled photonic crystal fiber

    Science.gov (United States)

    Hsu, Jui-Ming; Horng, Jing-Shyang; Hsu, Chia-Ling; Lee, Cheng-Ling

    2014-11-01

    This study proposes an ultracompact and highly sensitive liquid-filled photonic crystal fiber Michelson interferometer (LF-PCFMI) based on material dispersion engineering. Numerical simulations and experimental measurements are performed in the work, and both of their results show that the temperature sensitivity can be more greatly improved than those of conventional photonic crystal fiber interferometers (PCFIs). The experimental results indicate that a very high sensitivity with interference wavelength shifts of almost 27 nm within temperature variation of 5 °C has been achieved by the configuration. Numerical analysis for the proposed LF-PCFMI also exhibits a good agreement with the results of the experimental measurements.

  11. Crystallization kinetics and morphology of melt spun poly(ethylene terephthalate nanocomposite fibers

    Directory of Open Access Journals (Sweden)

    R. R. Hegde

    2013-10-01

    Full Text Available Natural nanoclay closite Na+ incorporated melt spun poly(ethylene terephthalate (PET fibers were investigated for crystallization kinetics and morphology. Nature of clay dispersion and nanocomposite morphology were assessed using wide angle X-ray diffraction (WAXD and transmission electron microscopy (TEM. Fiber mechanical properties were measured using single fiber tensile test. Combination of scanning electron microscopy (SEM and energy dispersive spectroscopy (EDS was used to investigate the fiber failure mode. Among nanocomposite PET fibers, sample with 1% clay performed better. WAXD and TEM micrographs of the fibers revealed intercalated and delaminated morphology. Size of agglomerate increased with percentage of add-on. SEM surface images showed significant variation in fiber diameter, voids and imperfections. Cross-sections of fractured surfaces revealed the presence of clay agglomerates at failure spots. Nanoclay reinforcement did not incur mechanical property benefits due to increase in voids and agglomerates in fiber section, especially at loading levels higher than one percent.

  12. Polishing Sapphire Substrates by 355 nm Ultraviolet Laser

    Directory of Open Access Journals (Sweden)

    X. Wei

    2012-01-01

    Full Text Available This paper tries to investigate a novel polishing technology with high efficiency and nice surface quality for sapphire crystal that has high hardness, wear resistance, and chemical stability. A Q-switched 355 nm ultraviolet laser with nanosecond pulses was set up and used to polish sapphire substrate in different conditions in this paper. Surface roughness Ra of polished sapphire was measured with surface profiler, and the surface topography was observed with scanning electronic microscope. The effects of processing parameters as laser energy, pulse repetition rate, scanning speed, incident angle, scanning patterns, and initial surface conditions on surface roughness were analyzed.

  13. Design of highly sensitive multichannel bimetallic photonic crystal fiber biosensor

    Science.gov (United States)

    Hameed, Mohamed Farhat O.; Alrayk, Yassmin K. A.; Shaalan, Abdelhamid A.; El Deeb, Walid S.; Obayya, Salah S. A.

    2016-10-01

    A design of a highly sensitive multichannel biosensor based on photonic crystal fiber is proposed and analyzed. The suggested design has a silver layer as a plasmonic material coated by a gold layer to protect silver oxidation. The reported sensor is based on detection using the quasi transverse electric (TE) and quasi transverse magnetic (TM) modes, which offers the possibility of multichannel/multianalyte sensing. The numerical results are obtained using a finite element method with perfect matched layer boundary conditions. The sensor geometrical parameters are optimized to achieve high sensitivity for the two polarized modes. High-refractive index sensitivity of about 4750 nm/RIU (refractive index unit) and 4300 nm/RIU with corresponding resolutions of 2.1×10-5 RIU, and 2.33×10-5 RIU can be obtained according to the quasi TM and quasi TE modes of the proposed sensor, respectively. Further, the reported design can be used as a self-calibration biosensor within an unknown analyte refractive index ranging from 1.33 to 1.35 with high linearity and high accuracy. Moreover, the suggested biosensor has advantages in terms of compactness and better integration of microfluidics setup, waveguide, and metallic layers into a single structure.

  14. Dataset on photonic crystal fiber based chemical sensor.

    Science.gov (United States)

    Ahmed, Kawsar; Paul, Bikash Kumar; Chowdhury, Sawrab; Islam, Md Shadidul; Sen, Shuvo; Islam, Md Ibadul; Asaduzzaman, Sayed; Bahar, Ali Newaz; Miah, Mohammad Badrul Alam

    2017-06-01

    This article represents the data set of micro porous core photonic crystal fiber based chemical sensor. The suggested structure is folded cladding porous shaped with circular air hole. Here is investigated four distinctive parameters including relative sensitivity, confinement loss, numerical aperture (NA), and effective area (Aeff). The numerical outcomes are computed over the E+S+C+L+U communication band. The useable sensed chemicals are methanol, ethanol, propanol, butanol, and pentanol whose are lies in the alcohol series (Paul et al., 2017) [1]. Furthermore, V-parameter (V), Marcuse spot size (MSS), and beam divergence (BD) are also investigated rigorously. All examined results have been obtained using finite element method based simulation software COMSOL Multiphysics 4.2 versions with anisotropic circular perfectly matched layer (A-CPML). The proposed PCF shows the high NA from 0.35 to 0.36; the low CL from ~10(-11) to ~10(-7) dB/m; the high Aeff from 5.50 to 5.66 µm(2); the MSS from 1.0 to 1.08 µm; the BD from 0.43 to 0.46 rad at the controlling wavelength λ = 1.55 µm for employing alcohol series respectively.

  15. Dataset on photonic crystal fiber based chemical sensor

    Directory of Open Access Journals (Sweden)

    Kawsar Ahmed

    2017-06-01

    Full Text Available This article represents the data set of micro porous core photonic crystal fiber based chemical sensor. The suggested structure is folded cladding porous shaped with circular air hole. Here is investigated four distinctive parameters including relative sensitivity, confinement loss, numerical aperture (NA, and effective area (Aeff. The numerical outcomes are computed over the E+S+C+L+U communication band. The useable sensed chemicals are methanol, ethanol, propanol, butanol, and pentanol whose are lies in the alcohol series (Paul et al., 2017 [1]. Furthermore, V-parameter (V, Marcuse spot size (MSS, and beam divergence (BD are also investigated rigorously. All examined results have been obtained using finite element method based simulation software COMSOL Multiphysics 4.2 versions with anisotropic circular perfectly matched layer (A-CPML. The proposed PCF shows the high NA from 0.35 to 0.36; the low CL from ~10–11 to ~10−7 dB/m; the high Aeff from 5.50 to 5.66 µm2; the MSS from 1.0 to 1.08 µm; the BD from 0.43 to 0.46 rad at the controlling wavelength λ = 1.55 µm for employing alcohol series respectively.

  16. Intermodal parametric gain of degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process.......Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process....

  17. Boundaries of Parametric Gain due to Four-wave Mixing in Hybrid Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2014-01-01

    Parametric gain by four-wave mixing is considered in photonic crystal fibers for an undepleted pump. The mode distributions are wavelength dependent, thus field overlap integrals cannot be simplified, and an extended gain region is observed......Parametric gain by four-wave mixing is considered in photonic crystal fibers for an undepleted pump. The mode distributions are wavelength dependent, thus field overlap integrals cannot be simplified, and an extended gain region is observed...

  18. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2015-01-01

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching...... the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber. (C) 2015 Optical Society of America...

  19. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-02-15

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber.

  20. Extremely Low Loss THz Guidance Using Kagome Lattice Porous Core Photonic Crystal Fiber

    DEFF Research Database (Denmark)

    Hossain, Anwar; Hasanuzzaman, G.K.M.; Habib, Selim;

    2015-01-01

    A novel porous core Kagome lattice photonic crystal fiber is proposed for extremely low loss THz waves guiding. It has been reported that 82.5% of bulk effective material loss of Topas can be reduced......A novel porous core Kagome lattice photonic crystal fiber is proposed for extremely low loss THz waves guiding. It has been reported that 82.5% of bulk effective material loss of Topas can be reduced...

  1. Optimization of Tapered Photonic Crystal Fibers for Blue-Enhanced Supercontinuum Generation

    DEFF Research Database (Denmark)

    Møller, Uffe; Sørensen, Simon Toft; Larsen, Casper;

    2012-01-01

    Tapering of photonic crystal fibers is an effective way of shifting the dispersive wavelength edge of a supercontinuum spectrum down in the deep-blue. We discuss the optimum taper profile for blue-enhanced supercontinuum generation.......Tapering of photonic crystal fibers is an effective way of shifting the dispersive wavelength edge of a supercontinuum spectrum down in the deep-blue. We discuss the optimum taper profile for blue-enhanced supercontinuum generation....

  2. Soliton compression to few-cycle pulses using quadratic nonlinear photonic crystal fibers: A design study

    DEFF Research Database (Denmark)

    Bache, Morten; Moses, Jeffrey; Lægsgaard, Jesper;

    2007-01-01

    We show theoretically that high-quality soliton compression from ~500 fs to ~10 fs is possible in poled silica photonic crystal fibers using cascaded (2):(2) nonlinearities. A moderate group-velocity mismatch optimizes the compression.......We show theoretically that high-quality soliton compression from ~500 fs to ~10 fs is possible in poled silica photonic crystal fibers using cascaded (2):(2) nonlinearities. A moderate group-velocity mismatch optimizes the compression....

  3. Supercontinuum generation in a photonic crystal fiber pumped by a gain-switched high-power fiber laser

    DEFF Research Database (Denmark)

    Larsen, Casper; Skovgaard, Peter M. W.; Noordegraaf, Danny;

    2011-01-01

    Supercontinuum (SC) generation in nonlinear photonic crystal fibers (NLF) using continuous-wave (CW) fiber lasers for pumping has been studied before[1,2]. The advantages of CW-SC are high spectral smoothness, high spectral power density, simplicity of the system, and lower noise than the more...... common picosecond-pumped SC. The cost of these features is increased nonlinear fiber lengths due to less efficient nonlinear processes at the lower power levels. Especially, the generation of light in the visible wavelength range has been a challenge. This has previously been tackled by increasing...

  4. A Novel Low Loss, Highly Birefringent Photonic Crystal Fiber in THz Regime

    DEFF Research Database (Denmark)

    Hasanuzzaman, G. K. M.; Rana, Sohel; Habib, Selim

    2016-01-01

    We present a new kind of dual-hole unit-based porous-core hexagonal photonic crystal fiber (H-PCF) with low loss and high birefringence in terahertz regime. The proposed fiber offers simultaneously high birefringence and low effective material loss (EML) in the frequency range of 0.5-0.85 THz wit...

  5. Applications of photonic crystal fibers in optical communications - What is in the future?

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Lin, Chinlon

    2005-01-01

    Superior control of guiding properties in photonic-crystal fibers led to several interesting applications in optical communications ranging from nonlinear optical signal processing to high-power fiber amplifiers. This paper will review recent developments and discuss the future possibilities....

  6. Sensitivity of photonic crystal fiber grating sensors: biosensing, refractive index, strain, and temperature sensing

    DEFF Research Database (Denmark)

    Rindorf, Lars Henning; Bang, Ole

    2008-01-01

    We study the sensitivity of fiber grating sensors in the applications of strain, temperature, internal label-free biosensing, and internal refractive index sensing. New analytical expressions for the sensitivities, valid for photonic crystal fibers are rigorously derived. These are generally valid...

  7. Photonic crystal rod fibers: Understanding a new class of active optical waveguides

    DEFF Research Database (Denmark)

    Laurila, Marko

    In this PhD thesis an experimental study of modal characterization methods on large mode area photonic crystal fibers (PCFs) is performed and the development of a new ytterbium-doped photonic bandgap PCF rod fiber is presented. The first focus of this work is to use modal characterization methods...

  8. Small core Chalcogenide photonic crystal fiber for midinfrared wavelength conversion: experiment and design

    OpenAIRE

    Xing, Sida; Grassani, Davide; Kharitonov, Svyatoslav; Billat, Adrien; Brès, Camille-Sophie

    2016-01-01

    Kerr index and dispersion parameter of a small core chalcogenide photonic crystal fiber are estimated via four-wave mixing near 2μm. From these values, new fiber design is proposed to efficiently generate idlers in mid-infrared.

  9. A Novel Low Loss, Highly Birefringent Photonic Crystal Fiber in THz Regime

    DEFF Research Database (Denmark)

    Hasanuzzaman, G. K. M.; Rana, Sohel; Habib, Selim

    2016-01-01

    We present a new kind of dual-hole unit-based porous-core hexagonal photonic crystal fiber (H-PCF) with low loss and high birefringence in terahertz regime. The proposed fiber offers simultaneously high birefringence and low effective material loss (EML) in the frequency range of 0.5-0.85 THz wit...

  10. Comparative properties of cellulose nano-crystals from native and mercerized cotton fibers

    Science.gov (United States)

    Stable aqueous suspensions of cellulose nano-crystals (CNCs) were fabricated from both native and mercerized cotton fibers by sulfuric acid hydrolysis, followed by high-pressure homogenization. Fourier Transform Infrared Spectrometry and Wide-angle X-Ray Diffraction data showed that the fibers had b...

  11. Thermo-optical properties of air-clad photonic crystal fiber lasers in high power operation

    Science.gov (United States)

    Limpert, J.; Schreiber, T.; Liem, A.; Nolte, S.; Zellmer, H.; Peschel, T.; Guyenot, V.; Tünnermann, A.

    2003-11-01

    We report on the investigation of the thermo-optical behavior of air-clad ytterbium-doped large-mode-area photonic crystal fiber lasers. Analytical and numerical models are applied to calculate the heat distribution and induced stresses in a microstructured fiber. The results are compared to conventional double-clad fiber lasers and design guidelines are provided to ensure maximum heat dissipation and scalability to power levels of several kWs.

  12. Four-wave mixing instabilities in tapered and photonic crystal fibers

    OpenAIRE

    Biancalana, Fabio; Skryabin, Dmitry V.; Ortigosa-Blanch, Arturo

    2002-01-01

    We present an analytical study of four-wave mixing instabilities in tapered fibers and photonic crystal fibers. Our approach avoids the use of Taylor expansion for the linear susceptibility and the slowly-varying envelope approximation. This allows us to describe the generation of sidebands strongly detuned from the pump wave with simultaneous account for the entire dispersion characteristic of a fiber, which is found to be important for describing properly the key role of the parametric inst...

  13. Three-Dimensional Thermal Analysis of 18-Core Photonic Crystal Fiber Lasers

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yi-Bo; YAO Jian-Quan; ZHANG Lei; WANG Yuan; WEN Wu-Qi; JING Lei; DI Zhi-Gang

    2012-01-01

    The three-dimensional thermal properties of 18-core photonic crystal fiber lasers operated under natural convection are investigated. The temperature sensing technique based on a fiber Bragg grating sensor array is proposed to measure the longitudinal temperature distribution of a 1.6-m-long ytterbium-doped 18-core photonic crystal fiber. The results show that the temperature decreases from the pump end to the launch end exponentially. Moreover, the radial temperature distribution of the fiber end is investigated by using the full-vector finite-element method. The numerical results match well with the experimental data and the coating temperature reaches 422.7K, approaching the critical value of polymer cladding, when the pumping power is 40 W. Therefore the fiber end cooling is necessary to achieve power scaling. Compared with natural convection methods, the copper cooling scheme is found to be an effective method to reduce the fiber temperature.%The three-dimensional thermal properties of 18-core photonic crystal fiber lasers operated under natural convection are investigated.The temperature sensing technique based on a fiber Bragg grating sensor array is proposed to measure the longitudinal temperature distribution of a 1.6-m-long ytterbium-doped 18-core photonic crystal fiber.The results show that the temperature decreases from the pump end to the launch end exponentially.Moreover,the radial temperature distribution of the fiber end is investigated by using the full-vector finite-element method.The numerical results match well with the experimental data and the coating temperature reaches 422.7K,approaching the critical value of polymer cladding,when the pumping power is 40 W.Therefore the fiber end cooling is necessary to achieve power scaling.Compared with natural convection methods,the copper cooling scheme is found to be an effective method to reduce the fiber temperature.

  14. Bending Loss Analysis of Optical Fiber with Out-Cladding of Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new type of optical fiber is presented here. It consists of a coaxial optical fiber, bounded by dielectric, multilayer and omnidirectional reflecting mirrors. Jones matrix method is used to analyze the influence of the layer number of one-Dimensional (1D) photonic crystals on their reflectivity. The numerical results show that this type of fiber can be used to guide light around sharp bends whose radius of curvature can be as small as the wavelength of light without significant scattering losses.

  15. Square-lattice large-pitch hollow-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Couny, F.; Roberts, John; Birks, T.A.;

    2008-01-01

    We report on the design, fabrication and characterization of silica square-lattice hollow core photonic crystal fibers optimized for low loss guidance over an extended frequency range in the mid-IR region of the optical spectrum. The fiber's linear optical properties include an ultra-low group...... velocity dispersion and a polarization cross-coupling as low as -13.4dB over 10m of fiber....

  16. Electromagnetically induced transparency in Rb-filled coated hollow-core photonic crystal fiber

    Science.gov (United States)

    Light, P. S.; Benabid, F.; Couny, F.; Maric, M.; Luiten, A. N.

    2007-05-01

    We report the observation of lambda-configuration electromagnetically induced transparency as well as optical pumping in rubidium-filled kagome-structure hollow-coated-core photonic crystal fiber. We show that a polydimethylsiloxane coating of the fiber core reduces the linewidth of the transparency below that which could be expected for an uncoated fiber. The measured 6 MHz linewidth was dominated by optical broadening.

  17. Reduction of Guided Acoustic Wave Brillouin Scattering in Photonic Crystal Fibers

    CERN Document Server

    Elser, D; Gloeckl, O; Korn, A; Leuchs, G; Lorenz, S; Marquardt, C; Marquardt, Ch.

    2005-01-01

    Guided Acoustic Wave Brillouin Scattering (GAWBS) generates phase and polarization noise of light propagating in glass fibers. This excess noise affects the performance of various experiments operating at the quantum noise limit. We experimentally demonstrate the reduction of GAWBS noise in a photonic crystal fiber in a broad frequency range using cavity sound dynamics. We compare the noise spectrum to the one of a standard fiber and observe a roughly 10-fold noise reduction in the frequency range up to 200 MHz.

  18. Photonic crystal fiber as lab-in-fiber optofluidic platform for sensing and process monitoring

    Science.gov (United States)

    Tian, Fei

    The ability to design and fabricate photonic crystal fiber (PCF) of vastly different microstructural and optical characteristics is arguably one of the most significant recent advances in the field of fiber optics. This dissertation aims to advance the PCF research frontier by exploring long-period fiber gratings (LPG) inscribed in PCF for sensing and process monitoring via combined numerical and experimental investigation. Specifically, a mode solver based on the Finite Element Method (FEM) has been employed to calculate the mode field distribution, the phase matching condition, and the dispersive characteristics associated with LPG-induced coupling of the fundamental core mode (LP01) to various cladding modes (LPmn, m=0,1; n=2,3, ...) in an endlessly single mode PCF. The numerical results have been used to guide the design and fabrication of LPG in PCF by CO2 laser inscription to maximize index sensitivity in gas or liquid medium. Cascaded PCF-LPG has been fabricated and shown to exhibit record sensitivity in excess of 1700 nm/RIU with high resolution for index measurements of gas phase. The inherent interference fringes in the transmission spectrum of cascaded PCF-LPG have been utilized to analyze mode coupling behaviour. In addition, we have developed and implemented a reflective mirror-aided method to allow symmetrical CO2 laser irradiation of PCF during LPG inscription. Both numerical analysis and experimental measurements have shown significantly improved mode coupling behaviour, mode field distribution, as well as reproducibility in LPG fabrication, critical for practical exploitation of the PCF-LPG platform. We have further exploited the high index sensitivity of PCF-LPG to monitor layer-by-layer (LbL) self-assembly of poly(vinyl pyrrolidone) (PVPON) and poly(methacrylic acid) (PMAA) polyelectrolyte layers as well as the pH responsiveness of the cross-linked PMAA hydrogel films. A shift of ˜1.625 nm in the resonance wavelength per polyelectrolyte layer

  19. Overcoming drug crystallization in electrospun fibers--Elucidating key parameters and developing strategies for drug delivery.

    Science.gov (United States)

    Seif, Salem; Franzen, Lutz; Windbergs, Maike

    2015-01-15

    For the development of novel therapeutics, uncontrolled crystallization of drugs within delivery systems represents a major challenge. Especially for thin and flexible polymeric systems such as oral films or dermal wound dressings, the formation and growth of drug crystals can significantly affect drug distribution and release kinetics as well as physical storage stability. In this context, electrospinning was introduced as a fabrication technique with the potential to encapsulate drugs within ultrafine fibers by rapid solvent evaporation overcoming drug crystallization during fabrication and storage. However, these effects could so far only be shown for specific drug-polymer combinations and an in-depth understanding of the underlying processes of drug-loaded fiber formation and influencing key parameters is still missing. In this study, we systematically investigated crystal formation of caffeine as a model drug in electrospun fibers comparing different polymers. The solvent polarity was found to have a major impact on the drug crystal formation, whereas only a minor effect was attributed to the electrospinning process parameters. Based on an in-depth understanding of the underlying processes determining drug crystallization processes in electrospun fibers, key parameters could be identified which allow for the rational development of drug-loaded electrospun fibers overcoming drug crystallization.

  20. The emulsion crystallization of hydrogenated castor oil into long thin fibers

    Science.gov (United States)

    De Meirleir, Niels; Pellens, Linda; Broeckx, Walter; De Malsche, Wim

    2013-11-01

    The present study discusses the optimal crystal growth conditions required for the emulsion crystallization of hydrogenated castor oil (HCO) into several crystal morphologies. The best possible crystal shape is furthermore identified in case high rheology modifying performance is required. HCO was crystallized in a meso- and micro-continuous process which allowed for a controlled and fast screening of several crystal morphologies at different crystallization conditions. Applying high isothermal temperatures (above 55 °C) resulted in a combination of rosettes, thick fibers and thin fibers. At lower isothermal temperatures (below 55 °C) the shape gradually evolved to a combination of short needles, spherically shaped and/or irregularly shaped crystals. Crystals with the highest aspect ratio were obtained when crystals were grown between 30 °C and 45 °C and were subsequently reheated above 63 °C, forming high amounts of large thin fibrous crystals. When diluted to 0.25 wt% these fibrous crystals increased the low shear viscosity far better compared to the other crystal shapes.

  1. Supercontinuum generation in a photonic crystal fiber with two zero dispersion wavelengths

    DEFF Research Database (Denmark)

    Hilligsøe, Karen Marie; Andersen, T.V.; Paulsen, H.N.;

    2004-01-01

    -wave mixing and not soliton fission as in the initial photonic crystal fibers. The supercontinuum has high spectral density and is extremely independent of the input pulse over a wide range of input pulse parameters. Simulations show that the supercontinuum can be compressed to ultrashort pulses.......We demonstrate supercontinuum generation in a highly nonlinear photonic crystal fiber with two closely lying zero dispersion wavelengths. The special dispersion of the fiber has a profound influence on the supercontinuum which is generated through self-phase modulation and phasematched four...

  2. Genetic algorithms optimization of photonic crystal fibers for half diffraction angle reduction of output beam.

    Science.gov (United States)

    Lu, Jyun-Hong; Cai, Dong-Po; Tsai, Ya-Lun; Chen, Chii-Chang; Lin, Chu-En; Yen, Ta-Jen

    2014-09-22

    In this work, we optimize the structure of the photonic crystal fibers by using genetic algorithms to provide strong light confinement in fiber and small half diffraction angle of output beam. Furthermore, this article shows the potentials of this study, such as optimizing three purposes at the same time and the arbitrary structure design is achieved. We report two optimized results obtained by different optimization conditions. The results show that the half diffraction angle of the output beam of the photonic crystal fibers can be reduced.

  3. Supercontinuum generation in a photonic crystal fiber with two zero dispersion wavelengths

    DEFF Research Database (Denmark)

    Hilligsøe, Karen Marie; Andersen, Thomas Vestergaard; Paulsen, Henrik Nørgaard

    2004-01-01

    We demonstrate supercontinuum generation in a highly nonlinear photonic crystal fiber with two closely lying zero dispersion wavelengths. The special dispersion of the fiber has a profound influence on the supercontinuum which is generated through self-phase modulation and phasematched four-wave...... mixing and not soliton fission as in the initial photonic crystal fibers. The supercontinuum has high spectral density and is extremely independent of the input pulse over a wide range of input pulse parameters. Simulations show that the supercontinuum can be compressed to ultrashort pulses....

  4. Polarization splitter based on dual core liquid crystal-filled holey fiber

    Science.gov (United States)

    Wang, Er-Lei; Jiang, Hai-Ming; Xie, Kang; Chen, Chun; Hu, Zhi-Jia

    2016-09-01

    Through filling the liquid crystal into the air holes of a dual-core holey fiber with a simple structure, the transmission mechanism of the fiber is changed from total internal reflection to photonic bandgap (PBG), and a polarization splitter based on the liquid crystal-filled dual-core PBG holey fiber is investigated. The results demonstrate that, by setting appropriate geometrical parameters, the polarization splitter possesses a short length of 890.5 μm, and its wide bandwidth of ˜150 nm almost covers all the S, C, and L communication bands. Besides, it has an excellent electro-interference-resistance property and certain sensitivity to temperature.

  5. High Thermal and Electrical Tunability of Negative Dielectric Liquid Crystal Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Scolari, Lara; Weirich, Johannes;

    2008-01-01

    We infiltrate photonic crystal fibers with negative dielectric liquid crystals. 400nm bandgap shift is obtained in the range 22ºC-80ºC and 119nm shift of the long-wavelength bandgap edge is achieved by applying a voltage of 200V....

  6. Light Diffraction of Aligned Polymer Fibers Periodically Dispersed by Phase Separation of Liquid Crystal and Polymer

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2004-12-01

    We have confirmed light diffraction of aligned polymer fibers obtained by a phase separation of an anisotropic-phase solution of liquid crystal and polymer. He—Ne laser light passing through the polymer fibers was scattered in the axis vertical to the fibers, and had two peaks of light intensity symmetrical to the center of the transmitting laser spot. The two peaks were found to be caused by light diffraction due to the periodic polymer-fiber dispersion because the peaks corresponded to values calculated by intervals between the fibers. The periodical fiber networks are considered to be formed by anisotropic spinodal decomposition. This effect can be used to measure the dispersion order of the polymer fibers.

  7. Depolarized guided acoustic wave Brillouin scattering in hollow-core photonic crystal fibers

    CERN Document Server

    Zhong, Wenjia Elser née; Elser, Dominique; Heim, Bettina; Marquardt, Christoph; Leuchs, Gerd

    2015-01-01

    By performing quantum-noise-limited optical heterodyne detection, we observe polarization noise in light after propagation through a hollow-core photonic crystal fiber (PCF). We compare the noise spectrum to the one of a standard fiber and find an increase of noise even though the light is mainly transmitted in air in a hollow-core PCF. Combined with our simulation of the acoustic vibrational modes in the hollow-core PCF, we are offering an explanation for the polarization noise with a variation of guided acoustic wave Brillouin scattering (GAWBS). Here, instead of modulating the strain in the fiber core as in a solid core fiber, the acoustic vibrations in hollow-core PCF influence the effective refractive index by modulating the geometry of the photonic crystal structure. This induces polarization noise in the light guided by the photonic crystal structure.

  8. Influence of surface treatment of carbon fibers on electrochemical crystallization of calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    TAO Ke; HUANG Su-ping; ZHOU Ke-chao

    2005-01-01

    Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.

  9. Double-clad hollow core photonic crystal fiber for coherent Raman endoscope.

    Science.gov (United States)

    Brustlein, Sophie; Berto, Pascal; Hostein, Richard; Ferrand, Patrick; Billaudeau, Cyrille; Marguet, Didier; Muir, Alistair; Knight, Jonathan; Rigneault, Hervé

    2011-06-20

    Performing label free coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) in endoscope imaging is a challenge, with huge potential clinical benefit. To date, this goal has remained inaccessible because of the inherent coherent Raman noise that is generated in the fiber itself. By developing double-clad hollow core photonic crystal fiber, we demonstrate coherent anti-Stokes Raman scattering and stimulated Raman scattering in an 'endoscope-like' scheme. Both the excitation beams and the collected CARS and SRS signals travel through the same fiber. No CARS and SRS signals are generated within the hollow core fiber even for temporally overlapping pump and Stokes beams, leading to excellent image quality. The CARS and SRS signals generated in the sample are coupled back into a high numerical aperture multimode cladding surrounding the central photonic crystal cladding. We demonstrate this scheme by imaging molecular vibrational bonds of organic crystal deposited on a glass surface.

  10. Kagome Hollow-Core Photonic Crystal Fiber Resonator for Rotation Sensing

    CERN Document Server

    Fsaifes, Ihsan; Debord, Benoît; Gérôme, Frédéric; Baz, Assaad; Humbert, Georges; Benabid, Fetah; Schwartz, Sylvain; Bretenaker, Fabien

    2016-01-01

    We investigate the performances of a Kagome Hollow-Core Photonic Crystal Fiber resonator for rotation sensing applications. The use of a large mode field diameter Kagome fiber permits to reduce the free space fiber-to-fiber coupling losses, allowing the realization of cavities with finesses compatible with the angular random walk required for medium to high performance rotation sensing, while minimizing the Kerr effect induced non reciprocities. Experiments show encouraging results that could lead to a compact, low cost, and robust medium for high performance gyroscope.

  11. Phase sensitivity to temperature of the guiding mode in polarization-maintaining photonic crystal fiber.

    Science.gov (United States)

    Song, Jingming; Sun, Kang; Li, Shuai; Cai, Wei

    2015-08-20

    The propagating phase changing of a polarization-maintaining photonic crystal fiber (PM-PCF) caused by temperature variation is theoretically studied, as well as compared with conventional PANDA fiber. As to verifying numerical analysis, a platform based on a Michelson interferometer for phase versus temperature measurement was built for both kinds of fiber. Experiments show that PM-PCF has similar temperature sensitivity with conventional polarization-maintaining fiber. With optimized PM-PCF design (thinner coating layer and coating material with smaller thermal expansion coefficient), the sensitivity could be further reduced to about 80% of the present level.

  12. Band gap of two-dimensional fiber-air photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shu, E-mail: yangshu5678@163.com; Li, Masha

    2016-04-15

    A two-dimensional photonic crystal (PC) composed of textile fiber and air is initially discussed in this paper. Textile materials are so called soft materials, which are different from the previous PCs composed of rigid materials. The plain wave expansion method is used to calculate band structure of different PCs by altering component properties or structural parameters. Results show that the dielectric constant of textile fibers, fiber filling ratio and lattice arrangement are effective factors which influence PCs' band gap. Yet lattice constant and fiber diameter make inconspicuous influence on the band gap feature.

  13. Crystallization kinetics and thermal resistance of bamboo fiber reinforced biodegradable polymer composites

    Science.gov (United States)

    Thumsorn, S.; Srisawat, N.; On, J. Wong; Pivsa-Art, S.; Hamada, H.

    2014-05-01

    Bamboo fiber reinforced biodegradable polymer composites were prepared in this study. Biodegradable poly(butylene succinate) (PBS) was blended with bamboo fiber in a twin screw extruder with varied bamboo content from 20-0wt%. PBS/bamboo fiber composites were fabricated by compression molding process. The effect of bamboo fiber contents on properties of the composites was investigated. Non-isothermal crystallization kinetic study of the composites was investigated based on Avrami equation. The kinetic parameters indicated that bamboo fiber acted as heterogeneous nucleation and enhanced crystallinity of the composites. Bamboo fiber was well dispersed on PBS matrix and good adhered with the matrix. Tensile strength of the composites slightly deceased with adding bamboo fiber. However, tensile modulus and impact strength of the composites increased when increasing bamboo fiber contents. It can be noted that bamboo fiber promoted crystallization and crystallinity of PBS in the composites. Therefore, the composites were better in impact load transferring than neat PBS, which exhibited improving on impact performance of the composites.

  14. [Study on phase-matching of four-wave mixing spectrum in photonic crystal fiber].

    Science.gov (United States)

    Liu, Xiao-xu; Wang, Shu-tao; Zhao, Xing-tao; Chen, Shuang; Zhou, Gui-yao; Wu, Xi-jun; Li, Shu-guang; Hou, Lan-Tian

    2014-06-01

    In the present paper, the four-wave mixing principle of fiber was analyzed, and the high-gain phase-matching conditions were shown. The nonlinear coefficient and dispersion characteristics of photonic crystal fibers were calculated by multipole method. The phase mismatch characteristics of fibers with multiple zero-dispersion wavelengths were analyzed for the first time. The changing rules of phase matching wavelength with the pump wavelength and the pump power were obtained, and the phase matching curves were shown. The characteristics of phase matching wavelengths for different dispersion curves were analyzed. There are four new excitation wavelengths of four-wave mixing spectrum in two zero-dispersion wavelength photonic crystal fiers. Four-wave mixing spectroscopy of photonic crystal fibers with two zero-dispersion wavelengths was obtained in the experi-ent, which is consistent with the theoretical analysis, and verified the reliability of the phase matching theory. The fiber with multiple zero-dispersion wavelengths can create a ricbhphase-matching topology, excite more four-wave mixing wavelengths, ena-ling enhanced control over the spectral locations of the four-wave mixing and resonant-radiation bands emitted by solitons and short pulses. These provide theoretical guidance for photonic crystal fiber wavelength conversion and supercontinoum generation based on four-wave mixing.

  15. Harnessing rogue wave for supercontinuum generation in cascaded photonic crystal fiber.

    Science.gov (United States)

    Zhao, Saili; Yang, Hua; Zhao, Chujun; Xiao, Yuzhe

    2017-04-03

    Based on induced modulation instability, we present a numerical study on harnessing rogue wave for supercontinuum generation in cascaded photonic crystal fibers. By selecting optimum modulation frequency, we achieve supercontinuum with a great improvement on spectrum stability when long-pulse is used as the pump. In this case, rogue wave can be obtained in the first segmented photonic crystal fiber with one zero dispersion wavelength in a controllable manner. Numerical simulations show that spectral range and flatness can be regulated in an extensive range by cascading a photonic crystal fiber with two zero dispersion wavelengths. Some novel phenomena are observed in the second segmented photonic crystal fiber. When the second zero dispersion wavelength is close to the first one, rogue wave is directly translated into dispersion waves, which is conducive to the generation of smoother supercontinuum. When the second zero dispersion wavelength is far away from the first one, rogue wave is translated into the form of fundamental soliton steadily propagating in the vicinity of the second zero dispersion wavelength. Meanwhile, the corresponding red-shifted dispersion wave is generated when the phase matching condition is met, which is beneficial to the generation of wider supercontinuum. The results presented in this work provide a better application of optical rogue wave to generate flat and broadband supercontinuum in cascaded photonic crystal fibers.

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

    Science.gov (United States)

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

    2016-11-20

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

  17. Integrated optic current transducers incorporating photonic crystal fiber for reduced temperature dependence.

    Science.gov (United States)

    Chu, Woo-Sung; Kim, Sung-Moon; Oh, Min-Cheol

    2015-08-24

    Optical current transducers (OCT) are indispensable for accurate monitoring of large electrical currents in an environment suffering from severe electromagnetic interference. Temperature dependence of OCTs caused by its components, such as wave plates and optical fibers, should be reduced to allow temperature-independent operation. A photonic crystal fiber with a structural optical birefringence was incorporated instead of a PM fiber, and a spun PM fiber was introduced to overcome the temperature-dependent linear birefringence of sensing fiber coil. Moreover, an integrated optic device that provides higher stability than fiber-optics was employed to control the polarization and detect the phase of the sensed optical signal. The proposed OCT exhibited much lower temperature dependence than that from a previous study. The OCT satisfied the 0.5 accuracy class (IIEC 60044-8) and had a temperature dependence less than ± 1% for a temperature range of 25 to 78 °C.

  18. Inner cladding influence on large mode area photonic crystal fiber properties under severe heat load

    Science.gov (United States)

    Coscelli, Enrico; Poli, Federica; Dauliat, Romain; Darwich, Dia; Cucinotta, Annamaria; Selleri, Stefano; Schuster, Kay; Benoît, Aurélien; Jamier, Raphael; Roy, Philippe

    2016-03-01

    Constant innovations of fiber technology over the last twenty years has fueled a huge improvement of the performances of fiber lasers. Further power scaling of fiber lasers is currently hindered by the phenomenon of transverse mode instabilities, a sudden deterioration of output beam quality occurring beyond a certain power threshold due to energy transfer from the fiber fundamental mode to high-order modes. Several studies have pinpointed a thermal origin for this phenomenon. A possible solution is to implement fiber designs capable of providing a robust single-mode operation even under severe heat load, in order to prevent such coupling. In this paper the effects on the propagating modes of the change of the inner cladding size and microstructuration in double-cladding photonic crystal fibers under heating condition are discussed, and related to field confinement and single-mode regime.

  19. Compact Design of an Electrically Tunable and Rotatable Polarizer Based on a Liquid Crystal Photonic Bandgap Fiber

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2009-01-01

    In this letter, a compact electrically controlled broadband liquid crystal (LC) photonic bandgap fiber polarizer is designed and fabricated. A good fiber coupling quality between two single-mode fibers and one 10-mm-long LC-filled photonic crystal fiber is obtained and protected by using SU-8 fiber...... fixing structures during the device assembly. The total insertion loss of this all-in-fiber device is 2.7 dB. An electrically tunable polarization extinction ratio of 21.3 dB is achieved with 45$^{circ}$ rotatable transmission axis as well as switched on and off in the wavelength range of 1300–1600 nm....

  20. Evolution of the sapphire industry: Rubicon Technology and Gavish

    Science.gov (United States)

    Harris, Daniel C.

    2009-05-01

    A. Verneuil developed flame fusion to grow sapphire and ruby on a commercial scale around 1890. Flame fusion was further perfected by Popov in the Soviet Union in the 1930s and by Linde Air Products Co. in the U.S. during World War II. Union Carbide Corp., the successor to Linde, developed Czochralski crystal growth for sapphire laser materials in the 1960s. Stepanov in the Soviet Union published his sapphire growth method in 1959. Edge-Defined Film-Fed Growth (EFG), which is similar to the Stepanov method, was developed by H. Labelle in the U. S. in the 1960s and 1970s. The Heat Exchanger Method (HEM), invented by F. Schmid and D. Viechnicki in 1967 was commercialized in the 1970s. Gradient solidification was invented in Israel in the 1970s by J. Makovsky. The Horizontal Directional Solidification Method (HDSM) proposed by Kh. S. Bagdasorov in the Soviet Union in the 1960s was further developed at the Institute for Single Crystals in Ukraine. Kyropoulos growth of sapphire, known as GOI crystal growth in the Soviet Union, was developed by M. Musatov at the State Optical Institute in St. Petersburg in the 1970s and 1980s. At the Institute for Single Crystals in Ukraine, E. Dobrovinskaya characterized Verneuil, Czochralsky, Bagdasarov, and GOI sapphire. In 1995, she emigrated to the United States and joined S&R Rubicon, founded near Chicago by R. Mogilevsky initially to import sapphire and ruby. Mogilevsky began producing sapphire by the Kyropoulos method in 1999. In 2000 the company name was changed to Rubicon Technology. Today, Dobrovinskaya is Chief Scientist and Rubicon produces high quality Kyropoulos sapphire substrates for solid-state lighting. In 1995, H. Branover of Ben Gurion University and a sole investor founded Gavish, which is Hebrew for "crystal." They invited another veteran of the Ukrainian Institute for Single Crystals, V. Pishchik, to become Chief Scientist. Under Pishchik's technical leadership and J. Sragowicz's business leadership, Gavish now

  1. Optical devices based on liquid crystal photonic bandgap fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard

    2005-01-01

    of LCs combined with the unique waveguiding features of PBG fibers gives the LC filled PCFs unique tunable properties. PBG guidance has been demonstrated for different mesophases of LCs and various functional compact fibers has been demonstrated, which utilitzes the high thermo-optical and electro-optical...... effects of LCs. Thermally controlled spectral filters and broadband switching functionalities, electrically controlled switches, polarizers and polarization rotators and an all-optical modulator has been demonstrated. The waveguiding mechanism of anistotropic PBGs fibers has been analyzed and spectral...

  2. Design of a low-bending-loss large-mode-area photonic crystal fiber

    Science.gov (United States)

    Napierala, Marek; Beres-Pawlik, Elzbieta; Nasilowski, Tomasz; Mergo, Pawel; Berghmans, Francis; Thienpont, Hugo

    2012-04-01

    We present a design of a photonic crystal fiber for high power laser and amplifier applications. Our fiber comprises a core with a diameter larger than 60 μm and exhibits single mode operation when the fiber is bent around a 10 cm radius at a wavelength of 1064 nm. Single mode guidance is enforced by the high loss of higher order modes which exceeds 80 dB/m whereas the loss of the fundamental mode (FM) is lower than 0.03 dB/m. The fiber can therefore be considered as an active medium for compact high power fiber lasers and amplifiers with a nearly diffraction limited beam output. We also analyze our fiber in terms of tolerance to manufacturing imperfections. To do so we employ a statistical design methodology. This analysis reveals those crucial parameters of the fiber that have to be controlled precisely during the fabrication process not to deteriorate the fiber performance. Finally we show that the fiber can be fabricated according to our design and we present experimental results that confirm the expected fiber performance.

  3. 1.55-μm supercontinuum based on dispersion-flattened photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A dispersion-flattened photonic crystal fiber with normal dispersion is designed for generating flat wideband supercontinuum, and the supercontinuum generation in this fiber is numerically analyzed. The results show that by appropriately designing the photonic crystal fiber, it can achieve flattened dispersion in the normal dispersion region. It is found that a fiber characterized by a flattened dispersion with a small normal dispersion is suitable for a flat wideband supercontinuum generation. In the process of spectral broadening, self-phase modulation effect plays a dominant role. By filtering the supercontinuum, pulses with different central wavelength over a wide spectral range can be obtained. The pulse width is determined by the bandwidth of the filter.

  4. Efficient generation of linearly polarized Cerenkov radiation in a photonic crystal fiber with suspended rectangle core

    Science.gov (United States)

    Luo, Xing; Cheng, Lan; Peng, Jinggang; Yang, Luyun; Dai, Nengli; Li, Haiqing; Li, Jinyan

    2017-10-01

    We report high efficiency linearly polarized Cerenkov radiation (CR) generation in a photonic crystal fiber with suspended rectangle core. The frequency up-conversion via the Cerenkov radiation upon pumping of Yb-doped femtosecond fiber laser is discussed in details. Experiment results show that the output spectrum contains, besides the infrared supercontinuum, intense green Cerenkov radiation around 536 nm, which carry about 43% of the pump energy at best. The influence of the high birefringence and dispersion character on the Cerenkov radiation generation is discussed. Experiment and simulation results indicate that the rectangle core photonic crystal fiber acts like single-mode single-polarization fiber at the pump wavelength. Only the pulse component along with the slow axis could be confined in the rectangle core well and release Cerenkov radiation efficiently. The Output green Cerenkov radiation is also demonstrated to be linearly polarized. Experiments results agree well with the theoretical predictions.

  5. Midinfrared optical rogue waves in soft glass photonic crystal fiber

    DEFF Research Database (Denmark)

    Buccoliero, Daniel; Steffensen, Henrik; Ebendorff-Heidepriem, Heike

    2011-01-01

    We investigate numerically the formation of extreme events or rogue waves in soft glass tellurite fibers and demonstrate that optical loss drastically diminishes shot-to-shot fluctuations characteristic of picosecond pumped supercontinuum (SC). When loss is neglected these fluctuations include...... distributions. Our results thus implicitly show that rogue waves will not occur in any SC spectrum that is limited by loss, such as commercial silica fiber based SC sources. © 2011 Optical Society of America....

  6. Optical parametric chirped pulse amplification and spectral shaping of a continuum generated in a photonic band gap fiber.

    Science.gov (United States)

    Hugonnot, E; Somekh, M; Villate, D; Salin, F; Freysz, E

    2004-05-31

    A chirped pulse, spectrally broadened in a photonic bandgap optical fiber by 120 fs Ti:Sapphire laser pulses, is parametrically amplified in a BBO crystal pumped by a frequency doubled nanosecond Nd:YAG laser pulse. Without changing the frequency of the Ti:Sapphire, a spectral tunability of the amplified pulses is demonstrated. The possibility to achieve broader spectral range amplification is confirmed for a non-collinear pump-signal interaction geometry. For optimal non-collinear interaction geometry, the pulse duration of the original and amplified pulse are similar. Finally, we demonstrate that the combination of two BBO crystals makes it possible to spectrally shape the amplified pulses.

  7. New Trends in Amplifiers and Sources via Chalcogenide Photonic Crystal Fibers

    Directory of Open Access Journals (Sweden)

    L. Mescia

    2012-01-01

    Full Text Available Rare-earth-doped chalcogenide glass fiber lasers and amplifiers have great applicative potential in many fields since they are key elements in the near and medium-infrared (mid-IR wavelength range. In this paper, a review, even if not exhaustive, on amplification and lasing obtained by employing rare-earth-doped chalcogenide photonic crystal fibers is reported. Materials, devices, and feasible applications in the mid-IR are briefly mentioned.

  8. Efficient optimization of hollow-core photonic crystal fiber design using the finite-element method

    DEFF Research Database (Denmark)

    Holzlöhner, Ronald; Burger, Sven; Roberts, John;

    2006-01-01

    We employ a finite-element (FE) solver with adaptive grid refinement to model hollow-core photonic crystal fibers (HC-PCFs) whose core is formed from 19 omitted cladding unit cells. We optimize the complete fiber geometry for minimal field intensity at material/air interfaces, which indicates low...... loss and high damage threshold, using multidimensional optimization. The optimal design shows a 99.8 % power fraction within the air and an overlap with a Gaussian mode of 96.9 %....

  9. Recent advancements in transparent ceramics and crystal fibers for high power lasers

    Science.gov (United States)

    Kim, W.; Baker, C.; Villalobos, G.; Florea, C.; Gibson, D.; Shaw, L. B.; Bowman, S.; Bayya, S.; Sadowski, B.; Hunt, M.; Askins, C.; Peele, J.; Aggarwal, I. D.; Sanghera, J. S.

    2013-05-01

    In this paper, we present our recent progress in the development of rare-earth (Yb3+ or Ho3+) doped Lu2O3 and Y2O3 sesquioxides for high power solid state lasers. We have fabricated high quality transparent ceramics using nano-powders synthesized by a co-precipitation method. This was accomplished by developments in high purity powder synthesis and low temperature scalable sintering technology developed at NRL. The optical, spectral and morphological properties as well as the lasing performance from our highly transparent ceramics are presented. In the second part of the paper, we discuss our recent research effort in developing cladded-single crystal fibers for high power single frequency fiber lasers has the potential to significantly exceed the capabilities of existing silica fiber based lasers. Single crystal fiber cores with diameters as small as 35μm have been drawn using high purity rare earth doped ceramic or single crystal feed rods by the Laser Heated Pedestal Growth (LHPG) process. Our recent results on the development of suitable claddings on the crystal fiber core are discussed.

  10. Compact optically-fed microwave true-time delay using liquid crystal photonic bandgap fiber device

    DEFF Research Database (Denmark)

    Wei, Lei; Xue, Weiqi; Chen, Yaohui

    2009-01-01

    Electrically tunable liquid crystal photonic bandgap fiber device based optically-fed microwave true-time delay is demonstrated. A maximum ~60° phase shift and an averaged ~7.2ps true time delay are obtained over the modulation frequency range 1GHz-19GHz.......Electrically tunable liquid crystal photonic bandgap fiber device based optically-fed microwave true-time delay is demonstrated. A maximum ~60° phase shift and an averaged ~7.2ps true time delay are obtained over the modulation frequency range 1GHz-19GHz....

  11. Cross-phase-modulation-induced instability in photonic-crystal fibers.

    Science.gov (United States)

    Serebryannikov, E E; Konorov, S O; Ivanov, A A; Alfimov, M V; Scalora, M; Zheltikov, A M

    2005-08-01

    Cross-phase-modulation-induced instability is identified as a significant mechanism for efficient parametric four-wave-mixing frequency conversion in photonic-crystal fibers. Fundamental-wavelength femtosecond pulses of a Cr, forsterite laser are used in our experiments to transform the spectrum of copropagating second-harmonic pulses of the same laser in a photonic-crystal fiber. Efficient generation of sidebands shifted by more than 80 THz with respect to the central frequency of the second harmonic is observed in the output spectrum of the probe field.

  12. Tailoring the parametric gain in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    The spectral width of parametric gain peaks due to degenerate four-wave mixing is investigated numerically in large-mode-area hybrid photonic crystal fibers. The width is varied for a maintained pump wavelength and gain maximum position by tailoring the dispersion.......The spectral width of parametric gain peaks due to degenerate four-wave mixing is investigated numerically in large-mode-area hybrid photonic crystal fibers. The width is varied for a maintained pump wavelength and gain maximum position by tailoring the dispersion....

  13. Tailoring the parametric gain in large mode areahybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    The spectral width of parametric gain peaks due to degenerate four-wave mixing is investigated numerically in large-mode-area hybrid photonic crystal fibers. The width is varied for a maintained pump wavelength and gain maximum position by tailoring the dispersion.......The spectral width of parametric gain peaks due to degenerate four-wave mixing is investigated numerically in large-mode-area hybrid photonic crystal fibers. The width is varied for a maintained pump wavelength and gain maximum position by tailoring the dispersion....

  14. Compact optically-fed microwave true-time delay using liquid crystal photonic bandgap fiber device

    DEFF Research Database (Denmark)

    Wei, Lei; Xue, Weiqi; Chen, Yaohui;

    2009-01-01

    Electrically tunable liquid crystal photonic bandgap fiber device based optically-fed microwave true-time delay is demonstrated. A maximum ~60° phase shift and an averaged ~7.2ps true time delay are obtained over the modulation frequency range 1GHz-19GHz.......Electrically tunable liquid crystal photonic bandgap fiber device based optically-fed microwave true-time delay is demonstrated. A maximum ~60° phase shift and an averaged ~7.2ps true time delay are obtained over the modulation frequency range 1GHz-19GHz....

  15. Compact Electrically tunable Waveplate Based on Liquid Crystal Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Keller, Stephan Urs

    2009-01-01

    A compact tunable waveplate based on negative dielectric liquid crystal photonic bandgap fibers is presented. The birefringence can be tuned electrically to work as a quarter-wave or a half-wave plate in the wavelength range 1520nm-1600nm.......A compact tunable waveplate based on negative dielectric liquid crystal photonic bandgap fibers is presented. The birefringence can be tuned electrically to work as a quarter-wave or a half-wave plate in the wavelength range 1520nm-1600nm....

  16. Highly tunable large core single-mode liquid crystal photonic bandgap fiber

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper; Bjarklev, Anders Overgaard;

    2006-01-01

    We demonstrate a highly tunable photonic bandgap fiber, which has a large-core diameter of 25 mu m and an effective mode area of 440 mu m(2). The tunability is achieved by infiltrating the air holes of a photonic crystal fiber with an optimized liquid-crystal mixture having a large temperature...... gradient of the refractive indices at room temperature. A bandgap tuning sensitivity of 27 nm/degrees C is achieved at room temperature. The insertion loss is estimated to be less than 0.5 dB and caused mainly by coupling loss between the index-guided mode and the bandgap-guided mode. (c) 2006 Optical...

  17. Polarization Properties of Elliptical-Hole Liquid Crystal Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Tartarini, Giovanni; Pansera, Marco; Alkeskjold, Thomas Tanggaard;

    2007-01-01

    ellipticity allow some phenomena that are not predicted yet, such as polarization-dependent losses and birefringence sign change in the wavelength range used for standard telecom fibers. Control of these features allows the design of new devices for sensing or telecommunication applications......The characteristics of triangular photonic crystal fibers (PCFs) with elliptical holes filled with a nematic liquid crystal (LC) are investigated theoretically. The analysis that is carried out using the finite-element method, including material dispersion effects, shows that LC anisotropy and hole...

  18. Ultraviolet Light Generation in Gas-Filled Kagome Photonic Crystal Fiber

    Science.gov (United States)

    Rodrigues, Sílvia M. G.; Facão, Margarida; Ferreira, Mário F. S.

    2015-03-01

    Kagome hollow-core photonic crystal fibers were found to be ideal for the occurrence of ultrafast non-linear optics. This article reports the optimal conditions for the generation of ultraviolet light using a gas filled kagome hollow-core-photonic crystal fiber. It is shown that by changing the pressure of the gas and the input pulse characteristics, the efficiency of conversion and quality of ultraviolet light can be improved, as well as tuning its central frequency. Results suggest that a highly coherent and tunable ultraviolet light source can be constructed, which can find numerous applications.

  19. Time-stretch analog-to-digital conversion with a photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    TENG Yun; YU Chong-xiu; YUAN Jin-hui; CHEN Jing-xuan; JIN Cang; XU Qian

    2011-01-01

    All-optical analog-to-digital conversion (ADC) has been extensively researched to break through the inherently limited operating speed of electronic devices. In this paper, we use the photonic crystal fiber (PCF) for time-stretch (TS) analog-todigital (A/D) conversion system through generating low noise, linear chirp distribution and fiat super-continuum (SC).Based on the radio frequency (RF) analog signal modulated to the linearly chirped super-continuum, the large-dispersion photonic crystal fiber is used for time-domain stretching.

  20. Analysis of a broadband dispersion compensating photonic crystal fiber raman amplifier

    DEFF Research Database (Denmark)

    Varshney, Shailendra K.; Saitoh, K.; Koshiba, M.;

    2006-01-01

    Using an accurate full-vectorial finite element method, a realistic model of a fabricated dispersion compensating photonic crystal fiber is analyzed. An almost flat Raman-gain spectrum (gain-ripples at just ±0.48-dB) is obtained using a single pump.......Using an accurate full-vectorial finite element method, a realistic model of a fabricated dispersion compensating photonic crystal fiber is analyzed. An almost flat Raman-gain spectrum (gain-ripples at just ±0.48-dB) is obtained using a single pump....

  1. Guiding and amplification properties of rod-type photonic crystal fibers with sectioned core doping

    DEFF Research Database (Denmark)

    Selleri, Stefano; Poli, Federica; Passaro, Davide

    2009-01-01

    been applied to properly design the low refractive index ring in the fiber core, which can provide an increase of the differential overlap between the fundamental and the higher-order mode. Then, the gain competition among the guided modes along the Yb-doped rod-type fibers has been investigated...... with a spatial and spectral amplifier model. Simulation results have shown the effectiveness of the sectioned core doping in worsening the higher-order mode overlap on the doped area, thus providing an effective single-mode behavior of the Yb-doped rod-type photonic crystal fibers....

  2. Hybrid Ytterbium-doped large-mode-area photonic crystal fiber amplifier for long wavelengths

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas T.; Poli, Federica

    2012-01-01

    A large-mode-area Ytterbium-doped photonic crystal fiber amplifier with build-in gain shaping is presented. The fiber cladding consists of a hexagonal lattice of air holes, where three rows are replaced with circular high-index inclusions. Seven missing air holes define the large-mode-area core....... Light confinement is achieved by combined index and bandgap guiding, which allows for single-mode operation and gain shaping through distributed spectral filtering of amplified spontaneous emission. The fiber properties are ideal for amplification in the long wavelength regime of the Ytterbium gain...

  3. Intermodal four-wave mixing from femtosecond pulse-pumped photonic crystal fiber.

    Science.gov (United States)

    Tu, H; Jiang, Z; Marks, D L; Boppart, S A

    2009-03-09

    Large Stokes-shift ( approximately 4700 cm(-1)) four-wave mixing is generated in a deeply normal dispersion regime from a 20 cm commercial large-mode-area photonic crystal fiber pumped by amplified approximately 800 nm femtosecond pulses. The phase-matching condition is realized through an intermodal scheme involving two pump photons in the fundamental fiber mode and a pair of Stokesanti-Stokes photons in a higher-order fiber mode. Over 7% conversion efficiency from the pump input to 586 nm anti-Stokes signal has been attained.

  4. Thermo-tunable hybrid photonic crystal fiber based on solution-processed chalcogenide glass nanolayers

    DEFF Research Database (Denmark)

    Markos, Christos

    2016-01-01

    The possibility to combine silica photonic crystal fiber (PCF) as low-loss platform with advanced functional materials, offers an enormous range of choices for the development of fiber-based tunable devices. Here, we report a tunable hybrid silica PCF with integrated As2S3 glass nanolayers inside...... antiresonances by taking advantage the high thermo-optic coefficient of the solution-processed nanolayers. Two different hybrid fiber structures, with core diameter 10 and 5 mu m, were developed and characterized using a supercontinuum source. The maximum sensitivity was measured to be as high as 3.6 nm...

  5. Selective filling of photonic crystal fibers using focused ion beam milled microchannels

    DEFF Research Database (Denmark)

    Wang, Fei; Yuan, Scott Wu; Hansen, Ole;

    2011-01-01

    We introduce a versatile, robust, and integrated technique to selectively fill fluid into a desired pattern of air holes in a photonic crystal fiber (PCF). Focused ion beam (FIB) is used to efficiently mill a microchannel on the end facet of a PCF before it is spliced to a single-mode fiber (SMF......). Selected air holes are therefore exposed to the atmosphere through the microchannel for fluid filling. A low-loss in-line tunable optical hybrid fiber device is demonstrated by using such a technique. (C) 2011 Optical Society of America...

  6. Large-pitch kagome-structured hollow-core photonic crystal fiber

    Science.gov (United States)

    Couny, F.; Benabid, F.; Light, P. S.

    2006-12-01

    We report the fabrication and characterization of a new type of hollow-core photonic crystal fiber based on large-pitch (˜12μm) kagome lattice cladding. The optical characteristics of the 19-cell, 7-cell, and single-cell core defect fibers include broad optical transmission bands covering the visible and near-IR parts of the spectrum with relatively low loss and low chromatic dispersion, no detectable surface modes and high confinement of light in the core. Various applications of such a novel fiber are also discussed, including gas sensing, quantum optics, and high harmonic generation.

  7. Laser-cooled atoms inside a hollow-core photonic-crystal fiber

    DEFF Research Database (Denmark)

    Bajcsy, Michal; Hofferberth, S.; Peyronel, Thibault

    2011-01-01

    We describe the loading of laser-cooled rubidium atoms into a single-mode hollow-core photonic-crystal fiber. Inside the fiber, the atoms are confined by a far-detuned optical trap and probed by a weak resonant beam. We describe different loading methods and compare their trade-offs in terms...... of implementation complexity and atom-loading efficiency. The most efficient procedure results in loading of ∼30,000 rubidium atoms, which creates a medium with an optical depth of ∼180 inside the fiber. Compared to our earlier study this represents a sixfold increase in the maximum achieved optical depth...

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

    Science.gov (United States)

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

    2011-08-01

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

  9. Investigation of sapphire detector designed for single particle detection

    Energy Technology Data Exchange (ETDEWEB)

    Karacheban, Olena; Hempel, Maria [DESY, Zeuthen (Germany); Brandenburg University of Technology, Cottbus (Germany); Afanaciev, Konstantin [NCPHEP, Minsk (Belarus); Henschel, Hans; Lange, Wolfgang; Leonard, Jessica [DESY, Zeuthen (Germany); Levy, Itamar [Tel Aviv University, Tel Aviv (Israel); Lohmann, Wolfgang [Brandenburg University of Technology, Cottbus (Germany); CERN, Geneva (Switzerland); Novgorodova, Olga [Technical University, Dresden (Germany); Schuwalow, Sergej [DESY, Hamburg (Germany)

    2015-07-01

    For beam halo and beam loss monitoring systems at accelerators extremely radiation hard sensors are needed. Single crystal sapphire is a promising material. Industrially grown sapphire wafers are available in large sizes, are low in cost and can be operated at room temperature. Currently sapphire sensors are used for a beam-loss monitor at FLASH,detecting bunches of particles crossing the sensors simultaneously. Here we present a multichannel detector designed for single minimum ionising particle detection using a stack of sapphire plates. The performance of the detector was studied in a 5 GeV electron beam at DESY-II. The detector was operated together with the EUDET beam telescope, which allowed the reconstruction of the position of the hits at the detector. For each sapphire plate the charge collection efficiency was measured as a function of the bias voltage and the signal size as a function of the hit position with respect to the metal electrodes. The data confirms that mainly electrons contribute to the signal. Based on these results the next generation sapphire detector will be designed.

  10. The tension sensor of Photonic Crystal Fiber based on core-offset splicing and waist-enlarged fiber taper

    Science.gov (United States)

    Fu, Guangwei; Li, Qifeng; Li, Yunpu; Yang, Jiandong; Fu, Xinghu; Bi, Weihong; Li, Yanjun

    2016-10-01

    A tension sensor of Photonic Crystal Fiber(PCF) is presented based on core-offset splicing and waist-enlarged fiber taper. The tension response characteristics of the sensor are studied experimentally. To analyzing the modal interference, many samples with different PCF lengths between the two splicing areas, different core-offset distances and different waist-enlarged fiber taper diameters are fabricated and tested. When the tension range is 0 to 4000μɛ, the results show that the spectrum is blue shift with the increasing of the axial tension. The sensitivity is-2.1 pm/μɛ. The experimental results show that the tension sensitivity can be not influenced by the PCF lengths, the core-offset distances.The waist-enlarged fiber taper diameters and the tension sensor is very sensitive to axial tension and the relationship between the wavelength shift and tension is linearity. To determine the number of the interfering modes, the transmission spectra of these sensor is transformed by the fast fourier transform (FFT) method. There are several peaks in the spatial frequency spectra at these sensors. Only one cladding mode is dominantly excited, while the other cladding modes are weak. The spatial frequency is proportional to the differential mode group index. Compared with the traditional fiber sensor, this sensor has some advantages including the easily fabricated, simple structure and high sensitivity. It can be used in industrial production, building monitoring, aerospace and other fields.

  11. Ultra flat supercontinuum generation in silicate dual core microstructured fiber

    Science.gov (United States)

    Buczynski, R.; Pysz, D.; Martynkien, T.; Lorenc, D.; Kujawa, I.; Nasilowski, T.; Berghmans, F.; Thienpont, H.; Stepien, R.

    2009-08-01

    In this paper we report on ultra flat supercontinuum generation in dual core photonic crystal fiber pumped in the normal dispersion regime. The fiber cladding is fabricated from custom NC21 borosilicate glass while the fiber cores is made of commercially available F2 high index lead-silicate glass from Schott Corp. We investigated the supercontinuum characteristics for single and double core excitation by a Ti:Sapphire oscillator delivering 100 fs pulses centered at 800 nm with an energy of 4.2 nJ. Dual core pumping resulted in appreciable flattening of the supercontinuum spectra in the range 875 - 950 nm.

  12. Polymeric THz 2D Photonic Crystal Filters Fabricated by Fiber Drawing

    DEFF Research Database (Denmark)

    Stecher, Matthias; Jansen, Christian; Ahmadi-Boroujeni, Mehdi

    2012-01-01

    In this paper, we report on a new form of polymeric 2D photonic crystal filters for THz frequencies fabricated using a standard fiber drawing technique. The band stop filters were modeled and designed using the generalized multipole technique. The frequency and angle-dependent transmission...

  13. Silica photonic crystal fiber structure in order to simplify the process of making them

    Directory of Open Access Journals (Sweden)

    Ashkan Ghanbari

    2014-04-01

    Full Text Available In this research, a new structure of photonic crystal fibers(PCFs will be proposed,in which instead of using the aire- holes in the cladding region, the flourine(2% doped solid silica rods in order to reduce the problems associated with deformities of air-holes in the cladding region will be used.Also, in the following, a few of the propagation charactristics of the proposed Photonic Crystal Fiber with a conventional silica Photonic Crystal Fiber such as, Normalized frequency,effective refractive index,total dispersion and higher order dispersions ( Group velocity dispersion and Third Order Dispersion will be analyzed and compared. Finally it will be observed that, the proposed PCF structure is much simpler than the conventional one in the fabrication process. But they are not suitable for femtosecond solitons propagation .Also, it will be shown that, the situation of the conventional Photonic Crystal Fiber is much better than the proposed structure in the femtosecond optical solitons propagation.

  14. Modal dynamics in hollow-core photonic-crystal fibers with elliptical veins.

    Science.gov (United States)

    Hochman, Amit; Leviatan, Yehuda

    2005-08-08

    Modal characteristics of hollow-core photonic-crystal fibers with elliptical veins are studied by use of a recently proposed numerical method. The dynamic behavior of bandgap guided modes, as the wavelength and aspect ratio are varied, is shown to include zero-crossings of the birefringence, polarization dependent radiation losses, and deformation of the fundamental mode.

  15. A selectively coated photonic crystal fiber based surface plasmon resonance sensor

    DEFF Research Database (Denmark)

    Yu, X; Zhang, Y.; Pan, S.S.

    2010-01-01

    We propose a novel design for a photonic crystal fiber based surface plasmonic resonance sensor. The sensor consists of selectively metal-coated air holes containing analyte channels, which enhance the phase matching between the plasmonic mode and the core-guided mode. Good refractive index sensi...

  16. Large-mode-area hybrid photonic crystal fiber amplifier at 1178 nm

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Chen, Mingchen; Shirakawa, Akira

    2015-01-01

    Amplification of 1178 nm light is demonstrated in a large-mode-area single-mode ytterbium-doped hybrid photonic crystal fiber, relying on distributed spectral filtering of spontaneous emission at shorter wavelengths. An output power of 53 W is achieved with 29 dB suppression of parasitic lasing...

  17. On-chip tunable long-period grating devices based on liquid crystal photonic bandgap fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Weirich, Johannes; Alkeskjold, Thomas Tanggaard;

    2009-01-01

    We design and fabricate an on-chip tunable long-period grating device by integrating a liquid crystal photonic bandgap fiber on silicon structures. The transmission axis of the device can be electrically rotated in steps of 45° as well as switched on and off with the response time in the millisec...

  18. Experimental investigation of hollow-core photonic crystal fibers with five photonic band-gaps

    Institute of Scientific and Technical Information of China (English)

    YUAN Jin-hui; HOU Lan-tian; WEI Dong-bin; WANG Hai-yun; ZHOU Gui-yao

    2008-01-01

    The hollow-core photonic crystal fibers (HC-PCFs) with integrity structure have been fabricated with an improved twice stack-and-draw technique. The transmission spectrum shows that five photonic band-gaps within 450-1100 nm have been obtained.And the green light transmission in the HC-PCFs'has been observed remarkably.

  19. Picosecond anti-Stokes generation in a photonic-crystal fiber for interferometric CARS microscopy

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn

    2006-01-01

    We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration...

  20. Tailoring the parametric gain in large mode areahybrid photonic crystal fibers

    OpenAIRE

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    The spectral width of parametric gain peaks due to degenerate four-wave mixing is investigated numerically in large-mode-area hybrid photonic crystal fibers. The width is varied for a maintained pump wavelength and gain maximum position by tailoring the dispersion.

  1. Continuous-wave wavelength conversion in a photonic crystal fiber with two zero-dispersion wavelengths

    DEFF Research Database (Denmark)

    Andersen, T.V.; Hilligsøe, Karen Marie; Nielsen, C.K.;

    2004-01-01

    We demonstrate continuous-wave wavelength conversion through four-wave mixing in an endlessly single mode photonic crystal fiber. Phasematching is possible at vanishing pump power in the anomalous dispersion regime between the two zero-dispersion wavelengths. By mixing appropriate pump and idler...

  2. Linear and nonlinear modeling of light propagation in hollow-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Roberts, John; Lægsgaard, Jesper

    2009-01-01

    Hollow core photonic crystal fibers (HC-PCFs) find applications which include quantum and non-linear optics, gas detection and short high-intensity laser pulse delivery. Central to most applications is an understanding of the linear and nonlinear optical properties. These require careful modeling...

  3. Low Loss Single-Mode Porous-Core Kagome Photonic Crystal Fiber for THz Wave Guidance

    DEFF Research Database (Denmark)

    Hasanuzzaman, G. K. M.; Habib, Selim; Abdur Razzak, S. M.;

    2015-01-01

    A novel porous-core kagome lattice photonic crystal fiber (PCF) is designed and analyzed in this paper for terahertz (THz) wave guidance. Using finite element method (FEM), properties of the proposed kagome lattice PCF are simulated in details including the effective material loss (EML...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  5. THz waveguides, devices and hybrid polymer-chalcogenide photonic crystal fibers

    DEFF Research Database (Denmark)

    Bao, Hualong; Markos, Christos; Nielsen, Kristian;

    2014-01-01

    In this contribution, we review our recent activities in the design, fabrication and characterization of polymer THz waveguides. Besides the THz waveguides, we finally will also briefly show some of our initial results on a novel hybrid polymer photonic crystal fiber with integrated chalcogenide...

  6. Low Loss and Highly Birefringent Hollow-Core Photonic Crystal Fiber

    DEFF Research Database (Denmark)

    Roberts, P. John; Williams, D.P.; Mangan, Brian J.;

    2006-01-01

    A hollow-core photonic crystal fiber design is proposed which enables both low-loss and polarization-maintained signal propagation. The design relies on an arrangement of antiresonant features positioned on the glass ring that surrounds the air core....

  7. Temperature influence on electrically controlled liquid crystal filled photonic bandgap fiber devices

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2009-01-01

    We experimentally investigate the temperature influence on electrically controlled liquid crystal filled photonic bandgap fiber device. The phase shift in the wavelength range 1520nm-1600nm for realizing quarter and half wave plates at different temperatures by applying a certain voltage...

  8. Influence of acoustic waves on supercontinuum generation in photonic crystal fibers.

    Science.gov (United States)

    Acuna Herrera, Rodrigo

    2012-05-01

    In this work, the influence of applying acoustic frequencies to photonic crystal fibers (PCF) on the supercontinuum (SC) generation is presented. We will show numerically the strong influence of coupling modes in PCF in the latest stage of SC and simulations of different scenarios of phase math condition between the modes.

  9. Low Loss and Highly Birefringent Hollow-Core Photonic Crystal Fiber

    OpenAIRE

    2006-01-01

    A hollow-core photonic crystal fiber design is proposed which enables both low-loss and polarization-maintained signal propagation. The design relies on an arrangement of antiresonant features positioned on the glass ring that surrounds the air core.

  10. Perturbative modeling of Bragg-grating-based biosensors in photonic-crystal fibers

    DEFF Research Database (Denmark)

    Burani, Nicola; Lægsgaard, Jesper

    2005-01-01

    We present a modeling study carried out to support the design of a novel, to our knowledge, kind of photonic-crystal fiber (PCF)-based sensor. This device, based on a PCF Bragg grating, detects the presence of selected single-stranded DNA molecules, hybridized to a biofilm in the air holes of the...

  11. Light source design using Kagome-lattice hollow core photonic crystal fibers

    Science.gov (United States)

    Hossain, Md. Anwar; Namihira, Yoshinori

    2014-09-01

    Supercontinuum (SC) light source is designed using high pressure Xe-filled hollow core Kagome-lattice photonic crystal fiber. Using finite element method with perfectly matched layer, SC spectra in normal chromatic dispersion region have been generated using picosecond optical pulses from relatively less expensive laser sources.

  12. Influences of chemical aging on the surface morphology and crystallization behavior of basaltic glass fibers

    DEFF Research Database (Denmark)

    Lund, Majbritt Deichgræber; Yue, Yuanzheng

    2008-01-01

    The impact of aging in high humidity and water on the surface morphology and crystallization behavior of basaltic glass fibers has been studied using scanning electron microscopy, transmission electron microscopy, calorimetry and X-ray diffraction. The results show that interaction between the fi...

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

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Joo; Hin; Chong; Ping; Shum

    2003-01-01

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

  15. Comment on "Design of a broadband highly dispersive pure silica photonic crystal fiber"

    DEFF Research Database (Denmark)

    Mortensen, Niels Asger

    2008-01-01

    In a recent paper, Subbaraman et al. [Appl. Opt. 46, 3263–3268 (2007)] reported a theoretical and numerical study of highly dispersive pure silica photonic crystal fiber supporting group-velocity dispersion exceeding −2 × 104 ps=nm=km. This Comment argues that the authors consider only one of two...

  16. Cascading nonlinearities in an organic single crystal core fiber: The Cerenkov regime

    NARCIS (Netherlands)

    Torruellas, William E.; Krijnen, Gijs; Kim, Dug Y.; Schiek, Roland; Stegeman, George J.; Vidakovic, Petar; Zyss, Joseph

    1994-01-01

    The large nonlinear phase shifts imparted to the fundamental beam during Cerenkov second harmonic generation (SHG) in a DAN, 4-(N,N-dimethylamino)-3-acetamidonitrobenzene, single crystal core fiber are explained and modelled numerically. Cascading upconversion and downconversion processes leads to n

  17. Long period gratings written in large-mode area photonic crystal fiber

    DEFF Research Database (Denmark)

    Nodop, D.; Linke, S.; Jansen, F.

    2008-01-01

    We report for the first time, to the best of our knowledge, on the fabrication and characterization of CO2-laser written long-period gratings in a large-mode area photonic crystal fiber with a core diameter of 25 mu m. The gratings have low insertion losses ( 10 d...

  18. Efficient Mid-Infrared Supercontinuum Generation in Tapered Large Mode Area Chalcogenide Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Petersen, Christian Rosenberg; Engelsholm, Rasmus Dybbro; Markos, Christos

    2017-01-01

    Mid-infrared supercontinuum spanning from 1.8-9  μm with an output power of 41.5 mW is demonstrated by pumping tapered large mode area chalcogenide photonic crystal fibers using a 4 μm optical parametric source....

  19. Switching and counting with atomic vapors in photonic-crystal fibers

    DEFF Research Database (Denmark)

    Peyronel, Thibault; Bajcsy, Michal; Hofferberth, Sebastian

    2012-01-01

    We review our recent experiments demonstrating a hollow-core photonic-crystal fiber loaded with laser-cooled atomic vapor as a system for all-optical switching with pulses containing few hundred photons. Additionally, we discuss the outlooks for improving the efficiency of this switching scheme...

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

    Institute of Scientific and Technical Information of China (English)

    Kevin Cook; John Canning; John Holdsworth; Chris Dewhurst

    2008-01-01

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

  1. Efficient terahertz wave generation from GaP crystals pumped by chirp-controlled pulses from femtosecond photonic crystal fiber amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiang; Shi, Junkai; Xu, Baozhong; Xing, Qirong; Wang, Chingyue [Ultrafast Laser Laboratory, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), Tianjin University, Tianjin 300072 (China); Chai, Lu, E-mail: lu-chai@tju.edu.cn, E-mail: yanfengli@tju.edu.cn; Liu, Bowen; Hu, Minglie; Li, Yanfeng, E-mail: lu-chai@tju.edu.cn, E-mail: yanfengli@tju.edu.cn [Ultrafast Laser Laboratory, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), Tianjin University, Tianjin 300072 (China); MOEMS Key Laboratory (Ministry of Education), Tianjin University, Tianjin 300072 (China); Fedotov, Andrey B. [Physics Department, Russian Quantum Center, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Zheltikov, Aleksei M. [Physics Department, Russian Quantum Center, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843 (United States)

    2014-01-20

    A chirp-tunable femtosecond 10 W, 42 MHz photonic-crystal-fiber oscillator-amplifier system that is capable of delivering sub-60 fs light pulses at 1040 nm is used to demonstrate high-efficiency terahertz radiation generation via optical rectification in GaP crystals only a few millimeters in length. The optimization of the chirp of the fiber-laser pulses is shown to radically enhance the terahertz output, indicating one possible way to more efficiently use these extended nonlinear crystals in compact fiber-pumped terahertz radiation sources.

  2. A Modeling of Photonic Crystal Fiber with a Boundary Integral Equations

    Science.gov (United States)

    Cho, Min Hyung; Cai, Wei; Her, Tsing-Hua; Lee, Youngpak

    2007-03-01

    A boundary integral equation (BIE) for the photonic crystal fiber is formulated using the free space Green's function and Huygen's principle. The BIE reduces the number of unknowns significantly and is flexible to handle the geometry of the fiber owing to its nature of the formulation. The real and imaginary parts of the propagating constant, which is related to the dispersion and the confinement loss of the fiber, are calculated as a function of wavelength for both the air-silica fiber and the photonic bandgap fiber by the root searching method. The numerical simulations show that the air-silica fiber guides the light according to the total internal reflection and that the photonic bandgap fiber guides the light based on the scattering from the Fabry-Perot-like high-index inclusion. As a consequence, the spectrum of photonic bandgap fiber shows the discontinuities, and the locations of discontinuities obtained with BIE are compared with the simple analytical model based on the AntiResonant Reflecting Optical Waveguide (ARROW) model suggested by Natalie et al.

  3. Enhanced four-wave mixing in a hollow-core photonic-crystal fiber.

    Science.gov (United States)

    Konorov, S O; Fedotov, A B; Zheltikov, A M

    2003-08-15

    Hollow-core photonic-crystal fibers are shown to substantially enhance four-wave mixing (FWM) of laser pulses in a gas filling the fiber core. Picosecond pulses of Nd:YAG fundamental radiation and its second harmonic are used to generate a signal at the frequency of the third harmonic by the FWM process 3omega = 2omega + 2omega - omega. The efficiency achieved for this process in a 9-cm-long, 13-microm-hollow-core-diameter photonic-crystal fiber, designed to simultaneously transmit a two-color pump and the FWM signal, is shown to be approximately 800 times higher than the maximum FWM efficiency attainable with the same laser pulses in the tight-focusing regime.

  4. Design of a novel multi channel photonic crystal fiber polarization beam splitter

    Science.gov (United States)

    Zhao, Yunyan; Li, Shuguang; Wang, Xinyu; Wang, Guangyao; Shi, Min; Wu, Junjun

    2017-10-01

    A kind of multi channel dual-core photonic crystal fiber polarization beam splitter is designed. We analyze the effects of the lattice parameters and the thickness of gold layer on the beam splitting by the finite element method. Numerical results show that the thickness of metal layer and the size of the air holes near the fiber cores are closely linked with the nature of the polarization beam splitter. We also obtain that extinction ratio can reach -73.87 dB at 1 . 55 μm wavelength and at 1 . 41 μm, 1 . 65 μm extinction ratio can reach 30.8978 dB and 31.1741 dB, respectively. The comparison of the effect on the characteristic of the photonic crystal fiber with coating no gold is also taken into account.

  5. Soliton compression to ultra-short pulses using cascaded quadratic nonlinearities in silica photonic crystal fibers

    DEFF Research Database (Denmark)

    Bache, Morten; Lægsgaard, Jesper; Bang, Ole;

    2007-01-01

    We investigate the possibility of using poled silica photonic crystal fibers for self-defocusing soliton compression with cascaded quadratic nonlinearities. Such a configuration has promise due to the desirable possibility of reducing the group-velocity mismatch. However, this unfortunately leads...... nonlinearity, and show that compression of nJ pulses to few-cycle duration is possible in such a fiber. A small amount of group-velocity mismatch optimizes the compression.......We investigate the possibility of using poled silica photonic crystal fibers for self-defocusing soliton compression with cascaded quadratic nonlinearities. Such a configuration has promise due to the desirable possibility of reducing the group-velocity mismatch. However, this unfortunately leads...

  6. Crystallization behavior of three-dimensional silica fiber reinforced silicon nitride composite

    Science.gov (United States)

    Qi, Gongjin; Zhang, Changrui; Hu, Haifeng; Cao, Feng; Wang, Siqing; Jiang, Yonggang; Li, Bin

    2005-10-01

    The crystallization behavior of a new type of ceramic matrix composites, three-dimensional silica fiber reinforced silicon nitride matrix composite prepared by perhydropolysilazane infiltration and pyrolysis, was investigated by X-ray diffractometry and Fourier transform infrared spectroscopy. With the post-annealing treatment of the amorphous as-received composite at elevated tempertures of 1400 and 1600 °C in nitrogen atmosphere, there was remarkable suppression of the crystallization of polymer-derived silicon nitride ceramic matrix into α-Si 3N 4 and silica fibers into α-cristobalite, which was probably attributed to the phase of silicon oxynitrides originating from the strong fiber/matrix interfacial chemical reaction.

  7. Midinfrared optical rogue waves in soft glass photonic crystal fiber.

    Science.gov (United States)

    Buccoliero, Daniel; Steffensen, Henrik; Ebendorff-Heidepriem, Heike; Monro, Tanya M; Bang, Ole

    2011-09-12

    We investigate numerically the formation of extreme events or rogue waves in soft glass tellurite fibers and demonstrate that optical loss drastically diminishes shot-to-shot fluctuations characteristic of picosecond pumped supercontinuum (SC). When loss is neglected these fluctuations include extreme events such as formation of highly energetic pulses located at the red end of the spectrum and we obtain right-skewed heavy-tailed distributions characteristic of extreme events statistics. On the other hand, when loss is included bandwidth fluctuations follow Gaussian-like statistical distributions. Our results thus implicitly show that rogue waves will not occur in any SC spectrum that is limited by loss, such as commercial silica fiber based SC sources.

  8. Optical Fiber Sensor Instrumentation for Slagging Coal Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Anbo Wang; Kristie Cooper

    2008-07-19

    Coal gasifier is one of the most promising solutions for clean fossil energy. Refractory thickness monitoring and online real-time temperature measurement is needed for improved reliability and advanced process control for current and future generation power plants. The objective of this program is to design and implement an optical fiber based sensing system that could potentially be used to monitor refractory wall thickness and temperature inside a coal gasifier. For the thickness monitoring, the system should be able to operate at temperatures up to 1000 C. For this temperature range, silica fiber can still work so it is chosen for the sensor design. The measurement is based on a photon counting optical time domain reflectometer. A narrow light pulse is launched into a silica fiber which could be embedded into the gasifier refractory wall, and is partially reflected by the far end of the fiber. The time of flight of the light pulse in the fiber then gives an indication of the position of the fiber end, which is a function of the wall thickness when the fiber is embedded. Results obtained show a measurement accuracy of {+-}2cm in environment of 1000 C with a saw cut fiber end. When the fiber end is corroded by sodium carbide at 900 C, the accuracy is {+-}3cm. For the temperature measurement, a single crystal sapphire fiber sensor is designed. The sapphire fiber guides the broadband light from a light emitting diode to a sapphire wafer functioning as a Fabry-Perot interferometer and the wafer optical thickness is a function of temperature. The returned optical signal is then demodulated by multimode fiber based whitelight interferometry. The system was tested up to 1500 C with a measurement accuracy of {+-}10 C for the entire measurement range.

  9. Anisotropic Laminar Piezocomposite Actuator Incorporating Machined PMN-PT Single Crystal Fibers

    Science.gov (United States)

    Wilkie, W. Keats; Inman, Daniel J.; Lloyd, Justin M.; High, James W.

    2006-01-01

    The design, fabrication, and testing of a flexible, laminar, anisotropic piezoelectric composite actuator utilizing machined PMN-32%PT single crystal fibers is presented. The device consists of a layer of rectangular single crystal piezoelectric fibers in an epoxy matrix, packaged between interdigitated electrode polyimide films. Quasistatic free-strain measurements of the single crystal device are compared with measurements from geometrically identical specimens incorporating polycrystalline PZT-5A and PZT-5H piezoceramic fibers. Free-strain actuation of the single crystal actuator at low bipolar electric fields (+/- 250 V/mm) is approximately 400% greater than that of the baseline PZT-5A piezoceramic device, and 200% greater than that of the PZT-5H device. Free-strain actuation under high unipolar electric fields (0-4kV/mm) is approximately 200% of the PZT-5A baseline device, and 150% of the PZT-5H alternate piezoceramic device. Performance increases at low field are qualitatively consistent with predicted increases based on scaling the low-field d33 piezoelectric constants of the respective piezoelectric materials. High-field increases are much less than scaled d33 estimates, but appear consistent with high-field freestrain measurements reported for similar bulk single-crystal and piezoceramic compositions. Measurements of single crystal actuator capacitance and coupling coefficient are also provided. These properties were poorly predicted using scaled bulk material dielectric and coupling coefficient data. Rules-of-mixtures calculations of the effective elastic properties of the single crystal device and estimated actuation work energy densities are also presented. Results indicate longitudinal stiffnesses significantly lower (50% less) than either piezoceramic device. This suggests that single-crystal piezocomposite actuators will be best suited to low induced-stress, high strain and deflection applications.

  10. Anisotropic Piezocomposite Actuator Incorporating Machined PMN-PT Single Crystal Fibers

    Science.gov (United States)

    Wilkie, W. Keats; Inman, Daniel J.; Lloyd, Justin M.; High, James W.

    2004-01-01

    The design, fabrication, and testing of a flexible, planar, anisotropic piezoelectric composite actuator utilizing machined PMN-32%PT single crystal fibers is presented. The device consists of a layer of rectangular single crystal piezoelectric fibers in an epoxy matrix, packaged between interdigitated electrode polyimide films. Quasistatic free-strain measurements of the single crystal device are compared with measurements from geometrically identical specimens incorporating polycrystalline PZT-5A and PZT-5H piezoceramic fibers. Free-strain actuation of the single crystal actuator at low bipolar electric fields (+/- 250 V/mm) is approximately 400% greater than that of the baseline PZT-5A piezoceramic device, and 200% greater than that of the PZT-5H device. Free-strain actuation under high unipolar electric fields (0-4kV/mm) is approximately 200% of the PZT-5A baseline device, and 150% of the PZT-5H alternate piezoceramic device. Performance increases at low field are qualitatively consistent with predicted increases based on scaling the low-field d(sub 33) piezoelectric constants of the respective piezoelectric materials. High-field increases are much less than scaled d(sub 33) estimates, but appear consistent with high-field freestrain measurements reported for similar bulk single-crystal and piezoceramic compositions. Measurements of single crystal actuator capacitance and coupling coefficient are also provided. These properties were poorly predicted using scaled bulk material dielectric and coupling coefficient data. Rules-of-mixtures calculations of the effective elastic properties of the single crystal device and estimated actuation work energy densities are also presented. Results indicate longitudinal stiffnesses significantly lower (50% less) than either piezoceramic device. This suggests that single-crystal piezocomposite actuators will be best suited to low induced-stress, high strain and deflection applications.

  11. Magneto-optic Crystal Polarization Controller Assisted Mode-Locked Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guang-Zhen; GUI Li-Li; XIAO Xiao-Sheng; YANG Chang-Xi

    2011-01-01

    We report a passively mode-locked erbium-doped fiber laser based on a compact magneto-optic crystal polarization controller. The length of the polarization controller consisting of four magneto-optic crystal rotators and two quarter wave-plates is only 10cm.Adjusting the polarization controller, central wavelength around 1559nm and repetition rate 21.10 MHz mode-locked pulse are obtained. Pulse duration and 3 dB spectrum width are 598.4fs and 6.24nm respectively. Single pulse energy is about 151.7pJ. Because of its small size, low insertion loss,good controllability and negligible dispersion, the magneto-optic crystal polarization controller could be an ideal polarization controller in fiber lasers.

  12. Nonlinear spatial mode imaging of hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Laurila, Marko;

    2013-01-01

    Degenerate spontaneous four wave mixing is studied for the rst time in a large mode area hybrid photonic crystal ber, where light con nement is achieved by combined index- and bandgap guiding. Four wave mixing products are generated on the edges of the bandgaps, which is veri ed by numerical...

  13. Optical trapping and control of nanoparticles inside evacuated hollow core photonic crystal fibers

    Energy Technology Data Exchange (ETDEWEB)

    Grass, David, E-mail: david.grass@univie.ac.at; Fesel, Julian; Hofer, Sebastian G.; Kiesel, Nikolai; Aspelmeyer, Markus, E-mail: markus.aspelmeyer@univie.ac.at [Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, A-1090 Vienna (Austria)

    2016-05-30

    We demonstrate an optical conveyor belt for levitated nanoparticles over several centimeters inside both air-filled and evacuated hollow-core photonic crystal fibers (HCPCF). Detection of the transmitted light field allows three-dimensional read-out of the particle center-of-mass motion. An additional laser enables axial radiation pressure based feedback cooling over the full fiber length. We show that the particle dynamics is a sensitive local probe for characterizing the optical intensity profile inside the fiber as well as the pressure distribution along the fiber axis. In contrast to some theoretical predictions, we find a linear pressure dependence inside the HCPCF, extending over three orders of magnitude from 0.2 mbar to 100 mbar. A targeted application is the controlled delivery of nanoparticles from ambient pressure into medium vacuum.

  14. Wavelength conversion of nanosecond pulses to the mid-IR in photonic crystal fibers.

    Science.gov (United States)

    Herzog, Amir; Shamir, Avishay; Ishaaya, Amiel A

    2012-01-01

    We investigate degenerate four wave mixing with nanosecond pulses in fused silica photonic crystal fibers. Phase-matching curves are calculated taking into account the material and waveguide dispersion. Experiments with a nanosecond pulsed Nd:YAG pump laser and relatively short fiber lengths show more than an octave spanning conversion to idler and signal wavelengths at 3.105 μm and 0.642 μm, respectively. Conversion efficiency depends on the fiber length and pump intensity and is limited in our experiments by damage of the fiber input facet. Our results represent a new stretch towards the limit of the silica transmission window in the mid-infrared (IR).

  15. Optimisation of high average power optical parametric generation using a photonic crystal fiber.

    Science.gov (United States)

    Sloanes, Trefor; McEwan, Ken; Lowans, Brian; Michaille, Laurent

    2008-11-24

    In this paper the length of a photonic crystal fiber is optimised to perform high average output power parametric generation with maximum efficiency. It is shown that the fiber length has to be increased up to 150 m, well beyond the walk-off distance between the pump and signal/idler, to optimize the generation efficiency. In this regime, the Raman process can take over from four-wave mixing and lead to supercontinuum generation. It is shown that the parametric wavelength conversion is directional; probably due to small variations in the core dimensions along the fiber length. The fiber exhibits up to 40% conversion efficiency, with the idler (0.9 microm) and the signal (1.3 microm) having a combined output power of over 1.5 W.

  16. Mach-Zehnder interferometric photonic crystal fiber for low acoustic frequency detections

    Energy Technology Data Exchange (ETDEWEB)

    Pawar, Dnyandeo; Rao, Ch. N.; Kale, S. N., E-mail: sangeetakale2004@gmail.com [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411 025, Maharashtra (India); Choubey, Ravi Kant [Department of Applied Physics, Amity Institute of Applied Sciences, Amity University, Noida 201 313 (India)

    2016-01-25

    Low frequency under-water acoustic signal detections are challenging, especially for marine applications. A Mach-Zehnder interferometric hydrophone is demonstrated using polarization-maintaining photonic-crystal-fiber (PM-PCF), spliced between two single-mode-fibers, operated at 1550 nm source. These data are compared with standard hydrophone, single-mode and multimode fiber. The PM-PCF sensor shows the highest response with a power shift (2.32 dBm) and a wavelength shift (392.8 pm) at 200 Hz. High birefringence values and the effect of the imparted acoustic pressure on this fiber, introducing the difference between the fast and slow axis changes, owing to the phase change in the propagation waves, demonstrate the strain-optic properties of the sensor.

  17. Fluorescence-based remote irradiation sensor in liquid-filled hollow-core photonic crystal fiber

    Science.gov (United States)

    Zeltner, R.; Bykov, D. S.; Xie, S.; Euser, T. G.; Russell, P. St. J.

    2016-06-01

    We report an irradiation sensor based on a fluorescent "flying particle" that is optically trapped and propelled inside the core of a water-filled hollow-core photonic crystal fiber. When the moving particle passes through an irradiated region, its emitted fluorescence is captured by guided modes of the fiber core and so can be monitored using a filtered photodiode placed at the fiber end. The particle speed and position can be precisely monitored using in-fiber Doppler velocimetry, allowing the irradiation profile to be measured to a spatial resolution of ˜10 μm. The spectral response can be readily adjusted by appropriate choice of particle material. Using dye-doped polystyrene particles, we demonstrate detection of green (532 nm) and ultraviolet (340 nm) light.

  18. Nanoparticle detection using fano-resonance photonic crystal on optical fiber-tip

    Science.gov (United States)

    Yang, Daquan; Yuan, Wei; Ji, Yuefeng

    2016-10-01

    Recently, Fano-resonance photonic crystals (PhC) have been employed within a wide variety of nanophotonic structures for different applications, including imaging, filtering, switching, sensing, and so on. In this paper, we propose a convenient and compact fiber-optic sensor based on optical fiber-tips integrated with Fano-resonance pillar-array PhC. The quality factor 1.04×104 and refractive index sensitivity of 226 nm per refractive index unit (RIU) have been demonstrated. In addition, the proposed Fiber-PhC integrated senor structure can be used for nanoparticle detection by checking the reflection spectrum shift with a narrow line-width. Using this method, we demonstrate that the detection of polystyrene nanoparticles with dimensions down to 50 nm in radius can be achieved. Thus, we believe that the design and results presented here are promising and enable the implementation of simple but functional fiber-optic sensors and devices.

  19. Optical trapping and control of nanoparticles inside evacuated hollow core photonic crystal fibers

    CERN Document Server

    Grass, David; Hofer, Sebastian G; Kiesel, Nikolai; Aspelmeyer, Markus

    2016-01-01

    We demonstrate an optical conveyor belt for levitated nano-particles over several centimeters inside both air-filled and evacuated hollow-core photonic crystal fibers (HCPCF). Detection of the transmitted light field allows three-dimensional read-out of the particle center-of-mass motion. An additional laser enables axial radiation pressure based feedback cooling over the full fiber length. We show that the particle dynamics is a sensitive local probe for characterizing the optical intensity profile inside the fiber as well as the pressure distribution along the fiber axis. In contrast to previous indirect measurement methods we find a linear pressure dependence inside the HCPCF extending over three orders of magnitude from 0.2 mbar to 100 mbar. A targeted application is the controlled delivery of nano-particles from ambient pressure into medium vacuum.

  20. Novel asymmetrical twin-core photonic crystal fiber for gain-flattened Raman amplifier

    Institute of Scientific and Technical Information of China (English)

    JIANG HaiMing; XIE Kang; WANG YaFei

    2009-01-01

    A novel asymmetrical twin-core photonic crystal fiber was proposed,whose effective overlap core areaAeff can be designed to synchronize the variation of Raman gain coefficient with respect to frequency.This fiber possesses a higher and flatter Raman gain efficiency coefficient curve rR=gR/Aeff over a specified band of wavelength than a conventional fiber.Therefore,it is a good candidate of gain medium for a flat,broad gain band fiber Raman amplifier.It was numerically demonstrated that for the Raman gain efficiency rR,relative fluctuations of less than 2.2% and 5.7% are achievable in the C (1530-1565 nm)band and L(1565-1625 nm)band,respectively.

  1. Novel asymmetrical twin-core photonic crystal fiber for gain-flattened Raman amplifier

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A novel asymmetrical twin-core photonic crystal fiber was proposed, whose effective overlap core area Aeff can be designed to synchronize the variation of Raman gain coefficient with respect to frequency. This fiber possesses a higher and flatter Raman gain efficiency coefficient curve rR=gR/Aeff over a specified band of wavelength than a conventional fiber. Therefore, it is a good candidate of gain me- dium for a flat, broad gain band fiber Raman amplifier. It was numerically demonstrated that for the Raman gain efficiency rR, relative fluctuations of less than 2.2% and 5.7% are achievable in the C (1530―1565 nm) band and L (1565―1625 nm) band, respectively.

  2. Two-octave supercontinuum generation in a water-filled photonic crystal fiber.

    Science.gov (United States)

    Bethge, J; Husakou, A; Mitschke, F; Noack, F; Griebner, U; Steinmeyer, G; Herrmann, J

    2010-03-15

    Supercontinuum generation in a water-filled photonic crystal fiber is reported. By only filling the central hollow core of this fiber with water, the fiber properties are changed such that the air cladding provides broadband guiding. Using a pump wavelength of 1200 nm and few-microjoule pump pulses, the generation of supercontinua with two-octave spectral coverage from 410 to 1640 nm is experimentally demonstrated. Numerical simulations confirm these results, revealing a transition from a soliton-induced mechanism to self-phase modulation dominated spectral broadening with increasing pump power. Compared to supercontinua generated in glass core photonic fibers, the liquid core supercontinua show a higher degree of coherence, and the larger mode field area and the higher damage threshold of the water core enable significantly higher pulse energies of the white light pulses, ranging up to 0.39microJ.

  3. Mach-Zehnder interferometric photonic crystal fiber for low acoustic frequency detections

    Science.gov (United States)

    Pawar, Dnyandeo; Rao, Ch. N.; Choubey, Ravi Kant; Kale, S. N.

    2016-01-01

    Low frequency under-water acoustic signal detections are challenging, especially for marine applications. A Mach-Zehnder interferometric hydrophone is demonstrated using polarization-maintaining photonic-crystal-fiber (PM-PCF), spliced between two single-mode-fibers, operated at 1550 nm source. These data are compared with standard hydrophone, single-mode and multimode fiber. The PM-PCF sensor shows the highest response with a power shift (2.32 dBm) and a wavelength shift (392.8 pm) at 200 Hz. High birefringence values and the effect of the imparted acoustic pressure on this fiber, introducing the difference between the fast and slow axis changes, owing to the phase change in the propagation waves, demonstrate the strain-optic properties of the sensor.

  4. Core temperature in super-Gaussian pumped air-clad photonic crystal fiber lasers compared with double-clad fiber lasers

    Indian Academy of Sciences (India)

    P Elahi; H Nadgaran; F Kalantarifard

    2007-03-01

    In this paper we investigate the core temperature of air-clad photonic crystal fiber (PCF) lasers pumped by a super-Gaussian (SG) source of order four. The results are compared with conventional double-clad fiber (DCF) lasers pumped by the same super-Gaussian and by top-hat pump profiles.

  5. High-birefringence photonic crystal fiber Michelson interferometer with cascaded fiber Bragg grating for pressure and temperature discrimination

    Science.gov (United States)

    Tan, Xiaoling; Geng, Youfu; Li, Xuejin

    2016-09-01

    A simple and compact interferometer for temperature and pressure discrimination is proposed and demonstrated experimentally. It consists of a short section of high-birefringence photonic crystal fiber (Hi-Bi PCF) and a cascaded fiber Bragg grating (FBG). In the Hi-Bi PCF, two orthogonal polarized modes are employed as optical arms to construct, such as a Michelson interferometer. Combined with a cascaded FBG, pressure and temperature measurements are discriminated by a matrix method, and the pressure sensitivity of Hi-Bi PCF is determined to be around 3.65 nm/MPa. The proposed Michelson interferometer is easy-to-fabricate, flexible, and low-cost, which shows great potential in future applications of remote sensing.

  6. Bandgaps of the Chalcogenide Glass Hollow-Core Photonic Crystal Fiber

    Institute of Scientific and Technical Information of China (English)

    LI Shu-Guang; ZHOU Hong-Song; YIN Guo-Bing

    2011-01-01

    Bandgaps of chalcogenide glass hollow-core photonic crystal fibers (GLS HC-PCFs) are analyzed by using the plane-wave expansion method. A mid-infrared laser can propagate in these low confinement loss fibers when the wavelength falls into the bandgaps. For enlarging the bandgap width, an improved GLS HC-PCF is put forward, the normalized frequency kA of the improved fiber is from 7.2 to 8.5 in its first bandgap. The improved GLS HC-PCF with pitch of 4.2μm can transmit the lights with wavelengths ranging from 3.1μm to 3.7μm.%Bandgaps of chalcogenide glass hollow-core photonic crystal fibers (GLS HC-PCFs) are analyzed by using the plane-wave expansion method.A mid-infrared laser can propagate in these low confinement loss fibers when the wavelength falls into the bandgaps.For enlarging the bandgap width,an improved GLS HC-PCF is put forward,the normalized frequency κA of the improved fiber is from 7.2 to 8.5 in its first bandgap.The improved GLS HC-PCF with pitch of 4.2μm can transmit the lights with wavelengths ranging from 3.1 μm to 3.7 μm.Photonic crystal fibers (PCFs) can be classified into total internal reflection PCFs and photonic bandgap (PBG) PCFs[1] Solid core PCFs are one kind of the total internal reflection PCFs;hollow-core PCFs (HC-PCFs) are a kind of typical PBG fibers.The conception of HC-PCFs was first proposed by Russel in 1991.[2] Later,it was theoretically demonstrated by Birks et al.[3] in 1995.A bandgap photonic crystal fiber was mde by Knight et al.[4] for the first time in 1998.On the basis of these works,the first HC-PCF was designed and made by Cregan et al.[5] in 1999.

  7. Determining residual impurities in sapphire by means of electron paramagnetic resonance and nuclear activation analysis

    Science.gov (United States)

    Bletskan, D. I.; Bratus', V. Ya.; Luk'yanchuk, A. R.; Maslyuk, V. T.; Parlag, O. A.

    2008-07-01

    Sapphire (α-Al2O3) single crystals grown using the Verneuil and Kyropoulos methods have been analyzed using electron paramagnetic resonance and γ-ray spectroscopy with 12-MeV bremsstrahlung excitation. It is established that uncontrolled impurities in the final sapphire single crystals grown by the Kyropoulos method in molybdenum-tungsten crucibles are supplied both from the initial materials and from the furnace and crucible materials

  8. Two Octaves Supercontinuum Generation in Lead-Bismuth Glass Based Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    Ryszard Buczynski

    2014-06-01

    Full Text Available In this paper we report a two octave spanning supercontinuum generation in a bandwidth of 700–3000 nm in a single-mode photonic crystal fiber made of lead-bismuth-gallate glass. To our knowledge this is the broadest supercontinuum reported in heavy metal oxide glass based fibers. The fiber was fabricated using an in-house synthesized glass with optimized nonlinear, rheological and transmission properties in the range of 500–4800 nm. The photonic cladding consists of 8 rings of air holes. The fiber has a zero dispersion wavelength (ZDW at 1460 nm. Its dispersion is determined mainly by the first ring of holes in the cladding with a relative hole size of 0.73. Relative hole size of the remaining seven rings is 0.54, which allows single mode performance of the fiber in the infrared range and reduces attenuation of the fundamental mode. The fiber is pumped into anomalous dispersion with 150 fs pulses at 1540 nm. Observed spectrum of 700–3000 nm was generated in 2 cm of fiber with pulse energy below 4 nJ. A flatness of 5 dB was observed in 950–2500 nm range.

  9. Analysis of band gap of non-bravais lattice photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    Yichao MA; Heming CHEN

    2009-01-01

    This article designs a novel type ofnon-bravais lattice photonic crystal fiber. To form the nesting complexperiod with positive and negative refractive index materials respectively, a cylinder with the same radius and negative refractive index is introduced into the center of each lattice unit cell in the traditional square lattice air-holes photonic crystal fiber. The photonic band-gap of the photonic crystal fiber is calculated numerically by the plane wave expansion method. The result shows that compared with the traditional square photonic band-gap fiber (PBGF),when R/A is 0.35, the refractive index of the substrate, airhole, and medium-column are 1.30, 1.0, and -1.0,respectively. This new PBGF can transmit signal by the photonic band-gap effect. When the lattice constant Λvaries from 1.5 μm to 3.0 μm, the range of the wavelength ranges from 880 nm to 2300 nm.

  10. World's largest sapphire for many applications

    Science.gov (United States)

    Khattak, Chandra P.; Shetty, Raj; Schwerdtfeger, C. Richard; Ullal, Saurabh

    2016-10-01

    Sapphire has been used for many high technology applications because of its excellent optical, mechanical, high temperature, abrasion resistance and dielectric properties. However, it is expensive and the volume of sapphire used has been limited. The potential sapphire requirements for LED and consumer electronic applications are very high. Emphasis has been on producing larger sapphire boules to achieve significant cost reductions so these applications are realized. World's largest sapphire boules, 500 mm diameter 300+kg, have been grown to address these markets.

  11. Continuously tunable all-in-fiber devices based on thermal and electrical control of negative dielectric anisotropy liquid crystal photonic bandgap fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Eskildsen, Lars; Weirich, Johannes;

    2009-01-01

    We infiltrate photonic crystal fibers with a negative dielectric anisotropy liquid crystal. 396nm bandgap shift is obtained in the temperature range 22°C-80°C, and 67 nm shift of long-wavelength bandgap edge is achieved by applying a voltage of 200Vrms. The polarization sensitivity and correspond...

  12. Multiwatt octave-spanning supercontinuum generation in multicore photonic-crystal fiber.

    Science.gov (United States)

    Fang, Xiao-hui; Hu, Ming-lie; Huang, Li-li; Chai, Lu; Dai, Neng-li; Li, Jin-yan; Tashchilina, A Yu; Zheltikov, Aleksei M; Wang, Ching-yue

    2012-06-15

    High-power supercontinuum spanning over more than an octave was generated using a high power femtosecond fiber laser amplifier and a multicore nonlinear photonic crystal fiber (PCF). Long multicore PCFs (as long as 20 m in our experiments) are shown to enable supercontinuum generation in an isolated fundamental supermode, with the manifold of other PCF modes suppressed due to the strong evanescent fields coupling between the cores, providing a robust 5.4 W coherent supercontinuum output with a high spatial and spectral quality within the range of wavelengths from 500 to 1700 nm.

  13. Design of low-loss and highly birefringent hollow-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Roberts, Peter John; Williams, D.P.; Sabert, H.;

    2006-01-01

    A practical hollow-core photonic crystal fiber design suitable for attaining low-loss propagation is analyzed. The geometry involves a number of localized elliptical features positioned on the glass ring that surrounds the air core and separates the core and cladding regions. The size of each...... feature is tuned so that the composite core-surround geometry is antiresonant within the cladding band gap, thus minimizing the guided mode field intensity both within the fiber material and at material / air interfaces. A birefringent design, which involves a 2-fold symmetric arrangement of the features...

  14. Identification of Bloch-modes in hollow-core Photonic Crystal Fiber cladding

    DEFF Research Database (Denmark)

    Couny, F.; Benabid, F.; Roberts, John;

    2007-01-01

    length of fiber. A detailed study of the modes near the edges of the band gap shows that it is formed by the influence of three types of resonator: the glass interstitial apex, the silica strut which joins the neighboring apexes, and the air hole. The cladding electromagnetic field which survives......We report on the experimental visualization of the cladding Bloch-modes of a hollow-core photonic crystal fiber. Both spectral and spatial field information is extracted using the approach, which is based on measurement of the near-field and Fresnel-zone that results after propagation over a short...

  15. Black-light continuum generation in a silica-core photonic crystal fiber.

    Science.gov (United States)

    Sylvestre, T; Ragueh, A R; Lee, M W; Stiller, B; Fanjoux, G; Barviau, B; Mussot, A; Kudlinski, A

    2012-01-15

    We report the observation of a broadband continuum spanning from 350 to 470 nm in the black-light region of the electromagnetic spectrum as a result of picosecond pumping a solid-core silica photonic crystal fiber at 355 nm. This was achieved despite strong absorption and a large normal dispersion of silica glass in the UV. Further investigations reveal that the continuum generation results from the interplay of intermodally phase-matched four-wave mixing and cascaded Raman scattering. We also discuss the main limitations in terms of bandwidth and power due to temporal walk-off, fiber absorption, and the photo darkening effect, and we suggest simple solutions.

  16. Measurement of group-velocity dispersion of Bloch modes in photonic-crystal-fiber rocking filters.

    Science.gov (United States)

    Wong, G K L; Zang, L; Kang, M S; Russell, P St J

    2010-12-01

    We use low-coherence interferometry to measure the group-velocity dispersion (GVD) of the fast and slow Bloch modes of structural rocking filters, produced by twisting a highly birefringent photonic crystal fiber to and fro while scanning a focused CO(2) laser beam along it. The GVD curves in the vicinity of the resonant wavelength differ dramatically from those of the unperturbed fiber, suggesting that rocking filters could be used in the optimization of, e.g., four-wave mixing and supercontinuum generation. Excellent agreement is obtained between theory and experiment.

  17. A photonic crystal cavity-optical fiber tip nanoparticle sensor for biomedical applications

    CERN Document Server

    Shambat, Gary; Khurana, Aman; Provine, J; Sarmiento, Tomas; Cheng, Kai; Cheng, Zhen; Harris, James; Daldrup-Link, Heike; Gambhir, Sanjiv Sam; Vuckovic, Jelena

    2012-01-01

    We present a sensor capable of detecting solution-based nanoparticles using an optical fiber tip functionalized with a photonic crystal cavity. When sensor tips are retracted from a nanoparticle solution after being submerged, we find that a combination of convective fluid forces and optically-induced trapping cause an aggregation of nanoparticles to form directly on cavity surfaces. A simple readout of quantum dot photoluminescence coupled to the optical fiber shows that nanoparticle presence and concentration can be detected through modified cavity properties. Our sensor can detect both gold and iron oxide nanoparticles and can be utilized for molecular sensing applications in biomedicine.

  18. Domain-Reversed Lithium Niobate Single-Crystal Fibers are Potentially for Efficient Terahertz Wave Generation

    Directory of Open Access Journals (Sweden)

    Kitt Reinhardt

    2008-10-01

    Full Text Available Nonlinear frequency conversion remains one of the dominant approaches to efficiently generate THz waves. Significant material absorption in the THz range is the main factor impeding the progress towards this direction. In this research, a new multicladding nonlinear fiber design was proposed to solve this problem, and as the major experimental effort, periodic domain structure was introduced into lithium niobate single-crystal fibers by electrical poling. The introduced periodic domain structures were nondestructively revealed using a crossly polarized optical microscope and a confocal scanning optical microscope for quality assurance.

  19. Investigation on bismuth-oxide photonic crystal fiber for optical parametric amplification

    Institute of Scientific and Technical Information of China (English)

    JIN Cang; RAO Lan; YUAN Jin-hui; SHEN Xiang-wei; YU Chong-xiu

    2011-01-01

    A hexagonal solid-core bismuth-oxide micro-structure fiber is developed to balance its dispersion and nonlinearity. This simulation and calculation results show that the bismuth-oxide photonic crystal fiber (Bi-PCF) has near zero dispersion around 1550 nm. Its dispersion slop in the communication wavelength range is also relatively flat. Moreover, both nonlinear coefficient and model field distribution are obtained. Compared with the experimental results by SiO-PCF, it can be seen that the Bi-PCF shows excellent characteristics for the optical parametric amplification (OPA).

  20. Molecular Dynamics Modeling of PPTA Crystals in Aramid Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Mercer, Brian Scott [Univ. of California, Berkeley, CA (United States)

    2016-05-19

    In this work, molecular dynamics modeling is used to study the mechanical properties of PPTA crystallites, which are the fundamental microstructural building blocks of polymer aramid bers such as Kevlar. Particular focus is given to constant strain rate axial loading simulations of PPTA crystallites, which is motivated by the rate-dependent mechanical properties observed in some experiments with aramid bers. In order to accommodate the covalent bond rupture that occurs in loading a crystallite to failure, the reactive bond order force eld ReaxFF is employed to conduct the simulations. Two major topics are addressed: The rst is the general behavior of PPTA crystallites under strain rate loading. Constant strain rate loading simulations of crystalline PPTA reveal that the crystal failure strain increases with increasing strain rate, while the modulus is not a ected by the strain rate. Increasing temperature lowers both the modulus and the failure strain. The simulations also identify the C N bond connecting the aromatic rings as weakest primary bond along the backbone of the PPTA chain. The e ect of chain-end defects on PPTA micromechanics is explored, and it is found that the presence of a chain-end defect transfers load to the adjacent chains in the hydrogen-bonded sheet in which the defect resides, but does not in uence the behavior of any other chains in the crystal. Chain-end defects are found to lower the strength of the crystal when clustered together, inducing bond failure via stress concentrations arising from the load transfer to bonds in adjacent chains near the defect site. The second topic addressed is the nature of primary and secondary bond failure in crystalline PPTA. Failure of both types of bonds is found to be stochastic in nature and driven by thermal uctuations of the bonds within the crystal. A model is proposed which uses reliability theory to model bonds under constant strain rate loading as components with time-dependent failure rate

  1. Photonic crystal fiber coil sensor for water-depth sensing

    Science.gov (United States)

    Fan, Chen-Feng; Yu, Chin-Ping

    2013-05-01

    We fabricate a PCF coil sensor for water-depth sensing by winding a PCF on a plastic straw. Due to the bending-induced birefringence along the PCF, we can observe clear interference pattern in the output spectrum by placing the PCF coil into a Sagnac fiber loop. As we horizontally immerse the fabricated PCF coil into water, a nonlinear relationship between the water depth and the wavelength shift can be obtained. We have also measured the interference spectrum by vertically immersing the PCF coil into water. We can observe a linear relationship between the water depth and the wavelength shift, and the measured water-depth sensitivity for vertical immersion is -1.17 nm/mm.

  2. Curved Space-Times by Crystallization of Liquid Fiber Bundles

    Science.gov (United States)

    Hélein, Frédéric; Vey, Dimitri

    2017-01-01

    Motivated by the search for a Hamiltonian formulation of Einstein equations of gravity which depends in a minimal way on choices of coordinates, nor on a choice of gauge, we develop a multisymplectic formulation on the total space of the principal bundle of orthonormal frames on the 4-dimensional space-time. This leads quite naturally to a new theory which takes place on 10-dimensional manifolds. The fields are pairs of ((α ,ω ),π), where (α ,ω ) is a 1-form with coefficients in the Lie algebra of the Poincaré group and π is an 8-form with coefficients in the dual of this Lie algebra. The dynamical equations derive from a simple variational principle and imply that the 10-dimensional manifold looks locally like the total space of a fiber bundle over a 4-dimensional base manifold. Moreover this base manifold inherits a metric and a connection which are solutions of a system of Einstein-Cartan equations.

  3. Kinetics of Passive Oxidation of Hi-Nicalon-S SiC Fibers in Wet Air: Relationships between Si02 Scale Thickness, Crystallization, and Fiber Strength (Preprint)

    Science.gov (United States)

    2012-07-01

    crystallize to cristobalite and tridymite in 100 hours at 1000°C or in one hour at 1300°C. Crystallization kinetics for oxidation in wet air were...measured by TEM. Oxidation initially produces an amorphous scale that starts to crystallize to cristobalite and tridymite in 100 hours at 1000°C or in...using reflected light interference fringes observed by optical microscopy. Cross-sectional TEM specimens were prepared from oxidized fibers by

  4. Thermal Stress-Induced Depolarization Loss in Conventional and Panda-Shaped Photonic Crystal Fiber Lasers

    Science.gov (United States)

    Mousavi, Seyedeh Laleh; Sabaeian, Mohammad

    2016-10-01

    We report on the modeling of the depolarization loss in the conventional and panda-shaped photonic crystal fiber lasers (PCFLs) due to the self-heating of the fiber, which we call it thermal stress-induced depolarization loss (TSIDL). We first calculated the temperature distribution over the fiber cross sections and then calculated the thermal stresses/strains as a function of heat load per meter. Thermal stress-induced birefringence (TSIB), which is defined as | n x - n y |, in the core and cladding regions was calculated. Finally, TSIDL was calculated for the conventional and panda-shaped PCFLs as a function of fiber length and, respectively, saturated values of 22 and 25 % were obtained which were independent of heat load per meter. For panda-shaped PCFLs, prior to being saturated, an oscillating and damping behavior against the fiber length was seen where in some lengths reached 35 %. The results are close to an experimental value of 30 % reported for a pulsed PCFL (Limpert et al., Opt Express 12:1313-1319, 2004) where the authors reported a degree of polarization of 70 % (i.e., a depolarization of 30 %). The most important result of this work is a saturation behavior of TSIDL at long-enough lengths of the fiber laser which is independent of heat load per meter. To our knowledge, this the first report of TSIBL for PCFLs.

  5. Molecular Spectroscopy in Hollow-Core Photonic Crystal Fiber at the 10 kHz Level

    Science.gov (United States)

    Wang, Chenchen; Knabe, Kevin; Wu, Shun; Lim, Jinkang; Tillman, Karl; Washburn, Brian; Corwin, Kristan; Wheeler, Natalie; Couny, Francois; Benabid, Fetah

    2010-03-01

    High-accuracy spectroscopy in hollow-core photonic crystal fiber (HC-PCF) is desirable for many applications, including frequency references and trace gas analysis. We demonstrate the narrowest sub-Doppler linewidths attained in HC-PCF using large-core kagome structured fiber. Such fibers can yield highly accurate frequency measurements that are about two orders of magnitude higher than previously reported. A fiber laser is locked to the ^12C2H2 ν1+ν3 P(13) transition inside kagome fiber, and compared with two optical frequency combs referenced to a GPS-disciplined Rb oscillator. The absolute frequency of the measured line center agrees with those measured in power build-up cavities to within 9.3 kHz (1 σ error). Approaches to further narrow the linewidths and improve systematic errors are investigated. The present system thus combines accuracy approaching that of power build-up cavities with the potential to be compact, robust, and integrated into an all-fiber system for a portable near-infrared frequency reference. Supported by AFOSR FA9950-05-1-0304 and NSF ECS-0449295.

  6. Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions

    DEFF Research Database (Denmark)

    Jensen, Jesper Bo Damm; Pedersen, Lars H.; Hoiby, Poul E.

    2004-01-01

    We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding...... crystal guide light with a large fraction of the optical field penetrating into the sample even at wavelengths in the visible range. An effective interaction length of several centimeters is obtained when a sample volume of less than 1 µL is used....

  7. Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions.

    Science.gov (United States)

    Jensen, Jesper B; Pedersen, Lars H; Hoiby, Poul E; Nielsen, Lars B; Hansen, T P; Folkenberg, J R; Riishede, J; Noordegraaf, Danny; Nielsen, Kristian; Carlsen, A; Bjarklev, A

    2004-09-01

    We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding crystal guide light with a large fraction of the optical field penetrating into the sample even at wavelengths in the visible range. An effective interaction length of several centimeters is obtained when a sample volume of less than 1 microL is used.

  8. Numerical modeling of mid-infrared fiber optical parametric oscillator based on the degenerated FWM of tellurite photonic crystal fiber.

    Science.gov (United States)

    Cheng, Huihui; Luo, Zhengqian; Ye, Chenchun; Huang, Yizhong; Liu, Chun; Cai, Zhiping

    2013-01-20

    Mid-infrared fiber optical parametric oscillators (MIR FOPOs) based on the degenerate four-wave mixing (DFWM) of tellurite photonic crystal fibers (PCFs) are proposed and modeled for the first time. Using the DFWM coupled-wave equations, numerical simulations are performed to analyze the effects of tellurite PCFs, single-resonant cavity, and pump source on the MIR FOPO performances. The numerical results show that: (1) although a longer tellurite PCF can decrease the pump threshold of MIR FOPOs to a few watts only, the high conversion-efficiency of MIR idler usually requires a short-length optimum PCF with low loss; (2) compared with the single-pass DFWM configurations of the MIR fiber sources published previously, the stable oscillation of signal light in single-resonant cavity can significantly promote the MIR idler output efficiency. With a suggested tellurite PCF as parametric gain medium, the theoretical prediction indicates that such a MIR FOPO could obtain a wide MIR-tunable range and a high conversion efficiency of more than 10%.

  9. Dual Readout With PWO Crystals and LuAG Crystal Scintillating Fibers

    CERN Document Server

    Auffray, E; Mavromanolakis, G; Abler, D

    2010-01-01

    One of the main challenges for detectors at future high-energy collider experiments is high-precision measurement of hadrons and jet energy and momentum. Such measurement can be provided by the particle flow approach (PFA) that requires a complex highly segmented calorimeter system to identify and to track all particles in a jet. An alternative so-called dual-readout approach consists of simultaneously recording, in an active medium, scintillation light that is proportional to total energy deposit and Cerenkov light that is proportional to the electromagnetic part only, thus allowing extracting the electromagnetic fraction of the total shower energy on an event-by-event basis. The dual-readout method approach can be implemented using several techniques. The first method proposed uses a copper absorber structure containing two types of fibers: quartz fibers that produce Cerenkov light and plastic scintillating fibers that produce scintillation light. A second method proposed is based on the separation of scint...

  10. A compact gamma-ray detector using wavelength-shifting fibers coupled to YAP scintillation crystal

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The performance of a compact position sensitive gamma-ray detector based on wavelength-shifting fibers coupled to YAlO3:Ce scintillation crystal was evaluated using a Monte-Carlo simulation method.The simulation model has been setup using the GEANT4 codes.Compared with the gamma-ray detector based on the YAlO3:Ce scintillation crystal coupled to Hamamastu R2486 position sensitive photomultiplier tube.the results indicate that the gamma-ray detector based on wavelength-shifting fibers readout has good position linearity,good spatial resolution and larger effective field of view.The image and point spread function of measured point were presented.The spatial resolution reaponse as a function of position was obtained.The factors influencing spatial resolution and position linearity were discussed.

  11. Controlled chemical modification of the internal surface of photonic crystal fibers for application as biosensitive elements

    Science.gov (United States)

    Pidenko, Sergey A.; Burmistrova, Natalia A.; Pidenko, Pavel S.; Shuvalov, Andrey A.; Chibrova, Anastasiya A.; Skibina, Yulia S.; Goryacheva, Irina Y.

    2016-10-01

    Photonic crystal fibers (PCF) are one of the most promising materials for creation of constructive elements for bio-, drug and contaminant sensing based on unique optical properties of the PCF as effective nanosized optical signal collectors. In order to provide efficient and controllable binding of biomolecules, the internal surface of glass hollow core photonic crystal fibers (HC-PCF) has been chemically modified with silanol groups and functionalized with (3-aminopropyl) triethoxysilane (APTES). The shift of local maxima in the HC-PCF transmission spectrum has been selected as a signal for estimating the amount of silanol groups on the HC-PCF inner surface. The relationship between amount of silanol groups on the HC-PCF inner surface and efficiency of following APTES functionalization has been evaluated. Covalent binding of horseradish peroxidase (chosen as a model protein) on functionalized PCF inner surface has been performed successively, thus verifying the possibility of creating a biosensitive element.

  12. Tuning quadratic nonlinear photonic crystal fibers for zero group-velocity mismatch

    DEFF Research Database (Denmark)

    Bache, Morten; Nielsen, Hanne; Lægsgaard, Jesper;

    2006-01-01

    We consider an index-guiding silica photonic crystal fiber with a triangular hole pattern and a periodically poled quadratic nonlinearity. By tuning the pitch and the relative hole size, second-harmonic generation with zero group-velocity mismatch is found for any fundamental wavelength above 780...... nm. The nonlinear strength is optimized when the fundamental has maximum confinement in the core. The conversion bandwidth allows for femtosecond-pulse conversion, and 4%-180% W-1 cm-2 relative efficiencies were found. © 2006 Optical Society of America......We consider an index-guiding silica photonic crystal fiber with a triangular hole pattern and a periodically poled quadratic nonlinearity. By tuning the pitch and the relative hole size, second-harmonic generation with zero group-velocity mismatch is found for any fundamental wavelength above 780...

  13. Highly birefringent extruded elliptical-hole photonic crystal fibers with single defect and double defects

    Institute of Scientific and Technical Information of China (English)

    Zhongjiao He

    2009-01-01

    Highly birefringent elliptical-hole photonic crystal fibers(PCFs)with single defect and double defects are proposed,which are suppoosed to be achieved by extruding normal circular-hole PCFs based on a triangular lattice photonic crystal structure.Comparative research on the birefringence and the confinement loss of the proposed PCFs with single defect and double defects is presented.Simulation results show that the proposed PCFs with single defect and double defects can be with high birefringence(even up to the order of 10-2).The confinement loss increases when the ellipticity of the air hole of the PCFs increases,which nevertheless can be overconle by increasing the ring number or the area of the air holes in the fiber cladding.

  14. Conventional and photonic crystal fiber based two-photon fluorescence biosensing

    Science.gov (United States)

    Myaing, Mon Thiri

    Optical fiber probes are widely used in the biomedical field for applications such as optical microscopy, endoscopy, and optical biopsy. Due to their flexibility and small size, optical fibers offer a minimally invasive light interface for imaging and spectroscopic analysis of internal tissue. The development of fluorescent probes for studies of biological processes has increased the importance of developing optical methods for quantitative, in vivo diagnosis. In this dissertation, we discuss the development of a novel two-photon optical fiber fluorescence (TPOFF) probe for real time, in vivo, quantitative fluorescence measurements in biological samples. In order to understand and optimize two-photon excitation through an optical fiber, pulse propagation effects must be considered. We found a simple phenomenological scaling behavior for the energy dependence of the pulse width for negatively pre-chirped pulses propagating in a normally dispersive fiber. As a consequence of this scaling behavior, the dependence of two-photon fluorescence (TPF) on the pulse intensity becomes sub-quadratic. The TPOFF probe employs a scheme where the same single-mode fiber (SMF) is used for both the excitation and collection of TPF. Using this fiber probe, we show quantification of tumor fluorescence both ex vivo and in vivo. In ex vivo measurements of tumors developed from cells expressing the green fluorescence protein (GFP), the TPOFF probe detected fluorescence from tumors with as little as 0.3% GFP cells. These results were similar to flow cytometry analysis of isolated cells from the tumors. The TPOFF measurements of GFP tumors in live, anesthetized mice showed a linear relationship between the measured fluorescence and the percentage of GFP expressing cells. The TPOFF probe was also used in targeted binding experiments of Herceptin antibody and folic acid-dendrimer nanoparticle conjugates. To improve the sensitivity of the TPOFF probe, a double-clad photonic crystal fiber (DCF

  15. Experiment study of wavelength conversion in a dispersion-flattened photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    Qiuguo Wang; Bojun Yang; Lan Zhang; Hu Zhang; Li He

    2007-01-01

    @@ Wavelength conversion based on four-wave mixing (FWM) has been demonstrated using a 40-m dispersion flattened highly nonlinear photonic crystal fiber (HNL-PCF). A conversion efficiency of -26 dB for a pump power of 19.5 dBm and a conversion bandwidth of 28 nm have been obtained, which are limited by the continuous wave (CW) laser wavelength range and tunability of optical band pass filters (OBPFs).

  16. Initial dynamics of supercontinuum generation in highly nonlinear photonic crystal fiber.

    Science.gov (United States)

    Moeser, J T; Wolchover, N A; Knight, J C; Omenetto, F G

    2007-04-15

    We present a theoretical and experimental analysis of supercontinuum generation in very short lengths of high-nonlinearity photonic crystal fibers. The Raman response function for Schott SF6 glass is presented for what is believed to be the first time and used for numerical modeling of pulse propagation. Simulation and experiments are in excellent agreement and demonstrate the rapid transition to regimes of spectral complexity due to higher-order nonlinear effects.

  17. Supercontinuum generation for coherent anti- Stokes Raman scattering microscopy with photonic crystal fibers

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Isomäki, Antti; Hansen, Kim P.

    2011-01-01

    Photonic crystal fiber (PCF) designs with two zero-dispersion wavelengths (ZDWs) are experimentally investigated in order to suggest a novel PCF for coherent anti-Stokes Raman scattering (CARS) microscopy. From our investigation, we select the optimum PCF design and demonstrate a tailored spectrum...... analysis, the nonlinear effects responsible for the spectral broadening are explained to be soliton fission processes, dispersive waves, and stimulated Raman scattering....

  18. Birefringence and dispersion of cylindrically polarized modes in nanobore photonic crystal fiber

    CERN Document Server

    Euser, T G; Joly, N Y; Gabriel, C; Marquardt, C; Zang, L Y; Förtsch, M; Banzer, P; Brenn, A; Elser, D; Scharrer, M; Leuchs, G; Russell, P St J

    2010-01-01

    We demonstrate experimentally and theoretically that a nanoscale hollow channel placed centrally in the solid glass core of a photonic crystal fiber strongly enhances the cylindrical birefringence (the modal index difference between radially and azimuthally polarized modes). Furthermore, it causes a large split in group velocity and group velocity dispersion. We show analytically that all three parameters can be varied over a wide range by tuning the diameters of the nanobore and the core.

  19. Accelerating Solitons in Gas-Filled Hollow-Core Photonic Crystal Fibers

    CERN Document Server

    Facao, M; Almeida, P

    2013-01-01

    We found the self-similar solitary solutions of a recently proposed model for propagation of pulses in gas filled hollow-core photonic crystal fibers that includes a plasma induced nonlinearity. As anticipated for a simpler model and using a perturbation analysis, there are indeed stationary solitary waves that accelerate and self-shift to higher frequencies. However, if the plasma nonlinearity strength is large or the pulse amplitudes are small, the solutions have distinguished long tails and decay as they propagate.

  20. Enhanced nonlinearity in photonic crystal fiber by germanium doping in the core region

    Institute of Scientific and Technical Information of China (English)

    Tingting Sun; Guiyun Kai; Zhi Wang; Shuzhong Yuan; Xiaoyi Dong

    2008-01-01

    Germanium doping in silica can be used as a method for nonlinearity enhancement.Properties of the enhanced nonlinearity in photonic crystal fiber(PCF)with a GeO2-doped core are investigated theoretically by using all-vector finite element method.Numerical result shows that the nonlinear coefficient of PCF is greatly enhanced with increasing doping concentration,furthermore,optimal radius of the doped region should be considered for the desired operating wavelength.

  1. Direct fiber-coupled single photon source based on a photonic crystal waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Byeong-Hyeon, E-mail: seygene@kaist.ac.kr; Lee, Chang-Min; Lim, Hee-Jin [Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); Schlereth, Thomas W.; Kamp, Martin [Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg (Germany); Höfling, Sven [Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg (Germany); SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Lee, Yong-Hee [Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); Graduate School of Nanoscience and Technology (WCU), KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-08-24

    A single photon source plays a key role in quantum applications such as quantum computers and quantum communications. Epitaxially grown quantum dots are one of the promising platforms to implement a good single photon source. However, it is challenging to realize an efficient single photon source based on semiconductor materials due to their high refractive index. Here we demonstrate a direct fiber coupled single photon source with high collection efficiency by employing a photonic crystal (PhC) waveguide and a tapered micro-fiber. To confirm the single photon nature, the second-order correlation function g{sup (2)}(τ) is measured with a Hanbury Brown-Twiss setup. The measured g{sup (2)}(0) value is 0.15, and we can estimate 24% direct collection efficiency from a quantum dot to the fiber.

  2. Degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper

    2013-01-01

    Spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers, in which photonic bandgap guidance and index guidance is combined. Calculations show the parametric gain is maximum on the edge of a photonic bandgap, for a large range of pump...... wavelengths. The FWM products are observed on the edges of a transmission band experimentally, in good agreement with the numerical results. Thereby the bandedges can be used to control the spectral positions of FWM products through a proper fiber design. The parametric gain control combined with a large mode...... area fiber design potentially allows for power scaling of light at wavelengths not easily accessible with e.g. rare earth ions....

  3. Four-wave mixing instabilities in photonic-crystal and tapered fibers.

    Science.gov (United States)

    Biancalana, F; Skryabin, D V; Russell, P St J

    2003-10-01

    Four-wave mixing instabilities are theoretically studied for continuous wave propagation in ultrasmall core photonic-crystal and tapered fibers. The waveguide, or geometrical, contribution to the overall dispersion of these structures is much stronger than in conventional fibers. This leads to the appearance of unstable frequency bands that are qualitatively and quantitatively different from those seen in conventional fibers. The four-wave mixing theory developed here is based on the full wave equation, which allows rigorous study of the unstable bands even when the detunings are of the order of the pump frequency itself. Solutions obtained using the generalized nonlinear Schrödinger equation, which is an approximate version of the full wave equation, reveal that it suffers from several deficiencies when used to describe four-wave mixing processes.

  4. Degenerate four wave mixing in large mode area hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Lægsgaard, Jesper

    2013-07-29

    Spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers, in which photonic bandgap guidance and index guidance is combined. Calculations show the parametric gain is maximum on the edge of a photonic bandgap, for a large range of pump wavelengths. The FWM products are observed on the edges of a transmission band experimentally, in good agreement with the numerical results. Thereby the bandedges can be used to control the spectral positions of FWM products through a proper fiber design. The parametric gain control combined with a large mode area fiber design potentially allows for power scaling of light at wavelengths not easily accessible with e.g. rare earth ions.

  5. Fluorescein filled photonic crystal fiber sensor for simultaneous ultraviolet light and temperature monitoring

    Science.gov (United States)

    Tatar, Peter; Kacik, Daniel; Tarjanyi, Norbert

    2016-07-01

    We present a novel structure composed of a photonic crystal fiber filled with fluorescein dissolved in water spliced between two conventional multimode fibers. Based on unique features of the fluorescein luminescence it is possible to adjust its emission spectrum to required spectral region. With increasing value of the fluorescein solvent pH factor, the peak wavelength of the emission spectrum is shifting to longer wavelength values. Since the excitation spectrum of fluorescein is relatively wide, this optical fiber sensor could be used for an efficient ultraviolet light monitoring. The detection limit at the level 0.24 mW with 490 nm excitation wavelength is presented. Moreover the emission spectrum is temperature sensitive what provides possibility of simultaneous ultraviolet light and temperature monitoring. Also the temperature sensitivity of the structure based on intermodal interference investigation for a compensation purposes and structure usage as spectrum enlarger are outlined.

  6. Photonic crystal fiber in-line Mach-Zehnder interferometer for explosive detection.

    Science.gov (United States)

    Tao, Chuanyi; Wei, Heming; Feng, Wenlin

    2016-02-08

    We report a photonic crystal fiber (PCF) in-line Mach-Zehnder interferometer used as a gas sensor device which exhibits high sensitivity to the explosive trinitrotoluene (TNT). The interferometric sensor head is formed by embedding a segment of large-mode-area/grapefruit PCF between standard single-mode fibers via butt coupling, which produces two small air gaps in between terminated fiber ends with ceramic ferrule connectors as coupling regions, which also serve as inlet/outlet for the gas. The spectral response of the interferometer is investigated in terms of its wavelength spectrum. The selectivity to TNT vapor is achieved by immobilizing a molecular recognition ployallylamine layer on the inner surface of the holey region of the PCF. The TNT-induced variations of the interference fringes are measured and the sensing capability of the proposed sensor is demonstrated experimentally.

  7. Bandgaps of the Chalcogenide Glass Hollow-Core Photonic Crystal Fiber

    Science.gov (United States)

    Li, Shu-Guang; Zhou, Hong-Song; Yin, Guo-Bing

    2011-11-01

    Bandgaps of chalcogenide glass hollow-core photonic crystal fibers (GLS HC-PCFs) are analyzed by using the plane-wave expansion method. A mid-infrared laser can propagate in these low confinement loss fibers when the wavelength falls into the bandgaps. For enlarging the bandgap width, an improved GLS HC-PCF is put forward, the normalized frequency kΛ of the improved fiber is from 7.2 to 8.5 in its first bandgap. The improved GLS HC-PCF with pitch of 4.2 μm can transmit the lights with wavelengths ranging from 3.1 μm to 3.7 μm.

  8. Photonic liquid crystal fibers tuning by four electrode system produced with 3D printing technology

    Science.gov (United States)

    Ertman, Slawomir; Bednarska, Karolina; Czapla, Aleksandra; Woliński, Tomasz R.

    2015-09-01

    Photonic liquid crystal fiber has been intensively investigated in last few years. It has been proved that guiding properties of such fibers could be tuned with an electric field. In particular efficient tuning could be obtained if multi-electrode system allowing for dynamic change of not only intensity of the electric field, but also its direction. In this work we report a simple to build four electrode system, which is based on a precisely aligned four cylindrical microelectrodes. As an electrodes we use enameled copper wire with diameter adequate to the diameter of the fiber to be tuned. To ensure uniform and parallel alignment of the wires a special micro-profiles has been designed and then produced with filament 3D printer. The possibility of the dynamic change of the electric field direction in such scalable and cost effective electrode assembly has been experimentally confirmed.

  9. Photonic nanojet focusing for hollow-core photonic crystal fiber probes.

    Science.gov (United States)

    Ghenuche, Petru; Rigneault, Hervé; Wenger, Jérôme

    2012-12-20

    Large-pitch kagome-lattice hollow-core photonic crystal fibers (HC-PCFs) offer appealing optical properties for beam delivery and remote sensing. However, focusing their optical mode on a submicrometer spot can be challenging due to the large mode diameter and low numerical aperture of these fibers. Here, we demonstrate that a 30 μm latex microsphere directly set at the HC-PCF end-face provides an efficient means to focus the fiber mode down to a spot of 540 nm full width at half-maximum thanks to a photonic nanojet effect. The system is used for fluorescence imaging and direct laser writing on a thin absorbing layer. Potential applications include inspection of semiconductor wafers, photolithography, laser surgery, fluorescence sensing, or optical transfection.

  10. Surface plasmon resonance sensor based on polymer photonic crystal fibers with metal nanolayers.

    Science.gov (United States)

    Lu, Ying; Hao, Cong-Jing; Wu, Bao-Qun; Musideke, Mayilamu; Duan, Liang-Cheng; Wen, Wu-Qi; Yao, Jian-Quan

    2013-01-15

    A large-mode-area polymer photonic crystal fiber made of polymethyl methacrylate with the cladding having only one layer of air holes near the edge of the fiber is designed and proposed to be used in surface plasmon resonance sensors. In such sensor, a nanoscale metal film and analyte can be deposited on the outer side of the fiber instead of coating or filling in the holes of the conventional PCF, which make the real time detection with high sensitivity easily to realize. Moreover, it is relatively stable to changes of the amount and the diameter of air holes, which is very beneficial for sensor fabrication and sensing applications. Numerical simulation results show that under the conditions of the similar spectral and intensity sensitivity of 8.3 × 10(-5)-9.4 × 10(-5) RIU, the confinement loss can be increased dramatically.

  11. Surface Plasmon Resonance Sensor Based on Polymer Photonic Crystal Fibers with Metal Nanolayers

    Directory of Open Access Journals (Sweden)

    Jian-Quan Yao

    2013-01-01

    Full Text Available A large-mode-area polymer photonic crystal fiber made of polymethyl methacrylate with the cladding having only one layer of air holes near the edge of the fiber is designed and proposed to be used in surface plasmon resonance sensors. In such sensor, a nanoscale metal film and analyte can be deposited on the outer side of the fiber instead of coating or filling in the holes of the conventional PCF, which make the real time detection with high sensitivity easily to realize. Moreover, it is relatively stable to changes of the amount and the diameter of air holes, which is very beneficial for sensor fabrication and sensing applications. Numerical simulation results show that under the conditions of the similar spectral and intensity sensitivity of 8.3 × 10−5–9.4 × 10−5 RIU, the confinement loss can be increased dramatically.

  12. Thermal-Induced Refractive Index Change Effects on Distributed Modal Filtering Properties of Rod-Type Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Coscelli, E.; Poli, Federica; Jørgensen, Mette Marie

    2012-01-01

    The effects of thermally-induced refractive index change on distributed modal filtering rod-type photonic crystal fibers are numerically investigated. Results have shown a significant blue-shift of the single-mode range for increasing temperature.......The effects of thermally-induced refractive index change on distributed modal filtering rod-type photonic crystal fibers are numerically investigated. Results have shown a significant blue-shift of the single-mode range for increasing temperature....

  13. Improving efficiency of supercontinuum generation in photonic crystal|fibers by direct degenerate four-wave-mixing

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov; Bang, Ole; Bjarklev, Anders Overgaard

    2002-01-01

    The efficiency of supercontinuum generation in photonic crystal fibers is significantly improved by designing the dispersion to allow widely separated spectral lines generated by degenerate four-wave-mixing directly from the pump to broaden and merge.......The efficiency of supercontinuum generation in photonic crystal fibers is significantly improved by designing the dispersion to allow widely separated spectral lines generated by degenerate four-wave-mixing directly from the pump to broaden and merge....

  14. Numerical analysis of a photonic crystal fiber based on two polarized modes for biosensing applications

    Institute of Scientific and Technical Information of China (English)

    Qin Wei; Li Shu-Guang; Xue Jian-Rong; Xin Xü-Jun; Zhang Lei

    2013-01-01

    This paper presents a theoretical study on a photonic crystal fiber plasmonic refractive index biosensor.The proposed photonic crystal fiber sensor introduces the concept of simultaneous detection with the linearly polarized and radially polarized modes because the sensing performance of the sensor based on both modes is relatively high,which will be useful for selecting the modes to make the detection accurately.The sharp single resonant peaks of the linearly polarized mode and radially polarized mode,are stronger and more sensitive to the variation of analyte refractive index than that of any other polarized mode in this kind of photonic crystal fiber.For linearly polarized mode and radially polarized mode,the maximum sensitivities of 10448.5 nm per refractive index unit and 8230.7 nm per refractive index unit can be obtained,as well as 949.8 and 791.4 for figure of merits in the sensing range of 1.33-1.45,respectively.Compared with the conventional Au-metalized surface plasmon resonance sensors,our device is better and can be applied as a biosensor.

  15. High numerical aperture large-core photonic crystal fiber for a broadband infrared transmission

    Science.gov (United States)

    Pniewski, J.; Stepniewski, G.; Kasztelanic, R.; Siwicki, B.; Pierscinska, D.; Pierscinski, K.; Pysz, D.; Borzycki, K.; Stepien, R.; Bugajski, M.; Buczynski, R.

    2016-11-01

    In this paper we present a large mode area photonic crystal fiber made of the heavy metal oxide glass CS-740, dedicated for a broadband light guidance in the visible, near- and mid-infrared regions of wavelengths from 0.4 to 4.7 μm. The fiber is effectively multi-mode in the considered wavelength range. It is composed of a ring of air-holes surrounding the core, with a high linear filling factor of 0.97. The fiber was made using a standard stack-and-draw technique. Each hole has a size of approx. 2.5 × 3.0 μm and diameter of core is 80 μm. Fiber attenuation is below 3 dB/m in the 0.9-1.7 μm wavelength range, while at 4.4 μm (mid-IR) it is approx. 5 dB/cm. Bending loss at the 1.55 μm wavelength is 0.45 dB per loop of 8 mm radius. Fiber numerical aperture is 0.53 at 1.55 μm. The effective mode area of the fundamental mode is approx. 2400 μm2 in the wavelength range of 0.8-1.7 μm. We present a proof-of-concept demonstration that our large core photonic crystal fiber is able to efficiently collect light directly from a mid-IR quantum cascade laser without use of additional optics and can be used for pigtailing mid-IR sources and detectors.

  16. Ytterbium-doped large-mode-area photonic crystal fiber amplifier with gain shaping for use at long wavelengths

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas T.; Poli, Federica

    2012-01-01

    A large-mode-area Ytterbium-doped photonic crystal fiber amplifier with efficient suppression of amplified spontaneous emission is presented. The fiber cladding consists of a hexagonal lattice of air holes, where three rows are replaced with circular high-index inclusions. Seven missing air holes...... wavelength regime of the Ytterbium gain spectrum above 1100 nm....

  17. Modal analysis of a large-mode area photonic crystal fiber amplifier using spectral-resolved imaging

    DEFF Research Database (Denmark)

    Laurila, Marko; Alkeskjold, Thomas T.; Lægsgaard, Jesper

    2011-01-01

    We perform modal characterization on an ytterbium-doped large mode area photonic-crystal-fiber (PCF) amplifier using spatial and spectral (S 2) resolved imaging and compare results to conventional cutoff methods. We apply numerical simulations and step-index fiber experiments to calibrate our...

  18. Selective-fluid-filled photonic crystal fibers and applications

    Science.gov (United States)

    Wang, Yiping; Liao, Changrui; Zhong, Xiaoyong; Li, Zhengyong; Liu, Yingjie; Zhou, Jiangtao; Yang, Kaiming

    2013-08-01

    A selective-filling technique was demonstrated to improve the optical properties of photonic crystal fibres (PCFs). Such a technique can be used to fill one or more fluid samples selectively into desired air holes. The technique is based on drilling a hole or carving a groove on the surface of a PCF to expose selected air holes to atmosphere by the use of a micromachining system comprising of a femtosecond infrared laser and a microscope. The exposed section was immersed into a fluid and the air holes are then filled through the well-known capillarity action. Provided two or more grooves are fabricated on different locations and different orientation along the fibre surface, different fluids may be filled into different airholes to form a hybrid fibre. As an example, we filled half of a pure-silica PCF by a fluid with n=1.480 by carving a rectangular groove on the fibre. Consequently, the half-filled PCF became a bandgap-guiding structure (upper half), resulted from a higher refractive index in the fluid rods than in the fibre core, and three bandgaps were observed within the wavelength range from 600 to 1700 nm. Whereas, the lower half (unfilled holes) of the fibre remains an air/silica index-guiding structure. When the hybrid PCF is bent, its bandgaps gradually narrowed, resulted from the shifts of the bandgap edges. The bandgap edges had distinct bend-sensitivities when the hybrid PCF was bent toward different directions. Especially, the bandgaps are hardly affected when the half-filled PCF was bent toward the fluid-filled region. Such unique bend properties could be used to monitor simultaneously the bend directions and the curvature of the engineering structures.

  19. Graphene in macroscopic order: liquid crystals and wet-spun fibers.

    Science.gov (United States)

    Xu, Zhen; Gao, Chao

    2014-04-15

    In nanotechnology, the creation of new nanoparticles consistently feeds back into efforts to design and fabricate new macroscopic materials with specific properties. As a two-dimensional (2D) building block of new materials, graphene has received widespread attention due to its exceptional mechanical, electrical, and thermal properties. But harnessing these attributes into new materials requires developing methods to assemble single-atom-thick carbon flakes into macroscopically ordered structures. Because the melt processing of carbon materials is impossible, fluid assembly is the only viable approach for meeting this challenge. But in the meantime, researchers need to solve two fundamental problems: creating orientational ordering in fluids and the subsequent phase-transformation from ordered fluids into ordered solid materials. To address these problems, this Account highlights our graphene chemistry methods that take advantage of liquid crystals to produce graphene fibers. We have successfully synthesized graphene oxide (GO) from graphite in a scalable manner. Using the size of graphite particles and post fractionation, we successfully tuned the lateral size of GO from submicron sizes to dozens of microns. Based on the rich chemistry of GO, we developed reliable methods for chemical or physical functionalization of graphene and produced a series of functionalized, highly soluble graphene derivatives that behave as single layers even at high concentrations. In the dispersive system of GO and functionalized graphenes, rich liquid crystals (LCs) formed spontaneously. Some of these liquid crystals had a conventional nematic phase with orientational order; others had a lamellar phase. Importantly, we observed a new chiral mesophase featuring a helical-lamellar structural model with frustrated disinclinations. The graphene-based LCs show ordered assembly behaviors in the fluid state of 2D colloids and lay a foundation for the design of ordered materials with optimal

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

    Science.gov (United States)

    Islam, Md. Asiful; Alam, M. Shah

    2013-05-01

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

  1. High-Density Polyethylene and Heat-Treated Bamboo Fiber Composites: Nonisothermal Crystallization Properties

    Directory of Open Access Journals (Sweden)

    Yanjun Li

    2015-01-01

    Full Text Available The effect of heat-treated bamboo fibers (BFs on nonisothermal crystallization of high-density polyethylene (HDPE was investigated using differential scanning calorimetry under nitrogen. The Avrami-Jeziorny model was used to fit the measured crystallization data of the HDPE/BF composites and to obtain the model parameters for the crystallization process. The heat flow curves of neat HDPE and HDPE/heat-treated BF composites showed similar trends. Their crystallization mostly occurred within a temperature range between 379 K and 399 K, where HDPE turned from the liquid phase into the crystalline phase. Values of the Avrami exponent (n were in the range of 2.8~3.38. Lamellae of neat HDPE and their composites grew in a three-dimensional manner, which increased with increased heat-treatment temperature and could be attributed to the improved ability of heterogeneous nucleation and crystallization completeness. The values of the modified kinetic rate constant (KJ first increased and then decreased with increased cooling rate because the supercooling was improved by the increased number of nucleating sites. Heat-treated BF and/or a coupling agent could act as a nucleator for the crystallization of HDPE.

  2. Laser heated pedestal growth system commissioning and fiber processing

    Science.gov (United States)

    Buric, Michael; Yip, M. J.; Chorpening, Ben; Ohodnicki, Paul

    2016-05-01

    A new Laser Heated Pedestal Growth system was designed and fabricated using various aspects of effective legacy designs for the growth of single-crystal high-temperature-compatible optical fibers. The system is heated by a 100-watt, DC driven, CO2 laser with PID power control. Fiber diameter measurements are performed using a telecentric video system which identifies the molten zone and utilizes edge detection algorithms to report fiber-diameter. Beam shaping components include a beam telescope; along with gold-coated reflaxicon, turning, and parabolic focusing mirrors consistent with similar previous systems. The optical system permits melting of sapphire-feedstock up to 1.5mm in diameter for growth. Details regarding operational characteristics are reviewed and properties of single-crystal sapphire fibers produced by the system are evaluated. Aspects of the control algorithm efficacy will be discussed, along with relevant alternatives. Finally, some new techniques for in-situ processing making use of the laser-heating system are discussed. Ex-situ fiber modification and processing are also examined for improvements in fiber properties.

  3. Sapphire hard X-ray Fabry-Perot resonators for synchrotron experiments.

    Science.gov (United States)

    Tsai, Yi Wei; Wu, Yu Hsin; Chang, Ying Yi; Liu, Wen Chung; Liu, Hong Lin; Chu, Chia Hong; Chen, Pei Chi; Lin, Pao Te; Fu, Chien Chung; Chang, Shih Lin

    2016-05-01

    Hard X-ray Fabry-Perot resonators (FPRs) made from sapphire crystals were constructed and characterized. The FPRs consisted of two crystal plates, part of a monolithic crystal structure of Al2O3, acting as a pair of mirrors, for the backward reflection (0 0 0 30) of hard X-rays at 14.3147 keV. The dimensional accuracy during manufacturing and the defect density in the crystal in relation to the resonance efficiency of sapphire FPRs were analyzed from a theoretical standpoint based on X-ray cavity resonance and measurements using scanning electron microscopic and X-ray topographic techniques for crystal defects. Well defined resonance spectra of sapphire FPRs were successfully obtained, and were comparable with the theoretical predictions.

  4. Origin of Difference in Photocatalytic Activity of ZnO (002 Grown on a- and c-Face Sapphire

    Directory of Open Access Journals (Sweden)

    Guoqiang Li

    2014-01-01

    Full Text Available The oriented (002 ZnO films were grown on a- and c-face sapphire by pulsed laser deposition. The X-ray diffraction analysis revealed that the oriented (002 ZnO films were epitaxially grown on the substrate successfully. The sample on a-face sapphire had higher crystal quality. However, the photocatalytic activity for Rhodamine B degradation of ZnO film on c-face sapphire was higher than that on a-face sapphire. The Raman spectrum and XPS analysis suggested that the sample on a-face sapphire had higher concentration of defects. The result of the contact angle measurement revealed that the sample on c-face sapphire had higher surface energy. And the investigation of the surface conductance implied that the higher light conductance was helpful for the photocatalytic activity.

  5. Effects of sapphire substrates surface treatment on the ZnO thin films grown by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yinzhen [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China)], E-mail: agwyz@yahoo.com.cn; Chu Benli [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China)

    2008-06-01

    The surface treatment effects of sapphire substrate on the ZnO thin films grown by magnetron sputtering were studied. The sapphire substrates properties have been investigated by means of atomic force microscopy (AFM) and X-ray diffraction rocking curves (XRCs). The results show that sapphire substrate surfaces have the best quality by CMP with subsequent chemical etching. The surface treatment effects of sapphire substrate on the ZnO thin films were examined by X-ray diffraction (XRD) and photoluminescence (PL) measurements. Results show that the intensity of (0 0 2) diffraction peak of ZnO thin films on sapphire substrates treated by CMP with subsequent chemical etching was strongest, FWHM of (0 0 2) diffraction peak is the narrowest and the intensity of UV peak of PL spectrum is strongest, indicating surface treatment on sapphire substrate preparation may improve ZnO thin films crystal quality and photoluminescent property.

  6. Passively mode-locked fiber laser based on a hollow-core photonic crystal fiber filled with few-layered graphene oxide solution.

    Science.gov (United States)

    Liu, Zhi-Bo; He, Xiaoying; Wang, D N

    2011-08-15

    We demonstrate a nanosecond-pulse erbium-doped fiber laser that is passively mode locked by a hollow-core photonic crystal fiber filled with few-layered graphene oxide solution. Owing to the good solution processing capability of few-layered graphene oxide, which can be filled into the core of a hollow-core photonic crystal fiber through a selective hole filling process, a graphene saturable absorber can be successfully fabricated. The output pulses obtained have a center wavelength, pulse width, and repetition rate of 1561.2 nm, 4.85 ns, and 7.68 MHz, respectively. This method provides a simple and efficient approach to integrate the graphene into the optical fiber system.

  7. High-resolution magnetic field imaging with a nitrogen-vacancy diamond sensor integrated with a photonic-crystal fiber.

    Science.gov (United States)

    Fedotov, I V; Blakley, S M; Serebryannikov, E E; Hemmer, P; Scully, M O; Zheltikov, A M

    2016-02-01

    We demonstrate high-resolution magnetic field imaging with a scanning fiber-optic probe which couples nitrogen-vacancy (NV) centers in diamond to a high-numerical-aperture photonic-crystal fiber integrated with a two-wire microwave transmission line. Magnetic resonance excitation of NV centers driven by the microwave field is read out through optical interrogation through the photonic-crystal fiber to enable high-speed, high-sensitivity magnetic field imaging with sub 30 μm spatial resolution.

  8. Strain and temperature characterization of LPGs written by CO2 laser in pure silica LMA photonic crystal fibers

    Science.gov (United States)

    Chaves, Roberta Cardoso; Pohl, Alexandre de Almeida Prado; Abe, Ilda; Sebem, Renan; Paterno, Aleksander

    2015-09-01

    This paper reports on the writing of long period gratings (LPGs) in a six-ring pure silica solid core, and large mode area photonic crystal fiber (fiber core diameter ρ = 10.1 μm) using a CO2 laser system, and the characterization of their strain and temperature sensitivities. Temperature and strain sensitivities in the order of -19.6 pm/°C and -88 pm/μɛ, respectively, were obtained, which were comparable or surpassed values of the similar photonic crystal fiber (PCF)-based LPG or sensor configurations found in the literature.

  9. Optical properties of photonic crystal fiber with integral micron-sized Ge wire.

    Science.gov (United States)

    Tyagi, H K; Schmidt, M A; Prill Sempere, L; Russell, P St J

    2008-10-27

    Using a selective hole closure technique, individual hollow channels in silica-air photonic crystal fibers are filled with pure Ge by pumping in molten material at high pressure. The smallest channels filled so far are 600 nm in diameter, which is 10x smaller than in previous work. Electrical conductivity and micro-Raman measurements indicate that the resulting cm-long wires have a high degree of crystallinity. Optical transmission spectra are measured in a sample with a single wire placed adjacent to the core of an endlessly single-mode photonic crystal fiber. This renders the fiber birefringent, as well as causing strongly polarization-dependent transmission losses, with extinction ratios as high as 30 dB in the visible. In the IR, anti-crossings between the glass-core mode and resonances on the high index Ge wire create a series of clear dips in the spectrum transmitted through the fiber. The measurements agree closely with the results of finite-element simulations in which the wavelength dependence of the dielectric constants is taken fully into account. A toy model based on a multilayer structure is used to help interpret the results. Finally, the temperature dependence of the anti-crossing wavelengths is measured, the preliminary results suggesting that the structure might form the basis of a compact optical thermometer. Since Ge provides electrical conductance together with low-loss guidance in the mid-IR, Ge-filled PCF seems likely to lead to new kinds of in-fiber detector and sensor, as well as having potential uses in ultra-low-threshold nonlinear optical devices.

  10. Coupling Characteristics of Fused Optical Fiber Coupler Formed with Single-Mode Fiber and Photonic Crystal Fiber Having Air Hole Collapsed Taper

    Directory of Open Access Journals (Sweden)

    Hirohisa Yokota

    2016-01-01

    Full Text Available Fused coupler forming with a single-mode fiber (SMF and a photonic crystal fiber (PCF is one of the solutions for optical coupling from a light source to a PCF. In this paper, we presented coupling characteristics of a fused fiber coupler formed with an ordinary SMF and a PCF having air hole collapsed taper. A prototype of SMF-PCF coupler with air hole collapsed taper was fabricated using CO2 laser irradiation. The coupling efficiency from SMF to PCF was −6.2 dB at 1554 nm wavelength in the fabricated coupler. The structure of the SMF-PCF coupler to obtain high coupling efficiency was theoretically clarified by beam propagation analysis using an equivalent model of the coupler with simplification. It was clarified that appropriately choosing the prestretched or etched SMF diameter and the length of air hole collapsed region was effective to obtain high coupling efficiency that was a result of high extinction ratio at cross port and low excess loss. We also demonstrated that the diameter of prestretched SMF to obtain high coupling efficiency was insensitive to the air hole diameter ratio to pitch of the PCF in the air hole collapsed SMF-PCF coupler.

  11. Pumping of titanium sapphire laser

    Science.gov (United States)

    Jelínková, H.; Vaněk, P.; Valach, P.; Hamal, K.; Kubelka, J.; Škoda, V.; Jelínek, M.

    1993-02-01

    Two methods of Ti:Sapphire pumping for the generation of tunable laser radiation in the visible region were studied. For coherent pumping, the radiation of the second harmonic of a Nd:YAP laser was used and a maximum output energy of E out=4.5 mJ was reached from the Ti:Sapphire laser. For noncoherent pumping, two different lengths of flashlamp pulses were used and a maximum of E out=300 mJ was obtained. Preliminary estimations of the wavelength range of tunability were made.

  12. Cut-off analysis of 19-cell Yb-doped double-cladding rod-type photonic crystal fibers.

    Science.gov (United States)

    Poli, F; Coscelli, E; Alkeskjold, T T; Passaro, D; Cucinotta, A; Leick, L; Broeng, J; Selleri, S

    2011-05-09

    Yb-doped double-cladding large mode area rod-type photonic crystal fibers are a key component for power scaling in fiber laser systems. Recently, designs with 19-cell core defect, that is with 19 missing air-holes in the center of the photonic crystal cladding, have been proposed, with reported core diameter up to 100 μm. In this paper an analysis of the cut-off wavelength of the first high-order mode in such low-NA fibers is reported, accounting for different approaches for the definition of the cladding effective index. Results have shown that taking into account the finite fiber cross-section and considering the first cladding mode of the actual fiber is mandatory to obtain a correct estimate of the cut-off wavelength.

  13. Generation of a VUV-to-visible Raman frequency comb in hydrogen-filled kagom\\'e photonic crystal fiber

    CERN Document Server

    Mridha, M K; Bauerschmidt, S T; Abdolvand, A; Russell, P St J

    2016-01-01

    We report the generation of a purely vibrational Raman comb, extending from the vacuum ultraviolet (184 nm) to the visible (478 nm), in hydrogen-filled kagom\\'e-style photonic crystal fiber pumped at 266 nm. Stimulated Raman scattering and molecular modulation processes are enhanced by higher Raman gain in the ultraviolet. Owing to the pressure-tunable normal dispersion landscape of the fiber-gas system in the ultraviolet, higher-order anti-Stokes bands are generated preferentially in higher-order fiber modes. The results pave the way towards tunable fiber-based sources of deep- and vacuum ultraviolet light for applications in, e.g., spectroscopy and biomedicine.

  14. Generation of a vacuum ultraviolet to visible Raman frequency comb in H2-filled kagomé photonic crystal fiber.

    Science.gov (United States)

    Mridha, M K; Novoa, D; Bauerschmidt, S T; Abdolvand, A; St J Russell, P

    2016-06-15

    We report on the generation of a purely vibrational Raman comb, extending from the vacuum ultraviolet (184 nm) to the visible (478 nm), in hydrogen-filled kagomé-style photonic crystal fiber pumped at 266 nm. Stimulated Raman scattering and molecular modulation processes are enhanced by higher Raman gain in the ultraviolet. Owing to the pressure-tunable normal dispersion landscape of the "fiber + gas" system in the ultraviolet, higher-order anti-Stokes bands are generated preferentially in higher-order fiber modes. The results pave the way toward tunable fiber-based sources of deep and vacuum ultraviolet light for applications in, e.g., spectroscopy and biomedicine.

  15. Coherent supercontinuum bandwidth limitations under femtosecond pumping at 2 µm in all-solid soft glass photonic crystal fibers

    DEFF Research Database (Denmark)

    Klimczak, Mariusz; Siwicki, Bartłomiej; Zhou, Binbin;

    2016-01-01

    Two all-solid glass photonic crystal fibers with all-normal dispersion profiles are evaluated for coherent supercontinuum generation under pumping in the 2.0 μm range. Inhouse boron-silicate and commercial lead-silicate glasses were used to fabricate fibers optimized for either flat dispersion......, albeit with lower nonlinearity, or with larger dispersion profile curvature but with much higher nonlinearity. Recorded spectra at the redshifted edge reached 2500-2800 nm depending on fiber type. Possible factors behind these differences are discussed with numerical simulations. The fiber enabling...

  16. Analysis of bias thermal stability of interferometer fiber-optic gyroscope using a solid-core polarization-maintaining photonic crystal fiber

    Science.gov (United States)

    Zuoming, Sun; Shuhua, Wang; Junwei, Li; Yazhou, Zhang; Dapeng, Chen

    2016-12-01

    Bias thermal stability of a fiber-optic gyroscope using polarization-maintaining photonic crystal (PM-PCF) was studied. The thermal sensitivity of birefringence in PM-PCF and polarization cross talking in fiber coil was measured. Using an OCDP method, the polarization cross talking causing phase error of the fiber-optic gyroscope (FOG) was analyzed. The contrast experiment result of the FOGs with the PM-PCF coil and PMF coil showed that using PM-PCF instead of PMF can improve the FOG's bias thermal stability by about 50 %.

  17. Newly designed multilayer thin film mirror for dispersion compensation in Ti: sapphire femtosecond lasers

    Institute of Scientific and Technical Information of China (English)

    Chunyan Liao; Jianda Shao; Jianbing Huang; Zhengxiu Fan; Hongbo He

    2005-01-01

    @@ There are two different effects to generate group delay dispersion by multilayer thin film mirrors: chirper effect and Gires-Tournois effect. Both effects are employed to introduce desired dispersion in the designed mirror. Thus the designed mirror provides large dispersion throughout broad waveband. Such mirror can be used for dispersion compensation in Ti:sapphire femtosecond lasers. Most group delay dispersion of a 5-mm Ti:sapphire crystal can be compensated perfectly with only four bounces of the designed mirror.

  18. Jones calculus modeling and analysis of the thermal distortion in a Ti:sapphire laser amplifier.

    Science.gov (United States)

    Cho, Seryeyohan; Jeong, Jihoon; Yu, Tae Jun

    2016-06-27

    The mathematical modeling of an anisotropic Ti:sapphire crystal with a significant thermal load is performed. The model is expressed by the differential Jones matrix. A thermally induced distortion in the chirped-pulse amplification process is shown by the solution of the differential Jones matrix. Using this model, the thermally distorted spatio-temporal laser beam shape is calculated for a high-power and high-repetition-rate Ti:sapphire amplifier.

  19. TAILORING OF FLATTENED DISPERSION IN TRIANGULAR-LATTICE PHOTONIC CRYSTAL FIBER

    Directory of Open Access Journals (Sweden)

    Sandhir Kumar Singh

    2011-12-01

    Full Text Available The interest of researchers and engineers in several laboratories, since the1980s, has been attracted by the ability to structure materials on the scale of the optical wavelength, a fraction of micrometers or less, in order to develop new optical medium, known as photonic crystals . Photonic crystals rely on a regular morphological microstructure of air-holes, incorporated into the material, which radically alters its optical properties. In Photonic Crystal Fiber (PCF it is possible to realize flat dispersion over a wide wavelength range that cannot be realized with a conventional single-mode fiber. In PCFs, the dispersion can be controlled and tailored with unprecedented freedom. In fact, due to the high refractive index difference between silica and air, and to the flexibility of changing air-hole sizes and patterns, the waveguide contribution to the dispersion parameter can be significantly changed, thus obtaining unusual position of the zero dispersion wavelength, as well as particular values of the dispersion curve slope. In particular, by manipulating the air- hole radius or the lattice period of the micro structured cladding, it is possible to control the zero-dispersion wavelength, which can be tuned over a very wide range, or the dispersion curves, which can be engineered to be ultra flattened. In this paper the geometric parameters of triangular PCF have been properly changed to optimize the dispersion compensation over a wide wavelength range.

  20. Comparison of different methods for rigorous modeling of photonic crystal fibers.

    Science.gov (United States)

    Szpulak, Marcin; Urbanczyk, Waclaw; Serebryannikov, Evgenii; Zheltikov, Aleksei; Hochman, Amit; Leviatan, Yehuda; Kotynski, Rafal; Panajotov, Krassimir

    2006-06-12

    We present a summary of the simulation exercise carried out within the EC Cost Action P11 on the rigorous modeling of photonic crystal fiber (PCF) with an elliptically deformed core and noncircular air holes with a high fill factor. The aim of the exercise is to calculate using different numerical methods and to compare several fiber characteristics, such as the spectral dependence of the phase and the group effective indices, the birefringence, the group velocity dispersion and the confinement losses. The simulations are performed using four rigorous approaches: the finite element method (FEM), the source model technique (SMT), the plane wave method (PWM), and the localized function method (LFM). Furthermore, we consider a simplified equivalent fiber method (EFM), in which the real structure of the holey fiber is replaced by an equivalent step index waveguide composed of an elliptical glass core surrounded by air cladding. All these methods are shown to converge well and to provide highly consistent estimations of the PCF characteristics. Qualitative arguments based on the general properties of the wave equation are applied to explain the physical mechanisms one can utilize to tailor the propagation characteristics of nonlinear PCFs.

  1. Zero-dispersion wavelength decreasing photonic crystal fibers for ultraviolet-extended supercontinuum generation.

    Science.gov (United States)

    Kudlinski, A; George, A K; Knight, J C; Travers, J C; Rulkov, A B; Popov, S V; Taylor, J R

    2006-06-12

    We report the fabrication of photonic crystal fibers with a continuously-decreasing zero-dispersion wavelength along their length. These tapered fibers are designed to extend the generation of supercontinuum spectra from the visible into the ultraviolet. We report on their performance when pumped with both nanosecond and picosecond sources at 1.064 microm. The supercontinuum spectra have a spectral width (measured at the 10 dB points) extending from 0.372 microm to beyond 1.75 microm. In an optimal configuration a flat (3 dB) spectrum from 395 to 850 nm, with a minimum spectral power density of 2 mW/nm was achieved, with a total continuum output power of 3.5 W. We believe that the shortest wavelengths were generated by cascaded four-wave mixing: the continuous decrease of the zero dispersion wavelength along the fiber length enables the phase-matching condition to be satisfied for a wide range of wavelengths into the ultraviolet, while simultaneously increasing the nonlinear coefficient of the fiber.

  2. Enhanced visible supercontinuum generation in seven-core photonic crystal fiber

    Science.gov (United States)

    Qi, Xue; Chen, Sheng-Ping; Liu, Tong; Hou, Jing

    2016-11-01

    The visible supercontinuum (SC) sources has played an important role in biomedical applications. However, the small core size of photonic crystal fiber (PCF) restrict the development of high power SC by its small mode field area. In addition, the zero dispersion wavelength (ZDW) of the PCF with small core diameter is usually below 1 μm, which is far away from the 1.06 μm laser which is the most commonly used pump source. As the ZDW of PCF shifts away from the pump, the intensity of visible light decreases correspondingly. We promote a new technique to get an enhanced visible SC with high output power, which involves enhanced visible SC generation in a seven-core PCF pumped by a high power 1016 nm fiber laser. Muti-core PCFs offer a possibility of scaling up the mode field area to a large extent without remarkable change in dispersion properties, which show great potential in high power SC generation. Using a 1016 nm fiber laser as the pump makes the pump wavelength closer to the ZDW of PCF, which could raise the intensity of visible light. In this paper, we report an enhanced visible SC generation ranging from 400 nm to 2300 nm in a seven-core PCF pumped by a 1016 nm picosecond fiber laser. The visible light (400 800 nm) occupies 31% of the total SC power 24 W and the power of the visible light is about 7.4 W.

  3. Progress in hollow core photonic crystal fiber for atomic vapour based coherent optics

    Science.gov (United States)

    Bradley, T. D.; Wang, Y. Y.; Alharbi, M.; Fourcade Dutin, C.; Mangan, B. J.; Wheeler, N. V.; Benabid, F.

    2012-03-01

    We report on progress in different hollow core photonic crystal fiber (HC-PCF) design and fabrication for atomic vapor based applications. We have fabricated a Photonic bandgap (PBG) guiding HC-PCF with a record loss of 107dB/km at 785nm in this class of fiber. A double photonic bandgap (DPBG) guiding HC-PCF with guidance bands centred at 780nm and 1064nm is reported. A 7-cell 3-ring Kagome HC-PCF with hypocycloid core is reported, the optical loss at 780nm has been reduced to 70dB/km which to the best of our knowledge is the lowest optical loss reported at this wavelength using HC-PCF. Details on experimental loading of alkali metal vapours using a far off red detuned laser are reported. This optical loading has been shown to decrease the necessary loading time for Rb into the hollow core of a fiber. The quantity of Rb within the fiber core has been enhanced by a maximum of 14% through this loading procedure.

  4. The Optimization of Dispersion Properties of Photonic Crystal Fibers Using a Real-Coded Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    YIN Guo-Bing; LI Shu-Guang; LIU Shuo; WANG Xiao-Yan

    2011-01-01

    @@ A real-coded genetic algorithm (GA) combined with a fully vectorial effective index method (FVEIM) is employed to design structures of photonic crystal fibers (PCFs) with user defined dispersion properties theoretically.The structures of PCFs whose solid cores axe doped GeO with zero-dispersions at 0.7-3.9μm are optimized and the flat dispersion ranges through the R+L+C band and the negative dispersion is -1576.26 ps.km·nm at 1.55μm.Analyses show that the zero-dispersion wavelength (ZDW) could be one of many ZDWs for the same fiber structure; PCFs couM alter the dispersion to be flattened through the R+L+C band with a single air-hole diameter; and negative dispersion requires high air filling rate at 1.55μm.The method is proved to be elegant for solving this inverse problem.

  5. Generation of logic gates based on a photonic crystal fiber Michelson interferometer

    Science.gov (United States)

    Sousa, J. R. R.; Filho, A. F. G. F.; Ferreira, A. C.; Batista, G. S.; Sobrinho, C. S.; Bastos, A. M.; Lyra, M. L.; Sombra, A. S. B.

    2014-07-01

    We present a numerical investigation of all-optical logical gates based in a Michelson interferometer (MI) of micro structured fibers, also known as photonic crystal fibers (PCF). We considered an ultra-short pulse propagating along the system in three distinct regimes of pump power. We determine several relevant quantities to characterize the system performance such as transmission, extinction ratio and crosstalk as a function of the dephasing added to one of the Bragg gratings of the Michelson interferometer (MI). High-order effects, such as third-order dispersion, intrapulse Raman scattering and self-steepening were included in the nonlinear generalized Schrödinger equation governing the pulse propagation. Our results show that the proposed device can be used to obtain all-optical XOR, OR and NOT logic gates.

  6. Three octave spanning supercontinuum by red-shifted dispersive wave in photonic crystal fibers

    CERN Document Server

    Sharma, Mohit

    2015-01-01

    This paper presents a three layer index guided lead silicate (SF57) photonic crystal fiber which simultaneously promises to yield large effective optical nonlinear coefficient and low anomalous dispersion that makes it suitable for supercontinuum generation. At an operating wavelength 1550 nm, the typical optimized value of anomalous dispersion and effective nonlinear coefficient turns out to be ~4 ps/km/nm and ~1078 W^(-1) km^(-1), respectively. Through numerical simulation it is realized that the designed fiber promises to exhibit three octave spanning supercontinuum from 900 to 7200 nm by using 50 fs sech optical pulses of 5 kW peak power. Due to the cross-phase modulation and four-wave mixing processes, a long range of red-shifted dispersive wave generated, which assist to achieve such large broadening. In addition, we have investigated the compatibility of supercontinuum generation with input pulse peak power increment and briefly discussed the impact of nonlinear processes on supercontinuum generation.

  7. Polarization maintaining highly nonlinear photonic crystal fiber with closely lying two zero dispersion wavelengths

    Science.gov (United States)

    Hasan, Md. Rabiul; Anower, Md. Shamim; Hasan, Md. Imran

    2016-05-01

    A simple hexagonal photonic crystal fiber is proposed to simultaneously achieve ultrahigh birefringence, large nonlinear coefficient, and two zero dispersion wavelengths (ZDWs). The finite element method with circular perfectly matched layer boundary condition is used to simulate the designed structure. Simulation results show that it is possible to achieve two closely lying ZDWs of 1.08 and 1.29 μm for x-polarization with 0.88 and 1.20 μm for y-polarization modes, respectively. In addition, an ultrahigh birefringence of 3.15×10-2 and a high nonlinear coefficient of 58 W-1 km-1 are also obtained at the excitation wavelength of 1.55 μm. The proposed fiber can have important applications in supercontinuum generation, parametric amplification, four-wave mixing, and optical sensors design.

  8. Single gain peak from modulation instability in As2Se3 chalcogenide glass photonic crystal fiber

    Science.gov (United States)

    Wang, Helin; Yang, Aijun

    2016-09-01

    With the As2Se3 photonic crystal fiber (PCF), the effect of pump power and wavelength on modulation instability (MI) gain is studied in detail. Due to high Raman scattering effect and high nonlinearity of As2Se3 PCF, ultra-broadband MI gain is obtained when appropriate pump power and wavelength is chosen, and the optimal MI gain bandwidth reaches 2812 nm. More importantly, competing between Raman scattering and four-wave mixing results in a single gain peak observed in the anti-Stokes region of As2Se3 PCF when pump power is higher than about 3000 W, while there is no gain spectrum in the fiber Stokes region. The phenomenon is found for the first time, and the obtained single gain peak mainly results from Raman scattering effect.

  9. Efficient generation of broad Raman sidebands in an index-guided photonic crystal fiber.

    Science.gov (United States)

    Li, Ying; Hou, Jing; Jiang, Zongfu; Leng, Jinyong

    2013-04-01

    The efficient generation of broad Raman sidebands is experimentally demonstrated in a short piece of index-guided photonic crystal fiber, which is pumped by a high-peak-power pulse near the zero-dispersion wavelength and seeded by a continuous-wave Stokes signal centered at 1117 nm. The Raman sidebands generated via stimulated Raman scattering and cascaded four-wave mixing contain five Stokes and six anti-Stokes peaks and span from 827 to 1398 nm, and the 3 dB linewidth for each peak is smaller than 1 nm. However, the pure Raman sidebands are largely dependent on the pulse pump power as well as the fiber length.

  10. High efficiency terahertz-wave photonic crystal fiber optical parametric oscillator.

    Science.gov (United States)

    Li, Shaopeng; Liu, Hongjun; Huang, Nan; Sun, Qibing; Li, Xuefeng

    2012-08-01

    We theoretically propose phase matched terahertz (THz)-wave generation via degenerate four-wave mixing (FWM) in a fiber optical parametric oscillator (FOPO) with our newly designed photonic crystal fiber (PCF). Perfect phase matching is realized when we locate the pump wavelength in the normal group-velocity dispersion (GVD) regime. The generated THz-wave can be tuned from 4.7578 to 5.9015 THz by varying the pump wavelength. Moreover, peak power of 27.38 W at 5.9015 THz with conversion efficiency of 1.37% is realized when the pump peak power of 2000 W is at 4.675 μm in our FOPO.

  11. Three octave spanning supercontinuum by red-shifted dispersive wave in photonic crystal fibers

    Science.gov (United States)

    Sharma, Mohit; Konar, S.

    2016-03-01

    This article presents a three-layer index guided lead silicate (SF57) photonic crystal fiber which simultaneously promises to yield large effective optical nonlinear coefficient and low anomalous dispersion that makes it suitable for supercontinuum (SC) generation. At an operating wavelength 1550 nm, the typical optimized value of anomalous dispersion and effective nonlinear coefficient turns out to be ~4 ps/km/nm and ~1078 W-1km-1, respectively. Through numerical simulation, it is realized that the designed fiber promises to exhibit three octave spanning SC from 900 to 7200 nm using 50 fs 'sech' optical pulses of 5 kW peak power. Due to the cross-phase modulation and four-wave mixing processes, a long range of red-shifted dispersive wave generated, which assists to achieve such large broadening. In addition, we have investigated the compatibility of SC generation with input pulse peak power increment and briefly discussed the impact of nonlinear processes on SC generation.

  12. High Sensitivity Refractive Index Sensor Based on Dual-Core Photonic Crystal Fiber with Hexagonal Lattice

    Directory of Open Access Journals (Sweden)

    Haiyang Wang

    2016-10-01

    Full Text Available A refractive index sensor based on dual-core photonic crystal fiber (PCF with hexagonal lattice is proposed. The effects of geometrical parameters of the PCF on performances of the sensor are investigated by using the finite element method (FEM. Two fiber cores are separated by two air holes filled with the analyte whose refractive index is in the range of 1.33–1.41. Numerical simulation results show that the highest sensitivity can be up to 22,983 nm/RIU(refractive index unit when the analyte refractive index is 1.41. The lowest sensitivity can reach to 21,679 nm/RIU when the analyte refractive index is 1.33. The sensor we proposed has significant advantages in the field of biomolecule detection as it provides a wide-range of detection with high sensitivity.

  13. High Sensitivity Refractive Index Sensor Based on Dual-Core Photonic Crystal Fiber with Hexagonal Lattice.

    Science.gov (United States)

    Wang, Haiyang; Yan, Xin; Li, Shuguang; An, Guowen; Zhang, Xuenan

    2016-10-08

    A refractive index sensor based on dual-core photonic crystal fiber (PCF) with hexagonal lattice is proposed. The effects of geometrical parameters of the PCF on performances of the sensor are investigated by using the finite element method (FEM). Two fiber cores are separated by two air holes filled with the analyte whose refractive index is in the range of 1.33-1.41. Numerical simulation results show that the highest sensitivity can be up to 22,983 nm/RIU(refractive index unit) when the analyte refractive index is 1.41. The lowest sensitivity can reach to 21,679 nm/RIU when the analyte refractive index is 1.33. The sensor we proposed has significant advantages in the field of biomolecule detection as it provides a wide-range of detection with high sensitivity.

  14. Structure fits the purpose: photonic crystal fibers for evanescent-field surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Khaing Oo, Maung Kyaw; Han, Yun; Kanka, Jiri; Sukhishvili, Svetlana; Du, Henry

    2010-02-15

    We report numerical simulation and hyperspectral Raman imaging of three index-guiding solid-core photonic crystal fibers (PCFs) of different air-cladding microstructures to assess their respective potential for evanescent-field Raman spectroscopy, with an emphasis on achieving surface-enhanced Raman scattering (SERS) over the entire fiber length. Suspended-core PCF consisting of a silica core surrounded by three large air channels conjoined by a thin silica web is the most robust of the three SERS-active PCFs, with a demonstrated detection sensitivity of 1x10(-10) M R6G in an aqueous solution of only approximately 7.3 microL sampling volume.

  15. Optical chromatography using a photonic crystal fiber with on-chip fluorescence excitation.

    Science.gov (United States)

    Ashok, P C; Marchington, R F; Mthunzi, P; Krauss, T F; Dholakia, K

    2010-03-15

    We describe the realization of integrated optical chromatography, in conjunction with on-chip fluorescence excitation, in a monolithically fabricated poly-dimethylsiloxane (PDMS) microfluidic chip. The unique endlessly-single-mode guiding property of the Photonic Crystal Fiber (PCF) facilitates simultaneous on-chip delivery of beams to perform optical sorting in conjunction with fluorescence excitation. We use soft lithography to define the chip and insert the specially capped PCF into it through a predefined fiber channel that is intrinsically aligned with the sorting channel. We compare the performance of the system to a standard ray optics model and use the system to demonstrate both size-driven and refractive index-driven separations of colloids. Finally we demonstrate a new technique of enhanced optofluidic separation of biological particles, by sorting of human kidney embryonic cells (HEK-293), internally tagged with fluorescing microspheres through phagocytocis, from those without microspheres and the separation purity is monitored using fluorescence imaging.

  16. Atomic mercury vapor inside a hollow-core photonic crystal fiber

    CERN Document Server

    Vogl, Ulrich; Joly, Nicolas Y; Russell, Philip St J; Marquardt, Christoph; Leuchs, Gerd

    2014-01-01

    We demonstrate high atomic mercury vapor pressure in a kagom\\'e-style hollow-core photonic crystal fiber at room temperature. After a few days of exposure to mercury vapor the fiber is homogeneously filled and the optical depth achieved remains constant. With incoherent optical pumping from the ground state we achieve an optical depth of 114 at the $6^3P_2 - 6^3D_3$ transition, corresponding to an atomic mercury number density of $6 \\times 10^{10}$ cm$^{-3}$. The use of mercury vapor in quasi one-dimensional confinement may be advantageous compared to chemically more active alkali vapor, while offering strong optical nonlinearities in the ultraviolet region of the optical spectrum.

  17. Supercontinuum Generation in Normal-dispersion Photonic Crystal Fiber Using Picosecond Pulse

    Institute of Scientific and Technical Information of China (English)

    YAO Li; HE Li; YANG Bo-jun

    2007-01-01

    Studied is the Super-continuum(SC) generation of a normal-dispersion photonic crystal fiber(PCF) using picosecond pulse excitation. In experimental analyses, a 237 nm broadband infrared continuum was generated pumped at 1 550 nm(normal dispersion regime) by 1.6 ps pulses from an erbium-doped fiber laser. In addition, we conduct the numerical analyses of SC based on generalized nonlinear Schr dionger equation. The results have been applied to investigate the dominant physical processes underlie the generation of SC. We conclude that dispersion, self-phase modulation(SPM),four-wave-mixing(FWM) and Raman scattering are determinants of SC generation rather than fission of soliton in normal-dispersion PCF.

  18. Identification of Bloch-modes in hollow-core photonic crystal fiber cladding.

    Science.gov (United States)

    Couny, F; Benabid, F; Roberts, P J; Burnett, M T; Maier, S A

    2007-01-22

    We report on the experimental visualization of the cladding Bloch-modes of a hollow-core photonic crystal fiber. Both spectral and spatial field nformation is extracted using the approach, which is based on measurement of the near-field and Fresnel-zone that results after propagation over a short length of fiber. A detailed study of the modes near the edges of the band gap shows that it is formed by the influence of three types of resonator: the glass interstitial apex, the silica strut which joins the neighboring apexes, and the air hole. The cladding electromagnetic field which survives the propagation is found to be spatially coherent and to contain contributions from just a few types of cladding mode.

  19. Design of low-loss and highly birefringent hollow-core photonic crystal fiber

    Science.gov (United States)

    Roberts, P. J.; Williams, D. P.; Sabert, H.; Mangan, B. J.; Bird, D. M.; Birks, T. A.; Knight, J. C.; Russell, P. St. J.

    2006-08-01

    A practical hollow-core photonic crystal fiber design suitable for attaining low-loss propagation is analyzed. The geometry involves a number of localized elliptical features positioned on the glass ring that surrounds the air core and separates the core and cladding regions. The size of each feature is tuned so that the composite core-surround geometry is antiresonant within the cladding band gap, thus minimizing the guided mode field intensity both within the fiber material and at material / air interfaces. A birefringent design, which involves a 2-fold symmetric arrangement of the features on the core-surround ring, gives rise to wavelength ranges where the effective index difference between the polarization modes is larger than 10-4. At such high birefringence levels, one of the polarization modes retains favorable field exclusion characteristics, thus enabling low-loss propagation of this polarization channel.

  20. Modelling a nonlinear optical switching in a standard photonic crystal fiber infiltrated with carbon disulfide

    Science.gov (United States)

    Munera, Natalia; Acuna Herrera, Rodrigo

    2016-06-01

    In this letter, a numerical analysis is developed for the propagation of ultrafast optical pulses through a standard photonic crystal fiber (PCF) consisting of two infiltrated holes using carbon disulfide (CS2). This material is a good choice since it has highly nonlinear properties, what makes it a good candidate for optical switching and broadband source at low power compared to traditional nonlinear fiber coupler. Based on supermodes theory, a set of generalized nonlinear equations is presented in order to study the propagation characteristics. It is shown in this letter that it is possible to get optical switching behavior at low power and how the dispersion, as well as, the two infiltrated holes separation influence this effect. Finally, we see that supercontinuum generation can be induced equally in both infiltrated holes despite no initial excitation at one hole.