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Sample records for fiber optic coupler

  1. Optical fiber couplers for precision spaceborne metrology.

    PubMed

    Killow, Christian J; Fitzsimons, Ewan D; Perreur-Lloyd, Michael; Robertson, David I; Ward, Henry; Bogenstahl, Johanna

    2016-04-01

    We describe the optical and mechanical design, construction philosophy, and testing of a pair of matched, spaceflight-qualified fiber couplers. The couplers were developed for the LISA Pathfinder mission but are relevant for other applications-both on ground and in space-where a robust fiber coupler with well-controlled beam parameters and stable beam pointing is required. This particular implementation of the design called for two couplers providing collimated beams with individual waist sizes and positions. The target values were a 522 μm waist 145 mm after the collimating lens for one coupler and a virtual 520 μm waist 194 mm before the collimating lens for the second coupler. Values of (542±4)  μm at (142±19) mm and (500±8)  μm at (-275±8)  mm were achieved, fully meeting the mission requirements. To control spurious noise effects in the interferometer, the optical system design also specified tight limits on relative beam curvature at an intended interference point. With nominal curvatures at this location of ∼2.35  m, the matching between the outputs of the two fiber couplers was measured to be λ/33 peak-valley over the central 1 mm of the beams. Results showing pointing stability of 3 μrad/°C over a 50°C range are presented. The vibration, shock, and thermal vacuum environmental testing conditions to which a pair of qualification fiber couplers were subjected-without change in performance-are listed.

  2. Single Fiber Star Couplers. [optical waveguides for spacecraft communication

    NASA Technical Reports Server (NTRS)

    Asawa, C. K.

    1979-01-01

    An ion exchange process was developed and used in the fabrication of state-of-the-art planar star couplers for distribution of optical radiation between optical fibers. An 8 x 8 planar transmission star coupler was packaged for evaluation purposes with sixteen fiber connectors and sixteen pigtails. Likewise a transmission star coupler and an eight-port reflection star coupler with eight-fiber ribbons rigidly attached to these couplers, and a planar coupler with silicon guides and a parallel channel guide with pigtails were also fabricated. Optical measurements of the transmission star couplers are included with a description of the manufacturing process.

  3. Fiber optic to integrated optical chip coupler

    NASA Technical Reports Server (NTRS)

    Pikulski, Joseph I. (Inventor); Ramer, O. Glenn (Inventor)

    1987-01-01

    Optical fibers are clamped by a block onto a substrate. Thereupon, metal is plated over the fibers to hold them in place upon the substrate. The clamp block is removed and the opening, resulting from the clamp block's presence, is then plated in. The built-up metallic body is a coupling which holds the fibers in position so that the ends can be polished for coupling to an integrated optical chip upon a coupling fixture.

  4. Optical design of a high power fiber optic coupler

    SciTech Connect

    English, R.E. Jr.; Halpin, J.M.; House, F.A.; Paris, R.D.

    1991-06-19

    Fiber optic beam delivery systems are replacing conventional mirror delivery systems for many reasons (e.g., system flexibility and redundancy, stability, and ease of alignment). Commercial products are available that use of fiber optic delivery for laser surgery and materials processing. Also, pump light of dye lasers can be delivered by optical fibers. Many laser wavelengths have been transported via optical fibers; high power delivery has been reported for argon, Nd:YAG, and excimer. We have been developing fiber optic beam delivery systems for copper vapor laser light; many of the fundamental properties of these systems are applicable to other high power delivery applications. A key element of fiber optic beam delivery systems is the coupling of laser light into the optical fiber. For our application this optical coupler must be robust to a range of operating parameters and laser characteristics. We have access to a high power copper vapor laser beam that is generated by a master oscillator/power amplifier (MOPA) chain comprised of three amplifiers. The light has a pulse width of 40--50 nsec with a repetition rate of about 4 kHz. The average power (nominal) to be injected into a fiber is 200 W. (We will refer to average power in this paper.) In practice, the laser beam's direction and collimation change with time. These characteristics plus other mechanical and operational constraints make it difficult for our coupler to be opto-mechanically referenced to the laser beam. We describe specifications, design, and operation of an optical system that couples a high-power copper vapor laser beam into a large core, multimode fiber. The approach used and observations reported are applicable to fiber optic delivery applications. 6 refs., 6 figs.

  5. Colorimetric sensor based on two optical fiber couplers

    NASA Astrophysics Data System (ADS)

    Dybko, Artur; Maciejewski, Janusz; Romaniuk, Ryszard S.; Wroblewski, Wojciech

    1994-02-01

    The aim of the paper is to present an idea of a low-cost optical fiber colorimetric pH sensor (with disposable probe). Most of colorimetric sensors consist of two fibers: the illuminating one and one for collecting reflected light. Only one optical fiber is used as a sensing probe in our pH sensor. The end of the fiber is covered by a pH-sensing membrane, which is made of polyvinyl chloride. The colorimetric indicator (bromothymol blue) was immobilized on an ion- exchange resin. The sensing fiber is connected with two optical fiber couplers (type Y). The first coupler guides analytical and reference wavelengths from the light emitting diodes (LED) and the second one transmits light to the photodetector. Only one photodetector is used. Optical signals are filtered electronically because the LEDs are modulated at different frequencies. The results of the measuring tests of the sensor are presented.

  6. Recent Advances in Fiber Optic Coupler Technology

    NASA Astrophysics Data System (ADS)

    Corke, Michael; Sweeney, Kevin L.; Schmidt, Kevin M.

    1987-01-01

    The performance requirements and device specifications of single mode couplers have been changing rapidly in recent years. This paper reviews the present state of the art in this technology and introduces new device concepts which rely on the fuse-taper technology in their fabrication process. Details will be given of the fabrication and application of single mode wavelength division multiplexers which have an insertion loss below 0.5 dB and have a 20 dB isolation over a 30 nm operating wavelength range. Wavelength division multiplexers with a narrow wavelength separation, <5 nm, will also be described in terms of their fabrication and application. Details of the utilization and performance of concatenated wavelength division multiplexers as filters for uni- and bi-directional communication will also be presented. Finally, techniques for reducing the wavelength sensitivity of the coupling ratio in single mode couplers will be discussed which result in the development of a broad band coupler, BBC.

  7. Velocity difference measurement with a fiber-optic coupler.

    PubMed

    Du, Y; Ackerson, B J; Tong, P

    1998-09-01

    Two single-mode fibers collect light with the same scattered wave vector from two spatially separated regions in a sample. These regions are illuminated by a single coherent laser beam, so that the collected signals interfere when combined by means of a fiber-optic coupler, before they are directed to a photomultiplier tube. The fibers and the coupler are polarization preserving to guarantee a high signal-to-noise ratio. The measured intensity fluctuations are used to determine the velocity difference omega v(L) for spatial separations L in the sample. Specifically, an intensity autocorrelation function is calculated theoretically for rigid body rotation and is tested experimentally. Experimental results span two orders of magnitude in L and agree with theoretical predictions with an error of less than 5%. This new technique will be very useful in the study of turbulent flow and particle settling dynamics.

  8. Fiber-optic couplers. January 1973-February 1988 (citations from the NTIS data base). Report for January 1973-February 1988

    SciTech Connect

    Not Available

    1988-03-01

    This bibliography contains citations concerning the design, fabrication, analysis, performance evaluation, and applications of fiber-optic couplers. Topics include optical coupling for fiber-optic transmission lines, frequency and wavelength division multiplexing, multiwavelength coupler-decouplers, single mode and multimode couplers, and fiber-optic gyroscope applications. Various types of couplers are examined including waveguide, star, access, duplex, data bus, passive, tee, and holographic. Patented fiber-optic devices using couplers are included. Citations concerning fiber-optic connectors are excluded and examined in a separate bibliography. (Contains 218 citations fully indexed and including a title list.)

  9. Φ80μm polarization-maintaining fiber coupler for fiber optic gyroscope

    NASA Astrophysics Data System (ADS)

    Pang, Lu; Li, Rui-chen; Huang, Bang-cai; Ning, Ding

    2008-12-01

    The polarization-maintaining fiber coupler (PMFC) is a kind of optical coupler manufactured with polarization-maintaining fiber (PMF). It is the pivotal device to realizing the linearly polarized light coupling, the dispersion of light as well as the multiplying. It is one of the core components of the high-precision fiber optic gyroscope (FOG) and fiber optic hydrophone. This paper reports a kind of thin-diameter PMFC (cladding diameter is 80μm), which is developed to adapt to the FOG's miniaturization. The difference between the thin-diameter PMFC (Φ80μm) and conventional PMFC (Φ125μm) in the manufacture technology has been compared. The key technologies of developing the thin-diameter PMFC (Φ80μm), such as "No tension fused taper", "On-line adjusting main axes of the PMF", "High stability package" and so on, has been discussed. In addition, it also has been carried on some Mechanical and environmental tests. The test results show that the thin-diameter PMFC can satisfy the requirements of the miniature FOG.

  10. Tapered rib fiber coupler for semiconductor optical devices

    DOEpatents

    Vawter, Gregory A.; Smith, Robert Edward

    2001-01-01

    A monolithic tapered rib waveguide for transformation of the spot size of light between a semiconductor optical device and an optical fiber or from the fiber into the optical device. The tapered rib waveguide is integrated into the guiding rib atop a cutoff mesa type semiconductor device such as an expanded mode optical modulator or and expanded mode laser. The tapered rib acts to force the guided light down into the mesa structure of the semiconductor optical device instead of being bound to the interface between the bottom of the guiding rib and the top of the cutoff mesa. The single mode light leaving or entering the output face of the mesa structure then can couple to the optical fiber at coupling losses of 1.0 dB or less.

  11. Optical Couplers

    DTIC Science & Technology

    1975-12-01

    market . In general, the fiber diameter and cladding thickness choices that give the highest (best) packing fraction also give the highest (worst...57) Using Eqs (54) and (57). the worst case fractional power ratio for the radia.l data bus is R P* mLm *l£lfkIm^o 2N N-l (58) From...Galileo fiber optic bundles at the LED and de- tector interface, Eq (58) becomes where m, 1*6 .7 R mLm *T.6 TfkTfNao P* 16 (140) .75

  12. Femtosecond laser inscription of asymmetric directional couplers for in-fiber optical taps and fiber cladding photonics.

    PubMed

    Grenier, Jason R; Fernandes, Luís A; Herman, Peter R

    2015-06-29

    Precise alignment of femtosecond laser tracks in standard single mode optical fiber is shown to enable controllable optical tapping of the fiber core waveguide light with fiber cladding photonic circuits. Asymmetric directional couplers are presented with tunable coupling ratios up to 62% and bandwidths up to 300 nm at telecommunication wavelengths. Real-time fiber monitoring during laser writing permitted a means of controlling the coupler length to compensate for micron-scale alignment errors and to facilitate tailored design of coupling ratio, spectral bandwidth and polarization properties. Laser induced waveguide birefringence was harnessed for polarization dependent coupling that led to the formation of in-fiber polarization-selective taps with 32 dB extinction ratio. This technology enables the interconnection of light propagating in pre-existing waveguides with laser-formed devices, thereby opening a new practical direction for the three-dimensional integration of optical devices in the cladding of optical fibers and planar lightwave circuits.

  13. Performance improvement of optical fiber coupler with electric heating versus gas heating.

    PubMed

    Shuai, Cijun; Gao, Chengde; Nie, Yi; Peng, Shuping

    2010-08-20

    Gas heating has been widely used in the process of fused biconical tapering. However, as the instability and asymmetric flame temperature of gas heating exist, the performance of the optical devices fabricated by this method was affected. To overcome the problems resulting from gas combustion, an electric heater is designed and manufactured using a metal-ceramic (MoSi(2)) as a heating material. Our experimental data show that the fused-taper machine with an electric heater has improved the performance of optical devices by increasing the consistency of the extinction ratio, excess loss, and the splitting ratio over that of the previous gas heating mode. Microcrystallizations and microcracks were observed at the fused region of the polarization-maintaining (PM) fiber coupler and at the taper region with scanning electron microscopy and atomic force microscopy respectively. The distribution of the microcrystallizations and microcracks are nonuniform along the fiber with gas heating, while their distribution is rather uniform with electric heating. These findings show that the novel optical fiber coupler with an electric heater has improved the performance of optical fiber devices by affecting the consistency of the optical parameters and micromorphology of the surface of PM fiber.

  14. Tunable mode coupler in the microfluidic channel for the fiber optics refractive index sensor

    NASA Astrophysics Data System (ADS)

    Gao, R.; Li, G.; Zhou, Y.; Jiang, Y.

    2014-11-01

    We propose and demonstrate a highly sensitive optical fiber microfluidic refractometer. A microhole is fabricated in the photonic crystal fiber (PCF) by using femtosecond laser beam, which combines the tunable mode coupler and microfluidic channel. The mode field diameter of the guided light is changed with the refractive index in the microfluidic channel, which results in the tunable coupling ratio between the core and the cladding in the PCF. Therefore, the refractive index of the liquid in the microfluidic channel is detected by interrogating the fringe visibility of the reflection spectrum. These experiments results demonstrate that the sensor is insensitive with the temperature and strain, and a RI sensitivity of up to 150.7 dB/RIU is achieved, establishing the tunable mode coupler as a sensitive and versatile sensor.

  15. Optical coupler

    DOEpatents

    Majewski, Stanislaw; Weisenberger, Andrew G.

    2004-06-15

    In a camera or similar radiation sensitive device comprising a pixilated scintillation layer, a light guide and an array of position sensitive photomultiplier tubes, wherein there exists so-called dead space between adjacent photomultiplier tubes the improvement comprising a two part light guide comprising a first planar light spreading layer or portion having a first surface that addresses the scintillation layer and optically coupled thereto at a second surface that addresses the photomultiplier tubes, a second layer or portion comprising an array of trapezoidal light collectors defining gaps that span said dead space and are individually optically coupled to individual position sensitive photomultiplier tubes. According to a preferred embodiment, coupling of the trapezoidal light collectors to the position sensitive photomultiplier tubes is accomplished using an optical grease having about the same refractive index as the material of construction of the two part light guide.

  16. Combined optical coherence tomography and hyperspectral imaging using a double-clad fiber coupler

    NASA Astrophysics Data System (ADS)

    Guay-Lord, Robin; Attendu, Xavier; Lurie, Kristen L.; Majeau, Lucas; Godbout, Nicolas; Bowden, Audrey K. Ellerbee; Strupler, Mathias; Boudoux, Caroline

    2016-11-01

    This work demonstrates the combination of optical coherence tomography (OCT) and hyperspectral imaging (HSI) using a double-clad optical fiber coupler. The single-mode core of the fiber is used for OCT imaging, while the inner cladding of the double-clad fiber provides an efficient way to capture the reflectance spectrum of the sample. The combination of both methods enables three-dimensional acquisition of the sample morphology with OCT, enhanced with complementary molecular information contained in the hyperspectral image. The HSI data can be used to highlight the presence of specific molecules with characteristic absorption peaks or to produce true color images overlaid on the OCT volume for improved tissue identification by the clinician. Such a system could be implemented in a number of clinical endoscopic applications and could improve the current practice in tissue characterization, diagnosis, and surgical guidance.

  17. Miniature mechanical transfer optical coupler

    DOEpatents

    Abel, Philip [Overland Park, KS; Watterson, Carl [Kansas City, MO

    2011-02-15

    A miniature mechanical transfer (MT) optical coupler ("MMTOC") for optically connecting a first plurality of optical fibers with at least one other plurality of optical fibers. The MMTOC may comprise a beam splitting element, a plurality of collimating lenses, and a plurality of alignment elements. The MMTOC may optically couple a first plurality of fibers disposed in a plurality of ferrules of a first MT connector with a second plurality of fibers disposed in a plurality of ferrules of a second MT connector and a third plurality of fibers disposed in a plurality of ferrules of a third MT connector. The beam splitting element may allow a portion of each beam of light from the first plurality of fibers to pass through to the second plurality of fibers and simultaneously reflect another portion of each beam of light from the first plurality of fibers to the third plurality of fibers.

  18. Symmetric 3 x 3 coupler-based demodulator for fiber optic interferometric sensors

    NASA Astrophysics Data System (ADS)

    Brown, David A.; Cameron, C. B.; Keolian, Robert M.; Gardner, David L.; Garrett, Steven L.

    1991-12-01

    A method for demodulation of fiber optic interferometric sensors that utilizes a 3 X 3 coupler is described. The passive demodulation scheme does not require carrier (phase) modulation. The demodulation scheme relies on the three outputs of a 3 X 3 coupler and uses all three of its phase modulated output signals to recreate the stimulus inducing the original optical phase modulation. The demodulator scale factor (volts/radian) is stable against fluctuations in both fringe visibility and average received power. Upon initial implementation of the scheme, a dynamic range of 116 dB was obtained (at 600 Hz in a 1 Hz bandwidth with maximum THD at 4%). The minimum detectable signal at 600 Hz was 220 (mu) rad/(root)Hz and the maximum tolerable signal was 140 radians. Both the maximum tolerable signal and the minimum detectable signal (noise floor) was observed to increase with decreasing frequency. Thus, depending on the frequency, the demodulation scheme is capable of detecting phase signals less than a milliradian to in excess of kiloradians.

  19. Laser tissue coagulation and concurrent optical coherence tomography through a double-clad fiber coupler.

    PubMed

    Beaudette, Kathy; Baac, Hyoung Won; Madore, Wendy-Julie; Villiger, Martin; Godbout, Nicolas; Bouma, Brett E; Boudoux, Caroline

    2015-04-01

    Double-clad fiber (DCF) is herein used in conjunction with a double-clad fiber coupler (DCFC) to enable simultaneous and co-registered optical coherence tomography (OCT) and laser tissue coagulation. The DCF allows a single channel fiber-optic probe to be shared: i.e. the core propagating the OCT signal while the inner cladding delivers the coagulation laser light. We herein present a novel DCFC designed and built to combine both signals within a DCF (>90% of single-mode transmission; >65% multimode coupling). Potential OCT imaging degradation mechanisms are also investigated and solutions to mitigate them are presented. The combined DCFC-based system was used to induce coagulation of an ex vivo swine esophagus allowing a real-time assessment of thermal dynamic processes. We therefore demonstrate a DCFC-based system combining OCT imaging with laser coagulation through a single fiber, thus enabling both modalities to be performed simultaneously and in a co-registered manner. Such a system enables endoscopic image-guided laser marking of superficial epithelial tissues or laser thermal therapy of epithelial lesions in pathologies such as Barrett's esophagus.

  20. Q-switching an all-fiber laser using acousto-optic null coupler

    NASA Astrophysics Data System (ADS)

    Berg, Yuval; Goldring, Sharone; Pearl, Shaul; Arie, Ady

    2013-05-01

    A new method for Q-switching an all-fiber laser is presented. It is based on induced acoustic long period grating operating on a null coupler, which acts as acoustically controlled tunable output coupler. Q-switching is achieved by switching on and off the acoustic wave in a burst mode, thereby generating laser pulses that are ~400 times shorter than the acoustically controlled coupler's rise time. Output pulse energy of 22 μJ and temporal width of ~100 ns were measured at a wavelength of 1.54 μm.

  1. New optical coupler devices

    NASA Astrophysics Data System (ADS)

    Ramadan, Tarek Abd-Elazim

    2000-06-01

    New optical coupler devices have been designed with both analytical and numerical simulation tools. Using these tools, design rules were derived for both 3dB and full adiabatic couplers. The design rules are in excellent agreement with numerical calculations using the beam propagation method (BPM). It is shown that the length scaling for the 3dB adiabatic couplers compared to full adiabatic couplers makes the former more difficult to design. The design in each case is optimized to obtain an upper limit of performance. A comparison is carried out between two different design geometries to select the optimum adiabatic coupler design which requires the shortest length for a given coupler performance. An improvement in, the fabrication tolerance of the optimum design has yielded a new more-tolerant 3dB adiabatic- coupler, which is distinguished by a coupler region where both waveguide width and separation are tapered. A novel 1 x 4 coupler-multiplexer permutation switch (CMPS) is proposed for applications in wavelength- division-multiplexing (WDM) networks. The CMPS integrates the functions of a 1 x 4 multiplexer followed by a 4 x 4 switch-array in a single compact device. It consists of a single-mode/multimode-waveguide grating-assisted backward-coupler multiplexer followed by a digital optical switch (DOS). Two different InP-based designs of the CMPS, which use InGaAsP/InP multiple-quantum well (MQW) output waveguides, are introduced. In both of these designs, the CMPS channels are unequally spaced which reduces unwanted four-wave mixing. Finally the electro-optic response is measured in single- crystal LiNbO 3 thin films obtained by crystal-ion-slicing (CIS). This technique uses ion implantation of singlecrystal bulk samples followed by selective etching. Post liftoff annealing (PLA) is shown to be a key step in improving the light transmission properties of these films for hybriddevice applications. It is shown that PLA must be used, as opposed to pre- liftoff

  2. Integrated optical XY coupler

    DOEpatents

    Vawter, G.A.; Hadley, G.R.

    1997-05-06

    An integrated optical XY coupler having two converging input waveguide arms meeting in a central section and a central output waveguide arm and two diverging flanking output waveguide arms emanating from the central section. In-phase light from the input arms constructively interferes in the central section to produce a single mode output in the central output arm with the rest of the light being collected in the flanking output arms. Crosstalk between devices on a substrate is minimized by this collection of the out-of-phase light by the flanking output arms of the XY coupler. 9 figs.

  3. Integrated optical XY coupler

    DOEpatents

    Vawter, G. Allen; Hadley, G. Ronald

    1997-01-01

    An integrated optical XY coupler having two converging input waveguide arms meeting in a central section and a central output waveguide arm and two diverging flanking output waveguide arms emanating from the central section. In-phase light from the input arms constructively interfers in the central section to produce a single mode output in the central output arm with the rest of the light being collected in the flanking output arms. Crosstalk between devices on a substrate is minimized by this collection of the out-of-phase light by the flanking output arms of the XY coupler.

  4. Analysis of distortion of a fiber optic Michelson interferometric sensor caused by the imperfect properties of its 3x3 coupler

    NASA Astrophysics Data System (ADS)

    Shih, Sung-Tsun; Chen, Mao-Hsiung; Lin, Wuu-Wen

    1997-07-01

    We investigate the distortion of demodulated output signal in a fiber optic Michelson interferometric sensor in relationship to the imperfect properties of its 3 by 3 coupler. A general guide rule in choosing a 3 by 3 coupler and its connection type in the interferometer to reduce this kind of signal distortion is also suggested.

  5. Laser phase and frequency noise measurement by Michelson interferometer composed of a 3 × 3 optical fiber coupler.

    PubMed

    Xu, Dan; Yang, Fei; Chen, Dijun; Wei, Fang; Cai, Haiwen; Fang, Zujie; Qu, Ronghui

    2015-08-24

    A laser phase and frequency noise measurement method by an unbalanced Michelson interferometer composed of a 3 × 3 optical fiber coupler is proposed. The relations and differences of the power spectral density (PSD) of differential phase and frequency fluctuation, PSD of instantaneous phase and frequency fluctuation, phase noise and linewidth are derived strictly and discussed carefully. The method obtains the noise features of a narrow linewidth laser conveniently without any specific assumptions or noise models. The technique is also used to characterize the noise features of a narrow linewidth external-cavity semiconductor laser, which confirms the correction and robustness of the method.

  6. A fiber-integrated optical component fabricated via photopolymerization: Mode-selective grating coupler

    NASA Astrophysics Data System (ADS)

    Sümer, Can; Dinleyici, M. Salih

    2013-11-01

    We demonstrate a mode-selective directional coupler based on a grating structure, which is fabricated by laser direct-writing on a photopolymer thin film. The device is implemented on the flat planar surface of the D-Fiber, enabling fiber integration, where an Acrylamide/Polyvinyl Alcohol based photopolymer material is used in the fabrication of the device. While the refractive index modulation properties of the polymer material are well known, surface relief and corrugation properties due to photopolymerization are investigated in this study. Theoretical model of the device is presented together with the optimization and simulation results of the final device; experimental results have been found to be in good agreement with simulations.

  7. Transmission performance of one waveguide and double micro-ring resonator using 3×3 optical fiber coupler

    NASA Astrophysics Data System (ADS)

    Zhao, Chao Ying; Tan, Wei Han

    2016-09-01

    This paper investigates theoretically the transmission characteristics of one waveguide and double micro-ring resonator using 3 × 3 optical fibre coupler. Our analytical solution of transmittance is suitable for either linearly distributed coupler or circularly symmetric distributed coupler. The all-optical analogue to electromagnetic inducted transparency spectrum of one waveguide and double micro-ring resonators can be controlled by changing the coupling strength between waveguide and micro-rings, the absorption coefficient around micro-rings, as well as the asymmetric coupling coefficients between non-adjacent waveguides. The curves show that the transitions of transmission spectra sensitively depend on asymmetric coupling coefficients.

  8. Combined optical coherence tomography and hyper-spectral imaging using a double clad fiber coupler

    NASA Astrophysics Data System (ADS)

    Guay-Lord, Robin; Lurie, Kristen L.; Attendu, Xavier; Mageau, Lucas; Godbout, Nicolas; Ellerbee Bowden, Audrey K.; Strupler, Mathias; Boudoux, Caroline

    2016-03-01

    This proceedings shows the combination of Optical Coherence Tomography (OCT) and Hyper-Spectral Imaging (HSI) using a double-clad optical fiber. The single mode core of the fiber is used to transmit OCT signals, while the cladding, with its large collection area, provides an efficient way to capture the reflectance spectrum of the sample. The combination of both methods enables three-dimensional acquisition of sample morphology with OCT, enhanced by the molecular information contained in its hyper-spectral image. We believe that the combination of these techniques could result in endoscopes with enhanced tissue identification capability.

  9. Pure-silica optical waveguides, fiber couplers, and high-aspect ratio submicrometer channels for electrokinetic separation devices.

    PubMed

    Mogensen, Klaus B; Eriksson, Fredrik; Gustafsson, Omar; Nikolajsen, Rikke P H; Kutter, Jörg P

    2004-11-01

    A new fabrication procedure for integration of ultraviolet transparent pure-silica planar waveguides, fiber couplers and high-aspect ratio submicrometer channels is presented. Only a single photolithographic mask step is required. The channels are 80-90 microm deep and the width can be reduced to about 0.5 microm, corresponding to a height-to-width ratio of more than 150. The core of the waveguides consists of pure silicon dioxide, which is favorable over doped silica, due to the absence of absorption centers associated with the dopants. This furthermore improves the long-term stability of the waveguides, because of an increased radiation resistance of the glass. The propagation loss decreases from 1.0 dB/cm at 200 nm to 0.2 dB/cm at 800 nm, which, to our knowledge, is the lowest propagation loss reported for integrated planar waveguides in the ultraviolet wavelength region to date. The effective optical path length is 1.2 mm for an absorbance cell with a nominal length of 1.0 mm, indicating effective suppression of stray light. The limit of detection for paracetamol when present in the entire channel network was determined to 3 microg/mL. Finally, the applicability of the fabricated devices for capillary electrophoresis was evaluated by separation of caffein, paracetamol and ketoprofone using absorbance detection at 254 nm.

  10. Design of single-polarization coupler based on dual-core photonic band-gap fiber implied in resonant fiber optic gyro

    NASA Astrophysics Data System (ADS)

    Xu, Zhenlong; Li, Xuyou; Zhang, Chunmei; Ling, Weiwei; Liu, Pan; Xia, Linlin; Yang, Hanrui

    2016-12-01

    A novel (to our knowledge) type of single-polarization (SP) coupler based on a dual-core photonic band-gap fiber (PBF) is proposed. The effects of structure parameters on the performance of this coupler are studied numerically based on the full vector finite element method (FEM). Finally, an optimal design with a length of 0.377 mm at the wavelength of 1.55 μm is achieved, and its implication in PBF-based fiber ring resonator (FRR), the effect of angular misalignment on the SP coupler are analyzed as well. When the SP coupler is incorporated into a PBF-based FRR, it functions as the power splitter and the polarizer simultaneously, and can extinct the secondary eigenstate of polarization (ESOP) propagating in the FRR. The mode field of SP coupler can match with the polarization-maintaining (PM) PBF with ultra-low temperature sensitivity proposed in previous study, and an all PM-PBF based FRR can be established, which is of great significance in suppressing the temperature-related polarization fluctuation and improving the long-term stability for RFOG, and the SP coupler has high angular misalignment tolerance as well.

  11. Integrated Optical Asymmetric Coupler Pressure Sensor

    NASA Astrophysics Data System (ADS)

    Kiyat, Isa; Kocabas, Coskun; Aydinli, Atilla

    2004-05-01

    Analysis of a novel pressure sensor based on a silicon-on-insulator (SOI) asymmetric vertical coupler is presented. The integrated optical component is a coupler composed of a single mode (SM) low index waveguide and a thin silicon slab. High sensitivities of about 0.14 rad.kPa-1 should be achieved.

  12. Influence of load by high power on the optical coupler

    NASA Astrophysics Data System (ADS)

    Bednarek, Lukas; Poboril, Radek; Vanderka, Ales; Hajek, Lukas; Nedoma, Jan; Vasinek, Vladimir

    2016-12-01

    Nowadays, aging of the optical components is a very current topic. Therefore, some investigations are focused on this area, so that the aging of the optical components is accelerated by thermal, high power and gamma load. This paper deals by findings of the influence of the load by laser with high optical power on the transmission parameters of the optical coupler. The investigated coupler has one input and eight outputs (1x8). Load by laser with high optical power is realized using a fiber laser with a cascade configuration EDFA amplifiers. The output power of the amplifier is approximately 250 mW. Duration of the load is moving from 104 hours to 139 hours. After each load, input power and output powers of all branches are measured. Following parameters of the optical coupler are calculated using formulas: the insertion losses of the individual branches, split ratio, total losses, homogeneity of the losses and cross-talk between different branches. All measurements are performed at wavelengths 1310 nm and 1550 nm. Individual optical powers are measured 20 times, due to the exclusion of statistical error of the measurement. After measuring, the coupler is connected to the amplifier for next cycle of the load. The paper contains an evaluation of the results of the coupler before and after four cycles of the burden.

  13. Optical Waveguide Output Couplers Fabricated in Polymers

    NASA Technical Reports Server (NTRS)

    Watson, Michael D.; Abushagur, Mustafa A. G.; Ashley, Paul R.; Johnson-Cole, Helen

    1998-01-01

    Waveguide output couplers fabricated in Norland Optical Adhesive (NOA) #81 and AMOCO Ultradel 9020D polyimide are investigated. The output couplers are implemented using periodic relief gratings on a planar waveguide. Design theory of the couplers is based on the perturbation approach. Coupling of light from waveguide propagation modes to output radiation modes is described by coupled mode theory and the transmission line approximation of the perturbed area (grating structure). Using these concepts, gratings can be accurately designed to output a minimum number of modes at desired output angles. Waveguide couplers were designed using these concepts. These couplers were fabricated and analyzed for structural accuracy, output beam accuracy, and output efficiency. The results for the two different materials are compared.

  14. Hybrid fiber resonator employing LRSPP waveguide coupler for gyroscope.

    PubMed

    Qian, Guang; Fu, Xing-Chang; Zhang, Li-Jiang; Tang, Jie; Liu, Yi-Ran; Zhang, Xiao-Yang; Zhang, Tong

    2017-01-24

    Polarization error and temperature noise are two main limits to the performance of resonant fiber optic gyroscope (RFOG). To overcome these limits, we demonstrated a hybrid resonator consisting of a polymer-based long-range surface plasmon polariton (LRSPP) waveguide coupler and a silica fiber. Single-polarization property of LRSPP waveguide and the offsetting of the opposite thermo-optical characteristics between the polymer-based LRSPP waveguide and the silica fiber can effectively inhibit both the polarization error and the temperature noise of RFOG. The measured resonance spectrum of the hybrid resonator shows the absence of polarization noise. The temperature dependence of wavelength shift (TDWS) of resonator dropped to about 2 pm/°C, or even to 0 pm/°C with optimal structure, which dramatically improves the temperature stability of gyroscope system. In addition, the hybrid resonator also shows tremendous application potential in rate-grade and tactical-grade gyroscopes.

  15. Hybrid fiber resonator employing LRSPP waveguide coupler for gyroscope

    NASA Astrophysics Data System (ADS)

    Qian, Guang; Fu, Xing-Chang; Zhang, Li-Jiang; Tang, Jie; Liu, Yi-Ran; Zhang, Xiao-Yang; Zhang, Tong

    2017-01-01

    Polarization error and temperature noise are two main limits to the performance of resonant fiber optic gyroscope (RFOG). To overcome these limits, we demonstrated a hybrid resonator consisting of a polymer-based long-range surface plasmon polariton (LRSPP) waveguide coupler and a silica fiber. Single-polarization property of LRSPP waveguide and the offsetting of the opposite thermo-optical characteristics between the polymer-based LRSPP waveguide and the silica fiber can effectively inhibit both the polarization error and the temperature noise of RFOG. The measured resonance spectrum of the hybrid resonator shows the absence of polarization noise. The temperature dependence of wavelength shift (TDWS) of resonator dropped to about 2 pm/°C, or even to 0 pm/°C with optimal structure, which dramatically improves the temperature stability of gyroscope system. In addition, the hybrid resonator also shows tremendous application potential in rate-grade and tactical-grade gyroscopes.

  16. Hybrid fiber resonator employing LRSPP waveguide coupler for gyroscope

    PubMed Central

    Qian, Guang; Fu, Xing-Chang; Zhang, Li-Jiang; Tang, Jie; Liu, Yi-Ran; Zhang, Xiao-Yang; Zhang, Tong

    2017-01-01

    Polarization error and temperature noise are two main limits to the performance of resonant fiber optic gyroscope (RFOG). To overcome these limits, we demonstrated a hybrid resonator consisting of a polymer-based long-range surface plasmon polariton (LRSPP) waveguide coupler and a silica fiber. Single-polarization property of LRSPP waveguide and the offsetting of the opposite thermo-optical characteristics between the polymer-based LRSPP waveguide and the silica fiber can effectively inhibit both the polarization error and the temperature noise of RFOG. The measured resonance spectrum of the hybrid resonator shows the absence of polarization noise. The temperature dependence of wavelength shift (TDWS) of resonator dropped to about 2 pm/°C, or even to 0 pm/°C with optimal structure, which dramatically improves the temperature stability of gyroscope system. In addition, the hybrid resonator also shows tremendous application potential in rate-grade and tactical-grade gyroscopes. PMID:28117412

  17. Characterization of tunable photonic crystal fiber directional couplers

    NASA Astrophysics Data System (ADS)

    Jang, Hyun Soo; Park, Kwang No; Lee, Kyung Shik

    2007-06-01

    We present a tunable photonic crystal fiber (PCF) directional coupler fabricated by a side-polishing method. The PCF directional coupler was modeled as a typical single-mode fiber-based directional coupler and analyzed using the improved effective-index method (IEIM). The characteristics of the PCF directional coupler such as the coupling coefficient and the coupling ratio were measured and found to be in good agreement with those predicted by the theoretical model. The PCF directional coupler exhibited an insertion loss of ˜2 dB for a 3 dB coupler and was able to tune the coupling ratio between 0% and 100% by tilting the angle of the top side-polished quartz block against the fixed-bottom quartz block.

  18. Fiber coupler end face wavefront surface metrology

    NASA Astrophysics Data System (ADS)

    Compertore, David C.; Ignatovich, Filipp V.; Marcus, Michael A.

    2015-09-01

    Despite significant technological advances in the field of fiber optic communications, one area remains surprisingly `low-tech': fiber termination. In many instances it involves manual labor and subjective visual inspection. At the same time, high quality fiber connections are one of the most critical parameters in constructing an efficient communication link. The shape and finish of the fiber end faces determines the efficiency of a connection comprised of coupled fiber end faces. The importance of fiber end face quality becomes even more critical for fiber connection arrays and for in the field applications. In this article we propose and demonstrate a quantitative inspection method for the fiber connectors using reflected wavefront technology. The manufactured and polished fiber tip is illuminated by a collimated light from a microscope objective. The reflected light is collected by the objective and is directed to a Shack-Hartmann wavefront sensor. A set of lenses is used to create the image of the fiber tip on the surface of the sensor. The wavefront is analyzed by the sensor, and the measured parameters are used to obtain surface properties of the fiber tip, and estimate connection loss. For example, defocus components in the reflected light indicate the presence of bow in the fiber end face. This inspection method provides a contact-free approach for quantitative inspection of fiber end faces and for estimating the connection loss, and can potentially be integrated into a feedback system for automated inspection and polishing of fiber tips and fiber tip arrays.

  19. Optical Nonreciprocity in Asymmetric Optomechanical Couplers

    NASA Astrophysics Data System (ADS)

    Wang, Zheqi; Shi, Lei; Liu, Yi; Xu, Xinbiao; Zhang, Xinliang

    2015-03-01

    We propose an all-optical integrated nonreciprocal device on the optomechanical platform with a large nonreciprocal bandwidth and low operating power. The device is based on an asymmetric silicon coupler consisting of two branches. One of them is a conventional strip waveguide fixed on the substrate, and the other is a freestanding nanostring suspended above a groove in the substrate. When light is launched into the coupler, the optical gradient force between the freestanding nanostring and the underlying substrate leads to the deflection of the nanostring, and finally results in destruction of the initial phase-matching condition between the two branches. The suspended branch would achieve distinct deflections when light is incident from different ports. The simulation results show a nonreciprocal bandwidth of 13.1 nm with operating power of 390 μW. With the advantages of simple structure, low power consumption and large operating bandwidth, our work provides a promising solution for on-chip passive nonreciprocal device.

  20. The influence of thermal aging on the optical coupler

    NASA Astrophysics Data System (ADS)

    Bednarek, Lukas; Hajek, Lukas; Vanderka, Ales; Nedoma, Jan; Fajkus, Marcel; Zboril, Ondrej; Vasinek, Vladimir

    2016-09-01

    Nowadays, it appears that the optical components aging faster. Therefore, it is accelerate of the research of the aging of the optical coupler by thermal stress necessary. This paper discusses finding of the influence of the thermal aging on the basic parameters of the optical coupler. The examined coupler has one input and eight outputs (1:8). The process of heat stress is carried out at 95°C in the electric drying oven where the coupler is loaded during the period of 120 hours. The optical power at the input of the coupler and the output optical powers of the individual branches of the coupler are measured after cooling to room temperature (approximately 25°C). The insertion losses of the individual branches, split ratio, total losses, homogeneity of the losses and cross-talk between individual branches are calculated using formulas. Measurements are made at wavelengths 1310 nm and 1550 nm. All optical powers are measured 20 times due to the statistical exclusion of error of measurements. The coupler is loaded during the period of 120 hours again immediately after measuring. Storing of the optical coupler in the drying oven is carried out so that is completely uniform heating of all the parts. The coupler is turn around every 30 hours. The paper contains the exact procedure of measurement of optical powers, which is followed by an evaluation of results. The results are shown for measurements before and after 5 cycles of heating.

  1. Optical Nonreciprocity in Asymmetric Optomechanical Couplers

    PubMed Central

    Wang, Zheqi; Shi, Lei; Liu, Yi; Xu, Xinbiao; Zhang, Xinliang

    2015-01-01

    We propose an all-optical integrated nonreciprocal device on the optomechanical platform with a large nonreciprocal bandwidth and low operating power. The device is based on an asymmetric silicon coupler consisting of two branches. One of them is a conventional strip waveguide fixed on the substrate, and the other is a freestanding nanostring suspended above a groove in the substrate. When light is launched into the coupler, the optical gradient force between the freestanding nanostring and the underlying substrate leads to the deflection of the nanostring, and finally results in destruction of the initial phase-matching condition between the two branches. The suspended branch would achieve distinct deflections when light is incident from different ports. The simulation results show a nonreciprocal bandwidth of 13.1 nm with operating power of 390 μW. With the advantages of simple structure, low power consumption and large operating bandwidth, our work provides a promising solution for on-chip passive nonreciprocal device. PMID:25728978

  2. Optical nonreciprocity in asymmetric optomechanical couplers.

    PubMed

    Wang, Zheqi; Shi, Lei; Liu, Yi; Xu, Xinbiao; Zhang, Xinliang

    2015-03-02

    We propose an all-optical integrated nonreciprocal device on the optomechanical platform with a large nonreciprocal bandwidth and low operating power. The device is based on an asymmetric silicon coupler consisting of two branches. One of them is a conventional strip waveguide fixed on the substrate, and the other is a freestanding nanostring suspended above a groove in the substrate. When light is launched into the coupler, the optical gradient force between the freestanding nanostring and the underlying substrate leads to the deflection of the nanostring, and finally results in destruction of the initial phase-matching condition between the two branches. The suspended branch would achieve distinct deflections when light is incident from different ports. The simulation results show a nonreciprocal bandwidth of 13.1 nm with operating power of 390 μW. With the advantages of simple structure, low power consumption and large operating bandwidth, our work provides a promising solution for on-chip passive nonreciprocal device.

  3. Coupler Studies for PBG Fiber Accelerators

    SciTech Connect

    England, J.; Ng, C.; Noble, R.; Spencer, J.; Wu, Z.; Xu, D.; /SLAC

    2011-08-17

    Photonic band gap (PBG) fiber with hollow core defects are being designed and fabricated for use as laser driven accelerators because they can provide gradients of several GeV/m for picosecond pulse lengths. We expect to produce fiber down to {lambda} = 1.5-2.0 {micro}m wavelengths but still lack a viable means for efficient coupling of laser power into such structures due to the very different character of the TM-like modes from those used in the telecom field and the fact that the defect must function as both a longitudinal waveguide for the accelerating field and a transport channel for the particles. We discuss the status of our work in pursuing both end and side coupling. For both options, the symmetry of these crystals leads to significant differences with the telecom field. Side coupling provides more options and appears to be preferred. Our goals are to test gradients, mode content and coupling efficiencies on the NLCTA at SLAC. While there are many potential types of fiber based on very different fabrication methods and materials we will concentrate on 2D axisymmetric glass with hexagonal symmetry but will discuss several different geometries including 2D and 3D planar structures. Since all of these can be fabricated using modern techniques with a variety of dielectric materials they are expected to have desirable optical and radiation hardness properties. Thus, we expect a new generation of very high gradient accelerators that extends the Livingston-Panofsky chart of exponential growth in energy vs. time at greatly reduced costs. For illustration, Fig.1 shows a simulation of our first engineered fiber with an accelerating mode expected near 7.3 {micro}m that is now ready to test on the NLCTA. In this example, one sees the uniform longitudinal accelerating field in the central defect as first shown by Lin3 together with a hexagonal array of surrounding hot spots. Contrary to what one expects from the telecom field, Ng et al. have shown4 that the ideal end

  4. Ultralow loss, high Q, four port resonant couplers for quantum optics and photonics.

    PubMed

    Rokhsari, H; Vahala, K J

    2004-06-25

    We demonstrate a low-loss, optical four port resonant coupler (add-drop geometry), using ultrahigh Q (>10(8)) toroidal microcavities. Different regimes of operation are investigated by variation of coupling between resonator and fiber taper waveguides. As a result, waveguide-to-waveguide power transfer efficiency of 93% (0.3 dB loss) and nonresonant insertion loss of 0.02% (<0.001 dB) for narrow bandwidth (57 MHz) four port couplers are achieved in this work. The combination of low-loss, fiber compatibility, and wafer-scale design would be suitable for a variety of applications ranging from quantum optics to photonic networks.

  5. Crosstalk comparison of lattice-form optical interleaver with different coupler structures

    NASA Astrophysics Data System (ADS)

    Wan, Zhujun; Luo, Fengguang; Luo, Zhixiang

    2009-05-01

    Lattice circuit made from a cascade of couplers and delay-lines is a popular approach for optical interleaver based on planar lightwave circuit (PLC) technology. Different coupler structures can be employed in the lattice circuit, including 1-stage directional couplers (DCs), 4-stage DCs, and 2-stage multimode interference (MMI) couplers. We fabricated optical interleavers with above three coupler structures, respectively. The experimental results prove that the latter two coupler structures can help to reduce crosstalk, which meets the simulation results well.

  6. An all fiber apparatus for microparticles selective manipulation based on a variable ratio coupler and a microfiber

    NASA Astrophysics Data System (ADS)

    Li, Baoli; Luo, Wei; Xu, Fei; Lu, Yanqing

    2016-09-01

    We propose an all fiber apparatus based on a variable ratio coupler which can transport microparticles controllably and trap particles one by one along a microfiber. By connecting two output ports of a variable ratio coupler with two end pigtails of a microfiber and launching a 980 nm laser into the variable ratio coupler, particles in suspension were trapped to the waist of microfiber due to a gradient force and then transported along the microfiber due to a total scattering force generated by two counter-propagating beams. The direction of transportation was controlled by altering the coupling ratio of the variable ratio coupler. When the intensities of two output ports were equivalent, trapped particles stayed at fixed positions. With time going, another particle around the micro fiber was trapped onto the microfiber. There were three particles trapped in total in our experiment. This technique combines with the function of conventional tweezers and optical conveyor.

  7. Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method.

    PubMed

    Dupuis, Alexandre; Allard, Jean-François; Morris, Denis; Stoeffler, Karen; Dubois, Charles; Skorobogatiy, Maksim

    2009-05-11

    We report several strategies for the fabrication of porous subwavelength fibers using low density Polyethylene plastic for low-loss terahertz light transmission applications. We also characterize transmission losses of the fabricated fibers in terahertz using a novel non-destructive directional coupler method. Within this method a second fiber is translated along the length of the test fiber to probe the power attenuation of a guided mode. The method is especially suitable for measuring transmission losses through short fiber segments, a situation in which standard cutback method is especially difficult to perform. We demonstrate experimentally that introduction of porosity into a subwavelength rod fiber, further reduces its transmission loss by as much as a factor of 10. The lowest fiber loss measured in this work is 0.01 cm(-1) and it is exhibited by the 40% porous subwavelength fiber of diameter 380 microm. For comparison, the loss of a rod-in-the-air subwavelength fiber of a similar diameter was measured to be approximately 0.1 cm(-1), while the bulk loss of a PE plastic used in the fabrication of such fibers is >or= 1 cm(-1). Finally, we present theoretical studies of the optical properties of individual subwavelength fibers and a directional coupler. From these studies we conclude that coupler setup studied in this paper also acts as a low pass filter with a cutoff frequency around 0.3 THz. Considering that the spectrum of a terahertz source used in this work falls off rapidly below 0.25 THz, the reported loss measurements are, thus, the bolometer averages over the approximately 0.25 THz-0.3 THz region.

  8. An integrated photoluminescence sensing platform using a single-multi-mode fiber coupler-based probe.

    PubMed

    Long, Feng; Zhu, Anna; Shi, Hanchang

    2014-03-21

    We demonstrate an integrated fiber optic photoluminescence sensing platform using a novel single-multi-mode fiber coupler (SMFC)-based probe with high collection efficiency for fluorescence signals. The SMFC, prepared using fused biconical taper technology, not only transmits excitation light, but also collects and transmits fluorescence. The entire system does not use complex optical components and rarely requires optical alignment. The simple structure of the SMFC considerably improves the light transmission efficiency, signal-to-noise ratio, and sensitivity of the system. Theoretical and experimental results show that the proposed probe increases the collection efficiency by more than eight-fold compared with a bifurcated fiber probe. The performance of the proposed probe was experimentally evaluated by measuring the fluorescence spectra of well-known targets and a fresh Tall Fescue leaf.

  9. Non-linear switching based on dual-core non-linear optical fiber couplers with XPM and Raman intrapulse applied to femtosecond pulse propagation

    NASA Astrophysics Data System (ADS)

    Gonçalves Correia, Dayse; Viana Ávila, Kilvia Maria; Cavalcante, Daniel do Nascimento e. Sá; Ferreira Pinto, Paulo Victor; Tadeu de Carvalho Belchior Magalhães, Francisco; Pinheiro de Moura, Lucas; da Conceição Ferreira, Alisson; Mendonça Menezes, Jose Wally; de Freitas Guimarães, Glendo

    2016-03-01

    In this work, we investigated the optical switching process for three shapes of femtosecond pulses (soliton, Gaussian and super-Gaussian) propagating inside a symmetrical dual-core non-linear directional coupler by simulating their propagation via the coupled non-linear Schrödinger equations. In all simulations, we considered the dispersive effects of second and third order, besides the self-phase modulation and self-steepening non-linear effects. We studied three scenarios for each of the three pulse shapes under investigation. In the first scenario, we added only cross-phase modulation (XPM); in the second approach, we added only Raman scattering; in the third one, we combined both. The study was performed for distinct polarization modes and for different values of the Raman factor, with power range varying from 1 to 300 W. We noted that the XPM non-linear effect results in a decrease in the critical power threshold, whereas the Raman scattering causes an increase. For the first scenario (only XPM effect), the critical power threshold reduced from 113.72 to 104.69 W for the soliton pulse, from 111.49 to 100.77 W for the Gaussian and from 92.79 to 80.47 W for the Super-Gaussian pulse shape. For the second scenario (only Raman scattering), the critical power increased for a Raman factor varying from 1 to 10 fs, and the three pulse shapes reached thresholds above 150 W from a 5 fs factor, reaching more than 200 W for the super-Gaussian pulse as the Raman factor increased. For the third scenario (with both effects combined), we highlight that for a fixed XPM factor of 2, the critical power remained unchanged with the variation of the Raman factor. Hence, we observed that the Super-Gaussian pulse reached lower values for critical power when compared to the other pulse shapes.

  10. Optimization of fiber grating couplers on SOI using advanced search algorithms.

    PubMed

    Wohlfeil, Benjamin; Zimmermann, Lars; Petermann, Klaus

    2014-06-01

    A one-dimensional fiber grating coupler is derived from a waveguide with random etches using implementations of particle swarm and genetic algorithms. The resulting gratings yield a theoretical coupling efficiency of up to 1.1 dB and prompt clear design rules for the layout of highly efficient fiber grating couplers.

  11. Fiber optic diffraction grating maker

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1991-05-21

    A compact and portable diffraction grating maker is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate. 4 figures.

  12. Fiber optic diffraction grating maker

    DOEpatents

    Deason, Vance A.; Ward, Michael B.

    1991-01-01

    A compact and portable diffraction grating maker comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate.

  13. The fiber coupler and beam stabilization system of the GRAVITY interferometer

    NASA Astrophysics Data System (ADS)

    Pfuhl, O.; Haug, M.; Eisenhauer, F.; Kellner, S.; Haussmann, F.; Perrin, G.; Gillessen, S.; Straubmeier, C.; Ott, T.; Rousselet-Perraut, K.; Amorim, A.; Lippa, Magdalena; Janssen, A.; Brandner, W.; Kok, Yitping; Blind, N.; Burtscher, L.; Sturm, E.; Wieprecht, E.; Schoeller, M.; Weber, J.; Hans, O.; Huber, S.

    2014-07-01

    We present the installed and fully operational beam stabilization and fiber injection subsystem feeding the 2nd generation VLTI instrument GRAVITY. The interferometer GRAVITY requires an unprecedented stability of the VLTI optical train to achieve micro-arcsecond astrometry. For this purpose, GRAVITY contains four fiber coupler units, one per telescope. Each unit is equipped with actuators to stabilize the telescope beam in terms of tilt and lateral pupil displacement, to rotate the field, to adjust the polarization and to compensate atmospheric piston. A special roof-prism offers the possibility of on-axis as well as off-axis fringe tracking without changing the optical train. We describe the assembly, integration and alignment and the resulting optical quality and performance of the individual units. Finally, we present the closed-loop performance of the tip-tilt and pupil tracking achieved with the final systems in the lab.

  14. Forked grating coupler optical vortex beam interface for silicon photonics

    NASA Astrophysics Data System (ADS)

    Nadovich, Christopher T.; Kosciolek, Derek J.; Jemison, William D.; Crouse, David T.

    2016-09-01

    The forked grating coupler (FGC) is a novel low-profile device compatible with silicon photonics that is capable of sensitive detection or efficient radiation of Optical Vortex (OV) light beams conveying orbital optical angular momentum (OAM). The FGC device combines the idea of a Bragg coupler with the forked hologram to create an integrated optics device that can selectively and efficiently couple selected optical vortex modes at near-normal incidence into planar confined dielectric waveguide modes of a photonic IC. FGCs retain many of the advantages of Bragg couplers, including convenience of placement and fabrication, reasonable bandwidth, small size, and CMOS process compatibility. In this work, prototype designs of FGC structures for 1550 nm wavelength have been developed for implementation on silicon on insulator (SOI) substrate. Fully vectorial three-dimensional (3D) electromagnetic simulation has allowed performance to be optimized over a range of structural parameters. Results have been evaluated against optical performance metrics including overall efficiency, mode match efficiency, and crosstalk between OV modes. Candidate FGC devices have been fabricated on SOI with e-beam lithography and tested optically. Tolerance to etch depth error has been evaluated.

  15. Carbon dioxide laser fabrication of fused-fiber couplers and tapers.

    PubMed

    Dimmick, T E; Kakarantzas, G; Birks, T A; Russell, P S

    1999-11-20

    We report the development of a fiber taper and fused-fiber coupler fabrication rig that uses a scanning, focused, CO(2) laser beam as the heat source. As a result of the pointlike heat source and the versatility associated with scanning, tapers of any transition shape and uniform taper waist can be produced. Tapers with both a linear shape and an exponential transition shape were measured. The taper waist uniformity was measured and shown to be better than +/-1.2%. The rig was also used to make fused-fiber couplers. Couplers with excess loss below -0.1 dB were routinely produced.

  16. Suspended mid-infrared fiber-to-chip grating couplers for SiGe waveguides

    NASA Astrophysics Data System (ADS)

    Favreau, Julien; Durantin, Cédric; Fédéli, Jean-Marc; Boutami, Salim; Duan, Guang-Hua

    2016-03-01

    Silicon photonics has taken great importance owing to the applications in optical communications, ranging from short reach to long haul. Originally dedicated to telecom wavelengths, silicon photonics is heading toward circuits handling with a broader spectrum, especially in the short and mid-infrared (MIR) range. This trend is due to potential applications in chemical sensing, spectroscopy and defense in the 2-10 μm range. We previously reported the development of a MIR photonic platform based on buried SiGe/Si waveguide with propagation losses between 1 and 2 dB/cm. However the low index contrast of the platform makes the design of efficient grating couplers very challenging. In order to achieve a high fiber-to-chip efficiency, we propose a novel grating coupler structure, in which the grating is locally suspended in air. The grating has been designed with a FDTD software. To achieve high efficiency, suspended structure thicknesses have been jointly optimized with the grating parameters, namely the fill factor, the period and the grating etch depth. Using the Efficient Global Optimization (EGO) method we obtained a configuration where the fiber-to-waveguide efficiency is above 57 %. Moreover the optical transition between the suspended and the buried SiGe waveguide has been carefully designed by using an Eigenmode Expansion software. Transition efficiency as high as 86 % is achieved.

  17. Optical mode switch based on multimode interference couplers

    NASA Astrophysics Data System (ADS)

    Xiao, Huifu; Deng, Lin; Zhao, Guolin; Liu, Zilong; Meng, Yinghao; Guo, Xiaonan; Liu, Guipeng; Liu, Su; Ding, Jianfeng; Tian, Yonghui

    2017-02-01

    In this paper, we propose an optical mode switch based on two cascaded multimode interference (MMI) couplers. After a fundamental mode divided into two equal-power fundamental modes in the first MMI coupler, the thermo-optic effect is employed to modulate the phase of the two fundamental modes before directed to the next MMI for the purpose of mode switching. By adjusting the electric signals applied to the modulation arms, the proposed device can implement mode switching in three states: (a) one first-order and two fundamental modes simultaneously output, (b) one first-order mode output, and (c) two fundamental modes output. As a result, the simulated excess losses are -0.29 dB, -0.10 dB, and -0.63 dB, respectively.

  18. In-fiber directional coupler for high-sensitivity curvature measurement.

    PubMed

    Guzman-Sepulveda, J R; May-Arrioja, D A

    2013-05-20

    A curvature fiber optic sensor using a two-core fiber (TCF) is proposed and demonstrated. The TCF is designed to operate as a directional coupler with one core located exactly at the center of the fiber and the other off-axis, but close to the center of the fiber. This design allows straightforward splicing of the TCF to single mode fibers (SMF), and alignment of the off-axis core is not strictly required for optimum operation. The sensor is fabricated by simply splicing a 5 cm long section of TCF between two SMF sections, which provides a sinusoidal spectral response. When the fiber is bent, the coupling parameters are modified due to stress-optic and effective length effects, effectively blue-shifting the sinusoidal spectral response of the sensor and allowing for the measurement of curvature. The sensor exhibits linear response and a sensitivity of -137.87 nm/m(-1) for curvature ranging from 0 to 0.27 m(-1), making it suitable to measure small curvatures with high sensitivity.

  19. Cross two photon absorption in a silicon photonic crystal waveguide fiber taper coupler with a physical junction

    SciTech Connect

    Sarkissian, Raymond O'Brien, John

    2015-01-21

    Cross two photon absorption in silicon is characterized using a tapered fiber photonic crystal silicon waveguide coupler. There is a physical junction between the tapered fiber and the waveguide constituting a stand-alone device. This device is used to obtain the spectrum for cross two photon absorption coefficient per unit volume of interaction between photons of nondegenerate energy. The corresponding Kerr coefficient per unit volume of interaction is also experimentally extracted. The thermal resistance of the device is also experimentally determined and the response time of the device is estimated for on-chip all-optical signal processing and data transfer between optical signals of different photon energies.

  20. Supersymmetry-Inspired Non-Hermitian Optical Couplers

    PubMed Central

    Principe, Maria; Castaldi, Giuseppe; Consales, Marco; Cusano, Andrea; Galdi, Vincenzo

    2015-01-01

    Supersymmetry has been shown to provide a systematic and effective framework for generating classes of isospectral optical structures featuring perfectly-phase-matched modes, with the exception of one (fundamental) mode which can be removed. More recently, this approach has been extended to non-Hermitian scenarios characterized by spatially-modulated distributions of optical loss and gain, in order to allow the removal of higher-order modes as well. In this paper, we apply this approach to the design of non-Hermitian optical couplers with higher-order mode-selection functionalities, with potential applications to mode-division multiplexing in optical links. In particular, we highlight the critical role of the coupling between non-Hermitian optical waveguides, which generally induces a phase transition to a complex eigenspectrum, thereby hindering the targeted mode-selection functionality. With the specific example of an optical coupler that selects the second-order mode of a given waveguide, we illustrate the aforementioned limitations and propose possible strategies to overcome them, bearing in mind the practical feasibility of the gain levels required. PMID:25708887

  1. Compact cantilever couplers for low-loss fiber coupling to silicon photonic integrated circuits.

    PubMed

    Wood, Michael; Sun, Peng; Reano, Ronald M

    2012-01-02

    We demonstrate coupling from tapered optical fibers to 450 nm by 250 nm silicon strip waveguides using compact cantilever couplers. The couplers consist of silicon inverse width tapers embedded within silicon dioxide cantilevers. Finite difference time domain simulations are used to design the length of the silicon inverse width taper to as short as 6.5 μm for a cantilever width of 2 μm. Modeling of various strip waveguide taper profiles shows reduced coupling losses for a quadratic taper profile. Infrared measurements of fabricated devices demonstrate average coupling losses of 0.62 dB per connection for the quasi-TE mode and 0.50 dB per connection for the quasi-TM mode across the optical telecommunications C band. In the wavelength range from 1477 nm to 1580 nm, coupling losses for both polarizations are less than 1 dB per connection. The compact, broadband, and low-loss coupling scheme enables direct access to photonic integrated circuits on an entire chip surface without the need for dicing or cleaving the chip.

  2. Optically isolated signal coupler with linear response

    DOEpatents

    Kronberg, James W.

    1994-01-01

    An optocoupler for isolating electrical signals that translates an electrical input signal linearly to an electrical output signal. The optocoupler comprises a light emitter, a light receiver, and a light transmitting medium. The light emitter, preferably a blue, silicon carbide LED, is of the type that provides linear, electro-optical conversion of electrical signals within a narrow wavelength range. Correspondingly, the light receiver, which converts light signals to electrical signals and is preferably a cadmium sulfide photoconductor, is linearly responsive to light signals within substantially the same wavelength range as the blue LED.

  3. Impedance matching vertical optical waveguide couplers for dense high index contrast circuits.

    PubMed

    Sun, Rong; Beals, Mark; Pomerene, Andrew; Cheng, Jing; Hong, Ching-Yin; Kimerling, Lionel; Michel, Jurgen

    2008-08-04

    We designed and demonstrated a compact, high-index contrast (HIC) vertical waveguide coupler for TE single mode operation with the lowest coupling loss of 0.20 dB +/- 0.05 dB at 1550 nm. Our vertical coupler consists of a pair of vertically overlapping inverse taper structures made of SOI and amorphous silicon. The vertical coupler can suppress power oscillation observed in regular directional couplers and guarantees vertical optical impedance matching with great tolerance for fabrication and refractive index variations of the waveguide materials. The coupler furthermore shows excellent broadband coupling efficiencies between 1460 nm and 1570 nm.

  4. Optimization of optical filter using triple coupler ring resonators structure based on polyimide substrate

    NASA Astrophysics Data System (ADS)

    Mahmudin, D.; Estu, T. T.; Fathnan, A. A.; Maulana, Y. Y.; Daud, P.; Sugandhi, G.; Wijayanto, Y. N.

    2016-11-01

    Optical filter is very important components in WDM network. MRR is a basic structure to design the optical filter because of easy to design for improving its performance. This paper discusses an innovative structure of the MRR, which is Triple Coupler Ring Resonators (TCRR) for optical filter applications. Values of width between bus and ring and values of radius of the ring in the structure TCRR were analyzed and optimized for several variations for obtaining coupling coefficient values. Therefore, wide Free Spectral Range (FSR) and high crosstalk suppression bandwidth can be obtained. As results, at the optimized width of gap of 100 nm and the optimized radiation of 8 μm, FSR of 2.85 THz and crosstalk suppression bandwidth of 60 GHz were achieved. Based on the results, this structure can be used for filtering optical signals in optical fiber communication.

  5. On-chip optical mode exchange using tapered directional coupler

    PubMed Central

    Zhang, Zhonglai; Hu, Xiao; Wang, Jian

    2015-01-01

    We present an on-chip optical mode exchange between two multiplexed modes by using tapered directional couplers on silicon-on-insulator platform. The device consisting of mode multiplexing and mode exchange is compact with relatively large fabrication error tolerance. The simulation results show efficient higher order mode excitation and mode exchange. A low excess loss less than 0.5 dB and high extinction ratio larger than 15 dB over 10 nm wavelength range from 1535 to 1545 nm are achieved. PMID:26530728

  6. Generalized fiber Fourier optics.

    PubMed

    Cincotti, Gabriella

    2011-06-15

    A twofold generalization of the optical schemes that perform the discrete Fourier transform (DFT) is given: new passive planar architectures are presented where the 2 × 2 3 dB couplers are replaced by M × M hybrids, reducing the number of required connections and phase shifters. Furthermore, the planar implementation of the discrete fractional Fourier transform (DFrFT) is also described, with a waveguide grating router (WGR) configuration and a properly modified slab coupler.

  7. Fiber optic coupled optical sensor

    DOEpatents

    Fleming, Kevin J.

    2001-01-01

    A displacement sensor includes a first optical fiber for radiating light to a target, and a second optical fiber for receiving light from the target. The end of the first fiber is adjacent and not axially aligned with the second fiber end. A lens focuses light from the first fiber onto the target and light from the target onto the second fiber.

  8. High-sensitivity fiber optic acoustic sensors

    NASA Astrophysics Data System (ADS)

    Lu, Ping; Liu, Deming; Liao, Hao

    2016-11-01

    Due to the overwhelming advantages compared with traditional electronicsensors, fiber-optic acoustic sensors have arisen enormous interest in multiple disciplines. In this paper we present the recent research achievements of our group on fiber-optic acoustic sensors. The main point of our research is high sensitivity interferometric acoustic sensors, including Michelson, Sagnac, and Fabry-Pérot interferometers. In addition, some advanced technologies have been proposed for acoustic or acoustic pressure sensing such as single-mode/multimode fiber coupler, dual FBGs and multi-longitudinal mode fiber laser based acoustic sensors. Moreover, our attention we have also been paid on signal demodulation schemes. The intensity-based quadrature point (Q-point) demodulation, two-wavelength quadrature demodulation and symmetric 3×3 coupler methodare discussed and compared in this paper.

  9. Vibration measurements based on demodulating the phase of a fiber 3dB-coupler Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Li, Min; Xie, Fang; Ren, Junyu

    2009-11-01

    A fiber interferometric vibration measurement system which is based on demodulating the phase of a fiber Michelson interferometer which is made with a fiber 3dB-coupler is presented. In the work, the system employed the characteristics of fiber Brag gratings (FBGs) to interleave two fiber Michelson interferometers which share almost the same part of the main optical path. One of the fiber interferometers is used to stabilize the system, employing an electronic feedback loop to drive a piezoelectric actuator to tune the optical path of the reference beam in order to keep the interferometer in quadrature state. By this way, the low frequency drifts in the phase of the interferometric signals which are resulted from environmental disturbances are compensated for. The other one is used to perform the measurement task. By employing the characteristics of 3dB-coupler, the interferometric signals from the two outputs of the 3dB-couper are 180º out of phase. The two interferometric signals are input into an electronic processor and convert into currents, which are linear to the power of the optical interferometric light. The signals are collected by NI USB-5132 acquisition card and processed by a program in a personal computer. The measurement system is configured with fiber and fiber components which are integrated together. As the cutoff frequency of the feedback loop is 1.5Hz, the measurement system is capable of measuring vibration with frequencies bigger than 1.5Hz and the amplitude of the measured vibration is not limited.

  10. Fiber optic monitoring device

    DOEpatents

    Samborsky, James K.

    1993-01-01

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

  11. Multimode waveguide based directional coupler

    NASA Astrophysics Data System (ADS)

    Ahmed, Rajib; Rifat, Ahmmed A.; Sabouri, Aydin; Al-Qattan, Bader; Essa, Khamis; Butt, Haider

    2016-07-01

    The Silicon-on-Insulator (SOI) based platform overcomes limitations of the previous copper and fiber based technologies. Due to its high index difference, SOI waveguide (WG) and directional couplers (DC) are widely used for high speed optical networks and hybrid Electro-Optical inter-connections; TE00-TE01, TE00-TE00 and TM00-TM00 SOI direction couplers are designed with symmetrical and asymmetrical configurations to couple with TE00, TE01 and TM00 in a multi-mode semi-triangular ring-resonator configuration which will be applicable for multi-analyte sensing. Couplers are designed with effective index method and their structural parameters are optimized with consideration to coupler length, wavelength and polarization dependence. Lastly, performance of the couplers are analyzed in terms of cross-talk, mode overlap factor, coupling length and coupling efficiency.

  12. High efficiency source coupler for optical waveguide illumination system

    DOEpatents

    Siminovitch, Michael J.

    2000-01-01

    A fiber optic or optical waveguide illumination system includes a source coupling system. The source coupling system includes an optical channel with an internal cavity. A light source is disposed inside the driving circuit. Coupling losses are minimized by placing the light source within the optical channel. The source cavity and the source optical channel can be shaped to enhance the amount of light captured in the channel by total internal reflection. Multiple light distribution waveguides can be connected to the source coupling channel to produce an illumination system.

  13. Fiber optic configurations for local area networks

    NASA Technical Reports Server (NTRS)

    Nassehi, M. M.; Tobagi, F. A.; Marhic, M. E.

    1985-01-01

    A number of fiber optic configurations for a new class of demand assignment multiple-access local area networks requiring a physical ordering among stations are proposed. In such networks, the data transmission and linear-ordering functions may be distinguished and be provided by separate data and control subnetworks. The configurations proposed for the data subnetwork are based on the linear, star, and tree topologies. To provide the linear-ordering function, the control subnetwork must always have a linear unidirectional bus structure. Due to the reciprocity and excess loss of optical couplers, the number of stations that can be accommodated on a linear fiber optic bus is severely limited. Two techniques are proposed to overcome this limitation. For each of the data and control subnetwork configurations, the maximum number of stations as a function of the power margin, for both reciprocal and nonreciprocal couplers, is computed.

  14. Fiber optic connector

    DOEpatents

    Rajic, Slobodan; Muhs, Jeffrey D.

    1996-01-01

    A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled.

  15. Fiber optic temperature sensor

    NASA Technical Reports Server (NTRS)

    Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor)

    2000-01-01

    A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

  16. Fiber optic temperature sensor

    NASA Technical Reports Server (NTRS)

    Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor); Mattes, Brenton L. (Inventor); Charnetski, Clark J. (Inventor)

    1999-01-01

    A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

  17. Fiber optic connector

    DOEpatents

    Rajic, S.; Muhs, J.D.

    1996-10-22

    A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded are disclosed. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled. 3 figs.

  18. Multiplexed polymer surface plasmon sensor with integrated optical coupler

    NASA Astrophysics Data System (ADS)

    Pyo, Hyeon-Bong; Park, Se Ho; Chung, Kwang Hyo; Choi, Chang Auck

    2005-11-01

    In this paper, we describe a novel multiplexed surface plasmon resonance (SPR) sensor which is made of cyclic olefin copolymers (COCs, TOPAS TM). This material has excellent chemical resistance, low water uptake (< 0.01%), and high refractive index (n He- Ne=1.53) suitable to use as an optical coupler (prism) as well as a sensor substrate. We fabricated a standard slide glass sized, prism integrated, and injection molded COC-SPR sensor which are being applied toward the multiplexed detection of DNA single nucleotide polymorphism (SNP). To evaluate the sensitivity of COC-SPR sensor, we first patterned MgF II on gold-coated COC-SPR sensor and observed the shift of minimum reflectivity (SPR dip) in pixel address. As incident light source we used an expanded, collimated, rectangular shaped He-Ne laser, with a diffuser for beam homogenization. With expanded laser beam we varied incident angle so that the angular shift is expressed as the darkest pixel shift on CCD. For optimized SPR characteristics and sensor configuration, analytical calculations (Fresnel equation) were performed, and the best SPR conditions were found to be d Au~48 nm at wavelength λ=633 nm with respected resonance angle at θ SPR =44.2° for COC-SPR sensor.

  19. Nonlinear optical coupler using a doped optical waveguide

    DOEpatents

    Pantell, Richard H.; Sadowski, Robert W.; Digonnet, Michel J. F.; Shaw, Herbert J.

    1994-01-01

    An optical mode coupling apparatus includes an Erbium-doped optical waveguide in which an optical signal at a signal wavelength propagates in a first spatial propagation mode and a second spatial propagation mode of the waveguide. The optical signal propagating in the waveguide has a beat length. The coupling apparatus includes a pump source of perturbational light signal at a perturbational wavelength that propagates in the waveguide in the first spatial propagation mode. The perturbational signal has a sufficient intensity distribution in the waveguide that it causes a perturbation of the effective refractive index of the first spatial propagation mode of the waveguide in accordance with the optical Kerr effect. The perturbation of the effective refractive index of the first spatial propagation mode of the optical waveguide causes a change in the differential phase delay in the optical signal propagating in the first and second spatial propagation modes. The change in the differential phase delay is detected as a change in the intensity distribution between two lobes of the optical intensity distribution pattern of an output signal. The perturbational light signal can be selectively enabled and disabled to selectively change the intensity distribution in the two lobes of the optical intensity distribution pattern.

  20. Fiber optic monitoring device

    DOEpatents

    Samborsky, J.K.

    1993-10-05

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information. 4 figures.

  1. Application of optical fibers in microfluidic structures

    NASA Astrophysics Data System (ADS)

    Stadnik, Dorota; Brzozka, Zbigniew; Dybko, Artur

    2004-09-01

    Two constructions of microfluidic structures are described in this paper. A fiber optic chemical coupler and a microcell for spectrophotometric measurements were designed and tested. The structures were made of polymer optical fibers (PMMA) which were incorporated into polymeric material i.e. poly(dimethylsiloxane). The structures were tested as detectors in refractometric experiment (saccharose solutions with different concentrations were used), in absorbance measurement (solutions of a bromothymol blue with different pH were used) and in fluorescence tests (solution of erythrosine was used).

  2. Precision Fiber Optic Sensor Market Forecast

    NASA Astrophysics Data System (ADS)

    Montgomery, Jeff D.; Glasco, Jon; Dixon, Frank W.

    1986-01-01

    The worldwide market for precision fiber optic sensors is forecasted, 1984-1994. The forecast is based upon o Analysis of fiber optic sensor and related component current technology, and a forecast of technology advancement o Review and projection of demand for precision sensing, and the penetration which fiber optics will make into this market The analysis and projections are based mainly on interviews conducted worldwide with research teams, government agencies, systems contractors, medical and industrial laboratories, component suppliers and others. The worldwide market for precision (interferometric) fiber optic sensing systems is forecasted to exceed $0.8 billion by 1994. The forecast is segmented by geographical region (Europe, Japan and North America) and by function; o Gyroscope o Sonar o Gradiometer/Magnetometer o Other - Chemical Composition - Atmospheric Acoustic - Temperature - Position - Pressure Requirements for components are reviewed. These include special fiber, emitters and detectors, modulators, couplers, switches, integrated optical circuits and integrated optoelectronics. The advancement in component performance is forecasted. The major driving forces creating fiber optic sensor markets are reviewed. These include fiber optic sensor technical and economic advantages, increasingly stringent operational requirements, and technology evolution. The leading fiber optic sensor and related component development programs are reviewed. Component sources are listed. Funding sources for sensor and component development are outlined, and trends forecasted.

  3. Lightwave coupler utilizing a tapered buffer layer.

    PubMed

    Kishioka, K

    1988-06-01

    We discuss the performance of a lightwave coupler utilizing a tapered buffer layer. The coupler with a ridge waveguide is fabricated on a glass substrate and high coupling efficiencies of 75% and 50% are measured for the operations of coupling from the waveguide to a light beam and from the laser beam into the waveguide, respectively. Further, experimental results of the rigid connection between the optical fiber and the waveguide are demonstrated. We also describe how the coupler differs from the conventional tapered guiding-layer coupler.

  4. Fiber Optics Instrumentation Development

    NASA Technical Reports Server (NTRS)

    Chan, Patrick Hon Man; Parker, Allen R., Jr.; Richards, W. Lance

    2010-01-01

    This is a general presentation of fiber optics instrumentation development work being conducted at NASA Dryden for the past 10 years and recent achievements in the field of fiber optics strain sensors.

  5. Fiber Optics Technology.

    ERIC Educational Resources Information Center

    Burns, William E.

    1986-01-01

    Discusses various applications of fiber optics technology: information systems, industrial robots, medicine, television, transportation, and training. Types of jobs that will be available with fiber optics training (such as electricians and telephone cable installers and splicers) are examined. (CT)

  6. Fiber optic sensors

    NASA Technical Reports Server (NTRS)

    Hesse, J.; Sohler, W.

    1984-01-01

    A survey of the developments in the field of fiber optics sensor technology is presented along with a discussion of the advantages of optical measuring instruments as compared with electronic sensors. The two primary types of fiber optics sensors, specifically those with multiwave fibers and those with monowave fibers, are described. Examples of each major sensor type are presented and discussed. Multiwave detectors include external and internal fiber optics sensors. Among the monowave detectors are Mach-Zender interferometers, Michelson interferometers, Sagnac interferometers (optical gyroscopes), waveguide resonators, and polarimeter sensors. Integrated optical sensors and their application in spectroscopy are briefly discussed.

  7. Two Fiber Optical Fiber Thermometry

    NASA Technical Reports Server (NTRS)

    Jones, Mathew R.; Farmer, Jeffery T.; Breeding, Shawn P.

    2000-01-01

    An optical fiber thermometer consists of an optical fiber whose sensing tip is given a metallic coating. The sensing tip of the fiber is essentially an isothermal cavity, so the emission from this cavity will be approximately equal to the emission from a blackbody. Temperature readings are obtained by measuring the spectral radiative heat flux at the end of the fiber at two wavelengths. The ratio of these measurements and Planck's Law are used to infer the temperature at the sensing tip. Optical fiber thermometers have high accuracy, excellent long-term stability and are immune to electromagnetic interference. In addition, they can be operated for extended periods without requiring re-calibration. For these reasons. it is desirable to use optical fiber thermometers in environments such as the International Space Station. However, it has recently been shown that temperature readings are corrupted by emission from the fiber when extended portions of the probe are exposed to elevated temperatures. This paper will describe several ways in which the reading from a second fiber can be used to correct the corrupted temperature measurements. The accuracy and sensitivity to measurement uncertainty will be presented for each method.

  8. Omnidirectional fiber optic tiltmeter

    DOEpatents

    Benjamin, B.C.; Miller, H.M.

    1983-06-30

    A tiltmeter is provided which is useful in detecting very small movements such as earth tides. The device comprises a single optical fiber, and an associated weight affixed thereto, suspended from a support to form a pendulum. A light source, e.g., a light emitting diode, mounted on the support transmits light through the optical fiber to a group of further optical fibers located adjacent to but spaced from the free end of the single optical fiber so that displacement of the single optical fiber with respect to the group will result in a change in the amount of light received by the individual optical fibers of the group. Photodetectors individually connectd to the fibers produce corresponding electrical outputs which are differentially compared and processed to produce a resultant continuous analog output representative of the amount and direction of displacement of the single optical fiber.

  9. Honeywell FLASH fiber optic motherboard evaluations

    NASA Astrophysics Data System (ADS)

    Stange, Kent

    1996-10-01

    The use of fiber optic data transmission media can make significant contributions in achieving increasing performance and reduced life cycle cost requirements placed on commercial and military transport aircraft. For complete end-to-end fiber optic transmission, photonics technologies and techniques need to be understood and applied internally to the aircraft line replaceable units as well as externally on the interconnecting aircraft cable plant. During a portion of the Honeywell contribution to Task 2A on the Fly- by-Light Advanced System Hardware program, evaluations were done on a fiber optic transmission media implementation internal to a Primary Flight Control Computer (PFCC). The PFCC internal fiber optic transmission media implementation included a fiber optic backplane, an optical card-edge connector, and an optical source/detector coupler/installation. The performance of these optical media components were evaluated over typical aircraft environmental stresses of temperature, vibration, and humidity. These optical media components represent key technologies to the computer end-to-end fiber optic transmission capability on commercial and military transport aircraft. The evaluations and technical readiness assessments of these technologies will enable better perspectives on productization of fly-by-light systems requiring their utilizations.

  10. A variable reflectivity output coupler for optically pumped far infrared lasers

    NASA Astrophysics Data System (ADS)

    Graf, U. U.; Harris, A. I.; Stutzki, J.; Genzel, R.

    1992-06-01

    The design and performance of a variable reflectivity output coupler for optically pumped far infrared lasers are investigated. The output coupler is a compact, tunable Michelson interferometer. The output coupling ratio is adjustable between 0 and equal to or greater than 60% for laser line wavelengths between 110 and 500 micrometers. This output coupler provides increased output power and flexibility. Beam profile measurements show that the Michelson output coupler produces a well collimated Gaussian laser beam. Design features are: the use of a 10 micrometers reflection coated quartz vacuum window which acts as a dichroic mirror for the pump radiation; the high mechanical stability obtained by leaf sping flexure mount of the movable Michelson mirror and by restricted alignment devices.

  11. Fiber optic vibration sensor

    DOEpatents

    Dooley, J.B.; Muhs, J.D.; Tobin, K.W.

    1995-01-10

    A fiber optic vibration sensor utilizes two single mode optical fibers supported by a housing with one optical fiber fixedly secured to the housing and providing a reference signal and the other optical fiber having a free span length subject to vibrational displacement thereof with respect to the housing and the first optical fiber for providing a signal indicative of a measurement of any perturbation of the sensor. Damping or tailoring of the sensor to be responsive to selected levels of perturbation is provided by altering the diameter of optical fibers or by immersing at least a portion of the free span length of the vibration sensing optical fiber into a liquid of a selected viscosity. 2 figures.

  12. Fiber optic vibration sensor

    DOEpatents

    Dooley, Joseph B.; Muhs, Jeffrey D.; Tobin, Kenneth W.

    1995-01-01

    A fiber optic vibration sensor utilizes two single mode optical fibers supported by a housing with one optical fiber fixedly secured to the housing and providing a reference signal and the other optical fiber having a free span length subject to vibrational displacement thereof with respect to the housing and the first optical fiber for providing a signal indicative of a measurement of any perturbation of the sensor. Damping or tailoring of the sensor to be responsive to selected levels of perturbation is provided by altering the diameter of optical fibers or by immersing at least a portion of the free span length of the vibration sensing optical fiber into a liquid of a selected viscosity.

  13. Fiber optic micro accelerometer

    DOEpatents

    Swierkowski, Steve P.

    2005-07-26

    An accelerometer includes a wafer, a proof mass integrated into the wafer, at least one spring member connected to the proof mass, and an optical fiber. A Fabry-Perot cavity is formed by a partially reflective surface on the proof mass and a partially reflective surface on the end of the optical fiber. The two partially reflective surfaces are used to detect movement of the proof mass through the optical fiber, using an optical detection system.

  14. The Fiber Optic Connection.

    ERIC Educational Resources Information Center

    Reese, Susan

    2003-01-01

    Describes the fiber optics programs at the Career and Technical Center in Berlin, Pennsylvania and the Charles S. Monroe Technology Center in Loudoun County, Virginia. Discusses the involvement of the Fiber Optic Association with education, research and development, manufacturing, sales, distribution, installation, and maintenance of fiber optic…

  15. Industrial applications of fiber optic sensing

    NASA Astrophysics Data System (ADS)

    Desforges, Francois X.; Blocksidge, Robert

    1996-08-01

    Thanks to the growth of the fiber optics telecommunication industry, fiber optic components have become less expensive, more reliable and well known by potential fiber optic sensor users. LEDs, optical fibers, couplers and connectors are now widely distributed and are the building blocks for the fiber optic sensor manufacturer. Additionally, the huge demand in consumer electronics of the past 10 years has provided the manufacturer with cheap and powerful programmable logic components which reduce the development time as well as the cost of the associated instrumentation. This market trend has allowed Photonetics to develop, manufacture and sell fiber optic sensors for the last 10 years. The company contribution in the fields of fiber optic gyros (4 licenses sold world wide), white light interferometry and fiber optic sensor networks is widely recognized. Moreover, its 1992 acquisition of some of the assets of Metricor Inc., greatly reinforced its position and allowed it to pursue new markets. Over the past four years, Photonetics has done an important marketing effort to better understand the need of its customers. The result of this research has fed R&D efforts towards a new generation instrument, the Metricor 2000, better adapted to the expectations of fiber optic sensors users, thanks to its unique features: (1) universality -- the system can accept more than 20 different sensors (T, P, RI, . . .). (2) scalability -- depending on the customer needs, the system can be used with 1 to 64 sensors. (3) performance -- because of its improved design, overall accuracies of 0.01% FS can be reached. (4) versatility -- its modular design enables a fast and easy custom design for specific applications. This paper presents briefly the Metricor 2000 and its family of FO probes. Then, it describes two fiber optic sensing (FOS) applications/markets where FOS have proven to be very useful.

  16. All-optical switch using optically controlled two mode interference coupler.

    PubMed

    Sahu, Partha Pratim

    2012-05-10

    In this paper, we have introduced optically controlled two-mode interference (OTMI) coupler having silicon core and GaAsInP cladding as an all-optical switch. By taking advantage of refractive index modulation by launching optical pulse into cladding region of TMI waveguide, we have shown optically controlled switching operation. We have studied optical pulse-controlled coupling characteristics of the proposed device by using a simple mathematical model on the basis of sinusoidal modes. The device length is less than that of previous work. It is also seen that the cross talk of the OTMI switch is not significantly increased with fabrication tolerances (±δw) in comparison with previous work.

  17. Remote optical fiber dosimetry

    NASA Astrophysics Data System (ADS)

    Huston, A. L.; Justus, B. L.; Falkenstein, P. L.; Miller, R. W.; Ning, H.; Altemus, R.

    2001-09-01

    Optical fibers offer a unique capability for remote monitoring of radiation in difficult-to-access and/or hazardous locations. Optical fiber sensors can be located in radiation hazardous areas and optically interrogated from a safe distance. A variety of remote optical fiber radiation dosimetry methods have been developed. All of the methods take advantage of some form of radiation-induced change in the optical properties of materials such as: radiation-induced darkening due to defect formation in glasses, luminescence from native defects or radiation-induced defects, or population of metastable charge trapping centers. Optical attenuation techniques are used to measure radiation-induced darkening in fibers. Luminescence techniques include the direct measurement of scintillation or optical excitation of radiation-induced luminescent defects. Optical fiber radiation dosimeters have also been constructed using charge trapping materials that exhibit thermoluminescence or optically stimulated luminescence (OSL).

  18. All-optical switching structure based on a photonic crystal directional coupler

    NASA Astrophysics Data System (ADS)

    Cuesta-Soto, F.; Martínez, A.; García, J.; Ramos, F.; Sanchis, P.; Blasco, J.; Martí, J.

    2004-01-01

    A novel all-optical switching structure based on a photonic crystal directional coupler is proposed and analyzed. Efficient optical switching is achieved by modifying the refractive index of the coupling region between the coupled waveguides by means of an optical control signal that is confined in the central region. Small length (around 1.1 mm) and low optical power consumption (over 1.5 W) are the main features estimated for this switching structure.

  19. Factorizable state-space model for active optical filter structures with two-port couplers.

    PubMed

    Panahi, Issa; Kannan, Govind

    2008-06-10

    A state-space model (SSM) is developed for an integrated photonic architecture. This particular architecture is composed of two-port couplers and current-controllable semiconductor optical amplifiers (gains) fabricated on the same substrate. This device architecture leads to a new type of lattice filter structure. The SSM is shown to be factorizable into two matrices, one containing structural parameters of the two-port couplers, which are set during manufacturing, and the other containing the tunable gains. The SSM provides a systematic and practical approach to the analysis of the underlying filter structure, which can be easily extended to multiple-input, multiple-output optical filter structures with or without adjustable gains using two- or four-port couplers. A novel method of using the gains as loss compensation elements in addition to their tunable roles is developed.

  20. Femtosecond direct-written integrated mode couplers.

    PubMed

    Riesen, Nicolas; Gross, Simon; Love, John D; Withford, Michael J

    2014-12-01

    We report the design and fabrication of three-dimensional integrated mode couplers operating in the C-band. These mode-selective couplers were inscribed into a boro-aluminosilicate photonic chip using the femtosecond laser direct-write technique. Horizontally and vertically written two-core couplers are shown to allow for the multiplexing of the LP11a and LP11b spatial modes of an optical fiber, respectively, with excellent mode extinction ratios (25-37 + dB) and low loss (~1 dB) between 1500 and 1580 nm. Furthermore, optimized fabrication parameters enable coupling ratios close to 100%. When written in sequence, the couplers allow for the multiplexing of all LP01, LP11a and LP11b modes. This is also shown to be possible using a single 3-dimensional three-core coupler. These integrated mode couplers have considerable potential to be used in mode-division multiplexing for increasing optical fiber capacity. The three-dimensional capability of the femtosecond direct-write technique provides the versatility to write linear cascades of such two- and three-core couplers into a single compact glass chip, with arbitrary routing of waveguides to ensure a small footprint. This technology could be used for high-performance, compact and cost-effective multiplexing of large numbers of modes of an optical fiber.

  1. Waveguide silicon nitride grating coupler

    NASA Astrophysics Data System (ADS)

    Litvik, Jan; Dolnak, Ivan; Dado, Milan

    2016-12-01

    Grating couplers are one of the most used elements for coupling of light between optical fibers and photonic integrated components. Silicon-on-insulator platform provides strong confinement of light and allows high integration. In this work, using simulations we have designed a broadband silicon nitride surface grating coupler. The Fourier-eigenmode expansion and finite difference time domain methods are utilized in design optimization of grating coupler structure. The fully, single etch step grating coupler is based on a standard silicon-on-insulator wafer with 0.55 μm waveguide Si3N4 layer. The optimized structure at 1550 nm wavelength yields a peak coupling efficiency -2.6635 dB (54.16%) with a 1-dB bandwidth up to 80 nm. It is promising way for low-cost fabrication using complementary metal-oxide- semiconductor fabrication process.

  2. Fiber optic laser rod

    DOEpatents

    Erickson, G.F.

    1988-04-13

    A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

  3. Fiber Optic Feed

    DTIC Science & Technology

    1990-11-06

    Naval Research Laboratory IIK Washington, DC,20375 5000 NRL Memorandum Report 6741 0 N Fiber Optic Feed DENZIL STILWELL, MARK PARENT AND LEw GOLDBERG...SUBTITLE S. FUNDING NUMBERS Fiber Optic Feed 53-0611-A0 6. AUTHOR(S) P. D. Stilwell, M. G. Parent, L. Goldberg 7. PERFORMING ORGANIZATION NAME(S) AND...DISTRIBUTION CODE Approved for public release; distribution unlimited. 13. ABSTRACT (Maximum 200 words) This report details a Fiber Optic Feeding

  4. Compact fiber optic immunosensor using tapered fibers and acoustic enhancement

    NASA Astrophysics Data System (ADS)

    Zhou, Chonghua; Pivarnik, Philip E.; Auger, Steven; Rand, Arthur G.; Letcher, Stephen V.

    1997-06-01

    A compact fiber-optic sensing system that features all-fiber optical design and semiconductor-laser excitation has been developed and tested. A 2X2 fiber coupler directs the input light to the SMA connected sensing fiber tip and the fluorescent signal back to a CCD fiber spectrophotometer. In this system, the fluorescent signal is confined in the fiber system so the signal-to-noise ratio is greatly improved and the system can be operate in ambient light conditions. The utilization of a red laser diode has reduced the background signal of non-essential biomolecules. The fluorescent dye used is Cy5, which has an excitation wavelength of 650 nm and a fluorescent center wavelength of 680 nm. To illustrate the biosensor's diagnostic capabilities, a sandwich immunoassay to detect Salmonella is presented. Tapered fiber tips with different shapes and treatments were studied and optimized. An enhancement system employing ultrasonic concentration of target particles has also been developed and applied to the detection of Salmonella. The immunoassay was conducted in a test chamber that also serves as an ultrasonic standing-wave cell and allows microspheres to be concentrated in a column along the fiber probe. The system demonstrates broad promise in future biomedical application.

  5. Fourier transform optical profilometry using fiber optic Lloyd's mirrors.

    PubMed

    Kart, Türkay; Kösoğlu, Gülşen; Yüksel, Heba; İnci, Mehmet Naci

    2014-12-10

    A fiber optic Lloyd's mirror assembly is used to obtain various optical interference patterns for the detection of 3D rigid body shapes. Two types of fiber optic Lloyd's systems are used in this work. The first consists of a single-mode optical fiber and a highly reflecting flat mirror to produce bright and dark strips. The second is constructed by locating a single-mode optical fiber in a v-groove, which is formed by two orthogonal flat mirrors to allow the generation of square-type interference patterns for the desired applications. The structured light patterns formed by these two fiber Lloyd's techniques are projected onto 3D objects. Fringe patterns are deformed due to the object's surface topography, which are captured by a digital CCD camera and processed with a Fourier transform technique to accomplish 3D surface topography of the object. It is demonstrated that the fiber-optic Lloyd's technique proposed in this work is more compact, more stable, and easier to configure than other existing surface profilometry systems, since it does not include any high-cost optical tools such as aligners, couplers, or 3D stages. The fringe patterns are observed to be more robust against environmental disturbances such as ambient temperature and vibrations.

  6. Coupling analysis of non-circular-symmetric modes and design of orientation-insensitive few-mode fiber couplers

    NASA Astrophysics Data System (ADS)

    Li, Jiaxiong; Du, Jiangbing; Ma, Lin; Li, Ming-Jun; Jiang, Shoulin; Xu, Xiao; He, Zuyuan

    2017-01-01

    We study the coupling between two identical weakly-coupled few-mode fibers based on coupled-mode theory. The coupling behavior of non-circular-symmetric modes, such as LP11 and LP21, is investigated analytically and numerically. By carefully choosing the fiber core separation and coupler length, we can design orientation-insensitive fiber couplers for non-circular-symmetric modes at arbitrary coupling ratios. Based on the design method, we propose an orientation-insensitive two-mode fiber coupler at 850 nm working as a mode multiplexer/demultiplexer for two-mode transmission using standard single-mode fiber. Within the band from 845 to 855 nm, the insertion losses of LP01 and LP11 modes are less than 0.03 dB and 0.24 dB, respectively. When the two-mode fiber coupler is used as mode demultiplexer, the LP01/LP11 and LP11/LP01 extinction ratios in the separated branches are respectively above 12.6 dB and 21.2 dB. Our design method can be extended to two-mode communication or sensing systems at other wavelengths.

  7. Grating-assisted vertical couplers for signal routing in multilayer integrated optical networks

    NASA Astrophysics Data System (ADS)

    Calò, Giovanna; Petruzzelli, Vincenzo

    2017-03-01

    Grating-assisted vertical couplers, which behave as add-drop filters, are proposed for wavelength routing of the signal among the different layers of on-chip multilayer optical networks. The device implements a 2×2 wavelength router which can be assembled into higher-order three-dimensional matrices. In particular, simple design criteria are found through a rapid and efficient optimization approach based on the mode analysis and demonstrated by the Finite Difference Time Domain (FDTD) simulations. The proposed numerical method is valid either for in-plane or for vertical grating-assisted couplers and it requires negligible computational effort. Different configurations of grating-assisted vertical couplers are designed and their spectral behavior is analyzed by the FDTD. The proposed devices achieve low values of the crosstalk between the different ports (below -20 dB) and of the input reflection (below -15 dB).

  8. Fiber optic liquid refractive index sensor

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Vanita; Gangwar, Rahul Kumar; Singh, Vinod Kumar

    2015-08-01

    In this present work we report fabrication of fiber optic liquid refractive index (RI) measurement sensor based on Michelson Interferometer method. This sensor was assembled by using graded index multimode (MM) fiber with core diameter 50 µm and the cladding of fiber was removed by simple chemical method. To perform this experiment a 2×2 3dB coupler is used. The fiber ends are then immersed in solvent and solution to provide reference and refractive index measurements, respectively. This method was successfully used to measure refractive index of Sodium Chloride (NaCl)-Water solution at different concentrations. The fringe contrast sensitivity of device is 92.90 dB/RIU measured in the RI range from 1.34 to 1.42 which is better than Mach-Zehnder Interferometer sensor [1] and Fabry perot based sensor [2]. The fabrication of sensor is simple, low cost and highly sensitive.

  9. Embedded coupler based on selectively infiltrated photonic crystal fiber for strain measurement.

    PubMed

    Wang, Ying; Liao, C R; Wang, D N

    2012-11-15

    A photonic crystal fiber (PCF) with embedded coupler is demonstrated for strain measurement. The embedded coupler is constructed by the selective filling of one of the air holes in the PCF. Light propagated in the fiber core can be efficiently coupled to the liquid-filled rod waveguide under phase-matching conditions, resulting in sharp decreasing of resonant wavelength intensity. The highest strain sensitivity is calculated to be ~23.8 pm/με due to the coupling between core mode and fundamental mode of the liquid rod, when the refractive index (RI) of the liquid is 1.46. With the increase of the RI, the resonance can also be observed between the core mode and the higher-order modes of the liquid rod, whereas the strain sensitivity drops to ~6.4 pm/με. The experimentally obtained static strain sensitivity values are ~22 and ~3.8 pm/με for the coupling between the core mode and the fundamental mode or linearly polarized LP(11) modes of the liquid rod, respectively, which are in good agreement with the simulations. The dynamic strain measurement resolution obtained is ~1.2 nε/(Hz)(1/2).

  10. Coupling Efficiency In A Holocoupler-Optical Fiber System

    NASA Astrophysics Data System (ADS)

    Calvo, M. L.; De Pedraza, L.

    1989-01-01

    We present a mathematical model based on the eikonal approximation for the diffraction of a TM wave by an optical fiber with parabolic profile. Optimal conditions for the signal to be totally confined into the fiber have been studied and numerically controlled. The light coupler was a hololens acting as a holocoupler. The total coupling efficiency of the system has been estimated for particular physical parameters.

  11. Fiber optofluidic biosensor for the label-free detection of DNA hybridization and methylation based on an in-line tunable mode coupler.

    PubMed

    Gao, Ran; Lu, Dan-Feng; Cheng, Jin; Jiang, Yi; Jiang, Lan; Xu, Jian-Dong; Qi, Zhi-Mei

    2016-12-15

    An optical fiber optofluidic biosensor for the detection of DNA hybridization and methylation has been proposed and experimentally demonstrated. An in-line fiber Michelson interferometer was formed in the photonic crystal fiber. A micrhole in the collapsed region, which combined the tunable mode coupler and optofluidic channel, was fabricated by using femtosecond laser micromachining. The mode field diameter of the guided light is changed with the refractive index in the optofluidic channel, which results in the tunable coupling ratio. Label-free detections of the DNA hybridization and methylation have been experimentally demonstrated. The probe single stranded DNA (ssDNA) was bound with the surface of the optofluidic channel through the Poly-l-lysine layer, and the hybridization between a short 22-mer probe ssDNA and a complementary target ssDNA was carried out and detected by interrogating the fringe visibility of the reflection spectrum. Then, the DNA methylation was also detected through the binding between the methylated DNA and the 5-methylcytosine (5-mC) monoclonal antibody. The experiments results demonstrate that the limit of detection of 5nM is achieved, establishing the tunable mode coupler as a sensitive and versatile biosensor. The sensitive optical fiber optofluidic biosensor possesses high specificity and low temperature cross-sensitivity.

  12. Multimode optical fiber

    SciTech Connect

    Bigot-Astruc, Marianne; Molin, Denis; Sillard, Pierre

    2014-11-04

    A depressed graded-index multimode optical fiber includes a central core, an inner depressed cladding, a depressed trench, an outer depressed cladding, and an outer cladding. The central core has an alpha-index profile. The depressed claddings limit the impact of leaky modes on optical-fiber performance characteristics (e.g., bandwidth, core size, and/or numerical aperture).

  13. All optical fiber combined-imaging system of photoacoustic and optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Eom, Jonghyun; Shin, Jun Geun; Park, Soongho; Lee, Byeong Ha

    2016-03-01

    We present an all optical fiber combined-imaging system that integrates non-contact photoacoustic tomography (NPAT) and optical coherence tomography (OCT) to simultaneously provide PA and OCT images. The fiber-based PAT system utilizing a Mach-Zehnder interferometer with a fiber laser of 1550 nm measures the photoacoustic signal at the sample surface. For the generation of a PA signal, a pulse train from a bulk type Nd:YAG laser illuminates the sample via a large core multimode optical fiber. The fiber-based OCT operating at a center wavelength of 1310 nm allowed is combined with the fiber-based PAT system by sharing the same optical fiber probe. The two lights from the fiber laser and the OCT source are guided into the probe through each port of a 2 by 2 optical fiber coupler. The back-reflected lights from the sample are guided to respective imaging systems by the same coupler. With these both NPAT and OCT images could be co-registered without physical contact with the sample. To demonstrate the feasibility of the proposed system, a phantom experiment has been carried out with a phantom composed of a black PET fiber and a fishing wire. The proposed all fiber-optic combined-imaging system has the potential for minimally invasive and improved diagnosis.

  14. Fiber optic hydrophone

    DOEpatents

    Kuzmenko, P.J.; Davis, D.T.

    1994-05-10

    A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer is disclosed. The hydrophone, in one embodiment, includes a body having a shaped flexible bladder at one end which defines a volume containing air or suitable gas, and including a membrane disposed adjacent a vent. An optical fiber extends into the body with one end terminating in spaced relation to the membrane. Acoustic waves in the water that impinge on the bladder cause the pressure of the volume therein to vary causing the membrane to deflect and modulate the reflectivity of the Fabry-Perot cavity formed by the membrane surface and the cleaved end of the optical fiber disposed adjacent to the membrane. When the light is transmitted down the optical fiber, the reflected signal is amplitude modulated by the incident acoustic wave. Another embodiment utilizes a fluid filled volume within which the fiber optic extends. 2 figures.

  15. Fiber optic hydrophone

    DOEpatents

    Kuzmenko, Paul J.; Davis, Donald T.

    1994-01-01

    A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer. The hydrophone, in one embodiment, includes a body having a shaped flexible bladder at one end which defines a volume containing air or suitable gas, and including a membrane disposed adjacent a vent. An optic fiber extends into the body with one end terminating in spaced relation to the membrane. Acoustic waves in the water that impinge on the bladder cause the pressure of the volume therein to vary causing the membrane to deflect and modulate the reflectivity of the Fabry-Perot cavity formed by the membrane surface and the cleaved end of the optical fiber disposed adjacent to the membrane. When the light is transmitted down the optical fiber, the reflected signal is amplitude modulated by the incident acoustic wave. Another embodiment utilizes a fluid filled volume within which the fiber optic extends.

  16. Woven fiber optics.

    PubMed

    Schmidt, A C; Courtney-Pratt, J S; Ross, E A

    1975-02-01

    In this paper we describe how the art of weaving can be applied to fiber optics in order to produce precisely controlled reproducible image guides and image dissectors. As examples of the types of device for which woven fiber optics are applicable, we describe a 3:1 interleaver for use with a cathode-ray tube to produce color images, and a high speed alpha numeric output device. The techniques of weaving fiber optics are discussed in sufficient detail in order to allow for further work. Although, in principle, one might be able to weave glass optical fibers, all the work described here made use of plastic optical fibers 0.25 mm in diameter.

  17. Python fiber optic seal

    SciTech Connect

    Ystesund, K.; Bartberger, J.; Brusseau, C.; Fleming, P.; Insch, K.; Tolk, K.

    1993-08-01

    Sandia National Laboratories has developed a high security fiber optic seal that incorporates tamper resistance features that are not available in commercial fiber optic seals. The Python Seal is a passive fiber optic loop seal designed to give indication of unauthorized entry. The seal includes a fingerprint feature that provides seal identity information in addition to the unique fiber optic pattern created when the seal is installed. The fiber optic cable used for the seal loop is produced with tamper resistant features that increase the difficulty of attacking that component of a seal. A Seal Reader has been developed that will record the seal signature and the fingerprint feature of the seal. A Correlator software program then compares seal images to establish a match or mismatch. SNL is also developing a Polaroid reader to permit hard copies of the seal patterns to be obtained directly from the seal.

  18. Adaptive control of waveguide modes using a directional coupler.

    PubMed

    Lu, Peng; Shipton, Matthew; Wang, Anbo; Xu, Yong

    2014-08-25

    Using adaptive optics (AO) and a directional coupler, we demonstrate adaptive control of linearly polarized (LP) modes in a two mode fiber. The AO feedback is provided by the coupling ratio of the directional coupler, and does not depend on the spatial profiles of optical field distributions. As a proof of concept demonstration, this work confirms the feasibility of using AO and all fiber devices to control the waveguide modes in a multimode network in a quasi-distributed manner.

  19. Fiber optics for controls

    NASA Technical Reports Server (NTRS)

    Seng, Gary T.

    1987-01-01

    The challenge of those involved in control-system hardware development is to accommodate an ever-increasing complexity in aircraft control, while limiting the size and weight of the components and improving system reliability. A technology that displays promise towards this end is the area of fiber optics for controls. The primary advantages of employing optical fibers, passive optical sensors, and optically controlled actuators are weight and volume reduction, immunity from electromagnetic effects, superior bandwidth capabilities, and freedom from short circuits and sparking contacts. Since 1975, NASA Lewis has performed in-house, contract, and grant research in fiber optic sensors, high-temperature electro-optic switches, and fly-by-light control-system architecture. Passive optical sensor development is an essential yet challenging area of work and has therefore received much attention during this period. A major effort to develop fly-by-light control-system technology, known as the Fiber-Optic Control System Integration (FOCSI) program, was initiated in 1985 as a cooperative effort between NASA and DOD. Phase 1 of FOCSI, completed in 1986, was aimed at the design of a fiber-optic integrated propulsion/flight control system. Phase 2, yet to be initiated, will provide subcomponent and system development, and a system engine test. In addition to a summary of the benefits of fiber optics, the FOCSI program, sensor advances, and future directions in the NASA Lewis program will be discussed.

  20. Electro-optical logic application of multimode interference coupler by multivalued controlling.

    PubMed

    Zhou, Haifeng; Wang, Wanjun; Yang, Jianyi; Wang, Minghua; Jiang, Xiaoqing

    2011-05-20

    Electro-optical hybrid logic is a potential solution to implement both electrical and optical signal processing, which receives analog or digital, electrical or optical signals and produces logic signals in a desired manner. In light of the transfer matrix theory, we found that one can steer light into different output ports of a multimode interference coupler by controlling the phases in a multivalued manner on the image-extended arms. This implementation acts as an analog-to-digital convertor from electric domain to optical domain. Also, an electrical-to-optical 2-to-2(2) binary-coded decoder is described and examined by the 3D beam propagation method.

  1. Infrared fiber optic materials

    NASA Technical Reports Server (NTRS)

    Feigelson, Robert S.

    1987-01-01

    The development of IR fiber optics for use in astronomical and other space applications is summarized. Candidate materials were sought for use in the 1 to 200 micron and the 200 to 1000 micron wavelength range. Synthesis and optical characterization were carried out on several of these materials in bulk form. And the fabrication of a few materials in single crystal fiber optic form were studied.

  2. Fiber optic moisture sensor

    DOEpatents

    Kirkham, R.R.

    1984-08-03

    A method and apparatus for sensing moisture changes by utilizing optical fiber technology. One embodiment uses a reflective target at the end of an optical fiber. The reflectance of the target varies with its moisture content and can be detected by a remote unit at the opposite end of the fiber. A second embodiment utilizes changes in light loss along the fiber length. This can be attributed to changes in reflectance of cladding material as a function of its moisture content. It can also be affected by holes or inserts interposed in the cladding material and/or fiber. Changing light levels can also be coupled from one fiber to another in an assembly of fibers as a function of varying moisture content in their overlapping lengths of cladding material.

  3. Optical fiber metamagnetics.

    PubMed

    Wang, Xi; Venugopal, Gayatri; Zeng, Jinwei; Chen, Yinnan; Lee, Dong Ho; Litchinitser, Natalia M; Cartwright, Alexander N

    2011-10-10

    To date, magnetic and negative-index metamaterials at optical frequencies were realized on bulk substrates in the form of thin films with thicknesses on the order of, or less than, optical wavelengths. In this work, we design and experimentally demonstrate, for the first time, fiber-coupled magnetic metamaterials integrated on the transverse cross-section of an optical fiber. Such fiber-metamaterials integration may provide fundamentally new solutions for photonic-on-a-chip systems for sensing, subwavelength imaging, image processing, and biomedical applications.

  4. Fiber Optic Microphone

    NASA Technical Reports Server (NTRS)

    Cho, Y. C.; George, Thomas; Norvig, Peter (Technical Monitor)

    1999-01-01

    Research into advanced pressure sensors using fiber-optic technology is aimed at developing compact size microphones. Fiber optic sensors are inherently immune to electromagnetic noise, and are very sensitive, light weight, and highly flexible. In FY 98, NASA researchers successfully designed and assembled a prototype fiber-optic microphone. The sensing technique employed was fiber optic Fabry-Perot interferometry. The sensing head is composed of an optical fiber terminated in a miniature ferrule with a thin, silicon-microfabricated diaphragm mounted on it. The optical fiber is a single mode fiber with a core diameter of 8 micron, with the cleaved end positioned 50 micron from the diaphragm surface. The diaphragm is made up of a 0.2 micron thick silicon nitride membrane whose inner surface is metallized with layers of 30 nm titanium, 30 nm platinum, and 0.2 micron gold for efficient reflection. The active sensing area is approximately 1.5 mm in diameter. The measured differential pressure tolerance of this diaphragm is more than 1 bar, yielding a dynamic range of more than 100 dB.

  5. Fiber Optics: No Illusion.

    ERIC Educational Resources Information Center

    American School and University, 1983

    1983-01-01

    A campus computer center at Hofstra University (New York) that holds 70 terminals for student use was first a gymnasium, then a language laboratory. Strands of fiber optics are used for the necessary wiring. (MLF)

  6. Simulating Optical Fibers.

    ERIC Educational Resources Information Center

    Edgar, Dale

    1988-01-01

    Described is a demonstration of Snell's law using a laser beam and an optical fiber. Provided are the set-up method of the demonstration apparatus and some practical suggestions including "index matching" technique using vaseline. (YP)

  7. Fiber optics: A research paper

    NASA Technical Reports Server (NTRS)

    Drone, Melinda M.

    1987-01-01

    Some basic aspects concerning fiber optics are examined. Some history leading up to the development of optical fibers which are now used in the transmission of data in many areas of the world is discussed. Basic theory of the operation of fiber optics is discussed along with methods for improving performance of the optical fiber through much research and design. Splices and connectors are compared and short haul and long haul fiber optic networks are discussed. Fiber optics plays many roles in the commercial world. The use of fiber optics for communication applications is emphasized.

  8. Fiber optics: A research paper

    NASA Astrophysics Data System (ADS)

    Drone, Melinda M.

    1987-08-01

    Some basic aspects concerning fiber optics are examined. Some history leading up to the development of optical fibers which are now used in the transmission of data in many areas of the world is discussed. Basic theory of the operation of fiber optics is discussed along with methods for improving performance of the optical fiber through much research and design. Splices and connectors are compared and short haul and long haul fiber optic networks are discussed. Fiber optics plays many roles in the commercial world. The use of fiber optics for communication applications is emphasized.

  9. Fiber optic hydrogen sensor

    DOEpatents

    Buchanan, B.R.; Prather, W.S.

    1991-01-01

    Apparatus and method for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading, by a single spectrophotometer.

  10. Fiber optic hydrogen sensor

    DOEpatents

    Buchanan, B.R.; Prather, W.S.

    1992-10-06

    An apparatus and method are described for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading by a single spectrophotometer. 4 figs.

  11. Fiber optic hydrogen sensor

    DOEpatents

    Buchanan, Bruce R.; Prather, William S.

    1992-01-01

    An apparatus and method for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading by a single spectrophotometer.

  12. Fiber optics welder

    DOEpatents

    Higgins, R.W.; Robichaud, R.E.

    A system is described for welding fiber optic waveguides together. The ends of the two fibers to be joined together are accurately, collinearly aligned in a vertical orientation and subjected to a controlled, diffuse arc to effect welding and thermal conditioning. A front-surfaced mirror mounted at a 45/sup 0/ angle to the optical axis of a stereomicroscope mounted for viewing the junction of the ends provides two orthogonal views of the interface during the alignment operation.

  13. Fiber optic detector

    NASA Astrophysics Data System (ADS)

    Partin, Judy K.; Ward, Thomas E.; Grey, Alan E.

    1990-04-01

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  14. Fiber optic detector

    SciTech Connect

    Partin, J.K.; Ward, T.E.; Grey, A.E.

    1990-12-31

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  15. Tunable negative-tap photonic microwave filter based on a cladding-mode coupler and an optically injected laser of large detuning.

    PubMed

    Chan, Sze-Chun; Liu, Qing; Wang, Zhu; Chiang, Kin Seng

    2011-06-20

    A tunable negative-tap photonic microwave filter using a cladding-mode coupler together with optical injection locking of large wavelength detuning is demonstrated. Continuous and precise tunability of the filter is realized by physically sliding a pair of bare fibers inside the cladding-mode coupler. Signal inversion for the negative tap is achieved by optical injection locking of a single-mode semiconductor laser. To couple light into and out of the cladding-mode coupler, a pair of matching long-period fiber gratings is employed. The large bandwidth of the gratings requires injection locking of an exceptionally large wavelength detuning that has never been demonstrated before. Experimentally, injection locking with wavelength detuning as large as 27 nm was achieved, which corresponded to locking the 36-th side mode. Microwave filtering with a free-spectral range tunable from 88.6 MHz to 1.57 GHz and a notch depth larger than 35 dB was obtained.

  16. Optical Transformers with Integrated Couplers (OTIC) for Ultrahigh SERS Enhancement

    DTIC Science & Technology

    2012-01-13

    Report January 13, 2012 Optical Antenna Engineering For SERS PI : Prof. Ming Wu University of California, Berkeley The long-range goal of...enhancement. For theoretical understanding, the field enhancement of an optical antenna at resonance has been derived using coupled mode theory...CMT) as: (1) where Eloc and Ei are the local field amplitude at the high field region of an optical antenna and the field amplitude of incoming

  17. Bidirectional optical bistability in a dual-pumped erbium doped fiber ring laser.

    PubMed

    Lai, W J; Shum, P; Binh, L

    2004-11-15

    We investigate bidirectional optical wave propagations in a dual-pumped erbium doped fiber ring laser without isolator, and observe optical bistability behaviors. Consequently, we propose and construct a NOLM-NALM fiber ring laser to demonstrate and exploit this bidirectional optical bistability phenomenon in optical switching by introducing two tunable variable ratio couplers in the system. Numerical analyses based on the proposed laser structure have also been demonstrated corroborated with the experimental results.

  18. Optical fiber phase discriminator.

    PubMed

    Danielson, B L

    1978-11-15

    Phase discriminators are devices widely used at rf and microwave frequencies to convert phase, or frequency, changes to amplitude changes. They find widespread use in generating audio feedback signals for frequency stabilization of oscillators and in angle demodulation applications. This paper demonstrates that similar devices, with similar functions, can be constructed in the visible region using optical fibers as delay-line elements. The operating principles of an optical-fiber delay-line phase discriminator are discussed. The sensitivity is shown to be proportional to the fiber propagation-delay time. A device working at 0.6328 microm is described and compared with predictions.

  19. Splicing plastic optical fibers

    NASA Astrophysics Data System (ADS)

    Carson, Susan D.; Salazar, Roberto A.

    1991-12-01

    Polymethylmethacrylate (PMMA) plastic optical fiber (500 micrometers diameter, fluoropolymer cladding) has been spliced using a fused silica sleeve and a variety of solvent/PMMA solutions as adhesives. Mechanical splicing using index matching fluid has also been investigated. To ensure good bonding and minimize scattering, fiber ends are polished prior to application of adhesive. Using an LED ((lambda) max approximately 640 nm), losses are routinely less than 1.0 dB/splice, and some adhesive formulations have exhibited losses as low as 0.2 dB/splice. Five-meter fibers with as many as ten splices/fiber have been monitored over a period of several months. No fiber has exhibited an increase in optical loss with time.

  20. Fiber optics for controls

    NASA Technical Reports Server (NTRS)

    Seng, Gary T.

    1990-01-01

    The design, development, and testing of a fiber optic integrated propulsion/flight control system for an advanced supersonic dash aircraft (flies at supersonic speeds for short periods of time) is the goal of the joint NASA/DOD Fiber Optic Control System Integration (FOCSI) program. Phase 1 provided a comparison of electronic and optical control systems, identified the status of current optical sensor technology, defined the aircraft sensor/actuator environment, proposed architectures for fully optical control systems, and provided schedules for development. Overall, it was determined that there are sufficient continued efforts to develop such a system. It was also determined that it is feasible to build a fiber optic control system for the development of a data base for this technology, but that further work is necessary in sensors, actuators, and components to develop an optimum design, fully fiber optic integrated control system compatible with advanced aircraft environments. Phase 2 is to design, construct, and ground test a fly by light control system. Its first task is to provide a detailed design of the electro-optic architecture.

  1. Silicon fiber optic sensors

    DOEpatents

    Pocha, Michael D.; Swierkowski, Steve P.; Wood, Billy E.

    2007-10-02

    A Fabry-Perot cavity is formed by a partially or wholly reflective surface on the free end of an integrated elongate channel or an integrated bounding wall of a chip of a wafer and a partially reflective surface on the end of the optical fiber. Such a constructed device can be utilized to detect one or more physical parameters, such as, for example, strain, through the optical fiber using an optical detection system to provide measuring accuracies of less than aboutb0.1%.

  2. Measurement of chalcogenide glass optical dispersion using a mid-infrared prism coupler

    SciTech Connect

    Qiao, Hong; Anheier, Norman C.; Musgraves, Jonathan D.; Richardson, Kathleen; Hewak, Daniel W.

    2011-05-01

    Physical properties of chalcogenide glass, including broadband infrared transparency, high refractive index, low glass transition temperature, and nonlinear properties, make them attractive candidates for advanced mid-infrared (3 to 12 {micro}m) optical designs. Efforts focused at developing new chalcogenide glass formulations and processing methods require rapid quantitative evaluation of their optical contents to guide the materials research. However, characterization of important optical parameters such as optical dispersion remains a slow and costly process, generally with limited accuracy. The recent development of a prism coupler at the Pacific Northwest National Laboratory (PNNL) now enables rapid, high precision measurement of refractive indices at discrete wavelengths from the visible to the mid-infrared. Optical dispersion data of several chalcogenide glass families were collected using this method. Variations in the optical dispersion were correlated to glass composition and compared against measurements using other methods. While this work has been focused on facilitating chalcogenide glass synthesis, mid-infrared prism coupler analysis has broader applications to other mid-infrared optical material development efforts, including oxide glasses and crystalline materials.

  3. All-optical logic gates based on cross-phase modulation in an asymmetric coupler

    NASA Astrophysics Data System (ADS)

    Li, Qiliang; Yuan, Hongliang

    2014-05-01

    In this paper we propose an operation of an all-optical logical gate based on an asymmetric nonlinear directional coupler operating with the cross-phase modulation. Two-input OR and XOR gates and a new logical operation based on an asymmetric nonlinear directional coupler, which can be applied to transmission and processing of signals in all-optical systems, are examined. Initially, we evaluate the effect of the pump power on switching. We import a pulse into the nonlinear directional coupler, meanwhile adding a pump light via wavelength division multiplex in order to take advantage of Kerr effect and produce the cross-phase modulation. In this situation, we analyze two possible situations for the two-input logical gate, and draw a switching characteristic curve via Matlab. Finally, we define the truth table and it is clear that OR and XOR logic gates and a new logical operation can be realized by changing the pump power. Next the investigation also indicates that to change the input pulse's phase switching can be realized. In the same way, we define the truth table and it can be observed that different logic gates are realized.

  4. Optical fiber switch

    DOEpatents

    Early, James W.; Lester, Charles S.

    2002-01-01

    Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

  5. Study of optical output couplers for submillimeter wavelength backward-wave oscillators (BWO's)

    NASA Technical Reports Server (NTRS)

    Cook, Jerry D.; Stankiewicz, Norbert; Podany, Mark

    1988-01-01

    The machining of slow wave structures for high frequency backward-wave oscillators (BWO) is extremely difficult beyond 1 THz. Recently a microfabrication technique using photolithography and ion-beam assisted etching has been used to construct a prototype BWO operating at 200 to 265 GHz. The output coupler for such tubes remains a problem. Waveguides do not exist or are very lossy at the frequencies of interest (300 to 2000 GHz). This paper discusses several scaled experiments of optical output couplers for submillimeter BWOs. Various designs of planar antennas (Vivaldi horns) and lens-feed systems (Hyperhemispherical lens) were constructed and tested between 20 and 100 GHz using a spectrum analyzer. The lens system was also tested at 337 GHz using a CO2 pumped FIR laser.

  6. Electrospun Amplified Fiber Optics

    PubMed Central

    2015-01-01

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm–1). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics. PMID:25710188

  7. Electrospun amplified fiber optics.

    PubMed

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-03-11

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm(-1)). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics.

  8. Fiber-optic polarization diversity detection for rotary probe optical coherence tomography.

    PubMed

    Lee, Anthony M D; Pahlevaninezhad, Hamid; Yang, Victor X D; Lam, Stephen; MacAulay, Calum; Lane, Pierre

    2014-06-15

    We report a polarization diversity detection scheme for optical coherence tomography with a new, custom, miniaturized fiber coupler with single mode (SM) fiber inputs and polarization maintaining (PM) fiber outputs. The SM fiber inputs obviate matching the optical lengths of the X and Y OCT polarization channels prior to interference and the PM fiber outputs ensure defined X and Y axes after interference. Advantages for this scheme include easier alignment, lower cost, and easier miniaturization compared to designs with free-space bulk optical components. We demonstrate the utility of the detection system to mitigate the effects of rapidly changing polarization states when imaging with rotating fiber optic probes in Intralipid suspension and during in vivo imaging of human airways.

  9. Optical fiber stripper positioning apparatus

    DOEpatents

    Fyfe, Richard W.; Sanchez, Jr., Amadeo

    1990-01-01

    An optical fiber positioning apparatus for an optical fiber stripping device is disclosed which is capable of providing precise axial alignment between an optical fiber to be stripped of its outer jacket and the cutting blades of a stripping device. The apparatus includes a first bore having a width approximately equal to the diameter of an unstripped optical fiber and a counter bore axially aligned with the first bore and dimensioned to precisely receive a portion of the stripping device in axial alignment with notched cutting blades within the stripping device to thereby axially align the notched cutting blades of the stripping device with the axis of the optical fiber to permit the notched cutting blades to sever the jacket on the optical fiber without damaging the cladding on the optical fiber. In a preferred embodiment, the apparatus further includes a fiber stop which permits determination of the length of jacket to be removed from the optical fiber.

  10. Design and Performance of Ka-Band Fiber-Optic Delay Lines

    DTIC Science & Technology

    2012-12-28

    grade devices surpassing 110 GHz. Given such bandwidth and low-loss delay capability, FODL technology is incredibly useful as a buffer for signal...nearly 0.8 A/W. With a 60%/40% fiber optic coupler at the first EDFA output, this dictates that the first EDFA must source 13 dBm of optical power

  11. Infrared Fiber Optics.

    DTIC Science & Technology

    1979-12-01

    This unit is thca placed in a larger plastic tube which mates with the fiber connectors. Commercial AMP connectors are used that allow the fiber cable...AD-A082 450 HUSHES RESEARCH LABS MALIBU CA pie 20/6 INFRARED FIBER OPTICS.(U) DEC 79 J A HARRINSTON, R TURK, M HENDERSON F1962-R78-C-0109...Laboratories AE.WR r z7 3011 Malibu Canyon Road t 2 Hanscom AFB MA 01731 E I NUBROPAS I5s. OECLASSIFI ATION/DOWNGRADING SN/ A SCHEDULE 16. DISTRI13UTION

  12. Integrated optics for fiber optic sensors

    NASA Technical Reports Server (NTRS)

    Minford, W. J.; Depaula, R. P.

    1991-01-01

    Recent progress achieved in the field of fiber-optic sensor applications is discussed with emphasis placed on LiNbO3-based integrated optics (IO). Particular consideration is given to advanced electromagnetic-field sensors, an integrated laser vibrometer system, and a fiber-optic gyroscope system. It is shown that the multifunction IO chips have enabled high perforamance fiber-optic sensors (e.g., fiber-optic gyros), provided advanced and unique signal processing capabilities and advanced architectures, and have a potential of making fiber-optic sensors at low cost.

  13. Fiber optic fluid detector

    DOEpatents

    Angel, S. Michael

    1989-01-01

    Particular gases or liquids are detected with a fiber optic element (11, 11a to 11j) having a cladding or coating of a material (23, 23a to 23j) which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector (24, 24a to 24j) may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses.

  14. Fiber optic fluid detector

    DOEpatents

    Angel, S.M.

    1987-02-27

    Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses. 10 figs.

  15. Enhanced radiation resistant fiber optics

    DOEpatents

    Lyons, Peter B.; Looney, Larry D.

    1993-01-01

    A process for producing an optical fiber having enhanced radiation resitance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation.

  16. Enhanced radiation resistant fiber optics

    DOEpatents

    Lyons, P.B.; Looney, L.D.

    1993-11-30

    A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

  17. Fiber-Optic Sensing Technology

    SciTech Connect

    Milnes, M.; Baylor, L.C.; Bave, S.

    1996-10-24

    This article offers a basic review of fiber-optic sensing technology, or more specifically, fiber-optic sensing technology as applied to the qualitative or quantitative identification of a chemical sample, and how it works,

  18. Reduced Gravity Zblan Optical Fiber

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Workman, Gary L.; Smith, Guy A.

    2000-01-01

    Two optical fiber pullers have been designed for pulling ZBLAN optical fiber in reduced gravity. One fiber puller was designed, built and flown on board NASA's KC135 reduced gravity aircraft. A second fiber puller has been designed for use on board the International Space Station.

  19. A novel differential optical fiber accelerometer

    NASA Astrophysics Data System (ADS)

    Pi, Shaohua; Zhao, Jiang; Hong, Guangwei; Jia, Bo

    2013-08-01

    The development of sensitive fiber-optic accelerometers is a subject of continuing interest. To acquire high resolution, Michelson phase interferometric techniques are widely adopted. Among the variety structures, the compliant cylinder approach is particularly attractive due to its high sensitivity that is defined as the induced phase shift per applied acceleration. While the two arms of Michelson interferometer should be at the same optical path, it is inconvenient to adjust the two arms' length to equal, also the polarization instability and phase random drift will cause a signal decline. To overcome these limitations, a novel optical fiber accelerometer based on differential interferometric techniques is proposed and investigated. The interferometer is a Sagnac-like white light interferometer, which means the bandwidth of laser spectrum can be as wide as tens nanometers. This interferometer was firstly reported by Levin in 1990s. Lights are divided to two paths before entering the coupler. To induce time difference, one passes through a delay arm and another goes a direct arm. After modulated by the sensing component, they reflect to opposite arm. The sensing part is formed by a seismic mass that is held to only one compliant cylinder, where the single-mode optical fiber is wrapped tightly. When sticking to vibrations, the cylinder compresses or stretches as a spring. The corresponding changes in cylinder circumference lead to strain in the sensing fibers, which is detected as an optical phase shift by the interferometer. The lights from two arms reach the vibration source at different time, sensing a different accelerate speed; produce a different optic path difference. Integrating the dissimilarity of the accelerated speed by time can obtain the total acceleration graph. A shaker's vibration has been tested by the proposed accelerometer referring to a standard piezoelectric accelerometer. A 99.8% linearity of the optical phase shift to the ground acceleration

  20. High efficiency germanium-assisted grating coupler.

    PubMed

    Yang, Shuyu; Zhang, Yi; Baehr-Jones, Tom; Hochberg, Michael

    2014-12-15

    We propose a fiber to submicron silicon waveguide vertical coupler utilizing germanium-on-silicon gratings. The germanium is epitaxially grown on silicon in the same step for building photodetectors. Coupling efficiency based on FDTD simulation is 76% at 1.55 µm and the optical 1dB bandwidth is 40 nm.

  1. Optical Fiber Protection

    NASA Technical Reports Server (NTRS)

    1999-01-01

    F&S Inc. developed and commercialized fiber optic and microelectromechanical systems- (MEMS) based instrumentation for harsh environments encountered in the aerospace industry. The NASA SBIR programs have provided F&S the funds and the technology to develop ruggedized coatings and coating techniques that are applied during the optical fiber draw process. The F&S optical fiber fabrication facility and developed coating methods enable F&S to manufacture specialty optical fiber with custom designed refractive index profiles and protective or active coatings. F&S has demonstrated sputtered coatings using metals and ceramics and combinations of each, and has also developed techniques to apply thin coatings of specialized polyimides formulated at NASA Langley Research Center. With these capabilities, F&S has produced cost-effective, reliable instrumentation and sensors capable of withstanding temperatures up to 800? C and continues building commercial sales with corporate partners and private funding. More recently, F&S has adapted the same sensing platforms to provide the rapid detection and identification of chemical and biological agents

  2. Infrared Fiber Optic Sensors

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Successive years of Small Business Innovation Research (SBIR) contracts from Langley Research Center to Sensiv Inc., a joint venture between Foster-Miller Inc. and Isorad, Ltd., assisted in the creation of remote fiber optic sensing systems. NASA's SBIR interest in infrared, fiber optic sensor technology was geared to monitoring the curing cycles of advanced composite materials. These funds helped in the fabrication of an infrared, fiber optic sensor to track the molecular vibrational characteristics of a composite part while it is being cured. Foster-Miller ingenuity allowed infrared transmitting optical fibers to combine with Fourier Transform Infrared spectroscopy to enable remote sensing. Sensiv probes operate in the mid-infrared range of the spectrum, although modifications to the instrument also permits its use in the near-infrared region. The Sensiv needle-probe is built to be placed in a liquid or powder and analyze the chemicals in the mixture. Other applications of the probe system include food processing control; combustion control in furnaces; and maintenance problem solving.

  3. Fiber optic temperature sensor

    NASA Technical Reports Server (NTRS)

    Quick, William H. (Inventor); August, Rudolf R. (Inventor); James, Kenneth A. (Inventor); Strahan, Jr., Virgil H. (Inventor); Nichols, Donald K. (Inventor)

    1980-01-01

    An inexpensive, lightweight fiber optic micro-sensor that is suitable for applications which may require remote temperature sensing. The disclosed temperature sensor includes a phosphor material that, after receiving incident light stimulation, is adapted to emit phosphorescent radiation output signals, the amplitude decay rate and wavelength of which are functions of the sensed temperature.

  4. Improved Optical Fiber Chemical Sensors

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1994-01-01

    Calculations, based on exact theory of optical fiber, have shown how to increase optical efficiency sensitivity of active-core, step-index-profile optical-fiber fluorosensor. Calculations result of efforts to improve efficiency of optical-fiber chemical sensor of previous concept described in "Making Optical-Fiber Chemical Sensors More Sensitive" (LAR-14525). Optical fiber chemical detector of enhanced sensitivity made in several configurations. Portion of fluorescence or chemiluminescence generated in core, and launched directly into bound electromagnetic modes that propagate along core to photodetector.

  5. Buying Fiber-Optic Networks.

    ERIC Educational Resources Information Center

    Fickes, Michael

    2003-01-01

    Describes consortia formed by college and university administrators to buy, manage, and maintain their own fiber-optic networks with the goals of cutting costs of leasing fiber-optic cable and planning for the future. Growth capacity is the real advantage of owning fiber-optic systems. (SLD)

  6. Large core fiber optic cleaver

    DOEpatents

    Halpin, John M.

    1996-01-01

    The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 .mu.m.

  7. Fiber Optics and Library Technology.

    ERIC Educational Resources Information Center

    Koenig, Michael

    1984-01-01

    This article examines fiber optic technology, explains some of the key terminology, and speculates about the way fiber optics will change our world. Applications of fiber optics to library systems in three major areas--linkage of a number of mainframe computers, local area networks, and main trunk communications--are highlighted. (EJS)

  8. Large core fiber optic cleaver

    DOEpatents

    Halpin, J.M.

    1996-03-26

    The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 {micro}m. 30 figs.

  9. Aerogel-clad optical fiber

    DOEpatents

    Sprehn, Gregory A.; Hrubesh, Lawrence W.; Poco, John F.; Sandler, Pamela H.

    1997-01-01

    An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency.

  10. Aerogel-clad optical fiber

    DOEpatents

    Sprehn, G.A.; Hrubesh, L.W.; Poco, J.F.; Sandler, P.H.

    1997-11-04

    An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency. 4 figs.

  11. Direct writing of fiber optic components in photonic crystal fibers and other specialty fibers

    NASA Astrophysics Data System (ADS)

    Fernandes, Luis Andre; Sezerman, Omur; Best, Garland; Ng, Mi Li; Kane, Saidou

    2016-04-01

    Femtosecond direct laser writing has recently shown great potential for the fabrication of complex integrated devices in the cladding of optical fibers. Such devices have the advantage of requiring no bulk optical components and no breaks in the fiber path, thus reducing the need for complicated alignment, eliminating contamination, and increasing stability. This technology has already found applications using combinations of Bragg gratings, interferometers, and couplers for the fabrication of optical filters, sensors, and power monitors. The femtosecond laser writing method produces a local modification of refractive index through non-linear absorption of the ultrafast laser pulses inside the dielectric material of both the core and cladding of the fiber. However, fiber geometries that incorporate air or hollow structures, such as photonic crystal fibers (PCFs), still present a challenge since the index modification regions created by the writing process cannot be generated in the hollow regions of the fiber. In this work, the femtosecond laser method is used together with a pre-modification method that consists of partially collapsing the hollow holes using an electrical arc discharge. The partial collapse of the photonic band gap structure provides a path for femtosecond laser written waveguides to couple light from the core to the edge of the fiber for in-line power monitoring. This novel approach is expected to have applications in other specialty fibers such as suspended core fibers and can open the way for the integration of complex devices and facilitate miniaturization of optical circuits to take advantage of the particular characteristics of the PCFs.

  12. Optical fiber amplifiers based on PbS/CdS QDs modified by polymers.

    PubMed

    Sun, Xiaolan; Xie, Libin; Zhou, Wei; Pang, Fufei; Wang, Tingyun; Kost, Alan R; An, Zesheng

    2013-04-08

    Optical fiber amplifiers based on PbS/CdS semiconductor quantum dots (QDs) modified by an amphiphilic polymer were demonstrated. Well-defined QDs and an amphiphilic copolymer were first prepared and the amphiphilic copolymer was then used to disperse the QDs into silica sol to allow uniform and reproducible incorporation of QDs into the silica coating of the optical fibers. QD-doped silica sol was deposited on the fusion tapered fiber coupler via dip-coating. A 1550 nm semiconductor light emitting diode as the signal source and a 980 nm laser diode as the pump source were injected into the fiber coupler simultaneously. Through evanescent wave excitation, a signal gain as high as 8 dB was obtained within the wavelength range between 1450 and 1650 nm. In addition, the optical fiber amplifiers based on PbS/CdS QDs showed enhanced thermal stability when compared to amplifiers based on PbS QDs.

  13. Holograms for laser diode: Single mode optical fiber coupling

    NASA Technical Reports Server (NTRS)

    Fuhr, P. L.

    1982-01-01

    The low coupling efficiency of semiconductor laser emissions into a single mode optical fibers place a severe restriction on their use. Associated with these conventional optical coupling techniques are stringent alignment sensitivities. Using holographic elements, the coupling efficiency may be increased and the alignment sensitivity greatly reduced. Both conventional and computer methods used in the generation of the holographic couplers are described and diagrammed. The reconstruction geometries used are shown to be somewhat restrictive but substantially less rigid than their conventional optical counterparts. Single and double hologram techniques are examined concerning their respective ease of fabrication and relative merits.

  14. Interferometric Fiber-Optic Gyroscope

    NASA Technical Reports Server (NTRS)

    Depaula, Ramon P.; Bogert, Gail A.; Minford, William J.

    1990-01-01

    Integrated three-waveguide directional coupler functions as polarizer and splitter. Designed with transverse electric (TE) polarization in bar state (two coupling lengths) and transverse magnetic (TM) polarization in cross state (one coupling length). Intended for eventual fabrication as in mass-producible integrated optical circuit that provides advantages including low drive voltage, large-bandwidth phase modulation, preservation of polarization in transmission between devices on same substrate, and low cost.

  15. GaN directional couplers for on-chip optical interconnect

    NASA Astrophysics Data System (ADS)

    Yuan, Jialei; Gao, Xumin; Yang, Yongchao; Zhu, Guixia; Yuan, Wei; Choi, Hoi Wai; Zhang, Zhiyu; Wang, Yongjin

    2017-04-01

    Here, we propose, fabricate and characterize GaN directional couplers for on-chip optical interconnect on a GaN-on-silicon platform. Suspended InGaN/GaN multiple-quantum-well diodes are adopted for both the transmitter and the receiver, and GaN directional couplers are used to achieve the light coupling between suspended waveguides that are directly connected to the transmitter and the receiver. The proposed on-chip optical interconnects are experimentally demonstrated by light propagation and in-plane data transmission using visible light. The light propagation images directly show that the emitted light can be laterally coupled into the suspended waveguide, and the guided light from the input waveguide then couples to the coupled waveguide due to the overlapped slab. The receiver detects the transmitted light from the coupled waveguide to complete the in-plane visible light communication process, as confirmed by pseudo-random binary sequence data and eye diagrams at the transmission rate of 30 Mbps.

  16. Towards biochips using microstructured optical fiber sensors.

    PubMed

    Rindorf, Lars; Høiby, Poul Erik; Jensen, Jesper Bo; Pedersen, Lars Hagsholm; Bang, Ole; Geschke, Oliver

    2006-08-01

    In this paper we present the first incorporation of a microstructured optical fiber (MOF) into biochip applications. A 16-mm-long piece of MOF is incorporated into an optic-fluidic coupler chip, which is fabricated in PMMA polymer using a CO(2) laser. The developed chip configuration allows the continuous control of liquid flow through the MOF and simultaneous optical characterization. While integrated in the chip, the MOF is functionalized towards the capture of a specific single-stranded DNA string by immobilizing a sensing layer on the microstructured internal surfaces of the fiber. The sensing layer contains the DNA string complementary to the target DNA sequence and thus operates through the highly selective DNA hybridization process. Optical detection of the captured DNA was carried out using the evanescent-wave-sensing principle. Owing to the small size of the chip, the presented technique allows for analysis of sample volumes down to 300 nL and the fabrication of miniaturized portable devices.

  17. Study on a fiber optic gradient hydrophone based on interferometer

    NASA Astrophysics Data System (ADS)

    Lv, Wenlei; Pang, Meng; Shi, Qingping; Zhang, Min; Liao, Yanbiao; Yuan, Libo; Kang, Chong

    2008-12-01

    We proposed a kind of fiber-optic gradient hydrophone based on interferometer. Two arms of the interferometer are sensing fibers, each of which can be regard as a scalar pressure sensing element, and then the phase gradient between the two elements is transformed into the light intensity modulated output by the coupler. In this paper, a suit of analytical models for researching the sensor performance are developed. The theoretical and experimental research was carried out to demonstrate this kind of gradient hydrophone's phase sensitivity as the function of the measure frequency and the "8" directivity response.

  18. Piezo-phototronic UV/visible photosensing with optical-fiber-nanowire hybridized structures.

    PubMed

    Wang, Zhaona; Yu, Ruomeng; Pan, Caofeng; Liu, Ying; Ding, Yong; Wang, Zhong Lin

    2015-03-04

    An optical-fiber-nanowire hybridized UV-visible photodetector (PD) is reported. The PD is designed to allow direct integration in optical communication systems without requiring the use of couplers via fiber-welding technology. The PD works in two modes: axial and off-axial illumination mode. By using the piezo-phototronic effect, the performance of the PD is enhanced/optimized by up to 718% in sensitivity and 2067% in photoresponsivity.

  19. Optical Fiber Spectroscopy

    NASA Technical Reports Server (NTRS)

    Buoncristiani, A. M.

    1999-01-01

    This is the final report of work done on NASA Grant NAG-1-443. The work covers the period from July 1, 1992 to December 1, 1998. During this period several distinct but related research studies and work tasks were undertaken. These different subjects are enumerated below with a description of the work done on each of them. The focus of the research was the development of optical fibers for use as distributed temperature and stress sensors. The initial concept was to utilize the utilize the temperature and stress dependence of emission from rare earth and transition metal ions substitutionally doped into crystalline or glass fibers. During the course of investigating this it became clear that fiber Bragg gratings provided a alternative for making the desired measurements and there was a shift of research focus on to include the photo-refractive properties of germano-silicate glasses used for most gratings and to the possibility of developing fiber laser sources for an integrated optical sensor in the research effort. During the course of this work several students from Christopher Newport University and other universities participated in this effort. Their names are listed below. Their participation was an important part of their education.

  20. Optical fiber synaptic sensor

    NASA Astrophysics Data System (ADS)

    Pisarchik, A. N.; Jaimes-Reátegui, R.; Sevilla-Escoboza, R.; García-Lopez, J. H.; Kazantsev, V. B.

    2011-06-01

    Understanding neuron connections is a great challenge, which is needed to solve many important problems in neurobiology and neuroengineering for recreation of brain functions and efficient biorobotics. In particular, a design of an optical synapse capable to communicate with neuron spike sequences would be crucial to improve the functionality of neuromimmetic networks. In this work we propose an optical synaptic sensor based on an erbium-doped fiber laser driven by a FitzHung-Nagumo electronic neuron, to connect with another electronic neuron. Two possible optical synaptic configurations are analyzed for optoelectronic coupling between neurons: laser cavity loss modulation and pump laser modulation. The control parameters of the proposed optical synapse provide additional degrees of flexibility to the neuron connection traditionally controlled only by coupling strengths in artificial networks.

  1. Fiber Optic Velocity Interferometry

    SciTech Connect

    Neyer, Barry T.

    1988-04-01

    This paper explores the use of a new velocity measurement technique that has several advantages over existing techniques. It uses an optical fiber to carry coherent light to and from a moving target. A Fabry-Perot interferometer, formed by a gradient index lens and the moving target, produces fringes with a frequency proportional to the target velocity. This technique can measure velocities up to 10 km/s, is accurate, portable, and completely noninvasive.

  2. Optical fiber laser

    SciTech Connect

    Hakimi, F.; Po, H.; Snitzer, E.

    1987-07-14

    An optical fiber laser is described comprising: a gain cavity including a single mode optical fiber of given length having a core with a given index of refraction and a cladding surrounding the core and having an index of refraction lower than that of the core. The core comprises a host glass having incorporated a laser gain material with a fluorescence spectrum having at least one broadband region in which there is at least one peak emission line; filter means optically coupled to one end of the gain cavity and reflective to radiation emitted from the gain material over a predetermined wavelength interval about the peak emission line to provide feedback in the gain cavity; an etalon filter section butt coupled to the remaining end of the gain cavity optical fiber, the etalon filter section comprising a pair of filters spaced apart in parallel by a predetermined length of material transparent to any radiation emitted from the gain cavity. The predetermined length of the transparent material is such that the etalon filter section is no longer than the distance over which the wave train energy from the fiber core remains substantially planar so that the etalon filter section is inside the divergent region to enhance feedback in the gain cavity; and means for pumping energy into the gain cavity to raise the interval energy level such that only a small part of the ion population, corresponding to a predetermined bandwidth about the peak emission line, is raised above laser threshold. The laser emits radiation only over narrow lines over a narrow wavelength interval centered about the peak emission line.

  3. Fiber optic geophysical sensors

    DOEpatents

    Homuth, Emil F.

    1991-01-01

    A fiber optic geophysical sensor in which laser light is passed through a sensor interferometer in contact with a geophysical event, and a reference interferometer not in contact with the geophysical event but in the same general environment as the sensor interferometer. In one embodiment, a single tunable laser provides the laser light. In another embodiment, separate tunable lasers are used for the sensor and reference interferometers. The invention can find such uses as monitoring for earthquakes, and the weighing of objects.

  4. Shedding Light on Fiber Optics.

    ERIC Educational Resources Information Center

    Bunch, Robert M.

    1994-01-01

    Explains the principles of fiber optics as a medium for light-wave communication. Current uses of fiber systems on college campuses include voice, video, and local area network applications. A group of seven school districts in Minnesota are linked via fiber-optic cables. Other uses are discussed. (MLF)

  5. Advanced Optical Fiber Communication Systems

    DTIC Science & Technology

    1992-08-01

    Optical Network with Physical Star Topology," Advanced Fiber Communications Technologies , Leonid G. Kazovsky... advances in the performance and capabilities of optical fiber communication systems. While some of these technologies are interrelated (for example...multi gigabit per second hybrid circuit/packet switched lightwave network ," Proc. SPIE Advanced Fiber Communications Technologies , Boston 󈨟, Sept.

  6. Progressive ladder network topology combining interferometric and intensity fiber-optic-based sensors

    NASA Astrophysics Data System (ADS)

    Ribeiro, A. B. Lobo; Santos, J. L.; Caleya, R. F.

    1995-10-01

    Progressive ladder topology is studied by consideration of its properties of power budget and coupler tailoring. Optimization criteria are addressed for lossless and real systems, and their basic characteristics are compared with other topologies. Numerical results are presented, and an experiment is described for the case in which the network supports interferometric and intensity (with referentiation) fiber-optic-based sensors.

  7. Distributed Grating-Assisted Coupler for Optical All-Dielectric Electron Accelerator

    SciTech Connect

    Zhang, Z.; Tantawi, S.G.; Ruth, R.D.; /SLAC

    2005-09-23

    A Bragg waveguide consisting of multiple dielectric layers with alternating index of refraction becomes an excellent option to form electron accelerating structure powered by high power laser sources. It provides confinement of a synchronous speed-of-light mode with extremely low loss. However, laser field can not be coupled into the structure collinearly with the electron beam. There are three requirements in designing input coupler for a Bragg electron accelerator: side-coupling, selective mode excitation, and high coupling efficiency. We present a side coupling scheme using a distributed grating-assisted coupler to inject the laser power into the waveguide. Side coupling is achieved by a grating with a period on the order of an optical wavelength. The phase matching condition results in resonance coupling thus providing selective mode excitation capability. The coupling efficiency is limited by profile matching between the outgoing beam and the incoming beam, which has normally, a Gaussian profile. We demonstrate a non-uniform distributed grating structure generating an outgoing beam with a Gaussian profile, therefore, increasing the coupling efficiency.

  8. Micromachining of a fiber-to-waveguide coupler using grayscale lithography and through-wafer etch

    NASA Astrophysics Data System (ADS)

    Dillon, Thomas; Zablocki, Mathew; Shi, Shouyan; Murakowski, Janusz; Prather, Dennis

    2008-02-01

    For some time, the micro-optics and photonics fields have relied on fabrication processes and technology borrowed from the well-established silicon integrated circuit industry. However, new fabrication methodologies must be developed for greater flexibility in the machining of micro-optic devices. To this end, we have explored grayscale lithography as an enabler for the realization of such devices. This process delivers the ability to sculpt materials arbitrarily in three dimensions, thus providing the flexibility to realize optical surfaces to shape, transform, and redirect the propagation of light efficiently. This has opened the door for new classes of optical devices. As such, we present a fiber-to-waveguide coupling structure utilizing a smoothly contoured lensing surface in the device layer of a silicon-on insulator (SOI) wafer, fabricated using grayscale lithography. The structure collects light incident normally to the wafer from a singlemode optical fiber plugged through the back surface and turns the light into the plane of the device layer, focusing it into a single-mode waveguide. The basis of operation is total internal reflection, and the device therefore has the potential advantages of providing a large bandwidth, low polarization sensitivity, high efficiency, and small footprint. The structure was optimized with a simulated annealing algorithm in conjunction with two-dimensional finite-difference time-domain (FDTD) simulation accelerated on the graphics processing unit (GPU), and achieves a theoretical efficiency of approximately seventy percent, including losses due to Fresnel reflection from the oxide/silicon interface. Initial fabrication results validate the principle of operation. We discuss the grayscale fabrication process as well as the through-wafer etch for mechanical stabilization and alignment of the optical fiber to the coupling structure. Refinement of the through-wafer etch process for high etch rate and appropriate sidewall taper are

  9. Fiber optic systems for mobile platforms II

    SciTech Connect

    Lewis, N.E.; Moore, E.L.

    1988-01-01

    This book contains papers presented at the symposium of International Society for Optical Engineering. Topics covered/include: Fiber optic pressure sensor for internal combustion engine; Automotive fiber optic technology: application issues; and Fiber optic guided missile.

  10. Interferometric Fiber Optic Sensors

    PubMed Central

    Lee, Byeong Ha; Kim, Young Ho; Park, Kwan Seob; Eom, Joo Beom; Kim, Myoung Jin; Rho, Byung Sup; Choi, Hae Young

    2012-01-01

    Fiber optic interferometers to sense various physical parameters including temperature, strain, pressure, and refractive index have been widely investigated. They can be categorized into four types: Fabry-Perot, Mach-Zehnder, Michelson, and Sagnac. In this paper, each type of interferometric sensor is reviewed in terms of operating principles, fabrication methods, and application fields. Some specific examples of recently reported interferometeric sensor technologies are presented in detail to show their large potential in practical applications. Some of the simple to fabricate but exceedingly effective Fabry-Perot interferometers, implemented in both extrinsic and intrinsic structures, are discussed. Also, a wide variety of Mach-Zehnder and Michelson interferometric sensors based on photonic crystal fibers are introduced along with their remarkable sensing performances. Finally, the simultaneous multi-parameter sensing capability of a pair of long period fiber grating (LPG) is presented in two types of structures; one is the Mach-Zehnder interferometer formed in a double cladding fiber and the other is the highly sensitive Sagnac interferometer cascaded with an LPG pair. PMID:22736961

  11. Interferometric fiber optic sensors.

    PubMed

    Lee, Byeong Ha; Kim, Young Ho; Park, Kwan Seob; Eom, Joo Beom; Kim, Myoung Jin; Rho, Byung Sup; Choi, Hae Young

    2012-01-01

    Fiber optic interferometers to sense various physical parameters including temperature, strain, pressure, and refractive index have been widely investigated. They can be categorized into four types: Fabry-Perot, Mach-Zehnder, Michelson, and Sagnac. In this paper, each type of interferometric sensor is reviewed in terms of operating principles, fabrication methods, and application fields. Some specific examples of recently reported interferometeric sensor technologies are presented in detail to show their large potential in practical applications. Some of the simple to fabricate but exceedingly effective Fabry-Perot interferometers, implemented in both extrinsic and intrinsic structures, are discussed. Also, a wide variety of Mach-Zehnder and Michelson interferometric sensors based on photonic crystal fibers are introduced along with their remarkable sensing performances. Finally, the simultaneous multi-parameter sensing capability of a pair of long period fiber grating (LPG) is presented in two types of structures; one is the Mach-Zehnder interferometer formed in a double cladding fiber and the other is the highly sensitive Sagnac interferometer cascaded with an LPG pair.

  12. Extrinsic fiber optic displacement sensors and displacement sensing systems

    DOEpatents

    Murphy, Kent A.; Gunther, Michael F.; Vengsarkar, Ashish M.; Claus, Richard O.

    1994-01-01

    An extrinsic Fizeau fiber optic sensor comprises a single-mode fiber, used as an input/output fiber, and a multimode fiber, used purely as a reflector, to form an air gap within a silica tube that acts as a Fizeau cavity. The Fresnel reflection from the glass/air interface at the front of the air gap (reference reflection) and the reflection from the air/glass interface at the far end of the air gap (sensing reflection) interfere in the input/output fiber. The two fibers are allowed to move in the silica tube, and changes in the air gap length cause changes in the phase difference between the reference reflection and the sensing reflection. This phase difference is observed as changes in intensity of the light monitored at the output arm of a fused biconical tapered coupler. The extrinsic Fizeau fiber optic sensor behaves identically whether it is surface mounted or embedded, which is unique to the extrinsic sensor in contrast to intrinsic Fabry-Perot sensors. The sensor may be modified to provide a quadrature phase shift extrinsic Fizeau fiber optic sensor for the detection of both the amplitude and the relative polarity of dynamically varying strain. The quadrature light signals may be generated by either mechanical or optical means. A plurality of the extrinsic sensors may connected in cascade and multiplexed to allow monitoring by a single analyzer.

  13. Extrinsic fiber optic displacement sensors and displacement sensing systems

    DOEpatents

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

    1994-04-05

    An extrinsic Fizeau fiber optic sensor comprises a single-mode fiber, used as an input/output fiber, and a multimode fiber, used purely as a reflector, to form an air gap within a silica tube that acts as a Fizeau cavity. The Fresnel reflection from the glass/air interface at the front of the air gap (reference reflection) and the reflection from the air/glass interface at the far end of the air gap (sensing reflection) interfere in the input/output fiber. The two fibers are allowed to move in the silica tube, and changes in the air gap length cause changes in the phase difference between the reference reflection and the sensing reflection. This phase difference is observed as changes in intensity of the light monitored at the output arm of a fused biconical tapered coupler. The extrinsic Fizeau fiber optic sensor behaves identically whether it is surface mounted or embedded, which is unique to the extrinsic sensor in contrast to intrinsic Fabry-Perot sensors. The sensor may be modified to provide a quadrature phase shift extrinsic Fizeau fiber optic sensor for the detection of both the amplitude and the relative polarity of dynamically varying strain. The quadrature light signals may be generated by either mechanical or optical means. A plurality of the extrinsic sensors may connected in cascade and multiplexed to allow monitoring by a single analyzer. 14 figures.

  14. Optical true time delay based on contradirectional couplers with single sidewall-modulated Bragg gratings

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Liao, Shasha; Dong, Jianji

    2016-11-01

    We propose and demonstrate optical true time delay using tapered SOI contradirectional couplers with single sidewallmodulated Bragg gratings. The contradirectional couplers consist of two tapered rib waveguides with different width, and the Bragg gratings are modulated in the inner sidewall of the wider one. The optical signal is launched from the wide waveguide and coupled to the narrow waveguide through the Bragg gratings structure. Along the direction of light propagation, the waveguide width varies linearly, so the reflection wavelength is different at different positions. Therefore, linear delay line can be realized within the grating passband using the present structure. In the simulation, grating period is 310nm and grating number is 2400, corresponding to the grating length of 744μm. Using 2.5D FDTD simulation, the current structure can realize optical group delay of 20ps within bandwidth of 18nm. The proposed device is fabricated on a 220nm SOI chip with Electron Beam Lithography (EBL) and Inductively Coupled Plasma (ICP) etching. In the experiment, continuous light is modulated by 10GHz radio-frequency signal and travel through the chip, which is finally detected by the oscilloscope. By adjusting the wavelength of input light, group delay of different wavelength are recorded by the oscilloscope. The experimental results show that group delay of 28ps is realized within the bandwidth of 20nm. In the end, the drift of the reflection spectrum and delay lines under different temperature are analyzed. The reflection spectrum drifts 0.1nm/°C and causes redshift of the corresponding delay line.

  15. Process optimization for a 3D optical coupler and waveguide fabrication on a single substrate using buffer coat material

    NASA Astrophysics Data System (ADS)

    Summitt, Chris; Wang, Sunglin; Johnson, Lee; Zaverton, Melissa; Ge, Tao; Milster, Tom; Takashima, Yuzuru

    2015-03-01

    We have developed a hybrid lithography process necessary to fabricate a vertical optical coupler and an array of waveguide structures using the same buffer coat material on a single substrate. A virtual vernier scale built into the process enables precise alignment of both structures.

  16. Selenium semiconductor core optical fibers

    SciTech Connect

    Tang, G. W.; Qian, Q. Peng, K. L.; Wen, X.; Zhou, G. X.; Sun, M.; Chen, X. D.; Yang, Z. M.

    2015-02-15

    Phosphate glass-clad optical fibers containing selenium (Se) semiconductor core were fabricated using a molten core method. The cores were found to be amorphous as evidenced by X-ray diffraction and corroborated by Micro-Raman spectrum. Elemental analysis across the core/clad interface suggests that there is some diffusion of about 3 wt % oxygen in the core region. Phosphate glass-clad crystalline selenium core optical fibers were obtained by a postdrawing annealing process. A two-cm-long crystalline selenium semiconductor core optical fibers, electrically contacted to external circuitry through the fiber end facets, exhibit a three times change in conductivity between dark and illuminated states. Such crystalline selenium semiconductor core optical fibers have promising utility in optical switch and photoconductivity of optical fiber array.

  17. Surface-bonded fiber optic Sagnac sensors for ultrasound detection.

    PubMed

    Jang, Tae Seong; Lee, Seung Seok; Kim, Young Gil

    2004-04-01

    This paper describes a fiber optic sensor suitable for remote sensing and multi-point detection of ultrasound. This ultrasound sensor is based on the surface-bonded fiber optic Sagnac interferometer with the output fringe visibility of 1; it consists of a laser source, an ordinary single mode fiber delay line, a fiber coupler, a phase modulator and polarization controllers. For the validation of the sensor, surface acoustic waves and Lamb waves are excited by illuminating a steel specimen with an array of Q-switched Nd:YAG laser-generated line sources and the measurement of laser-generated ultrasonic waves are performed on the specimen surface using the surface-mounting fiber optic Sagnac sensor. The surface-bonded fiber optic sensor developed in this study has a simple configuration for detection of ultrasonic waves. Effectiveness of surface-bonded fiber optic Sagnac sensors for remote sensing of ultrasound and in situ monitoring of structures is investigated. The capability of multi-point detection of ultrasound by this Sagnac sensor is also discussed.

  18. Fiber optic TV direct

    NASA Technical Reports Server (NTRS)

    Kassak, John E.

    1991-01-01

    The objective of the operational television (OTV) technology was to develop a multiple camera system (up to 256 cameras) for NASA Kennedy installations where camera video, synchronization, control, and status data are transmitted bidirectionally via a single fiber cable at distances in excess of five miles. It is shown that the benefits (such as improved video performance, immunity from electromagnetic interference and radio frequency interference, elimination of repeater stations, and more system configuration flexibility) can be realized if application of the proven fiber optic transmission concept is used. The control system will marry the lens, pan and tilt, and camera control functions into a modular based Local Area Network (LAN) control network. Such a system does not exist commercially at present since the Television Broadcast Industry's current practice is to divorce the positional controls from the camera control system. The application software developed for this system will have direct applicability to similar systems in industry using LAN based control systems.

  19. Inexpensive 3dB coupler for POF communication by injection-molding production

    NASA Astrophysics Data System (ADS)

    Haupt, M.; Fischer, U. H. P.

    2011-01-01

    POFs (polymer optical fibers) gradually replace traditional communication media such as copper and glass within short distance communication systems. Primarily, this is due to their cost-effectiveness and easy handling. POFs are used in various fields of optical communication, e.g. the automotive sector or in-house communication. So far, however, only a few key components for a POF communication network are available. Even basic components, such as splices and couplers, are fabricated manually. Therefore, these circumstances result in high costs and fluctuations in components' performance. Available couplers have high insertion losses due to their manufacturing method. This can only be compensated by higher power budgets. In order to produce couplers with higher performances new fabrication methods are indispensable. A cheap and effective way to produce couplers for POF communication systems is injection molding. The paper gives an overview of couplers available on market, compares their performances, and shows a way to produce couplers by means of injection molding.

  20. System for testing optical fibers

    DOEpatents

    Golob, John E. [Olathe, KS; Looney, Larry D. [Los Alamos, NM; Lyons, Peter B. [Los Alamos, NM; Nelson, Melvin A. [Santa Barbara, CA; Davies, Terence J. [Santa Barbara, CA

    1980-07-15

    A system for measuring a combination of optical transmission properties of fiber optic waveguides. A polarized light pulse probe is injected into one end of the optical fiber. Reflections from discontinuities within the fiber are unpolarized whereas reflections of the probe pulse incident to its injection remain polarized. The polarized reflections are prevented from reaching a light detector whereas reflections from the discontinuities reaches the detector.

  1. System for testing optical fibers

    DOEpatents

    Golob, J.E.; Looney, L.D.; Lyons, P.B.; Nelson, M.A.; Davies, T.J.

    1980-07-15

    A system for measuring a combination of optical transmission properties of fiber optic waveguides. A polarized light pulse probe is injected into one end of the optical fiber. Reflections from discontinuities within the fiber are unpolarized whereas reflections of the probe pulse incident to its injection remain polarized. The polarized reflections are prevented from reaching a light detector whereas reflections from the discontinuities reaches the detector. 2 figs.

  2. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    DOEpatents

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings.

  3. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    DOEpatents

    Kuklo, T.C.

    1999-07-20

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings. 2 figs.

  4. Electro-Optic Modulator Based on Organic Planar Waveguide Integrated with Prism Coupler

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S.

    2002-01-01

    The objectives of the project, as they were formulated in the proposal, are the following: (1) Design and development of novel electro-optic modulator using single crystalline film of highly efficient electro-optic organic material integrated with prism coupler; (2) Experimental characterization of the figures-of-merit of the modulator. It is expected to perform with an extinction ratio of 10 dB at a driving signal of 5 V; (3) Conclusions on feasibility of the modulator as an element of data communication systems of future generations. The accomplishments of the project are the following: (1) The design of the electro-optic modulator based on a single crystalline film of organic material NPP has been explored; (2) The evaluation of the figures-of-merit of the electro-optic modulator has been performed; (3) Based on the results of characterization of the figures-of-merit, the conclusion was made that the modulator based on a thin film of NPP is feasible and has a great potential of being used in optic communication with a modulation bandwidth of up to 100 GHz and a driving voltage of the order of 3 to 5 V.

  5. Fiber optic geophysical sensors

    DOEpatents

    Homuth, E.F.

    1991-03-19

    A fiber optic geophysical sensor is described in which laser light is passed through a sensor interferometer in contact with a geophysical event, and a reference interferometer not in contact with the geophysical event but in the same general environment as the sensor interferometer. In one embodiment, a single tunable laser provides the laser light. In another embodiment, separate tunable lasers are used for the sensor and reference interferometers. The invention can find such uses as monitoring for earthquakes, and the weighing of objects. 2 figures.

  6. Ultrasensitive optical microfiber coupler based sensors operating near the turning point of effective group index difference

    NASA Astrophysics Data System (ADS)

    Li, Kaiwei; Zhang, Ting; Liu, Guigen; Zhang, Nan; Zhang, Mengying; Wei, Lei

    2016-09-01

    We propose and study an optical microfiber coupler (OMC) sensor working near the turning point of effective group index difference between the even supermode and odd supermode to achieve high refractive index (RI) sensitivity. Theoretical calculations reveal that infinite sensitivity can be obtained when the measured RI is close to the turning point value. This diameter-dependent turning point corresponds to the condition that the effective group index difference equals zero. To validate our proposed sensing mechanism, we experimentally demonstrate an ultrahigh sensitivity of 39541.7 nm/RIU at a low ambient RI of 1.3334 based on an OMC with the diameter of 1.4 μm. An even higher sensitivity can be achieved by carrying out the measurements at RI closer to the turning point. The resulting ultrasensitive RI sensing platform offers a substantial impact on a variety of applications from high performance trace analyte detection to small molecule sensing.

  7. Floquet control of the gain and loss in a PT-symmetric optical coupler

    NASA Astrophysics Data System (ADS)

    Wu, Yi; Zhu, Bo; Hu, Shu-Fang; Zhou, Zheng; Zhong, Hong-Hua

    2017-02-01

    Controlling the balanced gain and loss in a PT-symmetric system is a rather challenging task. Utilizing Floquet theory, we explore the constructive role of periodic modulation in controlling the gain and loss of a PT-symmetric optical coupler. It is found that the gain and loss of the system can be manipulated by applying a periodic modulation. Further, such an original non-Hermitian system can even be modulated into an effective Hermitian system derived by the high-frequency Floquet method. Therefore, compared with other PT symmetry control schemes, our protocol can modulate the unbroken PT-symmetric range to a wider parameter region. Our results provide a promising approach for controlling the gain and loss of a realistic system.

  8. A gold hybrid structure as optical coupler for quantum well infrared photodetector

    SciTech Connect

    Ding, Jiayi; Li, Qian; Jing, Youliang; Chen, Xiaoshuang Li, Zhifeng; Li, Ning; Lu, Wei

    2014-08-28

    A hybrid structure consisting of a square lattice of gold disk arrays and an overlaying gold film is proposed as an optical coupler for a backside-illuminated quantum well infrared photodetector (QWIP). Finite difference time-domain method is used to numerically simulate the reflection spectra and the field distributions of the hybrid structure combined with the QWIP device. The results show that the electric field component perpendicular to the quantum well is strongly enhanced when the plasmonic resonant wavelength of the hybrid structure coincides with the response one of the quantum well infrared photodetector regardless of the polarization of the incident light. The effect of the diameter and thickness of an individual gold disk on the resonant wavelength is also investigated, which indicates that the localized surface plasmon also plays a role in the light coupling with the hybrid structure. The coupling efficiency can exceed 50 if the structural parameters of the gold disk arrays are well optimized.

  9. Optical fiber networks for remote fiber optic sensors.

    PubMed

    Fernandez-Vallejo, Montserrat; Lopez-Amo, Manuel

    2012-01-01

    This paper presents an overview of optical fiber sensor networks for remote sensing. Firstly, the state of the art of remote fiber sensor systems has been considered. We have summarized the great evolution of these systems in recent years; this progress confirms that fiber-optic remote sensing is a promising technology with a wide field of practical applications. Afterwards, the most representative remote fiber-optic sensor systems are briefly explained, discussing their schemes, challenges, pros and cons. Finally, a synopsis of the main factors to take into consideration in the design of a remote sensor system is gathered.

  10. Optical Fiber Networks for Remote Fiber Optic Sensors

    PubMed Central

    Fernandez-Vallejo, Montserrat; Lopez-Amo, Manuel

    2012-01-01

    This paper presents an overview of optical fiber sensor networks for remote sensing. Firstly, the state of the art of remote fiber sensor systems has been considered. We have summarized the great evolution of these systems in recent years; this progress confirms that fiber-optic remote sensing is a promising technology with a wide field of practical applications. Afterwards, the most representative remote fiber-optic sensor systems are briefly explained, discussing their schemes, challenges, pros and cons. Finally, a synopsis of the main factors to take into consideration in the design of a remote sensor system is gathered. PMID:22666011

  11. Precision measurement system and analysis of low core signal loss in DCF couplers

    NASA Astrophysics Data System (ADS)

    Yan, P.; Wang, X. J.; Fu, Ch; Li, D.; Sun, J. Y.; Gong, M. L.; Xiao, Q. R.

    2016-07-01

    In order to achieve higher output power of double cladding fiber lasers, low signal loss has become a focus in researches on optical technology, especially double-clad fiber (DCF) couplers. According to the analysis, DCF couplers with low core signal loss (less than 1%) are produced. To obtain higher precision, we use the first-proposed method for core signal transfer efficiency measurement based on the fiber propagation field image processing. To the best of our knowledge, we report, for the first time, the results of the core signal loss less than 1% in DCF coupler measured by our measurement with high stability and relative precision. The measurement values can assess the quality of DCF couplers and be used as a signal to suggest the improvement on the processing technology of our self-made DCF couplers.

  12. Expanded beam non-imaging fiber optic connector

    DOEpatents

    Jannson, Tommasz; Jannson, Joanna; Yeung, Peter

    1990-01-01

    There is disclosed an expanded beam fiber to fiber connector, based on non-imaging optic principles for coupling light beams from one optical fiber to another. The system consists of two identical connector parts, referred to herein as a collimating part and a concentrating part, each having a preferred partially curved reflective boundary surface for minimizing power loss and surrounding either a hollow space or a space filled with a uniform transparent medium. In one embodiment the boundary is metallic while in a second embodiment the boundary is in the form of an interface allowing total internal reflection. In both the hollow and filled case a lens may be located at the expanded end of both the collimater part and the concentrator part forming the connector. The connector is preferably located in a housing in order to protect and preserve the mechanical stability of the coupler.

  13. Expanded beam non-imaging fiber optic connector

    DOEpatents

    Jannson, T.; Jannson, J.; Yeung, P.

    1990-02-06

    There is disclosed an expanded beam fiber to fiber connector, based on non-imaging optic principles for coupling light beams from one optical fiber to another. The system consists of two identical connector parts, referred to herein as a collimating part and a concentrating part, each having a preferred partially curved reflective boundary surface for minimizing power loss and surrounding either a hollow space or a space filled with a uniform transparent medium. In one embodiment the boundary is metallic while in a second embodiment the boundary is in the form of an interface allowing total internal reflection. In both the hollow and filled case a lens may be located at the expanded end of both the collimator part and the concentrator part forming the connector. The connector is preferably located in a housing in order to protect and preserve the mechanical stability of the coupler. 13 figs.

  14. Optical Fibers for Nonlinear Optics.

    DTIC Science & Technology

    1986-10-01

    wavelength, showing structure due to water absorption bands .............................. 21 11 Schematic diagram of the experimental apparatus for phase...Figure 10. (b) Spectrum of PK3 fiber attenuation versus wavelength, showing structure due to water absorption bands. -L -L1 D C- LCL 0 (0 o o wj 0 00zzo...crystal fibers (ADP). 1984 Development of traveling zone method converting polycrystalline extruded fiber to single-crystal fiber (AgCl, AgBr, CuCl

  15. Fiber optic control system integration

    NASA Technical Reports Server (NTRS)

    Poppel, G. L.; Glasheen, W. M.; Russell, J. C.

    1987-01-01

    A total fiber optic, integrated propulsion/flight control system concept for advanced fighter aircraft is presented. Fiber optic technology pertaining to this system is identified and evaluated for application readiness. A fiber optic sensor vendor survey was completed, and the results are reported. The advantages of centralized/direct architecture are reviewed, and the concept of the protocol branch is explained. Preliminary protocol branch selections are made based on the F-18/F404 application. Concepts for new optical tools are described. Development plans for the optical technology and the described system are included.

  16. Novel integrated optical I/O couplers on MCMs using MEMS techniques

    NASA Astrophysics Data System (ADS)

    Koh, Seungug; Ahn, Chong H.

    1996-03-01

    Optoelectronic interconnection can provide a practical solution for the ever increasing communication bottleneck problems among a multitude of information processing units. As research activities progress in the field of serial or parallel board-to-board and module-to- module interconnection, some of the research focus has shifted to smaller physical dimensions, like intra-module interconnection, which combines optoelectronic interconnection, multichip module packaging, and microelectromechanical system technologies at the module level. This paper describes novel integrated optical input/output couplers on multichip modules using micro-machined silicon mirrors to be used for optoelectronic multichip modules. The proposed microstructure integrates optical waveguide networks, multilayer electrical transmission line networks, micro-machined silicon mirrors, and flip-chip bonded photonic devices into a single structure. Using both sides of the silicon wafers, multiple metal layers and optical waveguide layers can be successfully fabricated for all metals or optical waveguides. The proposed input/output coupling method utilizes an innovative combination of through-holes across OE- MCM and micro-machined silicon mirrors integrated together into a single package.

  17. Fabrication of Optical Fiber Devices

    NASA Astrophysics Data System (ADS)

    Andres, Miguel V.

    In this paper we present the main research activities of the Laboratorio de Fibras Opticas del Instituto de Ciencia de los Materiales de la Universidad de Valencia. We show some of the main results obtained for devices based on tapered fibers, fiber Bragg gratings, acousto-optic effects and photonic crystal fibers.

  18. Optical-Fiber Leak Detector

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Kosten, Susan E.

    1994-01-01

    Proposed optical-fiber sensor detects small changes in pressure in elastomeric O-ring or similar pressure seal, which may indicate deterioration of seal and interpreted as indications of incipient failure. According to concept, length of optical fiber embedded in seal. Light-emitting diode illuminates one end of fiber; photodetector measures intensity of light emerging from other end. Pressure-induced changes in seal bend fiber slightly, altering microbending-induced loss of light from fiber and alter intensity of light at photodetector. Change in intensity approximately proportional to change in pressure.

  19. Fiber-optic signal processor with applications to matrix-vector multiplication and lattice filtering.

    PubMed

    Tur, M; Goodman, J W; Moslehi, B; Bowers, J E; Shaw, H J

    1982-09-01

    A new fiber-optic signal processor is proposed to implement systolic matrix-vector multipliers and lattice filters. 10(9) multiplications/sec can be achieved with currently available components for matrix-vector multiplications that involve Toeplitz matrices. A 2 x 2 (Toeplitz) matrix-vector multiplier has been experimentally demonstrated using single-mode fibers and directional couplers. The filtering characteristics of the device are also discussed.

  20. Experimental optical fiber communications link

    NASA Technical Reports Server (NTRS)

    Lutes, G. F.

    1980-01-01

    An optical fiber communications link 1.5 kilometers in length was installed between the Interim Frequency Standard Test Facility and the Timing and Frequency Systems Research Laboratory at JPL. It is being used to develop optical fiber technology for use in the DSN and particularly for precise time and frequency distribution.

  1. Fiber optic sensor and method for making

    DOEpatents

    Vartuli, James Scott; Bousman, Kenneth Sherwood; Deng, Kung-Li; McEvoy, Kevin Paul; Xia, Hua

    2010-05-18

    A fiber optic sensor including a fiber having a modified surface integral with the fiber wherein the modified surface includes an open pore network with optical agents dispersed within the open pores of the open pore network. Methods for preparing the fiber optic sensor are also provided. The fiber optic sensors can withstand high temperatures and harsh environments.

  2. Fiber-optic technology review

    SciTech Connect

    Lyons, P.B.

    1980-01-01

    A history of fiber technology is presented. The advantages of fiber optics are discussed (bandwidth, cost, weight and size, nonmetallic construction and isolation). Some aspects of the disadvantages of fiber systems briefly discussed are fiber and cable availability, fiber components, radiation effects, receivers and transmitters, and material dispersion. Particular emphasis over the next several years will involve development of fibers and systems optimized for use at wavelengths near 1.3 ..mu..m and development of wavelengths multiplexers for simultaneous system operation at several wavelengths.

  3. Optical fiber inspection system

    DOEpatents

    Moore, F.W.

    1985-04-05

    A remote optical inspection system including an inspection head. The inspection head has a passageway through which pellets or other objects are passed. A window is provided along the passageway through which light is beamed against the objects being inspected. A plurality of lens assemblies are arranged about the window so that reflected light can be gathered and transferred to a plurality of coherent optical fiber light guides. The light guides transfer the light images to a television or other image transducer which converts the optical images into a representative electronic signal. The electronic signal can then be displayed on a signal viewer such as a television monitor for inspection by a person. A staging means can be used to support the objects for viewing through the window. Routing means can be used to direct inspected objects into appropriate exit passages for accepted or rejected objects. The inspected objects are advantageously fed in a singular manner to the staging means and routing means. The inspection system is advantageously used in an enclosure when toxic or hazardous materials are being inspected. 10 figs.

  4. Optical fiber inspection system

    DOEpatents

    Moore, Francis W.

    1987-01-01

    A remote optical inspection system including an inspection head. The inspection head has a passageway through which pellets or other objects are passed. A window is provided along the passageway through which light is beamed against the objects being inspected. A plurality of lens assemblies are arranged about the window so that reflected light can be gathered and transferred to a plurality of coherent optical fiber light guides. The light guides transfer the light images to a television or other image transducer which converts the optical images into a representative electronic signal. The electronic signal can then be displayed on a signal viewer such as a television monitor for inspection by a person. A staging means can be used to support the objects for viewing through the window. Routing means can be used to direct inspected objects into appropriate exit passages for accepted or rejected objects. The inspected objects are advantageously fed in a singular manner to the staging means and routing means. The inspection system is advantageously used in an enclosure when toxic or hazardous materials are being inspected.

  5. Recycling optical fibers for sensing

    NASA Astrophysics Data System (ADS)

    André, Paulo; Domingues, Fátima; Alberto, Nélia; Marques, Carlos; Antunes, Paulo

    2016-04-01

    Optical fiber sensors has become one of the most promising sensing technologies. Within all the optical fiber sensing technologies, the Fabry-Perot interferometer (FPI) micro-cavities are one of the most attractive, due to the size, linearity and higher sensitivity. In this work we present the recent results, achieved by our group, regarding the production of optical sensors, by recycling optical fibers destroyed through the catastrophic fuse effect. This enabled the production of FPI sensors, in a cost effective way, tailored for the monitoring of several physical parameters, such as relative humidity (RH), refractive index (RI) and hydrostatic pressure.

  6. Fiber optic liquid mass flow sensor and method

    NASA Technical Reports Server (NTRS)

    Korman, Valentin (Inventor); Gregory, Don Allen (Inventor); Wiley, John T. (Inventor); Pedersen, Kevin W. (Inventor)

    2010-01-01

    A method and apparatus are provided for sensing the mass flow rate of a fluid flowing through a pipe. A light beam containing plural individual wavelengths is projected from one side of the pipe across the width of the pipe so as to pass through the fluid under test. Fiber optic couplers located at least two positions on the opposite side of the pipe are used to detect the light beam. A determination is then made of the relative strengths of the light beam for each wavelength at the at least two positions and based at least in part on these relative strengths, the mass flow rate of the fluid is determined.

  7. Fiber optic-based biosensor

    NASA Technical Reports Server (NTRS)

    Ligler, Frances S.

    1991-01-01

    The NRL fiber optic biosensor is a device which measures the formation of a fluorescent complex at the surface of an optical fiber. Antibodies and DNA binding proteins provide the mechanism for recognizing an analyze and immobilizing a fluorescent complex on the fiber surface. The fiber optic biosensor is fast, sensitive, and permits analysis of hazardous materials remote from the instrumentation. The fiber optic biosensor is described in terms of the device configuration, chemistry for protein immobilization, and assay development. A lab version is being used for assay development and performance characterization while a portable device is under development. Antibodies coated on the fiber are stable for up to two years of storage prior to use. The fiber optic biosensor was used to measure concentration of toxins in the parts per billion (ng/ml) range in under a minute. Immunoassays for small molecules and whole bacteria are under development. Assays using DNA probes as the detection element can also be used with the fiber optic sensor, which is currently being developed to detect biological warfare agents, explosives, pathogens, and toxic materials which pollute the environment.

  8. Optical fiber dispersion characterization study

    NASA Technical Reports Server (NTRS)

    Geeslin, A.; Arriad, A.; Riad, S. M.; Padgett, M. E.

    1979-01-01

    The theory, design, and results of optical fiber pulse dispersion measurements are considered. Both the hardware and software required to perform this type of measurement are described. Hardware includes a thermoelectrically cooled injection laser diode source, an 800 GHz gain bandwidth produce avalanche photodiode and an input mode scrambler. Software for a HP 9825 computer includes fast Fourier transform, inverse Fourier transform, and optimal compensation deconvolution. Test set construction details are also included. Test results include data collected on a 1 Km fiber, a 4 Km fiber, a fused spliced, eight 600 meter length fibers concatenated to form 4.8 Km, and up to nine optical connectors.

  9. Silicon photodetector structure for direct coupling of optical fibers to integrated circuits

    NASA Astrophysics Data System (ADS)

    Ade, Robert W.; Harstead, Edward E.; Amirfazli, A. H.; Cacouris, Theodore; Fossum, Eric R.

    1987-06-01

    A novel detector structure exhibiting real-estate efficient coupling of optical fibers to semiconductor devices is described. The integrated fiber-optic coupler employs vertical insertion of a tapered single-mode fiber into a laser-etched cylindrical hole in the substrate. It features a small surface footprint, mechanical stability, and accurate alignment. Fabricated in silicon, the p-n junction detectors have typically shown responsivities of 0.23 A/W at 0.63 micron, corresponding to a quantum efficiency of 45 percent, and dark currents below 1 nA.

  10. Fiber optic multiplex optical transmission system

    NASA Technical Reports Server (NTRS)

    Bell, C. H. (Inventor)

    1977-01-01

    A multiplex optical transmission system which minimizes external interference while simultaneously receiving and transmitting video, digital data, and audio signals is described. Signals are received into subgroup mixers for blocking into respective frequency ranges. The outputs of these mixers are in turn fed to a master mixer which produces a composite electrical signal. An optical transmitter connected to the master mixer converts the composite signal into an optical signal and transmits it over a fiber optic cable to an optical receiver which receives the signal and converts it back to a composite electrical signal. A de-multiplexer is coupled to the output of the receiver for separating the composite signal back into composite video, digital data, and audio signals. A programmable optic patch board is interposed in the fiber optic cables for selectively connecting the optical signals to various receivers and transmitters.

  11. Numerical analysis on using compound parabolic couplers for direct transmission of concentrated solar radiation via optical fibre (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Rahou, Maryam; Andrews, John; Rosengarten, Gary

    2016-09-01

    A challenge in high-temperature solar thermal applications is transfer of concentrated solar radiation to the load with minimum energy loss. The use of a solar concentrator in conjunction with optical fibres has potential advantages in terms of transmission efficiency, technical feasibility and cost-effectiveness compared to a conventional heat transfer system employing heat exchangers and a heat transfer fluid. For transferring higher levels of concentrated flux it is necessary to employ multiple optical fibres or fibre bundles. However, the losses at the incident plane of a bundle due to absorption by the epoxy and cladding between the individual fibres in a bundle are substantial, typically over 60% of the overall transmission loss. The optical transmission of the system can thus be enhanced by employing a coupler between the concentrated solar radiation and the entrance to the bundle that reflects all incident light into the cores of individual fibres rather than allowing it to strike the interstitial spaces between the cores. This paper describes the design for such couplers based on multiple compound parabolic (CP) reflectors each with its exit aperture coinciding with the core of an individual fibre within the bundle. The proposed design employs external reflection from a machined metallic aluminium surface. This CP arrangement has the additional benefit of increasing the concentration ratio of the primary solar concentrator used. Simulation modeling using LightTools is conducted into a parabolic Cassegrain solar concentrator employing these CP couplers prior to a fibre bundle. The dependence of overall transmission and total optical efficiency of the system over lengths of the bundle up to 100 m are investigated quantitatively. In addition, the influence on transmission of the angular distribution of radiation intensity at the aperture of the couplers is studied.

  12. Fiber optics that fly

    NASA Astrophysics Data System (ADS)

    Wilcox, Michael J.; Thelen, Donald C., Jr.

    1996-11-01

    analog integrated circuit using photodiodes and fiber optic waveguides as the nonlinear light sensing devices, current mirrors and opamp circuits for the processing. The outputs of this circuit will go to other artificial neural networks for further processing.

  13. Scintillator fiber optic long counter

    DOEpatents

    McCollum, T.; Spector, G.B.

    1994-03-29

    A flat response position sensitive neutron detector capable of providing neutron spectroscopic data utilizing scintillator fiber optic filaments embedded in a neutron moderating housing having an open end through which neutrons enter to be detected is described. 11 figures.

  14. Fiber Optics: A Bright Future.

    ERIC Educational Resources Information Center

    Rice, James, Jr.

    1980-01-01

    Presents an overview of the impact of fiber optics on telecommunications and its application to information processing and library services, including information retrieval, news services, remote transmission of library services, and library networking. (RAA)

  15. Connector For Embedded Optical Fiber

    NASA Technical Reports Server (NTRS)

    Wilkerson, Charles; Hiles, Steven; Houghton, J. Richard; Holland, Brent W.

    1994-01-01

    Partly embedded fixture is simpler and sturdier than other types of outlets for optical fibers embedded in solid structures. No need to align coupling prism and lenses. Fixture includes base, tube bent at 45 degree angle, and ceramic ferrule.

  16. Scintillator fiber optic long counter

    DOEpatents

    McCollum, Tom; Spector, Garry B.

    1994-01-01

    A flat response position sensitive neutron detector capable of providing neutron spectroscopic data utilizing scintillator fiber optic filaments embedded in a neutron moderating housing having an open end through which neutrons enter to be detected.

  17. Application of Fiber Optic Instrumentation

    NASA Technical Reports Server (NTRS)

    Richards, William Lance; Parker, Allen R., Jr.; Ko, William L.; Piazza, Anthony; Chan, Patrick

    2012-01-01

    Fiber optic sensing technology has emerged in recent years offering tremendous advantages over conventional aircraft instrumentation systems. The advantages of fiber optic sensors over their conventional counterparts are well established; they are lighter, smaller, and can provide enormous numbers of measurements at a fraction of the total sensor weight. After a brief overview of conventional and fiber-optic sensing technology, this paper presents an overview of the research that has been conducted at NASA Dryden Flight Research Center in recent years to advance this promising new technology. Research and development areas include system and algorithm development, sensor characterization and attachment, and real-time experimentally-derived parameter monitoring for ground- and flight-based applications. The vision of fiber optic smart structure technology is presented and its potential benefits to aerospace vehicles throughout the lifecycle, from preliminary design to final retirement, are presented.

  18. Optical directional coupler and Mach-Zehnder interferometer enhanced via 4H-SiC phonons

    NASA Astrophysics Data System (ADS)

    Finch, Michael F.; Saunders Filho, Claudio A. B.; Lail, Brian A.

    2016-09-01

    Surface phonon polaritons (SPhPs), similar to it cousin phenomenon surface plasmon polaitons (SPPs), are quasi-neutral particles resulting from light-matter coupling that can provide high modal confinement and long propagation in the mid to long infrared (IR). Mach-Zehnder interferometer (MZI) is a combination of two connected optical directional couplers (ODC). With the use of SPhPs, sub-wavelength feature sizes and modal areas can be achieved and to this end a hybrid SPhP waveguide, where propagation length and modal area can be trade-off, will be employed in the design of an ODC and MZI. This endeavor analyzes and characteristics both an ODC and MZI using commercially available numerical simulation software employing finite element method (FEM). The ODC and MZI are design using a novel SPhP hybrid waveguide design where a 4H-SiC substrate provides the polariton mode. The output ports power and relative phase difference between ports are investigated. SPhP enhanced ODC and MZI has applications including, but not limited to, next-generation ultra-compact photonic integrated circuits and waveguide based IR sensing.

  19. System for testing optical fibers

    DOEpatents

    Davies, Terence J.; Franks, Larry A.; Nelson, Melvin A.

    1981-01-01

    A system for nondestructively determining the attenuation coefficient, .alpha.(.lambda.), of low-loss optical fiber wave guides. Cerenkov light pulses are generated at a plurality of locations in the fiber by a beam of charged particles. The transit times of selected spectral components and their intensities are utilized to unfold the .alpha.(.lambda.) values over the measured spectrum.

  20. Fiber optic refractive index monitor

    SciTech Connect

    Weiss, Jonathan David

    2002-01-01

    A sensor for measuring the change in refractive index of a liquid uses the lowest critical angle of a normal fiber optic to achieve sensitivity when the index of the liquid is significantly less than the index of the fiber core. Another embodiment uses a liquid filled core to ensure that its index is approximately the same as the liquid being measured.

  1. Fiber optic and laser sensors X; Proceedings of the Meeting, Boston, MA, Sept. 8-11, 1992

    NASA Technical Reports Server (NTRS)

    Udd, Eric (Editor); Depaula, Ramon P. (Editor)

    1993-01-01

    Topics addressed include acoustic and pressure sensors; fiber optic gyros; electric and magnetic field sensors; bend, strain, and temperature sensors; industrial applications of sensors; and processing techniques. Particular attention is given to fiber optic interferometric acoustic sensors for wind tunnel applications, polished coupler and resonator fabrication, second-harmonic detection for rotation sensing in fiber optic gyros, simplified control theory in closed-loop fiber optic gyroscopes, and a Fabry-Perot sensor with digital signal processing for the measurement of magnetostriction. Also discussed are a Bragg fiber laser sensor, commercialization of fiber optic strain gauge systems, thermal ignition in hazardous environments due to stray light from optical fibers, a system for absolute measurements by interferometric sensors, and high-performance interferometric demodulation techniques.

  2. Fiber optics for advanced aircraft

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J.

    1988-01-01

    The increased use of composites makes the digital control more susceptible to electromagnetic effects. In order to provide the protection to the digital control additional shielding will be required as well as protective circuitry for the electronics. This results in increased weight and reduced reliability. The advantages that fiber optic technology provides for advanced aircraft applications is recognized. The use of optical signals to carry information between the aircraft and the control module provides immunity from contamination by electromagnetic sources as well as other important benefits such as reduced weight and volume resulting from the elimination of the shielding and the replacement of metal conductors with low weight glass fibers. In 1975 NASA began work to develop passive optical sensors for use with fiber optics in aircraft control systems. The problem now is to choose the best optical sensor concepts and evaluate them for use. In 1985 NASA and DOD entered into a joint program, Fiber Optic Control System Integration (FOCSI), to look at optical technology specifically for use in advanced aircraft systems. The results of this program are discussed. The conclusion of the study indicated that the use of fiber optic technology in advanced aircraft systems is feasible and desirable. The study pointed to a lack of available sensors from vendors capable of operating in the adverse environments of advanced aircraft.

  3. Fiber optics for advanced aircraft

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J.

    1989-01-01

    The increased use of composites makes the digital control more susceptible to electromagnetic effects. In order to provide the protection to the digital control additional shielding will be required as well as protective circuitry for the electronics. This results in increased weight and reduced reliability. The advantages that fiber optic technology provides for advanced aircraft applications is recognized. The use of optical signals to carry information between the aircraft and the control module provides immunity from contamination by electromagnetic sources as well as other important benefits such as reduced weight and volume resulting from the elimination of the shielding and the replacement of metal conductors with low weight glass fibers. In 1975 NASA began work to develop passive optical sensors for use with fiber optics in aircraft control systems. The problem now is to choose the best optical sensor concepts and evaluate them for use. In 1985 NASA and DOD entered into a joint program, Fiber Optic Control System Integration (FOCSI), to look at optical technology specifically for use in advanced aircraft systems. The results of this program are discussed. The conclusion of the study indicated that the use of fiber optic technology in advanced aircraft systems is feasible and desirable. The study pointed to a lack of available sensors from vendors capable of operating in the adverse environments of advanced aircraft.

  4. Neural networks within multi-core optic fibers

    PubMed Central

    Cohen, Eyal; Malka, Dror; Shemer, Amir; Shahmoon, Asaf; Zalevsky, Zeev; London, Michael

    2016-01-01

    Hardware implementation of artificial neural networks facilitates real-time parallel processing of massive data sets. Optical neural networks offer low-volume 3D connectivity together with large bandwidth and minimal heat production in contrast to electronic implementation. Here, we present a conceptual design for in-fiber optical neural networks. Neurons and synapses are realized as individual silica cores in a multi-core fiber. Optical signals are transferred transversely between cores by means of optical coupling. Pump driven amplification in erbium-doped cores mimics synaptic interactions. We simulated three-layered feed-forward neural networks and explored their capabilities. Simulations suggest that networks can differentiate between given inputs depending on specific configurations of amplification; this implies classification and learning capabilities. Finally, we tested experimentally our basic neuronal elements using fibers, couplers, and amplifiers, and demonstrated that this configuration implements a neuron-like function. Therefore, devices similar to our proposed multi-core fiber could potentially serve as building blocks for future large-scale small-volume optical artificial neural networks. PMID:27383911

  5. Neural networks within multi-core optic fibers

    NASA Astrophysics Data System (ADS)

    Cohen, Eyal; Malka, Dror; Shemer, Amir; Shahmoon, Asaf; Zalevsky, Zeev; London, Michael

    2016-07-01

    Hardware implementation of artificial neural networks facilitates real-time parallel processing of massive data sets. Optical neural networks offer low-volume 3D connectivity together with large bandwidth and minimal heat production in contrast to electronic implementation. Here, we present a conceptual design for in-fiber optical neural networks. Neurons and synapses are realized as individual silica cores in a multi-core fiber. Optical signals are transferred transversely between cores by means of optical coupling. Pump driven amplification in erbium-doped cores mimics synaptic interactions. We simulated three-layered feed-forward neural networks and explored their capabilities. Simulations suggest that networks can differentiate between given inputs depending on specific configurations of amplification; this implies classification and learning capabilities. Finally, we tested experimentally our basic neuronal elements using fibers, couplers, and amplifiers, and demonstrated that this configuration implements a neuron-like function. Therefore, devices similar to our proposed multi-core fiber could potentially serve as building blocks for future large-scale small-volume optical artificial neural networks.

  6. Neural networks within multi-core optic fibers.

    PubMed

    Cohen, Eyal; Malka, Dror; Shemer, Amir; Shahmoon, Asaf; Zalevsky, Zeev; London, Michael

    2016-07-07

    Hardware implementation of artificial neural networks facilitates real-time parallel processing of massive data sets. Optical neural networks offer low-volume 3D connectivity together with large bandwidth and minimal heat production in contrast to electronic implementation. Here, we present a conceptual design for in-fiber optical neural networks. Neurons and synapses are realized as individual silica cores in a multi-core fiber. Optical signals are transferred transversely between cores by means of optical coupling. Pump driven amplification in erbium-doped cores mimics synaptic interactions. We simulated three-layered feed-forward neural networks and explored their capabilities. Simulations suggest that networks can differentiate between given inputs depending on specific configurations of amplification; this implies classification and learning capabilities. Finally, we tested experimentally our basic neuronal elements using fibers, couplers, and amplifiers, and demonstrated that this configuration implements a neuron-like function. Therefore, devices similar to our proposed multi-core fiber could potentially serve as building blocks for future large-scale small-volume optical artificial neural networks.

  7. Light diffusing fiber optic chamber

    DOEpatents

    Maitland, Duncan J.

    2002-01-01

    A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

  8. Small Business Innovations (Fiber Optics)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Foster-Miller, Inc. Waltham, MA developed the In-Situ Fiber Optic Polymer Reaction Monitor which could lead to higher yields and lower costs in complex composite manufacturing. The monitor, developed under a Small Business Innovation Research (SBIR) contract with Langley Research Center, uses an infrared, fiber optic sensor to track the molecular vibrational characteristics of a composite part while it is being cured. It is the first analytical system capable of directly measuring the chemistry of advanced composite materials.

  9. Fiber-optic voltage sensor

    NASA Astrophysics Data System (ADS)

    Wood, C. B.

    1990-07-01

    A fiber-optic voltage sensor is described which includes a source of light, a reference fiber for receiving a known percentage of the light and an electrostrictive element having terminals across which is applied, and a voltage to be measured. The electrostrictive element is responsive to the applied voltage to assume an altered physical state. A measuring fiber also receives a known percentage of light from the light source and is secured about the electrostrictive element. The measuring fiber is provided with a cladding and exhibits an evanescent wave in the cladding. The measuring fiber has a known length which is altered when the electrostrictive element assumes its altered physical state. A differential sensor is provided which senses the intensity of light in both the reference fiber and the measuring fiber and provides an output indicative of the difference between the intensities.

  10. Direct observation of Landau-Zener tunneling in a curved optical waveguide coupler

    SciTech Connect

    Dreisow, F.; Szameit, A.; Heinrich, M.; Nolte, S.; Tuennermann, A.; Ornigotti, M.; Longhi, S.

    2009-05-15

    An electromagnetic realization of Landau-Zener (LZ) tunneling is experimentally demonstrated in femtosecond-laser written waveguide couplers with a cubically bent axis. Quantitative measurements of light evolution inside the coupler, based on fluorescence imaging, enable to trace the detailed dynamics of the LZ process. The experimental results are in good agreement with the theoretical LZ model for linear crossing of energy levels with constant coupling of finite duration.

  11. Fiber optic frequency transfer link

    NASA Technical Reports Server (NTRS)

    Primas, Lori E. (Inventor); Sydnor, Richard L. (Inventor); Lutes, George F. (Inventor)

    1991-01-01

    A reference frequency distribution system is disclosed for transmitting a reference frequency from a reference unit to a remote unit while keeping the reference frequency at the reference unit and the remote unit in phase. A fiber optic cable connects the reference unit to the remote unit. A frequency source at the reference unit produces a reference frequency having an adjustable phase. A fiber optic transmitter at the reference unit modulates a light beam with the reference frequency and transmits the light beam into the fiber optic cable. A 50/50 reflector at the remote unit reflects a first portion of the light beam from the reference unit back into the fiber optic cable to the reference unit. A first fiber optic receiver disposed at the remote unit receives a second portion of the light beam and demodulates the reference frequency to be used at the remote unit. A second fiber optic receiver disposed at the reference unit receives the first portion of the light beam and demodulates a reference frequency component. A phase conjugator is connected to the frequency source for comparing the phase of the reference frequency component to the phase of the reference frequency modulating the light beam being transmitted from the reference unit to maintain a conjugate (anti-symmetric) relationship between the reference frequency component and the reference frequency modulating the light beam where virtually no phase difference exists between the phase of the reference frequency component and the phase of the reference frequency modulating the light beam.

  12. Fiber Ring Optical Gyroscope (FROG)

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The design, construction, and testing of a one meter diameter fiber ring optical gyro, using 1.57 kilometers of single mode fiber, are described. The various noise components: electronic, thermal, mechanical, and optical, were evaluated. Both dc and ac methods were used. An attempt was made to measure the Earth rotation rate; however, the results were questionable because of the optical and electronic noise present. It was concluded that fiber ring optical gyroscopes using all discrete components have many serious problems that can only be overcome by discarding the discrete approach and adapting an all integrated optic technique that has the laser source, modulator, detector, beamsplitters, and bias element on a single chip.

  13. Optical pulse shaping based on discrete space-to-time mapping in cascaded co-directional couplers.

    PubMed

    Bazargani, Hamed Pishvai; Azaña, José

    2015-09-07

    We propose and numerically validate a new design concept for on-chip optical pulse shaping based on discrete space-to-time mapping in cascaded co-directional couplers. We show that under weak-coupling conditions, the amplitude and phase of the discrete complex apodization profile of the device can be directly mapped into its temporal impulse response. In this scheme, the amplitude and phase of the apodization profile can be controlled by tuning the coupling strength and relative time delay between the couplers, respectively. The proposed concept enables direct synthesis of the target temporal waveforms over a very broad range of time-resolution, from the femtosecond to the sub-nanosecond regime, using readily feasible integrated waveguide technologies. Moreover, the device offers compactness and the potential for reconfigurability.

  14. Fiber optic Adaline neural networks

    NASA Astrophysics Data System (ADS)

    Ghosh, Anjan K.; Trepka, Jim; Paparao, Palacharla

    1993-02-01

    Optoelectronic realization of adaptive filters and equalizers using fiber optic tapped delay lines and spatial light modulators has been discussed recently. We describe the design of a single layer fiber optic Adaline neural network which can be used as a bit pattern classifier. In our realization we employ as few electronic devices as possible and use optical computation to utilize the advantages of optics in processing speed, parallelism, and interconnection. The new optical neural network described in this paper is designed for optical processing of guided lightwave signals, not electronic signals. We analyzed the convergence or learning characteristics of the optically implemented Adaline in the presence of errors in the hardware, and we studied methods for improving the convergence rate of the Adaline.

  15. Supercontinuum Generation in Optical Fibers

    NASA Astrophysics Data System (ADS)

    Dudley, J. M.; Taylor, J. R.

    2010-04-01

    1. Introduction and history J. R. Taylor; 2. Supercontinuum generation in microstructure fiber - an historical note J. K. Ranka; 3. Nonlinear fiber optics overview J. C. Travers, M. H. Frosz and J. M. Dudley; 4. Fiber supercontinuum generation overview J. M. Dudley; 5. Silica fibers for supercontinuum generation J. C. Knight and W. Wadsworth; 6. Supercontinuum generation and nonlinearity in soft glass fibers J. H. V. Price and D. J. Richardson; 7. Increasing the blue-shift of a picosecond pumped supercontinuum M. H. Frosz, P. M. Moselund, P. D. Rasmussen, C. L. Thomsen and O. Bang; 8. Continuous wave supercontinuum generation J. C. Travers; 9. Theory of supercontinuum and interactions of solitons with dispersive waves D. V. Skryabin and A. V. Gorbach; 10. Interaction of four-wave mixing and stimulated Raman scattering in optical fibers S. Coen, S. G. Murdoch and F. Vanholsbeeck; 11. Nonlinear optics in emerging waveguides: revised fundamentals and implications S. V. Afshar, M. Turner and T. M. Monro; 12. Supercontinuum generation in dispersion varying fibers G. Genty; 13. Supercontinuum generation in chalcogenide glass waveguides Dong-Il Yeom, M. R. E. Lamont, B. Luther Davies and B. J. Eggleton; 14. Supercontinuum generation for carrier-envelope phase stabilization of mode-locked lasers S. T. Cundiff; 15. Biophotonics applications of supercontinuum generation C. Dunsby and P. M. W. French; 16. Fiber sources of tailored supercontinuum in nonlinear microspectroscopy and imaging A. M. Zheltikov; Index.

  16. Optical fiber instrumentation and applications

    NASA Astrophysics Data System (ADS)

    Claus, Richard O.

    1997-11-01

    Optical fiber-based sensor instrumentation has been used extensively for the measurement of physical observables including strain, temperature and chemical changes in smart materials and smart structures, and have been integrated with MEMS devices to provide multi-measurement capability along the length of a fiber link or network. This plenary paper briefly outlines recent developments in such optical fiber sensor instrumentation. Fiber optic sensors are small in size, immune to electromagnetic interference and can be easily integrated with existing optical fiber hardware and components that have been developed primarily for use in the larger telecommunications market. Such sensors can be easily multiplexed, resulting in networks that can be used for the health monitoring of large structures, or the real-time monitoring of structural parameters required for structural analysis and control. This paper briefly describes and compares three current fiber sensor configurations that use Fabry-Perot interferometry and fiber Bragg gratings (FBG) and long-period grating (LPG) elements to monitor strain, temperature and other parameters. Extensive details concerning additional related work and field test results and applications are discussed in the references.

  17. Optical fiber instrumentation and applications

    NASA Astrophysics Data System (ADS)

    Claus, Richard O.

    1997-11-01

    Optical fiber-based sensor instrumentation has been used extensively for the measurement of physical observables including strain, temperature and chemical changes in smart materials and smart structures, and have been integrated with MEMS devices to provide multi-measurement capability along the length of a fiber link or network. This plenary paper briefly outlines recent developments in such optical fiber sensor instrumentation. Fiber optic sensors are small in size, immune to electromagnetic interference and can be easily integrated with existing optical fiber hardware nd components that have been developed primarily for use in the larger telecommunications market. Such sensors can be easily multiplexed, resulting in networks that can be used for the health monitoring of large structures, or the real-time monitoring of structural parameters required for structural analysis and control. This paper briefly describes and compares three current fiber sensor configurations that use Fabry-Perot interferometry and fiber Bragg gratings and long-period grating elements to monitor strain, temperature and other parameters. Extensive details concerning additional related work and field test results and applications are discussed in the references.

  18. Monolithic fiber optic sensor assembly

    SciTech Connect

    Sanders, Scott

    2015-02-10

    A remote sensor element for spectrographic measurements employs a monolithic assembly of one or two fiber optics to two optical elements separated by a supporting structure to allow the flow of gases or particulates therebetween. In a preferred embodiment, the sensor element components are fused ceramic to resist high temperatures and failure from large temperature changes.

  19. Oceanic Applications of Fiber Optics

    DTIC Science & Technology

    1991-12-01

    Overview", Procof.IE, Vol. 566, Fiber Engine.ing, Vol. 5. pp. 97-103, July 1986. Optic and Laser Sensors I1, [566-01], 1985. [3) S. Shibata , M . Horiguchi...and Laser Sensors UII, [566-011, 1985. [3] S. Shibata , M . Horiguchi, S. Mitachi, and T. [161 N. Lagakos, "Multimode optical fiber displacement Manabe...Engineering, Vol. 5, pp. 97-103, July 1986. Optic and Laser Sensors HII, [566-01], 1985. [31 S. Shibata , M . Horiguchi, S. Mitachi, and T. [16] N

  20. Fiber optic crossbar switch for automatically patching optical signals

    NASA Technical Reports Server (NTRS)

    Bell, C. H. (Inventor)

    1983-01-01

    A system for automatically optically switching fiber optic data signals between a plurality of input optical fibers and selective ones of a plurality of output fibers is described. The system includes optical detectors which are connected to each of the input fibers for converting the optic data signals appearing at the respective input fibers to an RF signal. A plurality of RF to optical signal converters are arranged in rows and columns. The output of each of the optical detectors are each applied to a respective row of optical signal converted for being converters back to an optical signal when the particular optical signal converter is selectively activated by a dc voltage.

  1. Photochromic glass optical fiber

    NASA Astrophysics Data System (ADS)

    Alvi, Bilal A.; Israr, Amber; Asif, Muhammad; Aamir, Muhammad; Rehan, Muhammad

    2016-02-01

    This paper describes the fabrication and analysis of novel twin cored fiber which contains a transparent and silver halide doped photochromic core in same cladding. The Photochromic core fibers were fabricated in twin cored structure by rode and tube method. The diameter of photochromic core and transparent core is around 15 m. The distance between two cores is 1.5m. The transparent core was used to guide the probe beam and photochromic core was excited by UV source. The interaction of the probe beam with the excited photochromic core showed the photochromic behavior of the fiber.

  2. Fiber optic gas sensor

    NASA Technical Reports Server (NTRS)

    Chen, Peng (Inventor); Buric, Michael P. (Inventor); Swinehart, Philip R. (Inventor); Maklad, Mokhtar S. (Inventor)

    2010-01-01

    A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

  3. Practical coupling device based on a two-core optical fiber.

    PubMed

    Vallée, R; Drolet, D

    1994-08-20

    A practical coupling device that relies on a dual-core fiber in a loop configuration is presented. Its coupling properties are analyzed in terms of the optical path difference between the cores, which is controlled by the rotation of the fiber about its axis and by a small twist applied to it along the loop. The device actually acts as an anisotropic coupler, and the coupled power can be perfectly controlled from 0-100% by proper adjustment of the loop. A simple implementation of the device was used in the fabrication of a compact single-fiber Michelson interferometer.

  4. Light-guided localization within tissue using biocompatible surgical suture fiber as an optical waveguide.

    PubMed

    Choi, Woo June; Park, Kwan Seob; Lee, Byeong Ha

    2014-09-01

    In breast-conserving surgery, an optical wire is a useful surgical guiding tool to optically locate small lesions within the breast tissue. However, the use of a long silica glass fiber as the optical wire can be burdensome to patients because of its stiffness and nonbiocompatibility. We investigate the use of a biocompatible fiber for light localization in tissue. A surgical suture with a diameter of 400 μm and a few centimeters long is employed as the biocompatible optical waveguide to transport the visible laser light to the inner tissue site. Optical location is confirmed with glow ball-like red laser illumination at the tip of the suture embedded within a fresh chicken breast tissue. Effective optical power coupling to the suture is made by using a double-cladding fiber coupler. From this preliminary result, we realize practical light localization with biopolymer waveguides.

  5. Optical fiber feedback SQUID magnetometer

    SciTech Connect

    Naito, S.; Sampei, Y.; Takahashi, T. )

    1989-04-01

    This paper describes an optical fiber feedback superconducting quantum interference device (SQUID) magnetometer which was developed to improve electromagnetic interference characteristics. The SQUID consists of an RF SQUID probe, an RF amplifier, two multimode fibers, and a SQUID control unit. Phase-locked pulse width modulation (PWM) was used to construct a flux locked loop (FLL) circuit in the SQUID control unit. The operation of the optical fiber feedback SQUID is stable when a common mode voltage of ac 100 V/50 Hz is applied. It has an energy resolution of 1 x 10/sup -28/ J/Hz. This paper also describes the measurement of an auditory evoked field from the human brain in a magnetically shielded room using the fiber feedback SQUID with a gradiometer type pickup coil.

  6. Fiber-Optic Temperature Sensor

    NASA Technical Reports Server (NTRS)

    Maram, Jonathan M.

    1987-01-01

    Proposed sensor measures temperatures over wide range, from cryogenic liquids to burning gases. Made in part of optical fibers, sensor lighter in weight than thermocouple and immune to electromagnetic interference. Device does not respond to temperatures elsewhere than at sensing tip. Thermal expansion and contraction of distance between fiber end and mirror alters interference between light reflected from those two surfaces, thereby giving interferometric indication of temperatures.

  7. Campus fiber optic enterprise networks

    NASA Astrophysics Data System (ADS)

    Weeks, Richard A.

    1991-02-01

    The proliferation of departmental LANs in campus environments has driven network technology to the point where construction of token ring fiber-optic backbone systems is now a cost-effective alternative. This article will discuss several successful real life case history applications of token ring fiber in a campus setting each with unique distance and load factor requirements. It is hoped that these examples will aid in the understanding planning and implementation of similar installations. It will also attempt to provide important information on the emerging Fiber Distributed Data Interface (FDDI) standard.

  8. Optical fiber-based photocathode

    NASA Astrophysics Data System (ADS)

    Cǎsǎndruc, Albert; Bücker, Robert; Kassier, Günther; Miller, R. J. Dwayne

    2016-08-01

    We present the design of a back-illuminated photocathode for electron diffraction experiments based on an optical fiber, and experimental characterization of emitted electron bunches. Excitation light is guided through the fiber into the experimental vacuum chamber, eliminating typical alignment difficulties between the emitter metal and the optical trigger and position instabilities, as well as providing reliable control of the laser spot size and profile. The in-vacuum fiber end is polished and coated with a 30 nm gold (Au) layer on top of 3 nm of chromium (Cr), which emits electrons by means of single-photon photoemission when femtosecond pulses in the near ultraviolet (257 nm) are fed into the fiber on the air side. The emission area can be adjusted to any value between a few nanometers (using tapered fibers) and the size of a multi-mode fiber core (100 μm or larger). In this proof-of-principle experiment, two different types of fibers were tested, with emission spot diameters of 50 μm and 100 μm, respectively. The normalized thermal electron beam emittance (TE) was measured by means of the aperture scan technique, and a TE of 4.0 π nm was measured for the smaller spot diameter. Straightforward enhancements to the concept allowed to demonstrate operation in an electric field environment of up to 7 MV/m.

  9. Fiber Optics - An Aegis Experience

    NASA Astrophysics Data System (ADS)

    Saige, Vance

    1990-02-01

    The Navy has been involved in the exploitation of fiber optics over the decade for which many of the developmental efforts have represented a significant breakthrough in technology and also for applications. Significant among the Navy initiatives has been the effort of the AEGIS Program Office of the Naval Sea Systems Command located in Washington D.C. This paper presents some of these developmental efforts coming out of initiatives. The efforts lead to the implementation of some demonstrations aboard the AEGIS Cruisers for shipboard evaluation purposes. The program objectives were met and the efforts were considered successful demonstrations of the performance of fiber optics aboard a Navy ship.

  10. Refractive index engineering of high performance coupler for compact photonic integrated circuits

    NASA Astrophysics Data System (ADS)

    Liu, Lu; Zhou, Zhiping

    2017-04-01

    High performance couplers are highly desired in many applications, but the design is limited by nearly unchangeable material refractive index. To tackle this issue, refractive index engineering method is investigated, which can be realized by subwavelength grating. Subwavelength gratings are periodical structures with pitches small enough to locally synthesize the refractive index of photonic waveguides, which allows direct control of optical profile as well as easier fabrication process. This review provides an introduction to the basics of subwavelength structures and pay special attention to the design strategies of some representative examples of subwavelength grating devices, including: edge couplers, fiber-chip grating couplers, directional couplers and multimode interference couplers. Benefited from the subwavelength grating which can engineer the refractive index as well as birefringence and dispersion, these devices show better performance when compared to their conventional counterparts.

  11. Optical-fiber sensors challenge the competition

    NASA Astrophysics Data System (ADS)

    Giallorenzi, T. G.; Bucaro, J. A.; Dandridge, A.; Cole, J. H.

    1986-09-01

    Optical-fiber sensors which are based on intensity modulation of light are examined. The optical-fiber sensors consists of a glass core, a cladding, a light emitting diode or laser, and a photodetector, and are applicable to measuring instruments, medical probes, control systems, and military surveillance and navigation systems. The designs and capabilities of microbend sensors and interferometric fiber sensors are described. The development of fiber temperature sensors and fiber-optic acceleration sensors is considered. Procedures for measuring flow and liquid level with fiber sensors are discussed. The utilization of fiber-optic sensors in hydrophones, gyroscopes, and magnetometers is being studied.

  12. Fiber-optic currents measurements

    NASA Astrophysics Data System (ADS)

    Forman, P. R.; Looney, L. D.; Tabaka, L. J.

    Polarization maintaining pigtailed laser diodes have greatly increased the ease with which fiber-optic sensors for Faraday current measurements on large pulsed experiments can be deployed. 670, 830, and 1300 nm units are readily available. Such diode lasers can easily be mounted in an RF shielded box along with the simple electronics and batteries to power them. Our units measure 16.5 x 8 x 6 cm. and have a single external control; an on off switch. They use two 1.5 volt C cell batteries. By using an LT1073 chip in the electronics, the batteries are an energy source rather than a voltage source. These units can provide 100 mA drive to a LT015MD laser diode so that 1 mW of 830 nm light exits the fiber pigtail for up to 23 hours with no detectable droop in power. For the sensor element, twisted single mode low birefringence fibers are wrapped around the region of interest. The fiber pigtail is fused to the sensor section so changes in alignment are avoided. The light exiting the fiber sensor section is immediately analyzed by a compact, 3 x 3.5 x 5 cm, bulk optical unit which outputs quadrature optical signals into two multimode fibers leading to detectors in a screen room. The system is thus completely free of ground loops and is as immune to noise as the screen room. These sensors have the usual advantages claimed for them and the all dielectric feature was the original reason for their use on our experiments. The ease of deployment however is not usually cited. On our Pegasus 2 experiment, the need arose for a total current measurement at the main header of the capacitor banks. A single turn of optical fiber was easily strung in a 6.4 m diameter circle and attached to laser and analyzer in a few hours.

  13. Fiber-optic currents measurements

    SciTech Connect

    Forman, P.R.; Looney, L.D.; Tabaka, L.J.

    1993-03-01

    Polarization maintaining pigtailed laser diodes have greatly increased the ease with which fiber-optic sensors for Faraday current measurements on large pulsed experiments can be deployed. 670, 830, and 1300 nm units are readily available. Such diode lasers can easily be mounted in an RF shielded box along with the simple electronics and batteries to power them. Our units measure 16.5 {times} 8 {times} 6 cm. and have a single external control; an on off switch. They use two 1.5 volt ``C`` cell batteries. By using an LT1073 chip in the electronics the batteries are an energy source rather than a voltage source. These units can provide 100 mA drive to a LT015MD laser diode so that 1 mW of 830 nm fight exits the fiber pigtail for up to 23 hours with no detectable droop in power. For the sensor element twisted single mode low birefringence fibers are wrapped around the region of interest. The fiber pigtail is fused to the sensor section so changes in alignment are avoided. The light exiting the fiber sensor section is immediately analyzed by a compact, 3 {times} 3.5 {times} 5 cm, bulk optical unit which outputs quadrature optical signals into two multimode fibers leading to detectors in a screen room. The system is thus completely free of ground loops and is as immune to noise as the screen room. These sensors have the usual advantages claimed for them and the all dielectric feature was the original reason for their use on our experiments. The ease of deployment however is not usually cited. On our Pegasus II experiment the need arose for a total current measurement at the main header of the capacitor banks. A single turn of optical fiber was easily strung in a 6.4 m diameter circle and attached to laser and analyzer in a few hours.

  14. Fiber-Optic Differential Displacement Sensor

    NASA Technical Reports Server (NTRS)

    Tcheng, Ping

    1996-01-01

    Dual fiber-optic sensor measures small relative displacements of two proximate objects along common surface. Dual sensor comprises two fiber-optic sensors in differential configuration increasing sensitivity to displacement while decreasing sensitivity to thermal expansion and contraction.

  15. A novel method of the splitting ratio measurement of waveguide coupler using laser beam profiler

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Liu, Huilan; Feng, Lishuang; Liu, Jinrong

    2016-10-01

    At present, the splitting ratio test of the waveguide coupler usually adopts optical fiber coupling test method. The coupling process is complex and the coupling loss is different in two pigtail fibers, what can result in error in the splitting ratio. A new method for testing the splitting ratio of waveguide coupler using laser beam profiler is presented. Laser beam profiler is used to scan the horizontal directional light field in the cross-section of the waveguide. The measurement data are obtained. Data fitting and processing is carried out by data processing program. Finally, two light field curves are gotten, and the splitting ratio of the waveguide coupler is calculated. The feasibility of the new method is verified using fiber coupler. The error using the new method is only 0.68%. The waveguide coupler testing platform is built. The relationship between the measurement range of the splitting ratio and the minimum distances of the waveguide coupler is analyzed. The research provides an effective and convenient method for the test of splitting ratio of waveguide coupler.

  16. Sealed fiber-optic bundle feedthrough

    DOEpatents

    Tanner, Carol E.

    2002-01-01

    A sealed fiber-optic bundle feedthrough by which a multitude of fiber-optic elements may be passed through an opening or port in a wall or structure separating two environments at different pressures or temperatures while maintaining the desired pressure or temperature in each environment. The feedthrough comprises a rigid sleeve of suitable material, a bundle of individual optical fibers, and a resin-based sealing material that bonds the individual optical fibers to each other and to the rigid sleeve.

  17. Embedding Optical Fibers In Cast Metal Parts

    NASA Technical Reports Server (NTRS)

    Gibler, William N.; Atkins, Robert A.; Lee, Chung E.; Taylor, Henry F.

    1995-01-01

    Use of metal strain reliefs eliminates breakage of fibers during casting process. Technique for embedding fused silica optical fibers in cast metal parts devised. Optical fiber embedded in flange, fitting, or wall of vacuum or pressure chamber, to provide hermetically sealed feedthrough for optical transmission of measurement or control signals. Another example, optical-fiber temperature sensor embedded in metal structural component to measure strain or temperature inside component.

  18. High pressure fiber optic sensor system

    DOEpatents

    Guida, Renato; Xia, Hua; Lee, Boon K; Dekate, Sachin N

    2013-11-26

    The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

  19. Applications of fiber optics in physical protection

    SciTech Connect

    Buckle, T.H.

    1994-03-01

    The purpose of this NUREG is to provide technical information useful for the development of fiber-optic communications and intrusion detection subsystems relevant to physical protection. There are major sections on fiber-optic technology and applications. Other topics include fiber-optic system components and systems engineering. This document also contains a glossary, a list of standards and specifications, and a list of fiber-optic equipment vendors.

  20. Multiple object fiber optic spectroscopy

    NASA Technical Reports Server (NTRS)

    Hill, J. M.; Angel, J. R. P.; Scott, J. S.; Lindley, D.; Hintzen, P.

    1982-01-01

    The Steward Observatory of the University of Arizona employs short optical fiber lengths to bring light from galaxy images at the 2.3 m telescope's focus to a line along a spectrograph slit, thereby obtaining simultaneous spectra of many objects of the field of view. After describing this instrument, attention is given to the development of an improved version through which efficiency gains will be obtained by remotely positioning the fibers under computer control and by correctly matching fiber outputs to the spectrograph optics. A CCD will replace the presently employed image tube and photographic plate detector system, in order to permit sky subtraction, yield increased dynamic range, and provide more accurate wavelength calibration due to the detector's fixed format.

  1. A chip of fiber optical trap

    NASA Astrophysics Data System (ADS)

    Su, Heming; Hu, Huizhu; Zhang, Lei; Ge, Xiaojia; Shen, Yu

    2016-10-01

    A chip of fiber optical trap paves the way to realize the miniaturization and portability of devices based on dual beam optical trap, without loss of stability. We have designed two types of chip of fiber optical trap according to our theoretical simulation. The first one integrates dual beam optical trap with microfluidic chip, called a chip of semi-sealing fiber optical trap. It is generally used in chemical, biological, medical and other high-throughput experiments. The second one is a chip of full-sealing fiber optical trap. It is used to measure precisely the coefficient of viscosity or the Brownian movement of micro-object's in liquid. This paper focuses on the chip of fiber optical trap. We present two types of chips of fiber optical trap and detail their designs, fabrication and validation. The chip of semi-sealing fiber optical trap is integrated with optical fiber and microfluidic chip made of polydimethylsiloxane (PDMS). We have achieved the micro-sized alignment of optical paths and the trapping of micro-sized particles in the chip of semi-sealing fiber optical trap. In addition, it is easy to fabrication and clean. The chip of full-sealing fiber optical trap was based on a cubic micro-cavity made by a rectangular capillary tube and sealed by PDMS. We have achieved micro-sized alignment accuracy, high trapping efficiency and better trapping stability in the chip of full-sealing fiber optical trap as well.

  2. Passive Fiber Optic Gyro Study.

    DTIC Science & Technology

    1979-10-01

    34. FORWORD The report summarizes the principles of operation of the passive fiber optic gyro. It starts with a discussion of the Sagnac effect and...polarization and the angle of the " fast " axis varied nonlinearly and that the two effects are partially independent. Based on tests with a 200 meter length of

  3. Adjustable Optical-Fiber Attenuator

    NASA Technical Reports Server (NTRS)

    Buzzetti, Mike F.

    1994-01-01

    Adjustable fiber-optic attenuator utilizes bending loss to reduce strength of light transmitted along it. Attenuator functions without introducing measurable back-reflection or insertion loss. Relatively insensitive to vibration and changes in temperature. Potential applications include cable television, telephone networks, other signal-distribution networks, and laboratory instrumentation.

  4. Fiber Optics: Deregulate and Deploy.

    ERIC Educational Resources Information Center

    Suwinski, Jan H.

    1993-01-01

    Describes fiber optic technology, explains its use in education and commercial settings, and recommends regulations and legislation that will speed its use to create broadband information networks. Topics discussed include distance learning; interactive video; costs; and the roles of policy makers, lawmakers, public advocacy groups, and consumers.…

  5. Strain sensing using optical fibers

    NASA Technical Reports Server (NTRS)

    Houghton, Richard; Hiles, Steven

    1994-01-01

    The main source of attenuation which will be studied is the optical fiber's sensitivity to bending at radii that are much larger than the radius of the fiber. This type of environmental attenuation causes losses that are a function of the severity of the bend. The average attenuation caused by bending varies exponentially with the bend radius. There are many different fibers, sources, and testing equipment available. This thesis describes tests that were performed to evaluate the variables that effect bending related attenuation and will discuss the consistency of the results. Descriptions and comparisons will be made between single mode and multimode fibers as well as instrumentation comparisons between detection equipment. Detailed analysis of the effects of the whispering gallery mode will be performed along with theorized methods for characterization of these modes.

  6. Career Directions--Fiber Optic Installer

    ERIC Educational Resources Information Center

    Tech Directions, 2012

    2012-01-01

    Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber that is roughly the diameter of a human hair. The light forms an electromagnetic carrier wave that is modulated to carry information. Each optical fiber is capable of carrying an enormous amount of…

  7. Overview of Fiber-Optical Sensors

    NASA Technical Reports Server (NTRS)

    Depaula, Ramon P.; Moore, Emery L.

    1987-01-01

    Design, development, and sensitivity of sensors using fiber optics reviewed. State-of-the-art and probable future developments of sensors using fiber optics described in report including references to work in field. Serves to update previously published surveys. Systems incorporating fiber-optic sensors used in medical diagnosis, navigation, robotics, sonar, power industry, and industrial controls.

  8. Fiber-optic projected-fringe digital interferometry

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.; Beheim, Glenn

    1990-01-01

    A phase-stepped projected-fringe interferometer was developed which uses a closed-loop fiber-optic phase-control system to make very accurate surface profile measurements. The closed-loop phase-control system greatly reduces phase-stepping error, which is frequently the dominant source of error in digital interferometers. Two beams emitted from a fiber-optic coupler are combined to form an interference fringe pattern on a diffusely reflecting object. Reflections off of the fibers' output faces are used to create a phase-indicating signal for the closed-loop optical phase controller. The controller steps the phase difference between the two beams by pi/2 radians in order to determine the object's surface profile using a solid-state camera and a computer. The system combines the ease of alignment and automated data reduction of phase-stepping projected-fringe interferometry with the greatly improved phase-stepping accuracy of our closed-loop phase-controller. The system is demonstrated by measuring the profile of a plate containing several convex surfaces whose heights range from 15 to 25 micron high.

  9. Erbium Doped Fiber Optic Gravimeter

    NASA Astrophysics Data System (ADS)

    Pérez-Sánchez, G. G.; Pérez-Torres, J. R.; Flores-Bravo, J. A.; Álvarez-Chávez, J. A.; Martínez-Piñón, F.

    2017-01-01

    Gravimeters are devices that can be used in a wide range of applications, such as mining, seismology, geodesy, archeology, geophysics and many others. These devices have great sensibility, which makes them susceptible to external vibrations like electromagnetic waves. There are several technologies regarding gravimeters that are of use in industrial metrology. Optical fiber is immune to electromagnetic interference, and together with long period gratings can form high sensibility sensors of small size, offering advantages over other systems with different technologies. This paper shows the development of an optical fiber gravimeter doped with Erbium that was characterized optically for loads going from 1 to 10 kg in a bandwidth between 1590nm to 1960nm, displaying a weight linear response against power. Later on this paper, the experimental results show that the previous described behavior can be modeled as characteristic function of the sensor.

  10. Magneto-Optic Field Coupling in Optical Fiber Bragg Gratings

    NASA Technical Reports Server (NTRS)

    Carman, Gregory P. (Inventor); Mohanchandra, Panduranga K. (Inventor); Emmons, Michael C. (Inventor); Richards, William Lance (Inventor)

    2016-01-01

    The invention is a magneto-optic coupled magnetic sensor that comprises a standard optical fiber Bragg grating system. The system includes an optical fiber with at least one Bragg grating therein. The optical fiber has at least an inner core and a cladding that surrounds the inner core. The optical fiber is part of an optical system that includes an interrogation device that provides a light wave through the optical fiber and a system to determine the change in the index of refraction of the optical fiber. The cladding of the optical fiber comprises at least a portion of which is made up of ferromagnetic particles so that the ferromagnetic particles are subject to the light wave provided by the interrogation system. When a magnetic field is present, the ferromagnetic particles change the optical properties of the sensor directly.

  11. Coherent Fiber Optic Links

    DTIC Science & Technology

    1990-12-01

    local oscillator to achieve a receiver penalty of 1dB at a BER of 10- 9. REFERENCES [1] G Jacobsen and I Garrett: "Theory for heterodyne optical ASK...34Costas loop analysis for coherent optical receivers", Electronics Letters, 1986, Vol. 22, pp.394-396. [3] I Garrett and G Jacobsen : "Theoretical...DC block must be inserted and threshold on the BER set adjusted to zero volts. -5.21- Data [nj] POW Coherent Modulationcircuit op~ arn Diectn,, anua Rx

  12. Revised minimum reciprocity configuration and actualization methodology of interferometric all-fiber-optic gyroscopes.

    PubMed

    Wang, Xinyue; Wang, Ziyu

    2011-05-01

    We propose a revised minimum reciprocity configuration (MRC) of an interferometric all-fiber-optic gyroscope (all-fiber I-FOG), based on our design of a fused-taper polarization-maintaining fiber coupler. This MRC reduces the insertion loss and production cost of the optical path, yet maintains the principle of reciprocity. Experimental results show that this I-FOG with five optical components exhibits better performance than a conventional I-FOG with six optical components. Using the revised MRC, the angle random walk and the bias instability of an I-FOG are improved from 0.025 deg/√hr to 0.011 deg/√hr, and 0.48 deg/hr to 0.21 deg/hr, respectively.

  13. Fiber Optic Sensing: Prototype Results

    NASA Astrophysics Data System (ADS)

    Ortiz Martin, Jesus; Gonzalez Torres, Jose

    2015-09-01

    Airbus DS Crisa has been developing an interrogator of Fiber Bragg Grating sensors [1], aimed at measuring, mainly, temperature and strain by means of fiber optic links. This activity, funded by Airbus DS Crisa, ESA and HBM Fibersensing, finalizes with the manufacturing of a prototype. The present paper describes in detail the main outcomes of the testing activities of this prototype. At the moment of writing the paper all the functional tests have been concluded. The environmental tests, thermal and mechanical, will be conducted with the FOS interrogator forming part of the RTU2015, described in [2].

  14. Thermal lensing in optical fibers.

    PubMed

    Dong, Liang

    2016-08-22

    Average powers from fiber lasers have reached the point that a quantitative understanding of thermal lensing and its impact on transverse mode instability is becoming critical. Although thermal lensing is well known qualitatively, there is a general lack of a simple method for quantitative analysis. In this work, we first conduct a study of thermal lensing in optical fibers based on a perturbation technique. The perturbation technique becomes increasingly inaccurate as thermal lensing gets stronger. It, however, provides a basis for determining a normalization factor to use in a more accurate numerical study. A simple thermal lensing threshold condition is developed. The impact of thermal lensing on transverse mode instability is also studied.

  15. Material dispersion in optical fibers.

    PubMed

    Wemple, S H

    1979-01-01

    A three-parameter description of optical fiber material dispersion is proposed which fits the available data and reveals the key roles played by bond length, lattice structure, chemical valence, average energy gap, and atomic mass. Using broadly applicable trends in electronic and phonon oscillator strengths, simple expressions are deduced for material dispersion including the zero crossover wavelength lambda(c). These results impose severe constraints on fiber design which essentially limit the possibilities for significantly improving on pure silica to sulfates (particularly Li(2)SO(4)) and to BeF(2). The predicted value of lambda(c) for the latter material is 1.05 microm.

  16. Apodized grating coupler using fully-etched nanostructures

    NASA Astrophysics Data System (ADS)

    Wu, Hua; Li, Chong; Li, Zhi-Yong; Guo, Xia

    2016-08-01

    A two-dimensional apodized grating coupler for interfacing between single-mode fiber and photonic circuit is demonstrated in order to bridge the mode gap between the grating coupler and optical fiber. The grating grooves of the grating couplers are realized by columns of fully etched nanostructures, which are utilized to digitally tailor the effective refractive index of each groove in order to obtain the Gaussian-like output diffractive mode and then enhance the coupling efficiency. Compared with that of the uniform grating coupler, the coupling efficiency of the apodized grating coupler is increased by 4.3% and 5.7%, respectively, for the nanoholes and nanorectangles as refractive index tunes layer. Project supported by the National Natural Science Foundation of China (Grant Nos. 61222501, 61335004, and 61505003), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20111103110019), the Postdoctoral Science Foundation of Beijing Funded Project, China (Grant No. Q6002012201502), and the Science and Technology Research Project of Jiangxi Provincial Education Department, China (Grant No. GJJ150998).

  17. Aluminum nitride grating couplers.

    PubMed

    Ghosh, Siddhartha; Doerr, Christopher R; Piazza, Gianluca

    2012-06-10

    Grating couplers in sputtered aluminum nitride, a piezoelectric material with low loss in the C band, are demonstrated. Gratings and a waveguide micromachined on a silicon wafer with 600 nm minimum feature size were defined in a single lithography step without partial etching. Silicon dioxide (SiO(2)) was used for cladding layers. Peak coupling efficiency of -6.6 dB and a 1 dB bandwidth of 60 nm have been measured. This demonstration of wire waveguides and wideband grating couplers in a material that also has piezoelectric and elasto-optic properties will enable new functions for integrated photonics and optomechanics.

  18. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, John

    1999-01-01

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

  19. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, J.

    1999-04-06

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 23 figs.

  20. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, John

    1995-01-01

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

  1. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, J.

    1995-05-30

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 29 figs.

  2. Design of wide-angle broadband Luneburg lens based optical couplers for plasmonic slot nano-waveguides

    NASA Astrophysics Data System (ADS)

    Arigong, Bayaner; Ding, Jun; Ren, Han; Zhou, Rongguo; Kim, HyoungSoo; Lin, Yuankun; Zhang, Hualiang

    2013-10-01

    Gradient index (GRIN) structures have attracted great interests since their invention. Especially, the recent advance in the fields of transformation optics, plasmonics, and nanofabrication techniques has opened new directions for the applications of GRIN structures in nano-photonic devices. In this paper, we apply Luneburg lens and its transformed counterpart to realize efficient coupling to plasmonic nano-waveguides. We first briefly present the general structures of Luneburg lens and generalized Luneburg lens, as well as the design process of flattened Luneburg lens applying quasi-conformal mapping techniques. After that, we study the performance of these lenses for coupling electromagnetic signals to nano-waveguides (the metal-insulator-metal nano-waveguide). Different coupling schemes are investigated. It is found that the proposed Luneburg lens based optical couplers can be used to provide broadband light couplings to plasmonic nano-waveguides under wide incident angles.

  3. Liquid crystal cells and optical fibers in neural network implementation

    NASA Astrophysics Data System (ADS)

    Domanski, Andrzej W.; Buczynski, Ryszard; Sierakowski, Marek W.

    1995-08-01

    Optical binary computer may be as easy to operate as parallel system. For such configuration Boolean logic is not very convenient and therefore neural networks should be introduced. In works leading to the paper we used liquid crystal cells as a standard system of liquid crystalline layer between to conducting electrodes in 'sandwich' geometry. We have used 25 micrometers display cells filled with nematic 6CHBT working on 'twisted nematic' effect. Based on such elements a mode of a simple Hopfield network was set up. More advanced experiments were carried out on a model of neurone with supervised learning. The model consists of four laser diodes pigtailed to the multimode optical fibers with 50 micrometers core diameter. The directional couplers help to control the level of input optical power. Four liquid crystal cells allow to change the transmission level according to superivised learning requirements. All the signals were detected by one photodiode. The presented results of experiments are in excellent agreement with theoretical predictions. An additional study was done to check the possibility to build up a linear neural network with Grossberg layer, a neural network with Kohonen layer, and a counter propagation network with two layers of neurones. We have proved that such models may be set up based on simple liquid crystals cells and optical fiber networks.

  4. Efficient perfectly vertical fiber-to-chip grating coupler for silicon horizontal multiple slot waveguides.

    PubMed

    Covey, John; Chen, Ray T

    2013-05-06

    Horizontal multiple slot waveguides of polysilicon and silicon nanocrystalline oxide were grating coupled to a surface normal fiber array. Measurements yielded a coupling efficiency of 60% per grating. The fabrication-tolerant, four-stage grating design was genetically evolved from a random seed without starting from first-principle design. Theoretical coupling efficiency was 68% and was re-designed to 63% after accommodating all sources of fabrication error. To our knowledge, this is the first implementation of a purely polysilicon and silicon nanocrystalline oxide slot waveguide platform.

  5. Polarization-induced noise in a fiber-optic Michelson interferometer with Faraday rotator mirror elements

    NASA Astrophysics Data System (ADS)

    Ferreira, L. A.; Santos, J. L.; Farahi, F.

    1995-10-01

    Faraday rotator mirror elements have been used in a number of applications as compensators for induced birefringence in retracing paths. In interferometric systems, such as the fiber-optic Michelson interferometer, this approach proved to be useful in providing maximum fringe visibility and insensitivity to the polarization state of light injected into the interferometer. However, it is found that, when the characteristics of the fiber coupler depend on the polarization state of the input beam, the efficiency of the Faraday mirror elements is limited. Theoretical analysis and experimental results in support of this statement are presented.

  6. Polarization-induced noise in a fiber-optic Michelson interferometer with Faraday rotator mirror elements.

    PubMed

    Ferreira, L A; Santos, J L; Farahi, F

    1995-10-01

    Faraday rotator mirror elements have been used in a number of applications as compensators for induced birefringence in retracing paths. In interferometric systems, such as the fiber-optic Michelson interferometer, this approach proved to be useful in providing maximum fringe visibility and insensitivity to the polarization state of light injected into the interferometer. However, it is found that, when the characteristics of the fiber coupler depend on the polarization state of the input beam, the efficiency of the Faraday mirror elements is limited. Theoretical analysis and experimental results in support of this statement are presented.

  7. Multiple Beam Correlation Using Single-Mode Fiber Optics with Application to Interferometric Imaging

    NASA Astrophysics Data System (ADS)

    Shaklan, Stuart Bruce

    A study of the application of single-mode fiber optics to the multiple-beam interferometric recombination problem is presented. In the laboratory, the fibers have been used in wide bandwidth, two-arm, Mach-Zehnder test interferometers as well as a 5-telescope imaging interferometer connected to an all-fiber beam combiner. Based upon these experiments and some theoretical studies it is shown that fiber optics and fiber optic components such as directional couplers provide an excellent alternative to conventional optics such as mirrors, beamsplitters, and relay lenses. The equations describing the measurement of the complex degree of coherence in an interferometer with a single-mode fiber in each arm are derived. The equations reveal an important feature of the fibers: they filter phase fluctuations due to aberrations and turbulence at the input and convert them to intensity fluctuations at the output. This leads to a simplification of the calibration of measured visibilities. The coupling efficiency of light which has passed through a turbulent atmosphere is also studied as a function of fiber parameters and turbulence conditions for both image motion stabilized and non-stabilized cases. For the former case, coupling efficiency remains greater than 50% as long as telescope diameter is no larger than the turbulence coherence length. Beam combination architectures using arrays of directional couplers are fully discussed. Arrays accommodating up to 20 input beams are presented. The arrays require only N detector pixels for N input beams. A scheme of temporal multiplexing of the phase of each beam is used to identify individual fringe pairs. One possible scheme allows wide bandwidths even for large numbers of beams. A 5-telescope interferometer has been constructed and connected to an all-fiber beam combiner. Two extended objects were observed and reconstructed using standard radio astronomy VLBI software. The interferometer and beam combiner had good thermal and

  8. Miniaturized fiber-optic Michelson-type interferometric sensors

    NASA Technical Reports Server (NTRS)

    Murphy, Kent A.; Miller, William V., III; Tran, Tuan A.; Vengsarkar, Ashish M.; Claus, Richard O.

    1991-01-01

    A novel, miniaturized Michelson-type fiber-optic interferometric sensor that is relatively insensitive to temperature drifts is presented. A fused-biconical tapered coupler is cleaved immediately after the coupled length and polished down to the region of the fused cladding, but short of the interaction region. The end of one core is selectively coated with a reflective surface and is used as the reference arm; the other core serves as the sensing arm. The detection of surface acoustic waves, microdisplacements, and magnetic fields is reported. The sensor is shown to be highly stable in comparison to a classic homodyne, uncompensated Michelson interferometer, and signal-to-noise ratios of 65 dB have been obtained.

  9. Miniaturized fiber-optic Michelson-type interferometric sensors.

    PubMed

    Murphy, K A; Miller Iii, W V; Tran, T A; Vengsarkar, A M; Claus, R O

    1991-12-01

    We present a novel, miniaturized Michelson-type fiber-optic interferometric sensor that is relatively insensitive to temperature drifts. A fused-biconical tapered coupler is cleaved immediately after the coupled length and polished down to the region of the fused cladding, but short of the interaction region. The end of one core is selectively coated with a reflective surface and is used as the reference arm; the other core serves as the sensing arm. We report the detection of surface acoustic waves, microdisplacements, and magnetic fields. The sensor is shown to be highly stable in comparison to a classic homodyne, uncompensated Michelson interferometer, and signal-to-noise ratios of 65 dB have been obtained.

  10. LDEF fiber optic exposure experiment

    NASA Technical Reports Server (NTRS)

    Johnston, Alan R.; Bergman, Larry A.; Hartmayer, Ron

    1991-01-01

    Ten fiber optic cable samples of different types were exposed in low Earth orbit for over 5.5 years on the Long Duration Exposure Facility (LDEF). Four of the samples were mounted externally, and the remaining six were internal, under approximately .5 gc/sq m of aluminum. The experiment was recovered in January of 1990, and laboratory evaluation of the effects of the exposure has continued since. An increase in loss, presumed to be from radiation darkening, aging effects on polymer materials used in cabling, unique contamination effects on connector terminations, and micrometeoroid impacts were observed on some of the samples. In addition, the dependence of sample loss was measured as a function of temperature before and after the flight. All cable samples were functional, and the best exhibited no measurable change in performance, indicating that conventional fiber optic cables can perform satisfactorily in spacecraft. Experimental results obtained to date will be presented and discussed.

  11. Electro-optical phase-change 2 × 2 switching using three- and four-waveguide directional couplers.

    PubMed

    Liang, Haibo; Soref, Richard; Mu, Jianwei; Li, Xun; Huang, Wei-Ping

    2015-07-01

    Theoretical modeling and numerical simulation have been performed at λ=2100  nm on silicon-on-insulator channel-waveguide directional couplers in which the outer two Si waveguides are passive and the central waveguide(s) are electro-optical (EO) "islands." The EO channel(s) utilize a 10 nm layer of Ge2Sb2Te5 phase-change-material sited at midlevel of a doped Si channel. A voltage-driven phase change produces a large change in the effective index of the TE(o) and TM(o) modes, thereby inducing crossbar 2×2 switching. A mode-matching method is employed to estimate EO switching performance in the limit of strong interguide coupling. Low-loss switching is predicted for cross-to-bar and bar-to-cross coupling lengths. These "self-holding" switches had active lengths of 500-1000 μm, which are shorter than those in couplers relying upon free-carrier injection. The four-waveguide devices had lower cross talk but higher loss than the three-waveguide devices. For the crystalline phase we sometimes used an active length that was smaller than that for the amorphous phase.

  12. A compact optical fiber positioner

    NASA Astrophysics Data System (ADS)

    Hu, Hongzhuan; Wang, Jianping; Liu, Zhigang; Zhou, Zengxiang; Zhai, Chao; Chu, Jiaru

    2016-07-01

    In this paper, a compact optical fiber positioner is proposed, which is especially suitable for small scale and high density optical fiber positioning. Based on the positioning principle of double rotation, positioner's center shaft depends on planetary gear drive principle, meshing with the fixed annular gear central motor gear driving device to rotate, and the eccentric shaft rotated driving by a coaxial eccentric motor, both center and the eccentric shaft are supported by a rolling bearings; center and eccentric shaft are both designed with electrical zero as a reference point, and both of them have position-limiting capability to ensure the safety of fiber positioning; both eccentric and center shaft are designed to eliminating clearance with spring structure, and can eliminate the influence of gear gap; both eccentric and center motor and their driving circuit can be installed in the positioner's body, and a favorable heat sink have designed, the heat bring by positioning operation can be effectively transmit to design a focal plane unit through the aluminum component, on sleeve cooling spiral airway have designed, when positioning, the cooling air flow is inlet into install hole on the focal plate, the cooling air flow can effectively take away the positioning's heat, to eliminate the impact of the focus seeing. By measuring position device's sample results show that: the unit accuracy reached 0.01mm, can meet the needs of fiber positioning.

  13. Grating-flanked plasmonic coaxial apertures for efficient fiber optical tweezers.

    PubMed

    Saleh, Amr A E; Sheikhoelislami, Sassan; Gastelum, Steven; Dionne, Jennifer A

    2016-09-05

    Subwavelength plasmonic apertures have been foundational for direct optical manipulation of nanoscale specimens including sub-100 nm polymeric beads, metallic nanoparticles and proteins. While most plasmonic traps result in two-dimensional localization, three-dimensional manipulation has been demonstrated by integrating a plasmonic aperture on an optical fiber tip. However, such 3D traps are usually inefficient since the optical mode of the fiber and the subwavelength aperture only weakly couple. In this paper we design more efficient optical-fiber-based plasmonic tweezers combining a coaxial plasmonic aperture with a plasmonic grating coupler at the fiber tip facet. Using full-field finite difference time domain analysis, we optimize the grating design for both gold and silver fiber-based coaxial tweezers such that the optical transmission through the apertures is maximized. With the optimized grating, we show that the maximum transmission efficiency increases from 2.5% to 19.6% and from 1.48% to 16.7% for the gold and silver structures respectively. To evaluate their performance as optical tweezers, we calculate the optical forces and the corresponding trapping potential on dielectric particles interacting with the apertures. We demonstrate that the enahncement in the transmission translates into an equivalent increase in the optical forces. Consequently, the optical power required to achieve stable optical trapping is significantly reduced allowing for efficient localization and 3D manipulation of sub-30 nm dielectric particles.

  14. MX optical fiber communication system

    NASA Astrophysics Data System (ADS)

    Keiser, G.

    The fiber optic (FO) network for the proposed MX mobile basing scheme is described. C3 operations would be implemented through 15,000 km of FO links between 4800 sites. Burying the cables would ensure continued C3 operations in a hostile environment, although protection would be needed from burrowing rodents. Technology development criteria, such as optical sources and photodetectors for the 1300-1600 nm long wavelength region, are noted, together with construction of a test site at an Air Force base in California.

  15. Polyimide-coated embedded optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Nath, Dilip K.; Nelson, Gary W.; Griffin, Stephen E.; Harrington, C. T.; He, Yi-Fei; Reinhart, Lawrence J.; Paine, D. C.; Morse, Theodore F.

    1991-10-01

    The present paper describes the behavior of embedded optical sensor fibers in a high- temperature PEEK (polyether ether ketone) carbon fiber composite. Sheets of this material, 200 micrometers thick, were layered in alternating directions for the carbon fibers. Typically, 16 sheets were used to form 3' X 6' or 3' X 8' panels by placing the optical fibers in the middle of the `prepreg' sheets, which were then heated to the processing temperature, and subjected to a pressure of 300 psi during the cool-down phase. Since the ordinary polymeric coatings of optical fibers cannot survive the 380 degree(s)C to 400 degree(s)C processing temperature of PEEK impregnated fiber composites, all of the optical sensor fibers tested were polyimide coated. The optical, mechanical, and thermal properties are reported and it is concluded that polyimide coated fibers can withstand PEEK processing conditions.

  16. Machine Tests Optical Fibers In Flexure

    NASA Technical Reports Server (NTRS)

    Darejeh, Hadi; Thomas, Henry; Delcher, Ray

    1993-01-01

    Machine repeatedly flexes single optical fiber or cable or bundle of optical fibers at low temperature. Liquid nitrogen surrounds specimen as it is bent back and forth by motion of piston. Machine inexpensive to build and operate. Tests under repeatable conditions so candidate fibers, cables, and bundles evaluated for general robustness before subjected to expensive shock and vibration tests.

  17. Improved silica-PLC Mach-Zehnder interferometer type optical switches with error dependence compensation of directional coupler

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Yi, Jia; Guo, Lijun; Liu, Peng; Hall, Trevor J.; Sun, DeGui

    2017-03-01

    For the most popular structure of planer lightwave circuit (PLC) 2×2 thermo-optic switches, Mach-Zehnder interferometer (MZI), a full range of splitting ratio errors of directional coupler (DC) are investigated. All the parameters determining the splitting ratio are the dimensions and the refractive indices of the waveguide core and cladding layers. In this work, the coherent relationships between the waveguide size and the refractive indices are analyzed and then the error compensation between the width and the refractive index of waveguide core, and the controllable effect of over clad layer refractive index error upon the MZI-type optical switch are all discovered with numerical calculation and BPM simulations. Then, an MZI-type 2×2 thermo-optic switch having a higher error tolerance is established with the efficient optimizations of all the 3 dB-DC parameters. As a result, for the symmetric MZI switch, an insertion loss of 1.5 dB and optical extinction ratio of over 20 dB are realized for the average tolerance of±5.0%. An asymmetric arm optical phase and unequal arm lengths is also employed to improve the uniformities of insertion loss. The agreements between the designs and the experiments are recognized, leading to a wide adoption of practical silica-PLC optical switch products.

  18. Fiber optic vibration sensor using bifurcated plastic optical fiber

    NASA Astrophysics Data System (ADS)

    Abdullah, M.; Bidin, N.; Yasin, M.

    2016-11-01

    An extrinsic fiber optic vibration sensor is demonstrated for a fiber optic displacement sensor based on a bundled multimode fiber to measure a vibration frequency ranging from 100 until 3000 Hz. The front slope has a sensitivity of 0.1938mV/mm and linearity of 99.7% within a measurement range between 0.15-3.00 mm. By placing the diaphragm of the concave load-speaker within the linear range from the probe, the frequency of the vibration can be measured with error percentage of less than 1.54%. The graph of input against output frequency for low, medium and high frequency range show very high linearity up to 99%. Slope for low, medium, and high frequency range are calculated as 1.0026, 0.9934, and 1.0007 respectively. Simplicity, long term stability, low power consumption, wide dynamic and frequency ranges, noise reduction, ruggedness, linearity and light weight make it promising alternative to other well-establish methods for vibration frequency measurement.

  19. Use of optical fibers in spectrophotometry

    NASA Technical Reports Server (NTRS)

    Ramsey, Lawrence W.

    1988-01-01

    The use of single or small numbers of fiber optic fibers in astronomical spectroscopy with the goal of greater spectrophotometric and radial velocity accuracy is discussed. The properties of multimode step index fibers which are most important for this application are outlined, as are laboratory tests of currently available fibers.

  20. Optical fiber grating tuning device and application

    NASA Astrophysics Data System (ADS)

    Luo, Fei; Yeh, T.

    2008-12-01

    A new design for tuning optical fiber grating is proposed. The fiber grating is placed in the grooves between a pair of slides, in which one end of the fiber is bonded on the bottom slide, and the other end of the fiber is bonded on the top slide, the grating section of the fiber is confined in grooves, so that the fiber grating is remaining straight without buckling during axial compressive force applied to the fiber. An actuator is used for driving slide to apply force on fiber to axially compress or stretch the fiber grating. The wavelength of the fiber grating is tuned according to applied stress on the fiber. The applications of the device include tunable fiber laser, tunable fiber filter etc.

  1. Optical fiber voltage sensor based on Michelsion interferometer using Fabry-Perot demodulation interferometer

    NASA Astrophysics Data System (ADS)

    Chen, Xinwei; He, Shengnan; Li, Dandan; Wang, Kai; Fan, Yan'en; Wu, Shuai

    2014-11-01

    We present an optical fiber voltage sensor by Michelsion interferometer (MI) employing a Fabry-Perot (F-P) interferometer and the DC phase tracking (DCPT) signal processing method. By mounting a MI fabricated by an optical fiber coupler on a piezoelectric (PZT) transducer bar, a dynamic strain would be generated to change the optical path difference (OPD) of the interferometer when the measured voltage was applied on the PZT. Applying an F-P interferometer to demodulate the optical intensity variation output of the MI, the voltage can be obtained. The experiment results show that the relationship between the optical intensity variation and the voltage applied on the PZT is approximately linear. Furthermore, the phase generate carrier (PGC) algorithm was applied to demodulate the output of the sensor also.

  2. High-efficiency and wideband interlayer grating couplers in multilayer Si/SiO2/SiN platform for 3D integration of optical functionalities.

    PubMed

    Sodagar, Majid; Pourabolghasem, Reza; Eftekhar, Ali A; Adibi, Ali

    2014-07-14

    We have designed interlayer grating couplers with single/double metallic reflectors for Si/SiO(2)/SiN multilayer material platform. Out-of-plane diffractive grating couplers separated by 1.6 μm thick buffer SiO(2) layer are vertically stacked against each other in Si and SiN layers. Geometrical optimization using genetic algorithm coupled with electromagnetic simulations using two-dimensional (2D) finite element method (FEM) results in coupler designs with high peak coupling efficiency of up to 89% for double- mirror and 64% for single-mirror structures at telecom wavelength. Also, 3-dB bandwidths of 40 nm and 50 nm are theoretically predicted for the two designs, respectively. We have fabricated the grating coupler structure with single mirror. Measured values for insertion loss and 3-dB bandwidth in the fabricated single-mirror coupler confirms the theoretical results. This opens up the possibility of low-loss 3D dense integration of optical functionalities in hybrid material platforms.

  3. Intelligent Fiber Optic Sensor for Estimating the Concentration of a Mixture-Design and Working Principle

    PubMed Central

    Borecki, Michal

    2007-01-01

    This paper presents the construction and working principles of an intelligent fiber-optic intensity sensor used for examining the concentration of a mixture in conjunction with water. It can find applications e.g. in waste-water treatment plant for selection of a treatment process. The sensor head is the end of a large core polymer optical fiber, which constitutes one arm of an asymmetrical coupler. The head works on the reflection intensity basis. The reflected signal level depends on the Fresnel reflection from the air and from the mixture examined when the head is immersed in it. The sensor head is mounted on a lift. For detection purposes the signal can be measured on head submerging, submersion, emerging and emergence. Therefore, the measured signal depends on the surface tension, viscosity, turbidity and refraction coefficient of the solution. The signal coming from the head is processed electrically in an opto-electronic interface. Then it is fed to a neural network. The novelty of the proposed sensor lies in that it contains an asymmetrical coupler and a neural network that works in the generalization mode. The sensor resolution depends on the efficiency of the asymmetrical coupler, the precision of the opto-electronic signal conversion and the learning accuracy of the neural network. Therefore, the number and quality of the points used for the learning process is very important. By way of example, the paper describes a sensor intended for examining the concentration of liquid soap in water.

  4. Remotely readable fiber optic compass

    DOEpatents

    Migliori, Albert; Swift, Gregory W.; Garrett, Steven L.

    1986-01-01

    A remotely readable fiber optic compass. A sheet polarizer is affixed to a magnet rotatably mounted in a compass body, such that the polarizer rotates with the magnet. The optical axis of the sheet polarizer is preferably aligned with the north-south axis of the magnet. A single excitation light beam is divided into four identical beams, two of which are passed through the sheet polarizer and through two fixed polarizing sheets which have their optical axes at right angles to one another. The angle of the compass magnet with respect to a fixed axis of the compass body can be determined by measuring the ratio of the intensities of the two light beams. The remaining ambiguity as to which of the four possible quadrants the magnet is pointing to is resolved by the second pair of light beams, which are passed through the sheet polarizer at positions which are transected by two semicircular opaque strips formed on the sheet polarizer. The incoming excitation beam and the four return beams are communicated by means of optical fibers, giving a remotely readable compass which has no electrical parts.

  5. Remotely readable fiber optic compass

    DOEpatents

    Migliori, A.; Swift, G.W.; Garrett, S.L.

    1985-04-30

    A remotely readable fiber optic compass. A sheet polarizer is affixed to a magnet rotatably mounted in a compass body, such that the polarizer rotates with the magnet. The optical axis of the sheet polarizer is preferably aligned with the north-south axis of the magnet. A single excitation light beam is divided into four identical beams, two of which are passed through the sheet polarizer and through two fixed polarizing sheets which have their optical axes at right angles to one another. The angle of the compass magnet with respect to a fixed axis of the compass body can be determined by measuring the ratio of the intensities of the two light beams. The remaining ambiguity as to which of the four possible quadrants the magnet is pointing to is resolved by the second pair of light beams, which are passed through the sheet polarizer at positions which are transected by two semicircular opaque strips formed on the sheet polarizer. The incoming excitation beam and the four return beams are communicated by means of optical fibers, giving a remotely readable compass which has no electrical parts.

  6. Fiber optic microbend phase shifter and modulator

    NASA Astrophysics Data System (ADS)

    Taylor, H. F.

    1985-09-01

    The present invention relates generally to a fiber optic phase shifter and intensity modulator and more particularly to fiber optic phase shifters and modulators that utilize a microbend transducer. The ability to shift the phase of light propagating in a single mode fiber is quite useful in fiber optic sensors and may also be used in fiber-optic communications. A conventional way to shift the phase of light propagating in a single mode fiber is by stretching the fiber. This is done by wrapping and gluing the fiber around a cylinder of piezoelectric material. When a voltage is applied to the material, the cylinder expands thereby stretching the fiber. Long lengths on the order of 10 meters of fiber and large voltages are needed to drive the piezoelectric cylinder. The ability to modulate the intensity of light propagating in a optic fiber is also useful in fiber optic communication and sensing systems. Such modulation can be performed by a device external to the fiber such as an electrooptic modulator formed in a lithium niobate crystal.

  7. Fiber-Optic Sensor Would Monitor Growth of Polymer Film

    NASA Technical Reports Server (NTRS)

    Beamesderfer, Michael

    2005-01-01

    A proposed optoelectronic sensor system would measure the increase in thickness of a film of parylene (a thermoplastic polymer made from para-xylene) during growth of the film in a vapor deposition process. By enabling real-time monitoring of film thickness, the system would make it possible to identify process conditions favorable for growth and to tailor the final thickness of the film with greater precision than is now possible. The heart of the sensor would be a pair of fiber-optic Fabry-Perot interferometers, depicted schematically in the figure. (In principle, a single such interferometer would suffice. The proposal calls for the use of two interferometers for protective redundancy and increased accuracy.) Each interferometer would include a light source, a fiber-optic coupler, and photodetectors in a control box outside the deposition chamber. A single-mode optical fiber for each interferometer would run from inside the control box to a fused-silica faceplate in a sensor head. The sensory tips of the optical fibers would be polished flush with the free surface of the faceplate. In preparation for use, the sensor head would be mounted with a hermetic seal in a feed-through port in the deposition chamber, such that free face of the faceplate and the sensory tips of the optical fibers would be exposed to the deposition environment. During operation, light would travel along each optical fiber from the control box to the sensor head. A small portion of the light would be reflected toward the control box from the end face of each fiber. Once growth of the parylene film started, a small portion of the light would also be reflected toward the control box from the outer surface of the film. In the control box, the two reflected portions of the light beam would interfere in one of the photodetectors. The difference between the phases of the interfering reflected portions of the light beam would vary in proportion to the increasing thickness of the film and the known

  8. Effects of fiber manipulation methods on optical fiber properties

    NASA Astrophysics Data System (ADS)

    Reynolds, Robert O.; Bechter, Andrew; Crass, Jonathan

    2016-07-01

    Optical fibers are routinely used to couple high-resolution spectrographs to modern telescopes, enabling important advantages in areas such as the search for extrasolar planets using spectroscopic radial velocity measurements of candidate stars. Optical fibers partially scramble the input illumination, and this feature enables a fiber feed to provide more uniform illumination to the spectrograph optics, thereby reducing systematic errors in radial velocity measurements. However fibers suffer from focal ratio degradation (FRD), a spreading of the beam at the output of the fiber with respect to that at the fiber input, which results in losses in throughput and resolution. Modal noise, a measurement uncertainty caused by inherent fiber properties and evident as a varying spatial intensity at the fiber exit plane, reduces the signal to noise ratio in the data. Devices such as double scramblers are often used to improve scrambling, and better fiber end preparation can mitigate FRD. Many instruments agitate the fiber during an observation to reduce modal noise, and stretching the fiber during use has been shown to offer a greater reduction in that noise. But effects of agitation and stretching on fiber parameters such as total transmission and focal ratio degradation have not been adequately studied. In this paper we present measurements of transmission loss and focal ratio degradation for both agitated and stretched fibers.

  9. Fiber-Optic Ammonia Sensors

    NASA Technical Reports Server (NTRS)

    Carter, Michael T.

    2003-01-01

    Reversible, colorimetric fiber-optic sensors are undergoing development for use in measuring concentrations of ammonia in air at levels relevant to human health [0 to 50 parts per million (ppm)]. A sensor of this type includes an optical fiber that has been modified by replacing a portion of its cladding with a polymer coat that contains a dye that reacts reversibly with ammonia and changes color when it does so. The change in color is measured as a change in the amount of light transmitted from one end of the fiber to the other. Responses are reversible and proportional to the concentration of ammonia over the range from 9 to 175 ppm and in some cases the range of reversibility extends up to 270 ppm. The characteristic time for the response of a sensor to rise from 10 to 90 percent of full scale is about 25 seconds. These sensors are fully operational in pure carbon dioxide and are not adversely affected by humidity. This work was done by Michael T. Carter

  10. Optical fiber sensor for allergen detection

    NASA Astrophysics Data System (ADS)

    Bendoula, R.; Wacogne, B.; Giust, R.; Cherioux, F.; Sandoz, P.; Gharbi, T.

    2005-08-01

    The sensor is dedicated to the detection of allergens. We use a biochemical reaction in the vicinity of the core of an optical fiber which modifies the propagation conditions of the optical wave by evanescent coupling. The detection involves a intrinsic optical fiber Fabry-Perot interferometer.

  11. Optical Fibers Would Sense Local Strains

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1994-01-01

    Proposed fiber-optic transducers measure local strains. Includes lead-in and lead-out lengths producing no changes in phase shifts, plus short sensing length in which phase shift is sensitive to strain. Phase shifts in single-mode fibers vary with strains. In alternative version, multiple portions of optical fiber sensitive to strains characteristic of specific vibrational mode of object. Same principle also used with two-mode fiber.

  12. Great prospects for fiber optics sensors

    NASA Technical Reports Server (NTRS)

    Hansen, T. E.

    1983-01-01

    Fiber optic sensors provide noise immunity and galvanic insulation at the measurement point. Interest in such sensors is increasing for these reasons. In the United States sales are expected to increase from 12 million dollars in 1981 to 180 million in 1991. Interferometric sensors based on single modus fibers deliver extremely high sensitivity, while sensors based on multi-modus fibers are more easily manufactured. The fiber optic sensors which are available today are based on point measurements. Development of fiber optic sensors in Norway is being carried out at the Central institute and has resulted in the development of medical manometers which are now undergoing clinical testing.

  13. Optical fiber gas sensor development and application

    NASA Astrophysics Data System (ADS)

    Jin, W.; Ho, H. L.

    2008-12-01

    This paper reports recent development and application of optical fiber gas sensors using absorption spectroscopy, including open-path gas sensors using fiber coupled micro-optic cells and photonic bandgap (PBG) fibers. A fiber-optic sensor system capable of detecting dissolved fault gases in oil-insulated equipment in power industry is presented. The gases include methane (CH4), acetylene (C2H2) and ethylene (C2H4). In addition, the development of gas sensor using PBG fiber will be reported.

  14. Fiber Optic Detector For Liquid Chemical Leaks

    NASA Astrophysics Data System (ADS)

    Luukkala, Mauri; Raatikainen, Pekka; Salo, Olli

    1989-10-01

    This paper describes a simple and economical sensor which employs fiber optics to detect the presence of hazardous liquid chemicals, particularly undiluted hydrocarbons. The device is best suited to monitor the interstitial space of double walled underground storage tanks. Because the sensor is plastic and is situated at the end of a passive and insulating optical fiber the sensor can be considered inherently safe. The optical fiber used for this device can be up to several hundred meters long.

  15. Fiber-optic holography employing multiple beam fringe stabilization and object/reference beam intensity variability.

    PubMed

    Muhs, J D; Leilabady, P A; Corke, M

    1988-09-01

    The use of fiber optics in the field of optical holography is discussed with emphasis on the design of systems used to overcome several inherent shortcomings associated with fiber-optic holographic systems. Specifically, random environmentally induced optical phase changes within the fiber are minimized by employing a Michelson interferometer in conjunction with a closed loop feedback system. Furthermore, by using several passive single-mode couplers, complete object illumination via several illumination fibers is observed. Finally, by implementing a Mach-Zehnder interferometric technique, control of the object and reference beam intensity ratios in a fiber-optic holographic system can be accomplished. The resulting schemes are very stable and highly versatile systems suitable for remote holographic interferometric sensing and other applications where conventional holography techniques are impractical. Experimental results on fringe visibility, fringe stability, and the stabilization of object/reference beam intensity ratios are also given along with a composite summary of the overall system constraints associated with fiber-optic holographic systems.

  16. Fiber optic multimode displacement sensor

    NASA Astrophysics Data System (ADS)

    Fisher, Karl A.; Jarzynski, Jacek

    1996-04-01

    An underwater Optical Motion Sensor (OMS) based on a design first presented by W. B. Spillman, Schlieren multimode fiber-optic hydrophone, Applied Physics Letters 37(2), 15 July 1980, p. 145-146 is described. The displacement sensor uses the same acoustooptical intensity modulation mechanism as Spillman, however the sensing mechanism is isolated from the ambient fluid environment by a small cylindrical aluminum enclosure (1″ OD×3/4″). The enclosure contains an inertial mass and the fiber collimators. The inertial mass is suspended in the center of the enclosure by three small wires rigidly mounted to the walls. The mass and wires act as a cantilever beam system with a mechanical resonance near 100 Hz. The transduction mechanism consists of two opposed optical gratings aligned and positioned between the fiber collimators. One grating is mounted on the inertial mass while the other is mounted on the lower end cap of the enclosure. Relative motion between the gratings causes a modulation of the light transmitted through the gratings. The modulated beam is focused onto a photodetector and converted to electric current. The frequency response is flat from 200 Hz-9 kHz with a minimum detectable displacement of 0.002 A and the dynamic range is 136 dB. The small size and light weight give the sensor an effective density of 1.08 g/cm3 making it almost neutrally buoyant in water. This in conjunction with the performance characteristics make this sensor suitable for use in acoustical sensing applications.

  17. Optical solitons in PT-symmetric nonlinear couplers with gain and loss

    NASA Astrophysics Data System (ADS)

    Alexeeva, N. V.; Barashenkov, I. V.; Sukhorukov, Andrey A.; Kivshar, Yuri S.

    2012-06-01

    We study spatial and temporal solitons in the PT symmetric coupler with gain in one waveguide and loss in the other. Stability properties of the high- and low-frequency solitons are found to be completely determined by a single combination of the soliton's amplitude and the gain-loss coefficient of the waveguides. The unstable perturbations of the high-frequency soliton break the symmetry between its active and lossy components which results in a blowup of the soliton or a formation of a long-lived breather state. The unstable perturbations of the low-frequency soliton separate its two components in space, thereby blocking the power drainage of the active component and cutting the power supply to the lossy one. Eventually this also leads to the blowup or breathing.

  18. The silicon mold fabrication of a kind of micro-optical resonator and coupler

    NASA Astrophysics Data System (ADS)

    Ju, Hui; Ohta, Takayuki; Takao, Satoru; Ito, Masafumi; Sasaki, Minoru; Hane, Kazuhiro; Hori, Masaru

    2007-02-01

    We present the fabrication of a kind of hexagonal and triangular cavity mold, which can cast Polymethyl Methacrylate (PMMA) resonators and couplers. The mold is designed on (111) silicon wafer according to its crystal structure and anisotropic etching properties in the etchant of ethylene diamine, pyrocatechol, and water (EDP/EPW), forming sidewalls by six {110} crystal surfaces, which are perpendicular to the (111) plane and constitute precise hexagons and triangles. The RIE-ICP etching is used to define the depth of the triangle and hexagonal cavities, and the following EDP etching smoothes the sidewalls of cavities. Only high temperature EDP etching is proved to be able to get smooth sidewalls. Before etching, the wafer is aligned to the right crystal orientation by pre-etched marks. The etched results of different geometrical cavities are analyzed and discussed based on the crystal structure.

  19. Ultrasound generation from an optical fiber sidewall

    NASA Astrophysics Data System (ADS)

    Zhou, Jingcheng; Wu, Nan; Bi, Siwen; Wang, Xingwei

    2016-04-01

    Ultrasound generation from an optical fiber, based on the photoacoustic principle, could have broad applications, such as ultrasound nondestructive test (NDT) and biomedical ultrasound imaging. There are many advantages of these fiber-optic ultrasonic transducers, such as small size, light weight, ease of use, and immunity to electromagnetic interference. This paper will demonstrate a novel structure which the ultrasound signal is generated on the sidewall of the fiber. Two experimental configurations of the fiber-optic sidewall ultrasonic transducer are discussed. One is that a photoacoustic material is directly coated on the sidewall of the optical fiber. The other one is that the photoacoustic material is directly coated on an aluminum plate and the sidewall fiber is buried in the material. By using this novel sidewall ultrasound generator, we can effectively generate ultrasound signal at multiple, particular locations along one fiber.

  20. Thin film technologies for optoelectronic components in fiber optic communication

    NASA Astrophysics Data System (ADS)

    Perinati, Agostino

    1998-02-01

    will grow at an annual average rate of 22 percent from 1.3 million fiber-km in 1995 to 3.5 million fiber-km in 2000. The worldwide components market-cable, transceivers and connectors - 6.1 billion in 1994, is forecasted to grow and show a 19 percent combined annual growth rate through the year 2000 when is predicted to reach 17.38 billion. Fiber-in-the-loop and widespread use of switched digital services will dominate this scenario being the fiber the best medium for transmitting multimedia services. As long as communication will partially replace transportation, multimedia services will push forward technology for systems and related components not only for higher performances but for lower cost too in order to get the consumers wanting to buy the new services. In the long distance transmission area (trunk network) higher integration of electronic and optoelectronic functions are required for transmitter and receiver in order to allow for higher system speed, moving from 2.5 Gb/s to 5, 10, 40 Gb/s; narrow band wavelength division multiplexing (WDM) filters are required for higher transmission capacity through multiwavelength technique and for optical amplifier. In the access area (distribution network) passive components as splitters, couplers, filters are needed together with optical amplifiers and transceivers for point-to-multipoint optical signal distribution: main issue in this area is the total cost to be paid by the customer for basic and new services. Multimedia services evolution, through fiber to the home and to the desktop approach, will be mainly affected by the availability of technologies suitable for component consistent integration, high yield manufacturing processes and final low cost. In this paper some of the optoelectronic components and related thin film technologies expected to mainly affect the fiber optic transmission evolution, either for long distance telecommunication systems or for subscriber network, are presented.

  1. Coated fiber tips for optical instrumentation

    NASA Astrophysics Data System (ADS)

    Barton, John B.; Chanda, Sheetal; Locknar, Sarah A.; Carver, Gary E.

    2016-03-01

    Compact optical systems can be fabricated by integrating coatings on fiber tips. Examples include fiber lasers, fiber interferometers, fiber Raman probes, fiber based spectrometers, and anti-reflected endoscopes. These interference filters are applied to exposed tips - either connectorized or cleaved. Coatings can also be immersed within glass by depositing on one tip and connecting to another uncoated tip. This paper addresses a fiber spectrometer for multispectral imaging - useful in several fields including biomedical scanning, flow cytometry, and remote sensing. Our spectrometer integrates serial arrays of reflecting fiber tips, delay lines between these elements, and a single element detector.

  2. Sensitive fiber-optic immunoassay

    NASA Astrophysics Data System (ADS)

    Walczak, Irene M.; Love, Walter F.; Slovacek, Rudolf E.

    1991-07-01

    The principles of evanescent wave theory were applied to an immunological sensor for detecting the cardiac-specific isoenzyme creatine kinase-MB (CK-MB). The detection of the CK-MB isoenzyme is used in conjunction with the total CK measurement in the diagnosis of acute myocardial infarction. The clinical range for CK-MB is from 2-100 ng/ml. Previous work which utilized the fluorophor, Fluorescein isothiocyanate (FITC), was able to discriminate between 0 and 3 ng/ml CK-MB. Use of the fluorophor B-phycoerythrin (BPE) increased the assay sensitivity to 0.1 ng/ml CK-MB. The data was collected for 15 minutes using an optical launch and collection angle of 25 degree(s). This fiber optic based system is homogeneous and requires no subsequent washing, handling, or processing steps after exposure to the sample.

  3. Method for optical and mechanically coupling optical fibers

    DOEpatents

    Toeppen, J.S.

    1996-10-01

    A method and apparatus are disclosed for splicing optical fibers. A fluorescing solder glass frit having a melting point lower than the melting point of first and second optical fibers is prepared. The solder glass frit is then attached to the end of the first optical fiber and/or the end of the second optical fiber. The ends of the optical fibers are aligned and placed in close proximity to each other. The solder glass frit is then heated to a temperature which is lower than the melting temperature of the first and second optical fibers, but which is high enough to melt the solder glass frit. A force is applied to the first and second optical fibers pushing the ends of the fibers towards each other. As the solder glass flit becomes molten, the layer of molten solder glass is compressed into a thin layer between the first and second optical fibers. The thin compressed layer of molten solder glass is allowed to cool such that the first and second optical fibers are bonded to each other by the hardened layer of solder glass. 6 figs.

  4. Optical pulse generation using fiber lasers and integrated optics

    SciTech Connect

    Wilcox, R.B.; Browning, D.F.; Burkhart, S.C.; VanWonterghem, B.W.

    1995-03-27

    We have demonstrated an optical pulse forming system using fiber and integrated optics, and have designed a multiple-output system for a proposed fusion laser facility. Our approach is an advancement over previous designs for fusion lasers, and an unusual application of fiber lasers and integrated optics.

  5. Fiber-optic Michelson interferometer using an optical power divider.

    PubMed

    Imai, M; Ohashi, T; Ohtsuka, Y

    1980-10-01

    A fiber-optic interferometer consisting of a multimode fiber-optical power divider was constructed in the Michelson arrangement and applied to measure a micrometer-order displacement of the vibrating object based on an optical homodyne technique. Improvement in the sensitivity of the apparatus is discussed from the viewpoint of increasing the minimum detectable beat signal.

  6. Efficient Coupler for a Bessel Beam Dispersive Element

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Iltchenko, Vladimir; Matsko, Andrey; Le, Thanh; Yu, nan; Maleki, Lute

    2008-01-01

    A document discusses overcoming efficient optical coupling to high orbital momentum modes by slightly bending the taper dispersive element. This little shape distortion is not enough to scramble the modes, but it allows the use of regular, free-beam prism coupling, fiber coupling, or planar fiber on-chip coupling with, ultimately, 100 percent efficiency. The Bessel-beam waveguide is bent near the contact with the coupler, or a curved coupler is used. In this case, every Bessel-beam mode can be successfully coupled to a collimated Gaussian beam. Recently developed Bessel-beam waveguides allow long optical delay and very high dispersion. Delay values may vary from nanoseconds to microseconds, and dispersion promises to be at 100 s/nm. Optical setup consisted of a red laser, an anamorphic prism pair, two prism couplers, and a bent, single-mode fiber attached to prisms. The coupling rate increased substantially and corresponded to the value determined by the anamorphic prism pair.

  7. DIRECTIONAL COUPLERS

    DOEpatents

    Nigg, D.J.

    1961-12-01

    A directional coupler of small size is designed. Stripline conductors of non-rectilinear configuration, and separated from each other by a thin dielectric spacer. cross each other at least at two locations at right angles, thus providing practically pure capacitive coupling which substantially eliminates undesirable inductive coupling. The conductors are sandwiched between a pair of ground planes. The coupling factor is dependent only on the thickness and dielectric constant of the dielectric spacer at the point of conductor crossover. (AEC)

  8. Two-dimensional design and analysis of trench-coupler based Silicon Mach-Zehnder thermo-optic switch.

    PubMed

    Liu, Ke; Zhang, Chenglong; Mu, Sixuan; Wang, Shuang; Sorger, Volker J

    2016-07-11

    Optical switches are key components for routing of light transmission paths in data links. Existing waveguide-based Mach-Zehnder interferometer (MZI) switches occupy a significant amount of real estate on-chip. Here we propose a compact Silicon MZI thermo-optic 2 × 2 photonic switch, consisting of two frustrated total internal reflection (TIR) trench couplers and TIR mirror-based 90° waveguide bends, forming a rectangular MZI configuration. The switch allows for reconfigurable design footprints due to selected control of the optical signal being transmitted and reflected at the 90° crosses and bends. Our analysis results show that the switch exhibits a chip size of 42 µm × 42 µm, the extinction ratio of ~14 dB, the rise and fall time of 20 μs and 16 μs, and the low switching voltage and power of 0.35 V and 26 mW, respectively. This device configuration can readily scale its pattern at the two-dimensional directions, making them attractive for Silicon photonic integrated circuits.

  9. Waveguide Studies for Fiber Optics and Optical Signal Processing Applications.

    DTIC Science & Technology

    1980-04-01

    beam expander is shown in Fig. 2 -i. The beam, which is expanded to approximately 100 Wm, can be deflected acousto - optically to make a spectrum analyzer...3 2 . DBR Lasers for Fiber Optics and Optical Signal Processing Sources ......... ................. 4 4. Studies of LiNbO 3...6 Chapter 1. Wave Beam Expansion ....... ............. 9 Chapter 2 . DBR Lasers for Fiber Optics and Optical Signal Processing Sources

  10. Online fiber-optic spectrophotometry

    SciTech Connect

    Van Hare, D.R.; O'Rourke, P.E.; Prather, W.S.

    1989-01-01

    The Savannah River Plant operates two radio-chemical separations areas to recover uranium and plutonium from nuclear reactor fuel and target assemblies. Chemical processes in these areas are controlled based on laboratory analysis of samples extracted from the process. While analytical results from the laboratory are reliable, the process of pulling samples, transporting them to the laboratory, analyzing them, and then reporting results is time consuming and potentially exposes many workers to highly radioactive solutions. To improve the timeliness of chemical information and reduce personnel radiation exposure, the Savannah River Laboratory has developed an online fiber optic spectrophotometer which combines three new technologies, fiber optics, diode array spectrophotometers, and multivariate data analysis. The analyzer monitors the uranium and nitrate concentration of seven aqueous process streams in a uranium purification process. The analyzer remotely controls the sampling of each process stream and monitors the relative flow rate through each sampler. Spectrophotometric data from the analyzer is processed by multivariate data analysis to give both uranium and nitrate concentrations as well as an indication of the quality of the data.

  11. Multi-parameter optical fiber sensor based on enhanced multimode interference

    NASA Astrophysics Data System (ADS)

    Luo, Yiyang; Xia, Li; Yu, Can; Li, Wei; Sun, Qizhen; Wang, Yuanwu; Liu, Deming

    2015-06-01

    In this paper, a multi-parameter optical fiber sensor based on all-fiber in-line single-mode-multimode-no-core-single-mode (SMNS) structure is proposed and experimentally demonstrated. A section of multimode fiber (MMF) is utilized as the mode coupler to enhance the multimode interference (MMI). A 58.5 mm long no-core fiber (NCF) acts as the sensing head, which is modified by the surrounding medium. The experimental results exhibit that the sensor possesses a water level sensitivity of 215.98 pm/mm by monitoring the wavelength shift at 1586.03 nm, and -0.11 dB/mm of the power attenuation at the wavelength of 1600.05 nm with a measurement range of 58.33 mm. At the same time, the RI sensitivities of 131.71 nm/RIU and the axial strain sensitivity of -1.21 pm/με are also obtained.

  12. All-optical photoacoustic imaging system using fiber ultrasound probe and hollow optical fiber bundle.

    PubMed

    Miida, Yusuke; Matsuura, Yuji

    2013-09-23

    An all-optical 3D photoacoustic imaging probe that consists of an optical fiber probe for ultrasound detection and a bundle of hollow optical fibers for excitation of photoacoustic waves was developed. The fiber probe for ultrasound is based on a single-mode optical fiber with a thin polymer film attached to the output end surface that works as a Fabry Perot etalon. The input end of the hollow fiber bundle is aligned so that each fiber in the bundle is sequentially excited. A thin and flexible probe can be obtained because the probe system does not have a scanning mechanism at the distal end.

  13. Calibration and deployment of a fiber-optic sensing system for monitoring debris flows.

    PubMed

    Huang, Ching-Jer; Chu, Chung-Ray; Tien, Tsung-Mo; Yin, Hsiao-Yuen; Chen, Ping-Sen

    2012-01-01

    This work presents a novel fiber-optic sensing system, capable of monitoring debris flows or other natural hazards that produce ground vibrations. The proposed sensing system comprises a demodulator (BraggSCOPE, FS5500), which includes a broadband light source and a data logger, a four-port coupler and four Fiber Bragg Grating (FBG) accelerometers. Based on field tests, the performance of the proposed fiber-optic sensing system is compared with that of a conventional sensing system that includes a geophone or a microphone. Following confirmation of the reliability of the proposed sensing system, the fiber-optic sensing systems are deployed along the Ai-Yu-Zi and Chu-Shui Creeks in Nautou County of central Taiwan for monitoring debris flows. Sensitivity test of the deployed fiber-optic sensing system along the creek banks is also performed. Analysis results of the seismic data recorded by the systems reveal in detail the frequency characteristics of the artificially generated ground vibrations. Results of this study demonstrate that the proposed fiber-optic sensing system is highly promising for use in monitoring natural disasters that generate ground vibrations.

  14. Calibration and Deployment of a Fiber-Optic Sensing System for Monitoring Debris Flows

    PubMed Central

    Huang, Ching-Jer; Chu, Chung-Ray; Tien, Tsung-Mo; Yin, Hsiao-Yuen; Chen, Ping-Sen

    2012-01-01

    This work presents a novel fiber-optic sensing system, capable of monitoring debris flows or other natural hazards that produce ground vibrations. The proposed sensing system comprises a demodulator (BraggSCOPE, FS5500), which includes a broadband light source and a data logger, a four-port coupler and four Fiber Bragg Grating (FBG) accelerometers. Based on field tests, the performance of the proposed fiber-optic sensing system is compared with that of a conventional sensing system that includes a geophone or a microphone. Following confirmation of the reliability of the proposed sensing system, the fiber-optic sensing systems are deployed along the Ai-Yu-Zi and Chu-Shui Creeks in Nautou County of central Taiwan for monitoring debris flows. Sensitivity test of the deployed fiber-optic sensing system along the creek banks is also performed. Analysis results of the seismic data recorded by the systems reveal in detail the frequency characteristics of the artificially generated ground vibrations. Results of this study demonstrate that the proposed fiber-optic sensing system is highly promising for use in monitoring natural disasters that generate ground vibrations. PMID:22778616

  15. Optics in Microstructured and Photonic Crystal Fibers

    NASA Astrophysics Data System (ADS)

    Knight, J. C.

    2008-10-01

    The development of optical fibers with two-dimensional patterns of air holes running down their length has reinvigorated research in the field of fiber optics. It has greatly—and fundamentally—broadened the range of specialty optical fibers, by demonstrating that optical fibers can be more "special" than previously thought. Fibers with air cores have made it possible to deliver energetic femtosecond-scale optical pulses, transform limited, as solitons, using single-mode fiber. Other fibers with anomalous dispersion at visible wavelengths have spawned a new generation of single-mode optical supercontinuum sources, spanning visible and near-infrared wavelengths and based on compact pump sources. A third example is in the field of fiber lasers, where the use of photonic crystal fiber concepts has led to a new hybrid laser technology, in which the very high numerical aperture available sing air holes have enabled fibers so short they are more naturally held straight than bent. This paper describes some of the basic physics and technology behind these developments, illustrated with some of the impressive demonstrations of the past 18 months.

  16. Optical Fiber Grating Hydrogen Sensors: A Review

    PubMed Central

    Dai, Jixiang; Zhu, Li; Wang, Gaopeng; Xiang, Feng; Qin, Yuhuan; Wang, Min; Yang, Minghong

    2017-01-01

    In terms of hydrogen sensing and detection, optical fiber hydrogen sensors have been a research issue due to their intrinsic safety and good anti-electromagnetic interference. Among these sensors, hydrogen sensors consisting of fiber grating coated with sensitive materials have attracted intensive research interests due to their good reliability and distributed measurements. This review paper mainly focuses on optical fiber hydrogen sensors associated with fiber gratings and various materials. Their configurations and sensing performances proposed by different groups worldwide are reviewed, compared and discussed in this paper. Meanwhile, the challenges for fiber grating hydrogen sensors are also addressed. PMID:28287499

  17. Optical Fiber Grating Hydrogen Sensors: A Review.

    PubMed

    Dai, Jixiang; Zhu, Li; Wang, Gaopeng; Xiang, Feng; Qin, Yuhuan; Wang, Min; Yang, Minghong

    2017-03-12

    In terms of hydrogen sensing and detection, optical fiber hydrogen sensors have been a research issue due to their intrinsic safety and good anti-electromagnetic interference. Among these sensors, hydrogen sensors consisting of fiber grating coated with sensitive materials have attracted intensive research interests due to their good reliability and distributed measurements. This review paper mainly focuses on optical fiber hydrogen sensors associated with fiber gratings and various materials. Their configurations and sensing performances proposed by different groups worldwide are reviewed, compared and discussed in this paper. Meanwhile, the challenges for fiber grating hydrogen sensors are also addressed.

  18. Cavity-enhanced spectroscopy in optical fibers.

    PubMed

    Gupta, Manish; Jiao, Hong; O'Keefe, Anthony

    2002-11-01

    Cavity-enhanced methods have been extended to fiber optics by use of fiber Bragg gratings (FBGs) as reflectors. High-finesse fiber cavities were fabricated from FBGs made in both germanium/boron-co-doped photosensitive fiber and hydrogen-loaded Corning SMF-28 fiber. Optical losses in these cavities were determined from the measured Fabry-Perot transmission spectra and cavity ring-down spectroscopy. For a 10-m-long single-mode fiber cavity, ring-down times in excess of 2 ms were observed at 1563.6 nm, and individual laser pulses were resolved. An evanescent-wave access block was produced within a fiber cavity, and an enhanced sensitivity to optical loss was observed as the external medium's refractive index was altered.

  19. Optical fiber sensors for harsh environments

    DOEpatents

    Xu, Juncheng; Wang, Anbo

    2007-02-06

    A diaphragm optic sensor comprises a ferrule including a bore having an optical fiber disposed therein and a diaphragm attached to the ferrule, the diaphragm being spaced apart from the ferrule to form a Fabry-Perot cavity. The cavity is formed by creating a pit in the ferrule or in the diaphragm. The components of the sensor are preferably welded together, preferably by laser welding. In some embodiments, the entire ferrule is bonded to the fiber along the entire length of the fiber within the ferrule; in other embodiments, only a portion of the ferrule is welded to the fiber. A partial vacuum is preferably formed in the pit. A small piece of optical fiber with a coefficient of thermal expansion chosen to compensate for mismatches between the main fiber and ferrule may be spliced to the end of the fiber.

  20. Fiber Optics: A New World of Possibilities in Light.

    ERIC Educational Resources Information Center

    Hutchinson, John

    1990-01-01

    The background and history of light and fiber optics are discussed. Applications for light passed either directly or indirectly through optical fibers are described. Suggestions for science activities that use fiber optics are provided. (KR)

  1. Integrated asymmetric vertical coupler pressure sensors

    NASA Astrophysics Data System (ADS)

    Kiyat, Isa; Kocabas, Askin; Akcag, Imran; Aydinli, Atilla

    2004-08-01

    Design and analysis of a novel pressure sensor based on a silicon-on-insulator asymmetric integrated vertical coupler is presented. The coupler is composed of a single mode low index waveguide and a thin silicon slab. Wavelength selective optical modulation of asymmetric vertical coupler is examined in detail. Its potential for sensing applications is highlighted as an integrated optical pressure sensor which can be realized by standard silicon micro-fabrication. Sensitivity of transmission of such couplers on refractive index change of silicon slab ensures that they are good candidates for applications requiring high sensitivities.

  2. Electrothermal MEMS fiber scanner for optical endomicroscopy.

    PubMed

    Seo, Yeong-Hyeon; Hwang, Kyungmin; Park, Hyeon-Cheol; Jeong, Ki-Hun

    2016-02-22

    We report a novel MEMS fiber scanner with an electrothermal silicon microactuator and a directly mounted optical fiber. The microactuator comprises double hot arm and cold arm structures with a linking bridge and an optical fiber is aligned along a silicon fiber groove. The unique feature induces separation of resonant scanning frequencies of a single optical fiber in lateral and vertical directions, which realizes Lissajous scanning during the resonant motion. The footprint dimension of microactuator is 1.28 x 7 x 0.44 mm3. The resonant scanning frequencies of a 20 mm long optical fiber are 239.4 Hz and 218.4 Hz in lateral and vertical directions, respectively. The full scanned area indicates 451 μm x 558 μm under a 16 Vpp pulse train. This novel laser scanner can provide many opportunities for laser scanning endomicroscopic applications.

  3. Assessment of fiber optic pressure sensors

    SciTech Connect

    Hashemian, H.M.; Black, C.L.; Farmer, J.P.

    1995-04-01

    This report presents the results of a six-month Phase 1 study to establish the state-of-the-art in fiber optic pressure sensing and describes the design and principle of operation of various fiber optic pressure sensors. This study involved a literature review, contact with experts in the field, an industrial survey, a site visit to a fiber optic sensor manufacturer, and laboratory testing of a fiber optic pressure sensor. The laboratory work involved both static and dynamic performance tests. In addition, current requirements for environmental and seismic qualification of sensors for nuclear power plants were reviewed to determine the extent of the qualification tests that fiber optic pressure sensors may have to meet before they can be used in nuclear power plants. This project has concluded that fiber optic pressure sensors are still in the research and development stage and only a few manufacturers exist in the US and abroad which supply suitable fiber optic pressure sensors for industrial applications. Presently, fiber optic pressure sensors are mostly used in special applications for which conventional sensors are not able to meet the requirements.

  4. Fiber optic sensors for gas turbine control

    NASA Technical Reports Server (NTRS)

    Shu, Emily Yixie (Inventor); Brown, Dale Marius (Inventor); Petrucco, Louis Jacob (Inventor); Lovett, Jeffery Allan (Inventor); Daum, Wolfgang (Inventor); Dunki-Jacobs, Robert John (Inventor)

    2003-01-01

    An apparatus for detecting flashback occurrences in a premixed combustor system having at least one fuel nozzle includes at least one photodetector and at least one fiber optic element coupled between the at least one photodetector and a test region of the combustor system wherein a respective flame of the fuel nozzle is not present under normal operating conditions. A signal processor monitors a signal of the photodetector. The fiber optic element can include at least one optical fiber positioned within a protective tube. The fiber optic element can include two fiber optic elements coupled to the test region. The optical fiber and the protective tube can have lengths sufficient to situate the photodetector outside of an engine compartment. A plurality of fuel nozzles and a plurality of fiber optic elements can be used with the fiber optic elements being coupled to respective fuel nozzles and either to the photodetector or, wherein a plurality of photodetectors are used, to respective ones of the plurality of photodetectors. The signal processor can include a digital signal processor.

  5. Triboluminescent Fiber-Optic Sensors Measure Stresses

    NASA Technical Reports Server (NTRS)

    Rogowski, Robert S.

    1994-01-01

    Triboluminescence exploited in fiber-optic sensor system for measuring changes in pressures, strains, vibrations, and acoustic emissions, in structural members. Sensors embedded in members for in situ monitoring of condition of structure. System passive in sense no source of radiation required to interrogate optical fiber. Technique has potential for wide range of applications in which detection and measurement of structural stress required.

  6. Fiber optic sensors for gas turbine control

    NASA Technical Reports Server (NTRS)

    Shu, Emily Yixie (Inventor); Petrucco, Louis Jacob (Inventor); Daum, Wolfgang (Inventor)

    2005-01-01

    An apparatus for detecting flashback occurrences in a premixed combustor system having at least one fuel nozzle includes at least one photodetector and at least one fiber optic element coupled between the at least one photodetector and a test region of the combustor system wherein a respective flame of the fuel nozzle is not present under normal operating conditions. A signal processor monitors a signal of the photodetector. The fiber optic element can include at least one optical fiber positioned within a protective tube. The fiber optic element can include two fiber optic elements coupled to the test region. The optical fiber and the protective tube can have lengths sufficient to situate the photodetector outside of an engine compartment. A plurality of fuel nozzles and a plurality of fiber optic elements can be used with the fiber optic elements being coupled to respective fuel nozzles and either to the photodetector or, wherein a plurality of photodetectors are used, to respective ones of the plurality of photodetectors. The signal processor can include a digital signal processor.

  7. Fiber optic sensors for gas turbine control

    NASA Technical Reports Server (NTRS)

    Shu, Emily Yixie (Inventor); Brown, Dale Marius (Inventor); Petrucco, Louis Jacob (Inventor); Lovett, Jeffery Allan (Inventor); Daum, Wolfgang (Inventor); Dunki-Jacobs, Robert John (Inventor)

    1999-01-01

    An apparatus for detecting flashback occurrences in a premixed combustor system having at least one fuel nozzle includes at least one photodetector and at least one fiber optic element coupled between the at least one photodetector and a test region of the combustor system wherein a respective flame of the fuel nozzle is not present under normal operating conditions. A signal processor monitors a signal of the photodetector. The fiber optic element can include at least one optical fiber positioned within a protective tube. The fiber optic element can include two fiber optic elements coupled to the test region. The optical fiber and the protective tube can have lengths sufficient to situate the photodetector outside of an engine compartment. A plurality of fuel nozzles and a plurality of fiber optic elements can be used with the fiber optic elements being coupled to respective fuel nozzles and either to the photodetector or, wherein a plurality of photodetectors are used, to respective ones of the plurality of photodetectors. The signal processor can include a digital signal processor.

  8. Fiber optic applications for laser polarized targets

    SciTech Connect

    Cummings, W.J.; Kowalczyk, R.S.

    1997-10-01

    For the past two years, the laser polarized target group at Argonne has been used multi-mode fiber optic patch cords for a variety of applications. In this paper, the authors describe the design for transporting high power laser beams with optical fibers currently in use at IUCF.

  9. Fiber-optic liquid level sensor

    DOEpatents

    Weiss, Jonathan D.

    1991-01-01

    A fiber-optic liquid level sensor measures the height of a column of liquid through the hydrostatic pressure it produces. The sensor employs a fiber-optic displacement sensor to detect the pressure-induced displacement of the center of a corrugated diaphragm.

  10. Fiber-Optic Applications For Launch Vehicles

    NASA Astrophysics Data System (ADS)

    Curran, Mark E.; Clark, Timothy E.

    Conventional data buses, telemetry links, and sensors using wire harnesses as the transmission media suffer from numerous shortcomings, especially when utilized in spacecraft. This paper describes fiber optic networks which could be implemented in launch vehicles in the near-term. Special emphasis will be placed on the increase in reliability which fiber optics affords over conventional cable/wire approaches.

  11. Modelling a nonlinear optical switching in a standard photonic crystal fiber infiltrated with carbon disulfide

    NASA Astrophysics Data System (ADS)

    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.

  12. Metal-Coated Optical Fibers for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Zeakes, Jason; Murphy, Kent; Claus, Richard; Greene, Jonathan; Tran, Tuan

    1996-01-01

    This poster will highlight on-going research at the Virginia Tech Fiber & Electro-Optics Research Center (FEORC) in the area of thin films on optical fibers. Topics will include the sputter deposition of metals and metal; alloys onto optical fiber and fiber optic sensors for innovative applications. Specific information will be available on thin film fiber optic hydrogen sensors, corrosion sensors, and metal-coated optical fiber for high temperature aerospace applications.

  13. Eliminating crystals in non-oxide optical fiber preforms and optical fibers

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R. (Inventor); Tucker, Dennis S. (Inventor)

    2010-01-01

    A method is provided for eliminating crystals in non-oxide optical fiber preforms as well as optical fibers drawn therefrom. The optical-fiber-drawing axis of the preform is aligned with the force of gravity. A magnetic field is applied to the preform as it is heated to at least a melting temperature thereof. The magnetic field is applied in a direction that is parallel to the preform's optical-fiber-drawing axis. The preform is then cooled to a temperature that is less than a glass transition temperature of the preform while the preform is maintained in the magnetic field. When the processed preform is to have an optical fiber drawn therefrom, the preform's optical-fiber-drawing axis is again aligned with the force of gravity and a magnetic field is again applied along the axis as the optical fiber is drawn from the preform.

  14. Fiber optic sensors for corrosion detection

    NASA Technical Reports Server (NTRS)

    Smith, Alphonso C.

    1993-01-01

    The development of fiber optic sensors for the detection of a variety of material parameters has grown tremendously over the past several years. Additionally, the potential for analytical applications of fiber optic sensors have become more widely used. New pH sensors have also been developed using fiber optic techniques to detect fluorescence characteristics from immobilized fluorogenic reagent chemicals. The primary purpose of this research was to investigate the feasibility of using fiber optic sensors to detect the presence of Al(sup 3+) ions made in the process of environmental corrosion of aluminum materials. The Al(sup 3+) ions plus a variety of other type of metal ions can be detected using analytical techniques along with fiber optic sensors.

  15. Power system applications of fiber optics

    NASA Technical Reports Server (NTRS)

    Kirkham, H.; Johnston, A.; Lutes, G.; Daud, T.; Hyland, S.

    1984-01-01

    Power system applications of optical systems, primarily using fiber optics, are reviewed. The first section reviews fibers as components of communication systems. The second section deals with fiber sensors for power systems, reviewing the many ways light sources and fibers can be combined to make measurements. Methods of measuring electric field gradient are discussed. Optical data processing is the subject of the third section, which begins by reviewing some widely different examples and concludes by outlining some potential applications in power systems: fault location in transformers, optical switching for light fired thyristors and fault detection based on the inherent symmetry of most power apparatus. The fourth and final section is concerned with using optical fibers to transmit power to electric equipment in a high voltage situation, potentially replacing expensive high voltage low power transformers. JPL has designed small photodiodes specifically for this purpose, and fabricated and tested several samples. This work is described.

  16. Liquid crystal optical fibers for sensing applications

    NASA Astrophysics Data System (ADS)

    Choudhury, P. K.

    2013-09-01

    Propagation characteristics of optical fibers are greatly dependent on materials, which the guides are comprised of. Varieties of materials have been developed and investigated for their usage in fabricating optical fibers for specific applications. Within the context, a liquid crystal medium is both inhomogeneous and optically anisotropic, and fibers made of such mediums are greatly useful. Also, liquid crystals exhibit strong electro-optic behavior, which allows alternation in their optical properties under the influence of external electric fields. These features make liquid crystal fibers greatly important for optical applications. The present communication is aimed at providing a glimpse of the efficacy of liquid crystals and/or fibers made of liquid crystals, followed by the analytical investigation of wave propagation through such guides. The sustainment of modes is explored in these fibers under varying fiber dimensions, and the novelty is discussed. The case of tapered liquid crystal fibers is also briefly discussed highlighting the usefulness. Control on the dispersion characteristics of such fibers may be imposed by making the guide even more complex; the possibility of devising such options is also touched upon.

  17. Spontaneous inelastic Rayleigh scattering in optical fibers.

    PubMed

    Okusaga, Olukayode; Cahill, James P; Docherty, Andrew; Menyuk, Curtis R; Zhou, Weimin

    2013-02-15

    Rayleigh scattering (RS) adds noise to signals that are transmitted over optical fibers and other optical waveguides. This noise can be the dominant noise source in a range between 10 Hz and 100 kHz from the carrier and can seriously degrade the performance of optical systems that require low close-in noise. Using heterodyne techniques, we demonstrate that the backscattered close-in noise spectrum in optical fibers is symmetric about the carrier and grows linearly with both input power and fiber length. These results indicate that the RS is spontaneous and is due to finite-lifetime thermal fluctuations in the glass.

  18. Improved Optical-Fiber Temperature Sensors

    NASA Technical Reports Server (NTRS)

    Rogowski, Robert S.; Egalon, Claudio O.

    1993-01-01

    In optical-fiber temperature sensors of proposed type, phosphorescence and/or fluorescence in temperature-dependent coating layers coupled to photodetectors. Phosphorescent and/or fluorescent behavior(s) of coating material(s) depend on temperature; coating material or mixture of materials selected so one can deduce temperature from known temperature dependence of phosphorescence and/or fluorescence spectrum, and/or characteristic decay of fluorescence. Basic optical configuration same as that of optical-fiber chemical detectors described in "Making Optical-Fiber Chemical Detectors More Sensitive" (LAR-14525).

  19. Fiber optic sensors for smart taxiways

    NASA Astrophysics Data System (ADS)

    Janzen, Douglas D.; Fuerstenau, Norbert; Goetze, Wolfgang

    1995-09-01

    Fiber-optic sensors could offer advantages in the field of airport ground traffic monitoring: immunity to electromagnetic interference, installation without costly and time consuming airfield closures, and low loss, low noise optical connection between sensors and signal processing equipment. This paper describes fiber-optic sensors developed for airport taxiway monitoring and the first steps toward their installation in an experimental surface movement guidance and control system at the Braunschweig airport. Initial results obtained with fiber- optic light barriers and vibration sensors are reported. The feasibility of employing interferometric strain gauges for this application will be discussed based on sensor characteristics obtained through measurements of strain in an aircraft structure in flight.

  20. Optical sensors based on plastic fibers.

    PubMed

    Bilro, Lúcia; Alberto, Nélia; Pinto, João L; Nogueira, Rogério

    2012-01-01

    The recent advances of polymer technology allowed the introduction of plastic optical fiber in sensor design. The advantages of optical metrology with plastic optical fiber have attracted the attention of the scientific community, as they allow the development of low-cost or cost competitive systems compared with conventional technologies. In this paper, the current state of the art of plastic optical fiber technology will be reviewed, namely its main characteristics and sensing advantages. Several measurement techniques will be described, with a strong focus on interrogation approaches based on intensity variation in transmission and reflection. The potential applications involving structural health monitoring, medicine, environment and the biological and chemical area are also presented.

  1. Microbend fiber-optic temperature sensor

    DOEpatents

    Weiss, J.D.

    1995-05-30

    A temperature sensor is made of optical fiber into which quasi-sinusoidal microbends have been permanently introduced. In particular, the present invention includes a graded-index optical fiber directing steady light through a section of the optical fiber containing a plurality of permanent microbends. The microbend section of the optical fiber is contained in a thermally expansive sheath, attached to a thermally expansive structure, or attached to a bimetallic element undergoing temperature changes and being monitored. The microbend section is secured to the thermally expansive sheath which allows the amplitude of the microbends to decrease with temperature. The resultant increase in the optical fiber`s transmission thus allows temperature to be measured. The plural microbend section of the optical fiber is secured to the thermally expansive structure only at its ends and the microbends themselves are completely unconstrained laterally by any bonding agent to obtain maximum longitudinal temperature sensitivity. Although the permanent microbends reduce the transmission capabilities of fiber optics, the present invention utilizes this phenomenon as a transduction mechanism which is optimized to measure temperature. 5 figs.

  2. Harsh environment fiber optic connectors/testing

    NASA Astrophysics Data System (ADS)

    Parker, Douglas A.

    2014-09-01

    Fiber optic systems are used frequently in military, aerospace and commercial aviation programs. There is a long history of implementing fiber optic data transfer for aircraft control, for harsh environment use in local area networks and more recently for in-flight entertainment systems. The advantages of fiber optics include high data rate capacity, low weight, immunity to EMI/RFI, and security from signal tapping. Technicians must be trained particularly to install and maintain fiber systems, but it is not necessarily more difficult than wire systems. However, the testing of the fiber optic interconnection system must be conducted in a standardized manner to assure proper performance. Testing can be conducted with slight differences in the set-up and procedure that produce significantly different test results. This paper reviews various options of interconnect configurations and discusses how these options can affect the performance, maintenance required and longevity of a fiber optic system, depending on the environment. Proper test methods are discussed. There is a review of the essentials of proper fiber optic testing and impact of changing such test parameters as input launch conditions, wavelength considerations, power meter options and the basic methods of testing. This becomes important right from the start when the supplier test data differs from the user's data check upon receiving the product. It also is important in periodic testing. Properly conducting the fiber optic testing will eliminate confusion and produce meaningful test results for a given harsh environment application.

  3. Experiments on room temperature optical fiber-fiber direct bonding

    NASA Astrophysics Data System (ADS)

    Hao, Jinping; Yan, Ping; Xiao, Qirong; Wang, Yaping; Gong, Mali

    2012-08-01

    High quality permanent connection between optical fibers is a significant issue in optics and communication. Studies on room temperature optical large diameter fiber-fiber direct bonding, which is essentially surface interactions of glass material, are presented here. Bonded fiber pairs are obtained for the first time through the bonding technics illustrated here. Two different kinds of bonding technics are provided-fresh surface (freshly grinded and polished) bonding and hydrophobic surface (activated by H2SO4 and HF) bonding. By means of fresh surface bonding, a bonded fiber pair with light transmitting efficiency of 98.1% and bond strength of 21.2 N is obtained. Besides, in the bonding process, chemical surface treatment of fibers' end surfaces is an important step. Therefore, various ways of surface treatment are analyzed and compared, based on atomic force microscopy force curves of differently disposed surfaces. According to the comparison, fresh surfaces are suggested as the prior choice in room temperature optical fiber-fiber bonding, owing to their larger adhesive force, attractive force, attractive distance, and adhesive range.

  4. In-fiber integrated chemiluminiscence online optical fiber sensor.

    PubMed

    Yang, Xinghua; Yuan, Tingting; Yang, Jun; Dong, Biao; Liu, Yanxin; Zheng, Yao; Yuan, Libo

    2013-09-01

    We report an in-fiber integrated chemiluminiscence (CL) sensor based on a kind of hollow optical fiber with a suspended inner core. The path of microfluid is realized by etching microholes for inlets and outlets on the surface of the optical fiber without damaging the inner core and then constructing a melted point beside the microhole of the outlet. When samples are injected into the fiber, the liquids can be fully mixed and form steady microflows. Simultaneously, the photon emitted from the CL reaction is efficiently coupled into the core and can be detected at the end of the optical fiber. In this Letter, the concentration of H2O2 samples is analyzed through the emission intensity of the CL reaction among H2O2, luminol, K3Fe(CN)6, and NaOH in the optical fiber. The linear sensing range of 0.1-4.0 mmol/L of H2O2 concentration is obtained. The emission intensity can be determined within 400 ms at a total flow rate of 150 μL/min. Significantly, this work presents the information of developing in-fiber integrated online analyzing devices based on optical methods.

  5. Optical fiber sensor having an active core

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio Oliveira (Inventor); Rogowski, Robert S. (Inventor)

    1993-01-01

    An optical fiber is provided. The fiber is comprised of an active fiber core which produces waves of light upon excitation. A factor ka is identified and increased until a desired improvement in power efficiency is obtained. The variable a is the radius of the active fiber core and k is defined as 2 pi/lambda wherein lambda is the wavelength of the light produced by the active fiber core. In one embodiment, the factor ka is increased until the power efficiency stabilizes. In addition to a bare fiber core embodiment, a two-stage fluorescent fiber is provided wherein an active cladding surrounds a portion of the active fiber core having an improved ka factor. The power efficiency of the embodiment is further improved by increasing a difference between the respective indices of refraction of the active cladding and the active fiber core.

  6. High performace silicon 2x2 optical switch based on a thermo-optically tunable multimode interference coupler and efficient electrodes.

    PubMed

    Rosa, Álvaro; Gutiérrez, Ana; Brimont, Antoine; Griol, Amadeu; Sanchis, Pablo

    2016-01-11

    Optical switches based on tunable multimode interference (MMI) couplers can simultaneously reduce the footprint and increase the tolerance against fabrication deviations. Here, a compact 2x2 silicon switch based on a thermo-optically tunable MMI structure with a footprint of only 0.005 mm(2) is proposed and demonstrated. The MMI structure has been optimized using a silica trench acting as a thermal isolator without introducing any substantial loss penalty or crosstalk degradation. Furthermore, the electrodes performance have significantly been improved via engineering the heater geometry and using two metallization steps. Thereby, a drastic power consumption reduction of around 90% has been demonstrated yielding to values as low as 24.9 mW. Furthermore, very fast switching times of only 1.19 µs have also been achieved.

  7. Fiber optic D dimer biosensor

    DOEpatents

    Glass, R.S.; Grant, S.A.

    1999-08-17

    A fiber optic sensor for D dimer (a fibrinolytic product) can be used in vivo (e.g., in catheter-based procedures) for the diagnosis and treatment of stroke-related conditions in humans. Stroke is the third leading cause of death in the United States. It has been estimated that strokes and stroke-related disorders cost Americans between $15-30 billion annually. Relatively recently, new medical procedures have been developed for the treatment of stroke. These endovascular procedures rely upon the use of microcatheters. These procedures could be facilitated with this sensor for D dimer integrated with a microcatheter for the diagnosis of clot type, and as an indicator of the effectiveness, or end-point of thrombolytic therapy. 4 figs.

  8. Fiber optic D dimer biosensor

    DOEpatents

    Glass, Robert S.; Grant, Sheila A.

    1999-01-01

    A fiber optic sensor for D dimer (a fibrinolytic product) can be used in vivo (e.g., in catheter-based procedures) for the diagnosis and treatment of stroke-related conditions in humans. Stroke is the third leading cause of death in the United States. It has been estimated that strokes and stroke-related disorders cost Americans between $15-30 billion annually. Relatively recently, new medical procedures have been developed for the treatment of stroke. These endovascular procedures rely upon the use of microcatheters. These procedures could be facilitated with this sensor for D dimer integrated with a microcatheter for the diagnosis of clot type, and as an indicator of the effectiveness, or end-point of thrombolytic therapy.

  9. Recent Development in Optical Fiber Biosensors

    PubMed Central

    Bosch, María Espinosa; Sánchez, Antonio Jesús Ruiz; Rojas, Fuensanta Sánchez; Ojeda, Catalina Bosch

    2007-01-01

    Remarkable developments can be seen in the field of optical fibre biosensors in the last decade. More sensors for specific analytes have been reported, novel sensing chemistries or transduction principles have been introduced, and applications in various analytical fields have been realised. This review consists of papers mainly reported in the last decade and presents about applications of optical fiber biosensors. Discussions on the trends in optical fiber biosensor applications in real samples are enumerated.

  10. Rugged fiber optic probe for raman measurement

    DOEpatents

    O'Rourke, Patrick E.; Toole, Jr., William R.; Nave, Stanley E.

    1998-01-01

    An optical probe for conducting light scattering analysis is disclosed. The probe comprises a hollow housing and a probe tip. A fiber assembly made up of a transmitting fiber and a receiving bundle is inserted in the tip. A filter assembly is inserted in the housing and connected to the fiber assembly. A signal line from the light source and to the spectrometer also is connected to the filter assembly and communicates with the fiber assembly. By using a spring-loaded assembly to hold the fiber connectors together with the in-line filters, complex and sensitive alignment procedures are avoided. The close proximity of the filter assembly to the probe tip eliminates or minimizes self-scattering generated by the optical fiber. Also, because the probe can contact the sample directly, sensitive optics can be eliminated.

  11. Optical fiber head for providing lateral viewing

    DOEpatents

    Everett, Matthew J.; Colston, Billy W.; James, Dale L.; Brown, Steve; Da Silva, Luiz

    2002-01-01

    The head of an optical fiber comprising the sensing probe of an optical heterodyne sensing device includes a planar surface that intersects the perpendicular to axial centerline of the fiber at a polishing angle .theta.. The planar surface is coated with a reflective material so that light traveling axially through the fiber is reflected transverse to the fiber's axial centerline, and is emitted laterally through the side of the fiber. Alternatively, the planar surface can be left uncoated. The polishing angle .theta. must be no greater than 39.degree. or must be at least 51.degree.. The emitted light is reflected from adjacent biological tissue, collected by the head, and then processed to provide real-time images of the tissue. The method for forming the planar surface includes shearing the end of the optical fiber and applying the reflective material before removing the buffer that circumscribes the cladding and the core.

  12. Emerging technology in fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Dyott, Richard B.

    1991-03-01

    Some recent innovations in interferoinetric fiber optic sensors include special fibers new components and sensor systems. Many of the concepts have precedents in microwaves. 1. GENERAL PRINCIPLES The application of optical fibers to sensors is diffuse compared with their application to optical communications which is essentially focused on the single problem of how to get information from A to B. A fiber sensor is viable when it can do something not possible with better than more cheaply than any existing method. The probability of the emergence of a new sensor depends on the length of time that a need for the sensor and the possibility of meeting that need have co-existed regardless of whether the need or the possibility has appeared first. 2. TYPES OF SENSOR Fiber sensors can be divided into: a) Multimode fiber sensors which depend on amplitude effects b) Single mode (single path) fiber sensors which depend on phase effects. Since multimode fiber has existed for many decades the emergence of a new multimode sensor depends mostly on the discovery of a new need for such a sensor. On the other hand single mode/single path (i. e. polarization maintaining) fiber is relatively new and so is still being applied to existing needs. This is particularly so of recent innovations in fibers and components. SPIE Vol. 1396 Applications of Optical Engineering Proceedings of OE/Midwest ''90 / 709

  13. Biodegradable polymer optical fiber (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhang, Chenji; Kalaba, Surge; Shan, Dingying; Xu, Kaitian; Yang, Jian; Liu, Zhiwen

    2016-10-01

    Biocompatible and even biodegradable polymers have unique advantages in various biomedical applications. Recent years, photonic devices fabricated using biocompatible polymers have been widely studied. In this work, we manufactured an optical fiber using biodegradable polymer POC and POMC. This step index optical fiber is flexible and easy to handle. Light was coupled into this polymer fiber by directly using objective. The fiber has a good light guiding property and an approximate loss of 2db/cm. Due to the two layer structure, our fiber is able to support applications inside biological tissue. Apart from remarkable optical performance, our fiber was also found capable of performing imaging. By measuring the impulse response of this multimode polymer fiber and using the linear inversion algorithm, concept proving experiments were completed. Images input into our fiber were able to be retrieved from the intensity distribution of the light at the output end. Experiment result proves the capability of our optical fiber to be used as a fiber endoscopy no needs to remove.

  14. Curved Piezoelectric Actuators for Stretching Optical Fibers

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.

  15. The design of scanning fiber optical system

    NASA Astrophysics Data System (ADS)

    Bai, Yangbo; Xiang, Wanghua; Zu, Peng; Li, Xu; Ren, Fang; Shi, Xiaozhou; Xu, Xiaoyan

    2009-11-01

    A novel scanning fiber optical system for multi-channel optical switch has been demonstrated. This scanning fiber system consists of motor, photoelectric encoder, EPOS position controller, Field Programmable Gate Array (FPGA), fiber laser, transmitting energy fiber bundle, reflector, five-dimensional optical adjustable mounts, etc. In this device, the control system is composed of EPOS position controller and FPGA. Furthermore, the photoelectric encoder is directly connected to the central shaft of the motor to read its position information. The reflector is slantways fixed on the other end of the motor central shaft. Also, the fiber bundle is fixed by optical adjustable mounts to achieve slight position adjustment, which is used as launching system of this configuration. In the operation process, the motor in uniform rotation state drives the photoelectric encoder and the reflector at the same angle velocity. The photoelectric encoder reads the incremental signal and absolute position signal of motor, and then sends them to EPOS position controller and FPGA respectively. FPGA sends square wave signal to the fiber laser under the control of EPOS position controller and FPGA. Triggered by the square wave signal, the fiber laser emits a laser pulse to the center point of the reflector. At the same time, the reflector makes the laser pulse transmitting into a certain transmitting energy fiber according to the angle of the reflector at that moment. Therefore, with the motor rotates at uniform speed, the laser pulse is sent to different fibers, by which multi-channel optical switch is completed.

  16. [The recent development of fiber-optic chemical sensor].

    PubMed

    Wang, Jian; Wei, Jian-ping; Yang, Bo; Gao, Zhi-yang; Zhang, Li-wei; Yang, Xue-feng

    2014-08-01

    The present article provides a brief review of recent research on fiber-optic chemical sensor technology and the future development trends. Especially, fiber-optic pH chemical sensor, fiber-optic ion chemicl sensor, and fiber-optic gas chemical sensor are introduced respectively. Sensing film preparation methods such as chemical bonding method and sol-gel method were briefly reviewed. The emergence of new type fiber-microstructured optical fiber opened up a new development direction for fiber-optic chemical sensor. Because of its large inner surface area, flexible design of structure, having internal sensing places in fibers, it has rapidly become an important development direction and research focus of the fiber-optic chemical sensors. The fiber-optic chemical sensor derived from microstructured optical fiber is also discussed in detail. Finally, we look to the future of the fiber-optic chemical sensor.

  17. Wavelength-swept fiber laser based on acousto-optic tuning method

    NASA Astrophysics Data System (ADS)

    Chen, Ming-hui; Fan, Yun-ping; Zhang, Hao; Tao, Jian-feng; Zheng, Gang

    2016-10-01

    In this study, we have demonstrated a wavelength-swept fiber laser based on an acousto-optic tunable filter(AOTF) as a selective element and a semiconductor optical amplifier(SOA) as a gain medium in an internal fiber ring cavity. The light deriving from one port of the SOA goes through an optical isolator, the AOTF, a fiber coupler and a polarized controller successively, then it goes back to the other port of the SOA to form a ring cavity. The laser output is from another port of the fiber coupler. The laser made by this method is mainly used for swept-source optical coherence tomography(SS-OCT). The application of the SOA provides a sufficiently broad range and can ensure an increased axial resolution of SS-OCT. AOTF offers a wide tuning range, high switching speed and stable operation against vibration for the non-mechanical structure. The proposed wavelength-swept fiber laser ensures a high axial resolution of tomographic images and has a stable laser output. We have discussed the influence of the SOA injection current to the tuning range of the laser. In the SOA injection current of 280 mA, a continuous wavelength tuning range from 1295 to 1370 nm centered at a wavelength of 1330nm is obtained at the sweep rate of 1.06 kHz, and the power of the swept source was 1.14 mW. In addition, for quantitative characterization of the wavelength-swept performance with a AOTF, we have theoretically and experimentally analyzed the influence of the following controllable parameters: injection current, output power and sweeping frequency.

  18. Thermal strain analysis of optic fiber sensors.

    PubMed

    Her, Shiuh-Chuan; Huang, Chih-Ying

    2013-01-31

    An optical fiber sensor surface bonded onto a host structure and subjected to a temperature change is analytically studied in this work. The analysis is developed in order to assess the thermal behavior of an optical fiber sensor designed for measuring the strain in the host structure. For a surface bonded optical fiber sensor, the measuring sensitivity is strongly dependent on the bonding characteristics which include the protective coating, adhesive layer and the bonding length. Thermal stresses can be generated due to a mismatch of thermal expansion coefficients between the optical fiber and host structure. The optical fiber thermal strain induced by the host structure is transferred via the adhesive layer and protective coating. In this investigation, an analytical expression of the thermal strain and stress in the optical fiber is presented. The theoretical predictions are validated using the finite element method. Numerical results show that the thermal strain and stress are linearly dependent on the difference in thermal expansion coefficients between the optical fiber and host structure and independent of the thermal expansion coefficients of the adhesive and coating.

  19. Microbend fiber-optic temperature sensor

    DOEpatents

    Weiss, Jonathan D.

    1995-01-01

    A temperature sensor is made of optical fiber into which quasi-sinusoidal microbends have been permanently introduced. In particular, the present invention includes a graded-index optical fiber directing steady light through a section of the optical fiber containing a plurality of permanent microbends. The microbend section of the optical fiber is contained in a thermally expansive sheath, attached to a thermally expansive structure, or attached to a bimetallic element undergoing temperature changes and being monitored. The microbend section is secured to the thermally expansive sheath which allows the amplitude of the microbends to decrease with temperature. The resultant increase in the optical fiber's transmission thus allows temperature to be measured. The plural microbend section of the optical fiber is secured to the thermally expansive structure only at its ends and the microbends themselves are completely unconstrained laterally by any bonding agent to obtain maximum longitudinal temperature sensitivity. Although the permanent microbends reduce the transmission capabilities of fiber optics, the present invention utilizes this phenomenon as a transduction mechanism which is optimized to measure temperature.

  20. Structural diagnostics using optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Surace, Giuseppe; Chiaradia, Agostino

    1997-11-01

    After establishing the basis for assessing the structural implications of introducing a widespread sensor architecture in laminated composite materials in order to precisely identify and locate damage, the paper addresses the problem of structural diagnostics with a discussion of the development of several optical sensors. The research project will first investigate a passive optical fiber impact sensor to be implemented in the matrix of a composite material used in aeronautic and automotive applications. The senor's operating principle is based on the changes in propagation conditions occurring in a fiber subjected to transverse compression: under these circumstances, structural microdistortions produce local energy losses and hence a reduction in the optical power which propagates in the fiber and can be measured at its opposite end. As optical power losses also take place as a result of micro-bending of the optical fiber's longitudinal axis, a preliminary feasibility study will measure power attenuation versus fiber curve radius as the first step in the development of an optical fiber delamination sensor which locates separations between the layers of a composite material, i.e. debonding of sandwich panel core faces. Finally, an active impact sensor will be developed which uses optical fiber's sensitivity to pressure changes to detect the pressure gradient caused by an approaching vehicle or obstacle. The automotive industry will be able to make strategic use of these sensors, for example by installing them on vehicle sides to active the side airbag in the event of impact or collision.

  1. Novel optical fibers for data center applications

    NASA Astrophysics Data System (ADS)

    Li, Ming-Jun

    2016-02-01

    We discuss new optical fibers for high data rate short reach systems in data center applications. We review first recent development in MMF to improve system performance including high bandwidth MMF, bend insensitive MMF and MMF optimized for high bandwidth at longer wavelengths of 1060 nm or 1310 nm. Then we present a new universal fiber that can be used for both multimode transmission at 850 nm and single mode transmission at 1310 nm for data centers. Finally, we present a promising solution for high density parallel optical data links by using space division multiplexing (SDM) over multicore fibers and few mode fibers.

  2. Investigation of Optical Fibers for Nonlinear Optics.

    DTIC Science & Technology

    1985-11-01

    organic photoresists. From 1961 to 1968 he was employed at Korad, working on improving the Verneuil method of crystal growth and also on the development of...1 CCrystallFibers .................... 11C.BORAHE Crystal Fiber Growth ..................... 433. BOGR~p~x~ OF E~y ERSOL...matching value with temperature for 7052 glass fiber embedded in an ADP crystal ......................... 44 9 Horizontal traveling-zone fiber growth

  3. Investigation of Optical Fibers for Nonlinear Optics.

    DTIC Science & Technology

    1983-02-01

    growth was attempted in a Bridgman apparatus and showed limited success, produc- ing encapsulated fibers roughly 2 cm long. The poten- tial of...Method for SC Fiber Growth .................................. 4 C. Vapor-Stabilized Bridgman Method for SC Fibers ....... ..................... 8 D. Melt...7 4 Differential thermal analysis curve for encapsulated KDP ..... .......................... . 9 5 Stabilized Bridgman growth apparatus

  4. Optical fiber cable chemical stripping fixture

    NASA Technical Reports Server (NTRS)

    Kolasinski, John R. (Inventor); Coleman, Alexander M. (Inventor)

    1995-01-01

    An elongated fixture handle member is connected to a fixture body member with both members having interconnecting longitudinal central axial bores for the passage of an optical cable therethrough. The axial bore of the fixture body member, however, terminates in a shoulder stop for the outer end of a jacket of the optical cable covering both an optical fiber and a coating therefor, with an axial bore of reduced diameter continuing from the shoulder stop forward for a predetermined desired length to the outer end of the fixture body member. A subsequent insertion of the fixture body member including the above optical fiber elements into a chemical stripping solution results in a softening of the exposed external coating thereat which permits easy removal thereof from the optical fiber while leaving a desired length coated fiber intact within the fixture body member.

  5. Fiber optic links for antenna remoting

    NASA Astrophysics Data System (ADS)

    Glomb, Walter L., Jr.

    1992-12-01

    A high linearity, high dynamic range analog fiber optic link is described which allows high fidelity distortion-free communications transmission from 2 to 500 MHz and provides an alternative to conventional coaxial cables used to remote RF receivers from their antennas. All signals within four frequency bands (2-30, 30-90, 90-180, and 180-500 MHz) and within specified voltage ranges are detected and transmitted via fiber optics. This function is performed by a system of four separate analog fiber-optic links, one for each of the four bands. The discussion covers the electro-optic, mechanical, and thermal design of the fiber optic link, the performance model, reliability analysis, and performance tests.

  6. Fiber-optic project-fringe interferometry with sinusoidal phase modulating system

    NASA Astrophysics Data System (ADS)

    Zhang, Fukai; Duan, Fajie; Lv, Changrong; Duan, Xiaojie; Bo, En; Feng, Fan

    2013-06-01

    A fiber-optic sinusoidal phase-modulating (SPM) interferometer for fringe projection is presented. The system is based on the SPM technique and makes use of the Mach-Zehnder interferometer structure and Young's double pinhole interference principle to achieve interference fringe projection. A Michelson interferometer, which contains the detection of Fresnel reflection on its fiber end face and interference at one input port of a 3 dB coupler, is utilized to achieve feedback precise control of the fringe phase, which is sensitive to phase drifting produced by the nature of the fiber. The phase diversity for the closed-loop SPM system can be real-time measured with a precision of 3 mrad. External disturbances mainly caused by temperature fluctuations can be reduced to 57 mrad for the fringe map. The experimental results have shown the usefulness of the system.

  7. Study on high coupling efficiency Er-doped fiber laser for femtosecond optical frequency comb

    NASA Astrophysics Data System (ADS)

    Pang, Lihui; Liu, Wenjun; Han, Hainian; Wei, Zhiyi

    2016-09-01

    The femtosecond laser is crucial to the operation of the femtosecond optical frequency comb. In this paper, a passively mode-locked erbium-doped fiber laser is presented with 91.4 fs pulse width and 100.8 MHz repetition rate, making use of the nonlinear polarized evolution effect. Using a 976 nm pump laser diode, the average output power is 16 mW from the coupler and 27 mW from the polarization beam splitter at the pump power of 700 mW. The proposed fiber laser can offer excellent temporal purity in generated pulses with high power, and provide a robust source for fiber-based frequency combs and supercontinuum generation well suited for industrial applications.

  8. Stimulated thermal Rayleigh scattering in optical fibers.

    PubMed

    Dong, Liang

    2013-02-11

    Recently, mode instability was observed in optical fiber lasers at high powers, severely limiting power scaling for single-mode outputs. Some progress has been made towards understanding the underlying physics. A thorough understanding of the effect is critical for continued progress of this very important technology area. Mode instability in optical fibers is, in fact, a manifestation of stimulated thermal Rayleigh scattering. In this work, a quasi-closed-form solution for the nonlinear coupling coefficient is found for stimulated thermal Rayleigh scattering in optical fibers. The results help to significantly improve understanding of mode instability.

  9. Fiber optic communication in borehole applications

    SciTech Connect

    Franco, R.J.; Morgan, J.R.

    1997-04-01

    The Telemetry Technology Development Department have, in support of the Advanced Geophysical Technology Department and the Oil Recovery Technology Partnership, developed a fiber optic communication capability for use in borehole applications. This environment requires the use of packaging and component technologies to operate at high temperature (up to 175{degrees}C) and survive rugged handling. Fiber optic wireline technology has been developed by The Rochester Corporation under contract to Sandia National Labs and produced a very rugged, versatile wireline cable. This development has utilized commercial fiber optic component technologies and demonstrated their utility in extreme operating environments.

  10. Microbend fiber-optic chemical sensor

    DOEpatents

    Weiss, Jonathan D.

    2002-01-01

    A microbend fiber-optic chemical sensor for detecting chemicals in a sample, and a method for its use, is disclosed. The sensor comprises at least one optical fiber having a microbend section (a section of small undulations in its axis), for transmitting and receiving light. In transmission, light guided through the microbend section scatters out of the fiber core and interacts, either directly or indirectly, with the chemical in the sample, inducing fluorescence radiation. Fluorescence radiation is scattered back into the microbend section and returned to an optical detector for determining characteristics of the fluorescence radiation quantifying the presence of a specific chemical.

  11. Optical Fiber Sensors for the Cultural Heritage

    NASA Astrophysics Data System (ADS)

    Mignani, A. G.; Falciai, R.; Trono, C.

    Two examples of optical fiber sensors for the protection of the cultural heritage were given. The varnished optical fiber could be used also as temperature sensor. In fact, thanks to the good temperature sensitivity and reversibility of gum mastic, it could be considered as a transducer for the implementation of a temperature sensor to be permanently inlayed in the painting. By embedding the optical fiber in the painting together with the picture varnish for example on a comer, continuous temperature monitoring could be possible, in order to prevent risk conditions that can arise when illuminating the painting with the use of lamps, as happens during television shots.

  12. Intelsat and fiber optics - Challenge and opportunity

    NASA Astrophysics Data System (ADS)

    Hampton, John D.

    Fiber optic technology is both a challenge and an opportunity for Intelsat in developing competitive strategies. Intelsat compares favorably with fiber-optic undersea cables in terms of cost and capacity and can serve a greater variety of service and network requirements. Domestic fiber optic local and long distance networks present opportunities for Intelsat to expand access to its network. Intelsat also has a broad-based strategy designed to: (1) capitalize on Intelsat's strengths; (2) use existing and planned resources more efficiently and in new and innovative ways; (3) introduce new operational and planning initiatives; and (4) emphasize digital service capability and ISDN compatibility.

  13. Characterization of Fiber Optic CMM Probe System

    SciTech Connect

    K.W.Swallow

    2007-05-15

    This report documents a study completed on the fiber optic probe system that is a part of the Werth optical CMM. This study was necessary due to a lack of documentation from the vendor for the proper use and calibration of the fiber probe, and was performed in support of the Lithographie Galvanoformung Abformung (LIGA) development program at the FM&T. As a result of this study, a better understanding of the fiber optic probe has been developed, including guidelines for its proper use and calibration.

  14. Fiber optical ranging sensor for proximity fuse

    NASA Astrophysics Data System (ADS)

    Du, Fang; Chi, Zeying; You, Mingjun; Chen, Wenjian

    1996-09-01

    A fiber optical ranging sensor used in laser proximity fuze is described in this paper. In the fuze, pulse laser diode (LD) is used as light source and trigger signal is generated by comparing the reflected light pulses with the reference pulses by a correlator after they were converted into electric signals by PIN photodiodes. Multi-mode fibers and integrated optical devices are used in the system so that the structure can be more compact. Optical fiber delay line is used to offer precise delay time for reference channel.

  15. Stabilizing Fiber-Optic Transmission Lines

    NASA Technical Reports Server (NTRS)

    Lutes, G. F.; Lau, K. Y.

    1984-01-01

    Voltage-controlled optical phase shifter is key. Optical phase shifter stabilizes propagation delay of fiber-optic transmission line by compensating for temperature and pressure effects. Applicable to phased array antenna systems and very-long-baseline interferometer distribution systems.

  16. Lightning vulnerability of fiber-optic cables.

    SciTech Connect

    Martinez, Leonard E.; Caldwell, Michele

    2008-06-01

    One reason to use optical fibers to transmit data is for isolation from unintended electrical energy. Using fiber optics in an application where the fiber cable/system penetrates the aperture of a grounded enclosure serves two purposes: first, it allows for control signals to be transmitted where they are required, and second, the insulating properties of the fiber system help to electrically isolate the fiber terminations on the inside of the grounded enclosure. A fundamental question is whether fiber optic cables can allow electrical energy to pass through a grounded enclosure, with a lightning strike representing an extreme but very important case. A DC test bed capable of producing voltages up to 200 kV was used to characterize electrical properties of a variety of fiber optic cable samples. Leakage current in the samples were measured with a micro-Ammeter. In addition to the leakage current measurements, samples were also tested to DC voltage breakdown. After the fiber optic cables samples were tested with DC methods, they were tested under representative lightning conditions at the Sandia Lightning Simulator (SLS). Simulated lightning currents of 30 kA and 200 kA were selected for this test series. This paper documents measurement methods and test results for DC high voltage and simulated lightning tests performed at the Sandia Lightning Simulator on fiber optic cables. The tests performed at the SLS evaluated whether electrical energy can be conducted inside or along the surface of a fiber optic cable into a grounded enclosure under representative lightning conditions.

  17. Orbital angular momentum in optical fibers

    NASA Astrophysics Data System (ADS)

    Bozinovic, Nenad

    Internet data traffic capacity is rapidly reaching limits imposed by nonlinear effects of single mode fibers currently used in optical communications. Having almost exhausted available degrees of freedom to orthogonally multiplex data in optical fibers, researchers are now exploring the possibility of using the spatial dimension of fibers, via multicore and multimode fibers, to address the forthcoming capacity crunch. While multicore fibers require complex manufacturing, conventional multi-mode fibers suffer from mode coupling, caused by random perturbations in fibers and modal (de)multiplexers. Methods that have been developed to address the problem of mode coupling so far, have been dependent on computationally intensive digital signal processing algorithms using adaptive optics feedback or complex multiple-input multiple-output algorithms. Here we study the possibility of using the orbital angular momentum (OAM), or helicity, of light, as a means of increasing capacity of future optical fiber communication links. We first introduce a class of specialty fibers designed to minimize mode coupling and show their potential for OAM mode generation in fibers using numerical analysis. We then experimentally confirm the existence of OAM states in these fibers using methods based on fiber gratings and spatial light modulators. In order to quantify the purity of created OAM states, we developed two methods based on mode-image analysis, showing purity of OAM states to be 90% after 1km in these fibers. Finally, in order to demonstrate data transmission using OAM states, we developed a 4-mode multiplexing and demultiplexing systems based on free-space optics and spatial light modulators. Using simple coherent detection methods, we successfully transmit data at 400Gbit/s using four OAM modes at a single wavelength, over 1.1 km of fiber. Furthermore, we achieve data transmission at 1.6Tbit/s using 10 wavelengths and two OAM modes. Our study indicates that OAM light can exist

  18. All-optical repetition rate multiplication of pseudorandom bit sequences by employing power coupler and equalizer

    NASA Astrophysics Data System (ADS)

    Sun, Zhenchao; Wang, Zhi; Wu, Chongqing; Wang, Fu; Li, Qiang

    2015-10-01

    A scheme for all-optical repetition rate multiplication of pseudorandom bit sequences (PRBS) is demonstrated with a precision delay feedback loop cascaded with a terahertz optical asymmetric demultiplexer (TOAD)-based power equalizer. Its feasibility has been verified by experiments, which show a multiplication for PRBS at cycle 2^7-1 from 2.5 to 10 Gb/s. This scheme can be employed for the rate multiplication of a much longer cycle PRBS at a much higher bit rate over 40 Gb/s if the time-delay, the loss, and the dispersion of an optical delay line are all precisely managed.

  19. Fiber optic, Faraday rotation current sensor

    SciTech Connect

    Veeser, L.R.; Day, G.W.

    1986-01-01

    At the Second Megagauss Conference in 1979, there were reports of experiments that used the Faraday magneto-optic effect in a glass rod to measure large electric current pulses or magnetic fields. Since then we have seen the development of single-mode optical fibers that can carry polarized light in a closed loop around a current load. A fiber optic Faraday rotation sensor will integrate the flux, instead of sampling it at a discrete point, to get a measurement independent of the current distribution. Early Faraday rotation experiments using optical fibers to measure currents dealt with problems such as fiber birefringence and difficulties in launching light into the tiny fiber cores. We have built on those experiments, working to reduce the effects of shocks and obtaining higher bandwidths, absolute calibration, and computerized recording and data analysis, to develop the Faraday rotation sensors into a routine current diagnostic. For large current pulses we find reduced sensitivity to electromagnetic interference and other backgrounds than for Rogowski loops; often the fiber optic sensors are useful where conductive probes cannot be used at all. In this paper we describe the fiber optic sensors and some practical matters involved in fielding them.

  20. A Self-Referencing Intensity Based Polymer Optical Fiber Sensor for Liquid Detection

    PubMed Central

    Montero, David Sánchez; Vázquez, Carmen; Möllers, Ingo; Arrúe, Jon; Jäger, Dieter

    2009-01-01

    A novel self-referencing fiber optic intensity sensor based on bending losses of a partially polished polymer optical fiber (POF) coupler is presented. The coupling ratio (K) depends on the external liquid in which the sensor is immersed. It is possible to distinguish between different liquids and to detect their presence. Experimental results for the most usual liquids found in industry, like water and oil, are given. K value increases up to 10% from the nominal value depending on the liquid. Sensor temperature dependence has also been studied for a range from 25 °C (environmental condition) to 50 °C. Any sector requiring liquid level measurements in flammable atmospheres can benefit from this intrinsically safe technology. PMID:22454594

  1. Design, fabrication, and characterisation of fully etched TM grating coupler for photonic integrated system-in-package

    NASA Astrophysics Data System (ADS)

    Gili-de-Villasante, Oriol; Tcheg, Paul; Wang, Bei; Suna, Alpaslan; Giannoulis, Giannis; Lazarou, Ioannis; Apostolopoulos, Dimitrios; Avramopoulos, Hercules; Pleros, Nikos; Baus, Matthias; Karl, Matthias; Tekin, Tolga

    2012-06-01

    Grating couplers are the best solution for testing nano-photonic circuits. Their main benefit is that they allow access via an optical fiber from the top and therefore there is no need to dice the chip and prepare the facets crucially. In the PLATON project grating couplers were designed to couple TM mode into and out of the SOI waveguides. Simulations came up with a grating coupler layout capable of theoretical coupling losses lower than 3dB for 1550 nm in TM configuration. A fully etched grating structure was chosen for fabrication simplicity and the optimal filling factor was found. The structures were fabricated using proximity error correction (PEC) and show a uniform coupling efficiency for all couplers. Therefore they are well-suited for all applications which demand for stable fiber-to-chip coupling. The spectral response of the structures was measured from 1500 to 1580 nm with 2 nm step and measuring the fiber-tofiber losses of three straight waveguides equipped with three grating couplers with different gap widths. The optimal grating period exhibits adequate coupling losses of 3.23 dB per coupler at 1557 nm, being therefore the most promising design.

  2. Side-emitting fiber optic position sensor

    SciTech Connect

    Weiss, Jonathan D.

    2008-02-12

    A side-emitting fiber optic position sensor and method of determining an unknown position of an object by using the sensor. In one embodiment, a concentrated beam of light source illuminates the side of a side-emitting fiber optic at an unknown axial position along the fiber's length. Some of this side-illuminated light is in-scattered into the fiber and captured. As the captured light is guided down the fiber, its intensity decreases due to loss from side-emission away from the fiber and from bulk absorption within the fiber. By measuring the intensity of light emitted from one (or both) ends of the fiber with a photodetector(s), the axial position of the light source is determined by comparing the photodetector's signal to a calibrated response curve, look-up table, or by using a mathematical model. Alternatively, the side-emitting fiber is illuminated at one end, while a photodetector measures the intensity of light emitted from the side of the fiber, at an unknown position. As the photodetector moves further away from the illuminated end, the detector's signal strength decreases due to loss from side-emission and/or bulk absorption. As before, the detector's signal is correlated to a unique position along the fiber.

  3. Nd/sup 3 +/-doped cw fiber laser using all-fiber reflectors

    SciTech Connect

    Miller, I.D.; Mortimore, D.B.; Urquhart, P.; Ainslie, B.J.; Craig, S.P.; Miller, C.A.; Payne, D.B.

    1987-06-01

    We demonstrate a novel all-fiber resonant optical cavity which uses two-fiber reflectors, each formed by a single loop of fiber between the output ports of a fiber directional coupler. The reflectivities of the fiber mirrors are each determined by the coupling ratio and the insertion loss of the fused couplers. When the cavity is formed in this way using a continuous length of Nd/sup 3 +/-doped fiber and pumped using a GaAs laser diode, lasing occurs at a wavelength of 1064 nm. Both theoretical and practical descriptions of the device are given.

  4. Optical isolator system for fiber-optic uses

    NASA Technical Reports Server (NTRS)

    Lutes, George

    1988-01-01

    A low loss optical isolator suitable for fiber-optic uses has been assembled from commercial components. The isolator exhibits reverse isolation of greater than 70 dB, with a forward loss of less than 1.3dB. This system provides an effective approach for reducing instabilities encountered in the output signal of semiconductor lasers in certain applications of fiber-optic systems. The paper presents a phenomenological explanation for the superior performance of the isolator system.

  5. Optical isolator system for fiber-optic uses.

    PubMed

    Lutes, G

    1988-04-01

    A low loss optical isolator suitable for fiber-optic uses has been assembled from commercial components. The isolator exhibits reverse isolation of >70 dB, with a forward loss of <1.3 dB. This system provides an effective approach for reducing instabilities encountered in the output signal of semiconductor lasers in certain applications of fiber-optic systems. The paper presents a phenomenological explanation for the superior performance of the isolator system.

  6. Fiber optic electric field sensor technology

    NASA Technical Reports Server (NTRS)

    Jarzynski, J.; De Paula, R. P.

    1987-01-01

    The properties of piezoactive plastics are reviewed as well as the fiber-optic electric field sensors studied so far. A particular configuration consisting of a concentric piezoactive jacket on the glass fiber is discussed in detail and the frequency response of this sensor is projected over a wide range of frequencies. The present design has the practical advantages of leading to a compact lightweight sensor; longer fiber lengths may be used to increase sensitivity. It is predicted that, at low frequencies, a fiber-optic antenna using a 1-km length of fiber would be capable of detecting a minimum electric field of 43 microV/m assuming a minimum phase sensitivity of 10 to the -6th radians for the optical Mach-Zehnder interferometer.

  7. Metal-embedded optical fiber pressure sensor

    NASA Astrophysics Data System (ADS)

    Kidwell, J. J.; Berthold, John W.

    1991-02-01

    The paper reports the results of work to demonstrate the feasibility of embedding a metal-buffered optical fiber inside a thin metal diaphragm to create a pressure-sensitive transducer. A method was developed to embed butt-coupled optical fibers inside brass diaphragms. Butt-coupled fibers with two different end spacings were successfully embedded in the diaphragms. The pressure response of the diaphragms was calibrated by measuring the changes in light transmission through the butt coupling as a function of pressure. In addition to embedded fiber pressure sensors, this method may be useful for other applications. The calibration results indicate the method could be used to make connections between signal processors and optical fibers embedded in composites.

  8. Robust incoherent fiber optic bundle decoder

    NASA Technical Reports Server (NTRS)

    Roberts, Hilary E. (Inventor); DePlachett, Charles P. (Inventor); Deason, Brent E. (Inventor); Pilgrim, Robert A. (Inventor); Sanford, Harold S. (Inventor)

    2003-01-01

    Apparatus and method for calibrating an incoherent fiber optic bundle for use in transmitting visual or infrared coherent images. The apparatus includes a computer, a computer video monitor, an objective lens adjacent to the input end of the bundle, a second lens adjacent the output end of the bundle, and a CCD camera. The camera transmits video data to the monitor to produce an illuminated fiber optic image. The coordinates for the center of each fiber is found through an imaging process and the output fibers coordinates are related to the input fiber coordinates and processed in the computer to produce a mapping lookup-table (LUT) unique to the specific fiber bundle. Remapping of the LUT due to changes in the lens focus, CCD camera, or the addition of an infrared filter is accomplished by a software utility in the computer.

  9. Integrated optics implementation of a fiber optic rotation sensor - Analysis and development. [for Mariner Mark II planetary explorer

    NASA Technical Reports Server (NTRS)

    Bartman, R. K.; Youmans, B. R.; Nerheim, N. M.

    1987-01-01

    The Jet Propulsion Laboratory is developing a fiber optic rotation sensor (FORS) for use on the Mariner Mark II series of planetary explorer craft and in other space applications. FORS is a closed-loop phase-nulling device and embodies a number of interesting innovations. Chief among these are the incorporation of the device's couplers, phase modulators, and polarizer on a single lithium niobate (LinbO3) integrate optics chip and a novel means of reading out angular position and rotation rate based on optical beat detection. Various aspects of the FORS design and operation are described and discussed. Particular attention is paid to analyzing errors attributable to polarizer imperfection and the so-called residual Michelson effect.

  10. Optical model and optimal output coupler for a continuous wave Yb:YAG thin-disk laser with multiple-disk configuration.

    PubMed

    Zhu, Guangzhi; Zhu, Xiao; Zhu, Changhong; Shang, Jianli

    2012-09-10

    This article presents the fundamental principles of operational performance of a continuous wave (cw) thin-disk laser with multiple disks in one resonator. Based on the model of an end-pumped Yb:YAG thin-disk laser with nonuniform temperature distribution, the effect of the multiple disks in one resonator is considered. The analytic expressions are derived to analyze the laser output intensity, laser intensity in the resonator, threshold intensity, and the optical efficiency of a thin-disk laser with multiple disks arranged in series. The dependence of output coupler reflectivity and the number of thin disks on various parameters are investigated, which are useful to determine the optimal output coupler reflectivity of the thin-disk lasers and control the laser intensity in the resonator.

  11. Efficient waveguide coupler based on metal materials

    NASA Astrophysics Data System (ADS)

    Wu, Wenjun; Yang, Junbo; Chang, Shengli; Zhang, Jingjing; Lu, Huanyu

    2015-10-01

    Because of the diffraction limit of light, the scale of optical element stays in the order of wavelength, which makes the interface optics and nano-electronic components cannot be directly matched, thus the development of photonics technology encounters a bottleneck. In order to solve the problem that coupling of light into the subwavelength waveguide, this paper proposes a model of coupler based on metal materials. By using Surface Plasmon Polaritons (SPPs) wave, incident light can be efficiently coupled into waveguide of diameter less than 100 nm. This paper mainly aims at near infrared wave band, and tests a variety of the combination of metal materials, and by changing the structural parameters to get the maximum coupling efficiency. This structure splits the plane incident light with wavelength of 864 nm, the width of 600 nm into two uniform beams, and separately coupled into the waveguide layer whose width is only about 80 nm, and the highest coupling efficiency can reach above 95%. Using SPPs structure will be an effective method to break through the diffraction limit and implement photonics device high-performance miniaturization. We can further compress the light into small scale fiber or waveguide by using the metal coupler, and to save the space to hold more fiber or waveguide layer, so that we can greatly improve the capacity of optical communication. In addition, high-performance miniaturization of the optical transmission medium can improve the integration of optical devices, also provide a feasible solution for the photon computer research and development in the future.

  12. Theoretical Analysis Of A Sagnac Fiber Optic Interferometer

    NASA Astrophysics Data System (ADS)

    Szustakowski, Mieczyslaw; Jaroszewicz, Leszek R.

    1990-04-01

    The analytical description of a closed optical fiber interferometer system based on Jones calculus is presented. This calculus adapation for the optical fiber elements analysis allows for a uniform description of system built on the basis of a single-mode optical fiber. The analysis of a Sagnac fiber optic interferometer is an example of this method application.

  13. Electromagnetic enviromental effects on shipboard fiber optic installations

    NASA Astrophysics Data System (ADS)

    Bucholz, Roger C.

    1991-02-01

    The inherent immunity of fiber optic materials to electromagnetic environmental effects provides numerous opportunities for wide-spread use of fiber optics aboard ship. Federal budget constraints may reduce the development of new fiber optic systems to address military applications. However there are sufficient similarities between industrial and military sensor needs to warrant use of off-the-shelf fiber optic sensor systems.

  14. Gap soliton propagation in optical fiber gratings

    NASA Astrophysics Data System (ADS)

    Mohideen, U.; Slusher, R. E.; Mizrahi, V.; Erdogan, T.; Kuwata-Gonokami, M.; Lemaire, P. J.; Sipe, J. E.; Martijn de Sterke, C.; Broderick, Neil G. R.

    1995-08-01

    Intense optical pulse propagation in a GeO2 -doped silica glass fiber grating results in nonlinear pulse propagation velocities and increased transmission at wavelengths where the grating reflects light in the linear limit. These nonlinear pulse propagation effects are predicted by numerical simulations of gap soliton propagation. The large linear refractive-index variations used for the fiber gratings in these experiments permit the propagation of gap solitons in short lengths of fiber.

  15. Spaceborne Fiber Optic Data Bus (SFODB)

    NASA Technical Reports Server (NTRS)

    Bretthauer, Joy W.; Chalfant, Chuck H.; Orlando, Fred J.; Rezek, Ed; Sawyer, Marc

    1998-01-01

    The SFODB is a standardized, gigabit per second, highly reliable, fault tolerant fiber optic network. SFODB was designed to the harsh space environments and real-time, on-board data handling applications of high speed, remote sensing spacecraft.

  16. Multipurpose fiber-optic access network

    NASA Astrophysics Data System (ADS)

    Han, Kwan H.; Kim, Hoon; Chung, Yun C.

    2002-10-01

    We propose and demonstrate a multipurpose fiber-optic access network (MFAN). This network uses the same fiber infrastructure for a variety of services including baseband, cable television (CATV), personal communication service (PCS), wireless local loop (WLL), and local multipoint communication service (LMCS). The experimental results show that the proposed network could support the independent operation of these services.

  17. Fiber Optic Communications Technology. A Status Report.

    ERIC Educational Resources Information Center

    Hull, Joseph A.

    Fiber optic communications (communications over very pure glass transmission channels of diameter comparable to a human hair) is an emerging technology which promises most improvements in communications capacity at reasonable cost. The fiber transmission system offers many desirable characteristics representing improvements over conventional…

  18. Optical Fibers Would Sense Local Temperatures

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1994-01-01

    Proposed fiber-optic transducers measure local temperatures. Includes lead-in and lead-out lengths producing no changes in phase shifts, plus short sensing length in which phase shift sensitive to temperature. Phase shifts in two-mode fibers vary with temperatures.

  19. Proposal and testing for a fiber-optic-based measurement of flow vorticity.

    PubMed

    Yao, S; Tong, P; Ackerson, B J

    2001-08-20

    A fiber-optic arrangement is devised to measure the velocity difference, deltav(l), down to small separation l. With two sets of optical fibers and couplers the new technique becomes capable of measuring one component of the time- and space-resolved vorticity vector omega(r, t). The technique is tested in a steady laminar flow, in which the velocity gradient (or flow vorticity) is known. The experiment verifies the working principle of the technique and demonstrates its applications. It is found that the new technique measures the velocity difference (and hence the velocity gradient when l is known) with the same high accuracy and high sampling rate as laser Doppler velocimetry does for the local velocity measurement. It is nonintrusive and capable of measuring the velocity gradient with a spatial resolution as low as ~50 mum. The successful test of the fiber-optic technique in the laminar flow with one optical channel is an important first step for the development of a two-channel fiber-optic vorticity probe, which has wide use in the general area of fluid dynamics, especially in the study of turbulent flows.

  20. Fiber optics welder having movable aligning mirror

    DOEpatents

    Higgins, Robert W.; Robichaud, Roger E.

    1981-01-01

    A system for welding fiber optic waveguides together. The ends of the two fibers to be joined together are accurately, collinearly aligned in a vertical orientation and subjected to a controlled, diffuse arc to effect welding and thermal conditioning. A front-surfaced mirror mounted at a 45.degree. angle to the optical axis of a stereomicroscope mounted for viewing the junction of the ends provides two orthogonal views of the interface during the alignment operation.

  1. Fiber optic detector for immuno-testing

    DOEpatents

    Partin, Judy K.; Ward, Thomas E.; Grey, Alan E.

    1992-01-01

    A portable fiber optic detector that senses the presence of specific target chemicals in air or a gas by exchanging the target chemical for a fluoroescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  2. Fiber Optic Tactical Local Network (FOTLAN)

    NASA Technical Reports Server (NTRS)

    Bergman, L. A.; Hartmayer, R.; Wu, W. H.; Cassell, P.; Edgar, G.; Lambert, J.; Mancini, R.; Jeng, J.; Pardo, C.

    1991-01-01

    A 100 Mbit/s FDDI (fiber distributed data interface) network interface unit is described that supports real-time data, voice and video. Its high-speed interrupt-driven hardware architecture efficiently manages stream and packet data transfer to the FDDI network. Other enhancements include modular single-mode laser-diode fiber optic links to maximize node spacing, optic bypass switches for increased fault tolerance, and a hardware performance monitor to gather real-time network diagnostics.

  3. Fresnel drag effect in fiber optic gyroscope

    NASA Technical Reports Server (NTRS)

    Vali, V.; Berg, M. F.; Shorthill, R. W.

    1978-01-01

    Consideration is given to the development of a low-noise fiber-optic ring interferometer gyroscope. A technique for measuring the Fresnel drag coefficient of optical fibers is described, and the accuracy of the technique is considered. An experiment is performed which allows verification of the Einstein velocity addition theorem to the first nonlinear term. An experimental setup for measuring Fresnel drag is described: it consists of a Sagnac interferometer and a Fresnel drag measurement configuration.

  4. Research for Electronic Fiber Optics Technologists

    NASA Technical Reports Server (NTRS)

    Lawrence, Ellis E.

    1999-01-01

    The intent of this project was to provide research experiences for socially and economically disadvantaged students in networking via fiber optics. The objectives of this project were: 1) To provide knowledge and skills needed by students to use the tools and equipment essential to networking NASA's and the university's topologies; 2) To provide the student researchers with needed mathematical skills and concepts to progress in fiber optic technology; 3) To afford the principal investigator an opportunity to become certified in fiber optics; 4) To build a transmitter and receiver circuit that will be linked by fiber-optic cable to demonstrate mastery of concepts; and 5) To conduct research for NASA and the University in the fiber-optic system. The research will attempt to develop applications for THUNDER (Thin-layer Composite Unimorph Ferroelectric Driver and Sensor) and LARC-SI (Langley Research Center- Soluble Polyimide), (inventions at NASA/LaRC) and fiber-optic technology that will be beneficial to NASA, the university and the consumer. This research has the potential of improving the nation's manpower in the area of fiberoptic technology. It will allow students the opportunity to participate in visible research at NASA and in industry.

  5. Optical fiber sensor technique for strain measurement

    DOEpatents

    Butler, Michael A.; Ginley, David S.

    1989-01-01

    Laser light from a common source is split and conveyed through two similar optical fibers and emitted at their respective ends to form an interference pattern, one of the optical fibers having a portion thereof subjected to a strain. Changes in the strain cause changes in the optical path length of the strain fiber, and generate corresponding changes in the interference pattern. The interference pattern is received and transduced into signals representative of fringe shifts corresponding to changes in the strain experienced by the strained one of the optical fibers. These signals are then processed to evaluate strain as a function of time, typical examples of the application of the apparatus including electrodeposition of a metallic film on a conductive surface provided on the outside of the optical fiber being strained, so that strains generated in the optical fiber during the course of the electrodeposition are measurable as a function of time. In one aspect of the invention, signals relating to the fringe shift are stored for subsequent processing and analysis, whereas in another aspect of the invention the signals are processed for real-time display of the strain changes under study.

  6. Design and realization of a side-polished single-mode fiber optic high-sensitive temperature sensor

    NASA Astrophysics Data System (ADS)

    Nagaraju, B.; Varshney, R. K.; Pal, B. P.; Singh, A.; Monnom, G.; Dussardier, B.

    2008-11-01

    A high sensitive temperature sensor based on evanescent field coupling between a side-polished fiber half-coupler (SPFHC) and a thermo-optic multimode overlay waveguide (MMOW) is designed and demonstrated. Such a structure essentially functions as an asymmetric directional coupler with a band-stop characteristic attributable to the wavelengthdependent resonant coupling between the mode of the SPFHC and one or more modes of the MMOW. A slight change in temperature leads to a significant shift in the phase resonance-coupling wavelength ( λr ) between the MMOW and SPFHC λr, which is easily measurable. The wavelength sensitivity of the device is measured to be ~ 5.3 nm/°C within the measurement range of 26-70°C this sensitivity is more than 5 times higher compared to earlier reported temperature sensors of this kind. The SPFHC was fabricated by selective polishing of the cladding from one side of a bent telecommunication standard single-mode fiber and the MMOW was formed on top of the SPFHC through spin coating. A semi- numerical rigorous normal mode analysis was employed at the design stage by including the curvature effect of the fiber lay in the half-coupler block and the resultant z-dependent evanescent coupling mechanism. An excellent agreement between theoretical and experimental results is found.

  7. Optical-Fiber Fluorosensors With Polarized Light Sources

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1995-01-01

    Chemiluminescent and/or fluorescent molecules in optical-fiber fluorosensors oriented with light-emitting dipoles along transverse axis. Sensor of proposed type captures greater fraction of chemiluminescence or fluorescence and transmits it to photodetector. Transverse polarization increases sensitivity. Basic principles of optical-fiber fluorosensors described in "Making Optical-Fiber Chemical Sensors More Sensitive" (LAR-14525), "Improved Optical-Fiber Chemical Sensors" (LAR-14607), and "Improved Optical-Fiber Temperature Sensors" (LAR-14647).

  8. Fiber optic wide region temperature sensing system

    NASA Astrophysics Data System (ADS)

    Xu, Xunjian; Nonaka, Koji; Song, Hongbin

    2008-12-01

    A fiber optic wide region temperature sensing system based on optical pulse correlation measurement and SHG differential detection technique is proposed and demonstrated. In order to establish the reliability of this fiber optic temperature sensing system, a long-term wide region outside temperature monitoring experiment with a new designed 20ps time-bias optical pulse correlation unit for wide measurement rang was carried out. The temperature measured by means of a correlation sensor had the same variation as and higher sensitivity and quick measurement response than the digital thermometer. The resolution of the correlation sensor is approximately +/-0.01 oC . This fiber optic temperature sensor can measure even in very tough environment and low and high temperature range. Not only point temperature but also a field area average temperature can monitor by this system.

  9. Investigation of Microstructured Optical Fiber in Eight Fiber Laser

    NASA Astrophysics Data System (ADS)

    Bahloul, Faouzi; Ennejah, Tarek; Attia, Rabah

    2012-06-01

    In passively mode locked fiber laser, case of 8FL (Eight Fiber Laser), the management of length, linear and non linear parameters of the cavity plays a paramount role in the generation of stable ultra short pulses with high peak powers. In this work, we propose an 8FL consisted of MOF (Microstructured Optical Fiber). According to the various properties of the MOF, we studied the variation of the pulses peak power and width. We demonstrated that there are optimal parameters of the MOF for which the peak power is maximal and the width is minimal.

  10. Investigation of Microstructured Optical Fiber in Eight Fiber Laser

    NASA Astrophysics Data System (ADS)

    Bahloul, Faouzi; Ennejah, Tarek; Attia, Rabah

    2011-09-01

    In passively mode locked fiber laser, case of 8FL (Eight Fiber Laser), the management of length, linear and non linear parameters of the cavity plays a paramount role in the generation of stable ultra short pulses with high peak powers. In this work, we propose an 8FL consisted of MOF (Microstructured Optical Fiber). According to the various properties of the MOF, we studied the variation of the pulses peak power and width. We demonstrated that there are optimal parameters of the MOF for which the peak power is maximal and the width is minimal.

  11. Silicon nitride grating waveguide based directional coupler

    NASA Astrophysics Data System (ADS)

    Feng, Jijun; Li, Anyuan; Akimoto, Ryoichi; Zeng, Heping

    2016-10-01

    Silicon nitride is a promising wave-guiding material for integrated photonics applications with a wide transparency bandwidth from visible to mid-infrared, with a superior performance in fiber-coupling and propagation losses, more tolerant fabrication process to the structure parameters variation and compatible with the CMOS technology. Directional coupler (DC) is very popular for realizing beam splitter because of its structural simplicity and no excess loss intrinsically. Here, a conventional silicon nitride directional coupler, three-dimensional vertical coupler, and grating waveguide assisted coupler are designed and fabricated, and compared with each other. A grating waveguide based coupler with a period of 300 nm and coupling length of 26 um, can realize a wideband 3-dB splitter for the wavelength in the range from 1540 to 1620 nm, for a transverse electric (TE) polarized wave. With further optimization of the grating period and duty cycle, the device performance can be further improved with a wider bandwidth.

  12. Benefits of glass fibers in solar fiber optic lighting systems.

    PubMed

    Volotinen, Tarja T; Lingfors, David H S

    2013-09-20

    The transmission properties and coupling of solar light have been studied for glass core multimode fibers in order to verify their benefits for a solar fiber optic lighting system. The light transportation distance can be extended from 20 m with plastic fibers to over 100 m with the kind of glass fibers studied here. A high luminous flux, full visible spectrum, as well as an outstanding color rendering index (98) and correlated color temperature similar to the direct sun light outside have been obtained. Thus the outstanding quality of solar light transmitted through these fibers would improve the visibility of all kinds of objects compared to fluorescent and other artificial lighting. Annual relative lighting energy savings of 36% in Uppsala, Sweden, and 76% in Dubai were estimated in an office environment. The absolute savings can be doubled by using glass optical fibers, and are estimated to be in the order of 550 kWh/year in Sweden and 1160 kWh/year in Dubai for one system of only 0.159 m(2) total light collecting area. The savings are dependent on the fiber length, the daily usage time of the interior, the type of artificial lighting substituted, the system light output flux, and the available time of sunny weather at the geographic location.

  13. Construction of an Optical Fiber Strain Gauge

    NASA Astrophysics Data System (ADS)

    Sulaiman, Najwa

    This project is focused on the construction of an optical fiber strain gauge that is based on a strain gauge described by Butter and Hocker. Our gauge is designed to generate an interference pattern from the signals carried on two bare single-mode fibers that are fastened to an aluminum cantilever. When the cantilever experiences flexural stress, the interference pattern should change. By observing this change, it is possible to determine the strain experienced by the cantilever. I describe the design and construction of our optical fiber strain gauge as well as the characterization of different parts of the apparatus.

  14. Mobile fiber-optic laser Doppler anemometer.

    PubMed

    Stieglmeier, M; Tropea, C

    1992-07-20

    A laser Doppler anemometer (LDA) has been developed that combines the compactness and low power consumption of laser diodes and avalanche photodiodes with the flexibility and possibility of miniaturization by using fiber-optic probes. The system has been named DFLDA for laser diode fiber LDA and is especially suited for mobile applications, for example, in trains, airplanes, or automobiles. Optimization considerations of fiber-optic probes are put forward and several probe examples are described in detail. Measurement results from three typical applications are given to illustrate the use of the DFLDA. Finally, a number of future configurations of the DFLDA concept are discussed.

  15. Wide bandwidth and high coupling efficiency Si3N4-on-SOI dual-level grating coupler.

    PubMed

    Sacher, Wesley D; Huang, Ying; Ding, Liang; Taylor, Benjamin J F; Jayatilleka, Hasitha; Lo, Guo-Qiang; Poon, Joyce K S

    2014-05-05

    We propose and experimentally demonstrate fiber-to-chip grating couplers with aligned silicon nitride (Si(3)N(4)) and silicon (Si) grating teeth for wide bandwidths and high coupling efficiencies without the use of bottom reflectors. The measured 1-dB bandwidth is a record 80 nm, and the measured peak coupling efficiency is -1.3 dB, which is competitive with the best Si-only grating couplers. The grating couplers are integrated in a Si(3)N(4) on silicon-on-insulator (SOI) integrated optics platform with aligned waveguides in both the Si(3)N(4) and Si, and we demonstrate a 1 × 4 tunable multiplexer/demultiplexer using the Si(3)N(4)-on-SOI dual-level grating couplers and thermally-tuned Si microring resonators.

  16. Optical fiber modulator derivates from hollow optical fiber with suspended core.

    PubMed

    Yang, Xinghua; Liu, Yanxin; Tian, Fengjun; Yuan, Libo; Liu, Zhihai; Luo, Shenzi; Zhao, Enming

    2012-06-01

    A fiber optic integrated modulation-depth-tunable modulator based on a type of hollow optical fiber with suspended core is proposed and investigated. We synthesized magnetic fluid containing superparamagnetic Fe(3)O(4) nanoparticles and encapsulated it in the hollow optical fiber as the cladding layer of the suspended core by fusing the hollow optical fiber with the multimode optical fibers. The light with a wavelength of 632.8 nm is coupled in and out of the modulating element by a tapering technique. Experimental results show that the light attenuation in the system can be greatly influenced by only 2.0×10(-2) μL of the magnetic fluid under different magnetic field strengths. The saturated modulation depth is 43% when the magnetic field strength is 489 Oe. The response time of the system is <120 ms. Significantly, this work presents information for the development of all-fiber modulators, including other integrated electro-optic devices, such as optical switch, optical fiber filter, and magnetic sensors utilizing the special structure of this hollow optical fiber with suspended core and superparamagnetic magnetic fluid.

  17. Flow sensor using optical fiber strain gauges

    NASA Astrophysics Data System (ADS)

    Schmitt, Nicolas F.; Morgan, R.; Scully, Patricia J.; Lewis, Elfed; Chandy, Rekha

    1995-09-01

    A novel technique for the measurement of air flow velocity using an optical fiber sensor is reported. The sensor measures the deformation of a rubber cantilever beam when subjected to the stresses induced by drag forces in the presence of the airflow. Tests performed in a wind tunnel have indicated a sensitivity of 2 (mu) /(m/s). A qualitative model based on fiber mode propagation has been developed which allows the sensor to be characterized in terms of optical losses. A single 1 mm diameter polymer fiber is mounted on the rectangular section rubber cantilever (section 14 mm by 6 mm) and six grooves are etched into the fiber which extend into the core of the fiber. As the beam deviates the surface deforms (stretches or contracts) and the fiber is subjected to strain. As the strain is increased the grooves become wider and the amount of light transmitted through the fiber is reduced due to increased losses. The sensor described has all the advantages of optical fiber sensors including electrical noise immunity and intrinsic safety for use in hazardous environments. However, its simple construction, robustness, versatility for a number of different fluid applications, as well as relatively low cost make it attractive for use in a wide variety of measurement applications e.g. wind velocity measurement where airborne moisture or chemicals are present.

  18. Compensated vibrating optical fiber pressure measuring device

    DOEpatents

    Fasching, George E.; Goff, David R.

    1987-01-01

    A microbending optical fiber is attached under tension to a diaphragm to se a differential pressure applied across the diaphragm which it causes it to deflect. The fiber is attached to the diaphragm so that one portion of the fiber, attached to a central portion of the diaphragm, undergoes a change in tension; proportional to the differential pressure applied to the diaphragm while a second portion attached at the periphery of the diaphragm remains at a reference tension. Both portions of the fiber are caused to vibrate at their natural frequencies. Light transmitted through the fiber is attenuated by both portions of the tensioned sections of the fiber by an amount which increases with the curvature of fiber bending so that the light signal is modulated by both portions of the fiber at separate frequencies. The modulated light signal is transduced into a electrical signal. The separate modulation signals are detected to generate separate signals having frequencies corresponding to the reference and measuring vibrating sections of the continuous fiber, respectively. A signal proportional to the difference between these signals is generated which is indicative of the measured pressure differential across the diaphragm. The reference portion of the fiber is used to compensate the pressure signal for zero and span changes resulting from ambient temperature and humidity effects upon the fiber and the transducer fixture.

  19. Nanosecond laser damage of optical multimode fibers

    NASA Astrophysics Data System (ADS)

    Mann, Guido; Krüger, Jörg

    2016-07-01

    For pulse laser materials processing often optical step index and gradient index multimode fibers with core diameters ranging from 100 to 600 μm are used. The design of a high power fiber transmission system must take into account limitations resulting from both surface and volume damage effects. Especially, breakdown at the fiber end faces and selffocusing in the fiber volume critically influence the fiber performance. At least operation charts are desirable to select the appropriate fiber type for given laser parameters. In industry-relevant studies the influence of fiber core diameter and end face preparation on laser-induced (surface) damage thresholds (LIDT) was investigated for frequently used all-silica fiber types (manufacturer LEONI). Experiments on preform material (initial fiber material) and compact specimens (models of the cladding and coating material) accompanied the tests performed in accordance with the relevant LIDT standards ISO 21254-1 and ISO 21254-2 for 1-on-1 and S-on-1 irradiation conditions, respectively. The relation beam diameter vs. LIDT was investigated for fused silica fibers. Additionally, laser-induced (bulk) damage thresholds of fused silica preform material F300 (manufacturer Heraeus) in dependence on external mechanical stress simulating fiber bending were measured. All experiments were performed with 10-ns laser pulses at 1064 and 532 nm wavelength with a Gaussian beam profile.

  20. Fiber optic plantar pressure/shear sensor

    NASA Astrophysics Data System (ADS)

    Soetanto, William; Nguyen, Ngoc T.; Wang, Wei-Chih

    2011-04-01

    A full-scale foot pressure/shear sensor that has been developed to help diagnose the cause of ulcer formation in diabetic patients is presented. The design involves a tactile sensor array using intersecting optical fibers embedded in soft elastomer. The basic configuration incorporates a mesh that is comprised of two sets of parallel optical fiber plane; the planes are configured so the parallel rows of fiber of the top and bottom planes are perpendicular to each other. Threedimensional information is determined by measuring the loss of light from each of the waveguide to map the overall pressure distribution and the shifting of the layers relative to each other. In this paper we will present the latest development on the fiber optic plantar pressure/shear sensor which can measure normal force up from 19.09 kPa to 1000 kPa.

  1. Miniature fiber optic surface plasmon resonance biosensors

    NASA Astrophysics Data System (ADS)

    Slavik, Radan; Brynda, Eduard; Homola, Jiri; Ctyroky, Jiri

    1999-01-01

    A novel design of surface plasmon resonance fiber optic sensor is reported which leads to a compact, highly miniaturized sensing element with excellent sensitivity. The sensing device is based on a side-polished single-mode optical fiber with a thin metal overlayer supporting surface plasmon waves. The strength of interaction between a fiber mode and a surface plasmon wave depends strongly on the refractive index near the sensing surface. Therefore, refractive index changes associated with biospecific interaction between antibodies immobilized on the sensor and antigen molecules can be monitored by measuring light intensity variations. Detection of horse radish peroxidase (HRP) of the concentration of 100 ng/ml has been accomplished using the fiber optic sensor with a matrix of monoclonal antibodies against HRP immobilized on the sensor surface.

  2. Submicron diameter single crystal sapphire optical fiber

    DOE PAGES

    Hill, Cary; Homa, Daniel; Liu, Bo; ...

    2014-10-02

    In this work, a submicron-diameter single crystal sapphire optical fiber was demonstrated via wet acid etching at elevated temperatures. Etch rates on the order 2.3 µm/hr were achievable with a 3:1 molar ratio sulfuric-phosphoric acid solution maintained at a temperature of 343°C. A sapphire fiber with an approximate diameter of 800 nm was successfully fabricated from a commercially available fiber with an original diameter of 50 µm. The simple and controllable etching technique provides a feasible approach to the fabrication of unique waveguide structures via traditional silica masking techniques. The ability to tailor the geometry of sapphire optical fibers ismore » the first step in achieving optical and sensing performance on par with its fused silica counterpart.« less

  3. Submicron diameter single crystal sapphire optical fiber

    SciTech Connect

    Hill, Cary; Homa, Daniel; Liu, Bo; Yu, Zhihao; Wang, Anbo; Pickrell, Gary

    2014-10-02

    In this work, a submicron-diameter single crystal sapphire optical fiber was demonstrated via wet acid etching at elevated temperatures. Etch rates on the order 2.3 µm/hr were achievable with a 3:1 molar ratio sulfuric-phosphoric acid solution maintained at a temperature of 343°C. A sapphire fiber with an approximate diameter of 800 nm was successfully fabricated from a commercially available fiber with an original diameter of 50 µm. The simple and controllable etching technique provides a feasible approach to the fabrication of unique waveguide structures via traditional silica masking techniques. The ability to tailor the geometry of sapphire optical fibers is the first step in achieving optical and sensing performance on par with its fused silica counterpart.

  4. Analysis on vertical directional couplers with long range surface plasmons for multilayer optical routing

    NASA Astrophysics Data System (ADS)

    Alam, B.; Veroli, A.; Benedetti, A.

    2016-08-01

    A structure featuring vertical directional coupling of long-range surface plasmon polaritons between strip waveguides at λ = 1.55 μm is investigated with the aim of producing efficient elements that enable optical multilayer routing for 3D photonics. We have introduced a practical computational method to calculate the interaction on the bent part. This method allows us both to assess the importance of the interaction in the bent part and to control it by a suitable choice of the fabrication parameters that helps also to restrain effects due to fabrication issues. The scheme adopted here allows to reduce the insertion losses compared with other planar and multilayer devices.

  5. Fiber optics wavelength division multiplexing(components)

    NASA Technical Reports Server (NTRS)

    Hendricks, Herbert D.

    1985-01-01

    The long term objectives are to develop optical multiplexers/demultiplexers, different wavelength and modulation stable semiconductor lasers and high data rate transceivers, as well as to test and evaluate fiber optic networks applicable to the Space Station. Progress in each of the above areas is briefly discussed.

  6. Multiplexed fiber-optic transmission system

    NASA Technical Reports Server (NTRS)

    Bell, C. H.

    1977-01-01

    Digital, audio, and video data channels spanning 100 megahertz bandwidth are transmitted via single fiber-optical link. System is flexible by virtue of its plug-in modularity and optical patchboard that allows it to adjust to data and bandwidth changes.

  7. In Situ Fiber-Optic Reflectance Monitor

    NASA Technical Reports Server (NTRS)

    Linton, Roger C.; Gray, Perry A.

    1996-01-01

    In situ fiber-optic reflectance monitor serves as simple means of monitoring changes in reflectance of specimen exposed to simulated outerspace or other environments in vacuum chamber. Eliminates need to remove specimen from vacuum chamber, eliminating optical changes and bleaching such removal causes in coatings.

  8. Optical Fiber Communications Cable Connector.

    DTIC Science & Technology

    1981-07-01

    incorp- oration of the TRW Cinch Optalign 4 double elbow " fiber alignment guide concept. Means for connecting either Siecor or ITT six fiber cable were...the guide, and forced toward the top cusp by the double elbow con- figuration. The geometry of the guide is such that normal tolerances of molded or

  9. NITINOL Interconnect Device for Optical Fiber Waveguides

    DTIC Science & Technology

    1981-07-01

    LE EL,~NAVSEA REPORT NO. S27L~kV-NL 4P fNSWNC TR 81-129 1 JULY 1981 0 NITINOL INTERC&INECT DEVICE FOR OPTICAL FIBER WAVEGUIDES FINAL REPORT A...ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER NSWC TR 81-129I 1-19 -A )ci , ’ 4 TI TL E (and Sbtitle) S. TYPE OF REPORT & PERIOD COVERED NITINOL ... NITINOL Optical Fibers 20. ABSTRACT (Continue on reverse side if neceeewy and identify by block number) Two different interconnect devices for optical

  10. Multimode fiber optic wavelength division multiplexing

    NASA Technical Reports Server (NTRS)

    Spencer, J. L.

    1982-01-01

    Optical wavelength division multiplexing (WDM) systems, with signals transmitted on different wavelengths through a single optical fiber, can have increased bandwidth and fault isolation properties over single wavelength optical systems. Two WDM system designs that might be used with multimode fibers are considered and a general description of the components which could be used to implement the system are given. The components described are sources, multiplexers, demultiplexers, and detectors. Emphasis is given to the demultiplexer technique which is the major developmental component in the WDM system.

  11. Fiber optic phase stepping system for interferometry

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.; Beheim, Glenn

    1991-01-01

    A closed loop phase control system using an all-fiber optical configuration has been developed for use in phase-stepping interferometry. This system drives the relative phase of two interfering beams through a sequence of pi/2 rad increments so that the initial relative phase of these beams can be determined. This phase-stepping system uses optical fibers to provide spatially uniform phase steps from a flexible, easily aligned optical configuration. In addition, this system uses phase feedback to eliminate phase modulator errors and to compensate for phase drifts caused by environmental disturbances.

  12. Optical fiber sensors for life support applications

    NASA Astrophysics Data System (ADS)

    Lieberman, R. A.; Schmidlin, E. M.; Ferrell, D. J.; Syracuse, S. J.

    1992-07-01

    Preliminary experimental results on systems designed to demonstrate sensor operation in regenerative food production and crew air supply applications are presented. The systems use conventional fibers and sources in conjunction with custom wavelength division multiplexers in their optical signal processing sections and nonstandard porous optical fibers in the optical sensing elements. It is considered to be possible to create practical sensors for life-support system applications, and particularly, in regenerative food production environments, based on based on reversible sensors for oxygen, carbon monoxide, and humidity.

  13. Optical fiber sensors for life support applications

    NASA Technical Reports Server (NTRS)

    Lieberman, R. A.; Schmidlin, E. M.; Ferrell, D. J.; Syracuse, S. J.

    1992-01-01

    Preliminary experimental results on systems designed to demonstrate sensor operation in regenerative food production and crew air supply applications are presented. The systems use conventional fibers and sources in conjunction with custom wavelength division multiplexers in their optical signal processing sections and nonstandard porous optical fibers in the optical sensing elements. It is considered to be possible to create practical sensors for life-support system applications, and particularly, in regenerative food production environments, based on based on reversible sensors for oxygen, carbon monoxide, and humidity.

  14. Optical Sensors Based on Plastic Fibers

    PubMed Central

    Bilro, Lúcia; Alberto, Nélia; Pinto, João L.; Nogueira, Rogério

    2012-01-01

    The recent advances of polymer technology allowed the introduction of plastic optical fiber in sensor design. The advantages of optical metrology with plastic optical fiber have attracted the attention of the scientific community, as they allow the development of low-cost or cost competitive systems compared with conventional technologies. In this paper, the current state of the art of plastic optical fiber technology will be reviewed, namely its main characteristics and sensing advantages. Several measurement techniques will be described, with a strong focus on interrogation approaches based on intensity variation in transmission and reflection. The potential applications involving structural health monitoring, medicine, environment and the biological and chemical area are also presented. PMID:23112707

  15. Design of fiber optic adaline neural networks

    NASA Astrophysics Data System (ADS)

    Ghosh, Anjan K.; Trepka, Jim

    1997-03-01

    Based on possible optoelectronic realization of adaptive filters and equalizers using fiber optic tapped delay lines and spatial light modulators we describe the design of a single-layer fiber optic Adaline neural network that can be used as a bit pattern classifier. In our design, we employ as few electronic devices as possible and use optical computation to utilize the advantages of optics in processing speed, parallelism, and interconnection. The described new optical neural network design is for optical processing of guided light wave signals, not electronic signals. We analyze the convergence or learning characteristics of the optoelectronic Adaline in the presence of errors in the hardware. We show that with such an optoelectronic Adaline it is possible to detect a desired code word/token/header with good accuracy.

  16. Fiber-optic interconnection networks for spacecraft

    NASA Technical Reports Server (NTRS)

    Powers, Robert S.

    1992-01-01

    The overall goal of this effort was to perform the detailed design, development, and construction of a prototype 8x8 all-optical fiber optic crossbar switch using low power liquid crystal shutters capable of operation in a network with suitable fiber optic transmitters and receivers at a data rate of 1 Gb/s. During the earlier Phase 1 feasibility study, it was determined that the all-optical crossbar system had significant advantages compared to electronic crossbars in terms of power consumption, weight, size, and reliability. The result is primarily due to the fact that no optical transmitters and receivers are required for electro-optic conversion within the crossbar switch itself.

  17. Optical fiber Raman amplifier and distributed fiber Raman sensors

    NASA Astrophysics Data System (ADS)

    Zhang, Zaixuan; Jin, Shangzhong; Liu, Honglin; Kim, Insoo S.; Wang, Jianfeng; Wu, Xiaobiao; Guo, Ning; Liu, Tao; Yu, Xiangdong

    2003-06-01

    The backscattering spectrum of optical fiber has been measured by use 1427 nm Raman laser and Q8384 optical spectrum analyzer and Stokes and anti-Stokes ZX band backscattering spectrum has been first observed and discussed, ZX band frequency shift is 1THz, bandwidth 3THz(3dB). Optimum design of S-band negative dispersion DCF discrete fiber Raman amplifier has been researched by OPTIAMP DESIGN 3.3 SOFTWARE (made in Canada Optiwave Corporation) and gain spectrum and gain vs. power of DCF discrete fiber Raman amplifier have been measured, practical including Stokes ZX band backscattering gain effect. Pump on/off small signal gain is 13dB (pump power 700mw; fiber 5.1km) and gain band width is 88nm (1440nm-1528nm). The operation principle, configuration and performance of distributed fiber Raman temperature sensors system has been researched. Amplification of anti-Stokes spontaneity Raman scattering (ARS) effect of fiber and its temperature effect has been first observed and discussed. It has been applied to 30km distributed FRS system.

  18. Fiber optic strain measurement for machine monitoring

    NASA Astrophysics Data System (ADS)

    Hoffmann, L.; Mueller, M. S.; Koch, A. W.

    2007-06-01

    Monitoring machines during operation is an important issue in measurement engineering. The usual approach to monitoring specific machine components is using strain gauges. Strain gauges, however, may sometimes not be used if conditions are harsh or installation space is limited. Fiber optic sensors seem to be an alternative here, but dynamic health monitoring has been dificult so far. The focus of this field study is to measure vibration characteristics of machine parts during operation using fiber optic sensors with the objective of early damage detection. If that was possible, downtime and maintenance costs could be minimized. Therefore a field test for dynamic fiber optic strain measurement on a roller bearing was carried out. The test setup consisted of the bearing built into a gear test stand and equipped with an array of fiber Bragg grating sensors. Fifteen fiber sensors were interrogated with a sample rate of 1 kHz and the vibration pattern was extracted. The radial load distribution was measured with high spatial resolution and a high degree of compliance with simulation data was found. The findings suggest that fiber optic health monitoring for machine components is feasible and reasonable. Especially with the help of distributed sensing on various components extensive health monitoring on complex technical systems is possible.

  19. Compact parallel optical interface built with optical fiber tips

    NASA Astrophysics Data System (ADS)

    Kopp, Christophe; Gilbert, Karen; Bernabe, Stéphane; Albert, Blandine

    2006-09-01

    MultiChip Module approach and the use of micro-optics offer determinant solutions to reach the mechanical compactness required by most applications for high rate data communications transmitters and receivers. Such a miniaturization often leads to develop very challenging assembling processes when fiber coupling is needed. In this paper we present an original fabrication process to build very small parallel optical interface with optical fiber tips. This fabrication process is based on common fiber ribbon mounting into wet etched V shaped holder into silicon and a dicing-polishing step to create small pieces with optical quality considering flatness and roughness. The dicing-polishing principle is well-known in integrated waveguides technology. An example of realization is presented to connect a parallel optical subassembly transmitter with a MPO/MTP connector. The results show that the dicing-polishing step allows to obtain a diced-polished face with a roughness about 5 to 10nm onto the fiber. Such an optical quality is as good as a cleaved fiber when measuring light coupling performances. Thus, such micro-optical components offer a new building block for designers to extract the light from their photonic devices. Moreover, the fabrication process appears to be low cost and compatible with mass production.

  20. Experimental study of resonance fiber optic gyroscope employing a dual-ring resonator

    NASA Astrophysics Data System (ADS)

    Fan, Yue; Wang, Wei

    2016-09-01

    A dual-ring resonator which is available to alter the full width at half maximum (FWHM) without altering the free spectrum range (FSR) for practice applications is analyzed theoretically and set up in practice. The parameters of the dual-ring resonator have been optimized in simulation, the resonance depth and the dynamic range are enhanced. The prototype is set up with single mode fiber of 8 meter and two 95 : 5 couplers for open loop experiment. The FWHM of the dual-ring resonator is demonstrated less than 1.5MHz and the fineness is calculated to be 37 during the frequency sweeping experiment. The frequency locking experiment with demodulation curve method has been accomplished, and the locking time achieves less than 40ms. All these provide a basic reference for optimizing the resonance fiber optic gyro based on dual-ring resonator.

  1. Exploiting surface plasmon scattering on optical fibers

    NASA Astrophysics Data System (ADS)

    Klantsataya, Elizaveta; François, Alexandre; Sciacca, Beniamino; Zuber, Agnieszka; Ebendorff-Heidepriem, Heike; Hoffmann, Peter; Monro, Tanya M.

    2016-12-01

    For decades Surface Plasmon Resonance (SPR) has been one of the corner stones of label free biosensing with a wide range of architectures including optical fiber based SPR. Traditionally, the resonance is monitored through reflectivity measurements at a single wavelength as a function of the incident angle in a standard Kretschmann configuration, or transmission of broadband light through an optical fiber. In both cases, SPR is inferred through optical losses. An alternative approach is to use SPR scattering induced by rough metallic coatings, enabling to turn an intrinsically nonradiative process into a radiative one. As a result, the SPR signal corresponding to the resonance can be seen as light at specific wavelengths being re-emitted by the rough metallic coating. Here, we present results we have achieved using SPR scattering as an alternative approach for optical fiber based plasmonic sensors. Although the use of a rough metallic coating induces some inherent limitations, such as a lower resolution, the architectural advantages and simplicity of the approach offer additional opportunities, such as multiplexing and self-referencing, which are not possible otherwise with a single fiber SPR sensor. A way to overcome the lower resolution that involves the use of microstructured optical fibers, as well as a new perspective on a complementary application, such as Metal Enhanced Fluorescence, which greatly benefits from SPR scattering, will be presented.

  2. Single optical fiber probe for optogenetics

    NASA Astrophysics Data System (ADS)

    Falk, Ryan; Habibi, Mohammad; Pashaie, Ramin

    2012-03-01

    With the advent of optogenetics, all optical control and visualization of the activity of specific cell types is possible. We have developed a fiber optic based probe to control/visualize neuronal activity deep in the brain of awake behaving animals. In this design a thin multimode optical fiber serves as the head of the probe to be inserted into the brain. This fiber is used to deliver excitation/stimulation optical pulses and guide a sample of the emission signal back to a detector. The major trade off in the design of such a system is to decrease the size of the fiber and intensity of input light to minimize physical damage and to avoid photobleaching/phototoxicity but to keep the S/N reasonably high. Here the excitation light, and the associated emission signal, are frequency modulated. Then the output of the detector is passed through a time-lens which compresses the distributed energy of the emission signal and maximizes the instantaneous S/N. By measuring the statistics of the noise, the structure of the time lens can be designed to achieve the global optimum of S/N. Theoretically, the temporal resolution of the system is only limited by the time lens diffraction limit. By adding a second detector, we eliminated the effect of input light fluctuations, imperfection of the optical filters, and back-reflection of the excitation light. We have also designed fibers and micro mechanical assemblies for distributed delivery and detection of light.

  3. A new beat interference cancellation receiver with 3×3 optical coupler for the SSB-OOFDM signal with reduced guard band

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Ma, Jianxin

    2016-05-01

    In this paper, we present a new method to implement beat interference cancellation receiver (BICR) for single-sideband optical orthogonal frequency division multiplexing (SSB-OOFDM) signal, which improves the spectral efficiency (SE) by reducing the guard band (GB) between the optical carrier and the OOFDM signal while mitigating the impact of signal-signal beat interference (SSBI). This BICR structure is relatively simple using only an optical interleaver (IL), a 3×3 optical coupler (OC) and three photodiodes (PDs). A system simulation for the 40 Gbit/s 16-QAM SSB-OOFDM signal with the reduced GB is carried out to prove the feasibility of this new scheme. The simulation results show that our proposed BICR has a better performance to suppress SSBI and a higher SE than the conventional direct-detection receiver (CDDR) according to the EVMs and the constellations.

  4. Safely splicing glass optical fibers

    NASA Technical Reports Server (NTRS)

    Korbelak, K.

    1980-01-01

    Field-repair technique fuses glass fibers in flammable environment. Apparatus consists of v-groove vacuum chucks on manipulators, high-voltage dc power supply and tungsten electrodes, microscope to observe joint alignment and fusion, means of test transmission through joint. Apparatus is enclosed in gas tight bos filled with inert gas during fusion. About 2 feet of fiber end are necessary for splicing.

  5. Research and Development on Ultra-Lightweight Low-Loss Optical Fiber Communication Cable.

    DTIC Science & Technology

    FIBER OPTICS TRANSMISSION LINES, LIGHTWEIGHT), GLASS , FIBERS , ORGANIC COATINGS, POLYURETHANE RESINS, SOLUTIONS(GENERAL), POWDERS, ELECTROSTATICS...EXTRUSION, RUGGEDIZED EQUIPMENT, BROADBAND, OPTICAL COMMUNICATIONS, TACTICAL COMMUNICATIONS, FIBER OPTICS, LOSSES.

  6. Realization of efficient metal grating couplers for membrane-based integrated photonics.

    PubMed

    Higuera-Rodriguez, Aura; Dolores-Calzadilla, Victor; Jiao, Yuqing; Geluk, Erik J; Heiss, Dominik; Smit, Meint K

    2015-06-15

    Grating couplers are widely used to couple light between photonic integrated circuits and optical fibers. Here, we fabricate and characterize a device based on a buried metal grating. In contrast to dielectric gratings, simulations predict strongly reduced parasitic leakage of light to the substrate and are performance independent of the optical buffer thickness, while using standard fabrication processes with high yield. The gratings show a 3 dB bandwidth of 61 nm and chip-to-fiber coupling efficiency of 54%, which makes them attractive building blocks for on-wafer testing and dense optical interconnects.

  7. Fiber laser coupled optical spark delivery system

    DOEpatents

    Yalin, Azer; Willson, Bryan; Defoort, Morgan; Joshi, Sachin; Reynolds, Adam

    2008-03-04

    A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

  8. Fiber coupled optical spark delivery system

    DOEpatents

    Yalin, Azer; Willson, Bryan; Defoort, Morgan

    2008-08-12

    A spark delivery system for generating a spark using a laser beam is provided, the spark delivery system including a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. In addition, the laser delivery assembly includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. In accordance with embodiments of the present invention, the assembly may be used to create a spark in a combustion engine. In accordance with other embodiments of the present invention, a method of using the spark delivery system is provided. In addition, a method of choosing an appropriate fiber for creating a spark using a laser beam is also presented.

  9. Mode coupling in multimode plastic optical fiber

    NASA Astrophysics Data System (ADS)

    Wang, Jing

    1999-10-01

    In this thesis, we report the results of our experimental and theoretical studies of mode coupling in multi-mode optical fibers. We demonstrate that strong mode coupling in poly(methyl methacrylate) (PMMA) based multi-mode plastic optical fibers (POFs) effectively increases the bandwidth performance by a factor of as much as an order of magnitude. We investigate in detail the physical mechanisms of mode coupling. The most important feature of an optical fiber waveguide is its bandwidth, which defines its information carrying capacity. A major limitation on the bandwidth of multi- mode glass and plastic optical fibers is modal dispersion, in which different optical modes propagate at different velocities and the dispersion grows linearly with length. Modal dispersion in an optical fiber waveguide is reduced through mode coupling by allowing the energy packets of a signal pulse at different times to occupy different modes as they are propagating down the waveguide. With mode coupling, pulse broadening varies only as a characteristic square root function of the fiber length as opposed to following the usual linear dependence The bandwidths of both step index (SI) and graded index (GI) POF samples are carefully measured in the time domain and determined to be 80 +/- 10 MHz per 100m for SI POF and 3.0 +/- 0.4 GHz per 100m for GI POF. The index profiles are first directly measured by standard high accuracy techniques, such as the near field method, the refracted near field ray method, and the transverse interferometric method (TIM), and then probed with the highly sensitive differential mode delay (DMD) measurement. We developed a highly efficient numerical methodology based on the Streifer-Kurtz WKB theory for solving the scalar wave equation in fiber waveguides and implemented the new method in MathematicaTM to simulate fiber optical transmission characteristics for an arbitrary given index profile, such as the DMD profile, impulse response, and bandwidth performance

  10. Multimode-Optical-Fiber Imaging Probe

    NASA Technical Reports Server (NTRS)

    Jackson, Deborah

    1999-01-01

    Currently, endoscopic surgery uses single-mode fiber-bundles to obtain in vivo image information inside the orifices of the body. This limits their use to the larger natural orifices and to surgical procedures where there is plenty of room for manipulation. The knee joint, for example, can be easily viewed with a fiber optic viewer, but joints in the finger cannot. However, there are a host of smaller orifices where fiber endoscopy would play an important role if a cost effective fiber probe were developed with small enough dimensions (less than or equal to 250 microns). Examples of beneficiaries of micro-endoscopes are the treatment of the Eustatian tube of the middle ear, the breast ducts, tear ducts, coronary arteries, fallopian tubes, as well as the treatment of salivary duct parotid disease, and the neuro endoscopy of the ventricles and spinal canal. This work describes an approach for recovering images from tightly confined spaces using multimode. The concept draws upon earlier works that concentrated on image recovery after two-way transmission through a multimode fiber as well as work that demonstrated the recovery of images after one-way transmission through a multimode fiber. Both relied on generating a phase conjugated wavefront, which was predistorted with the characteristics of the fiber. The approach described here also relies on generating a phase conjugated wavefront, but utilizes two fibers to capture the image at some intermediate point (accessible by the fibers, but which is otherwise visually inaccessible).

  11. Liquid-filled hollow core microstructured polymer optical fiber.

    PubMed

    Cox, F M; Argyros, A; Large, M C J

    2006-05-01

    Guidance in a liquid core is possible with microstructured optical fibers, opening up many possibilities for chemical and biochemical fiber-optic sensing. In this work we demonstrate how the bandgaps of a hollow core microstructured polymer optical fiber scale with the refractive index of liquid introduced into the holes of the microstructure. Such a fiber is then filled with an aqueous solution of (-)-fructose, and the resulting optical rotation measured. Hence, we show that hollow core microstructured polymer optical fibers can be used for sensing, whilst also fabricating a chiral optical fiber based on material chirality, which has many applications in its own right.

  12. Evaluations of fiber optic sensors for interior applications

    SciTech Connect

    Sandoval, M.W.; Malone, T.P.

    1996-02-01

    This report addresses the testing and evaluation of commercial fiber optic intrusion detection systems in interior applications. The applications include laying optical fiber cable above suspended ceilings to detect removal of ceiling tiles, embedding optical fibers inside a tamper or item monitoring blanket that could be placed over an asset, and installing optical fibers on a door to detect movement or penetration. Detection capability of the fiber optic sensors as well as nuisance and false alarm information were focused on during the evaluation. Fiber optic sensor processing, system components, and system setup are described.

  13. Closed-loop phase stabilizing and phase stepping methods for fiber-optic projected-fringe digital interferometry.

    PubMed

    Chao, Zhang; Fa-Jie, Duan

    2011-11-01

    Closed-loop active homodyne control can be used to make an interferometer steady against phase fluctuating followed by, for example, temperature gradients. This technology is introduced to stabilize π/2 -rad phase steps in a full-field interferometer. Two beams emitted from a fiber-optic coupler are combined to form an interference fringe pattern on a diffusely reflecting object. Fresnel reflections from the distal fiber ends undergo a double pass in the fibers and interference at the fourth port of the coupler which formed a Michelson interferometer. We suggested two means of ac phase tracking (PTAC) and dc phase tracking (PTDC) to maintain the interference intensity at quadrature by feedback control. Stepping between quadrature positions forces a π/2 -rad phase step. A method based on the ratio of harmonic of the interference signal was proposed to estimate phase step accuracy. A root-mean-square phase stability of 1.5 mrad and phase step accuracy of 2.6 mrad were measured with PTAC and a root-mean-square phase stability of 2 mrad and phase step accuracy of 13.8 mrad were measured with PTDC for the fiber-optic projected-fringe digital interferometry following the same condition. It worked well in two hours without resetting the integrator.

  14. Compensated Fiber-Optic Frequency Distribution Equipment

    DTIC Science & Technology

    2010-11-01

    availability of long- haul components at 1550 nm. If installing a new system with new fiber, it may also make sense to use dispersion-shifted fiber, which...selected the 1550 nm (C-Band) for the optical wavelength. Although this wavelength requires CD correction in long haul systems, it makes good sense for...CD, we place both lasers on the same ITU channel, and adjust their center wavelengths to within a few GHz of each other. Ideally, the two signals

  15. Fiber optically isolated and remotely stabilized data transmission system

    DOEpatents

    Nelson, M.A.

    1992-11-10

    A fiber optically isolated and remotely stabilized data transmission systems described wherein optical data may be transmitted over an optical data fiber from a remote source which includes a data transmitter and a power supply at the remote source. The transmitter may be remotely calibrated and stabilized via an optical control fiber, and the power source may be remotely cycled between duty and standby modes via an optical control fiber. 3 figs.

  16. Alternative Controller for a Fiber-Optic Switch

    NASA Technical Reports Server (NTRS)

    Peters, Robert

    2007-01-01

    A simplified diagram of a relatively inexpensive controller for a DiCon VX (or equivalent) fiber-optic switch -- an electromechanically actuated switch for optically connecting one or two input optical fibers to any of a number of output optical fibers is shown. DiCon VX fiber-optic switches are used primarily in research and development in the telecommunication industry. This controller can control any such switch having up to 32 output channels.

  17. Fiber optically isolated and remotely stabilized data transmission system

    DOEpatents

    Nelson, Melvin A.

    1992-01-01

    A fiber optically isolated and remotely stabilized data transmission system s described wherein optical data may be transmitted over an optical data fiber from a remote source which includes a data transmitter and a power supply at the remote source. The transmitter may be remotely calibrated and stabilized via an optical control fiber, and the power source may be remotely cycled between duty and standby modes via an optical control fiber.

  18. Compact free-space optical terminal for multi-gigabit signal transmissions with a single-mode fiber

    NASA Astrophysics Data System (ADS)

    Arimoto, Yoshinori

    2009-02-01

    This paper shows the design and the performance of a new free-space optical communication terminal including the results of the indoor and outdoor demonstration experiments in a short link distance. To provide flexible and high-speed connectivity to the terrestrial free-space optical communications, a new compact laser communication terminal has been developed at NICT. The terminal has a feature to connect the free-space laser beam directly to single mode fiber by using a special fiber coupler to focus the free-space laser beam and couple it into the single mode fiber, fast and accurate fine tracking system and a small refractive-type telescope with diffraction limited performance. The bandwidth of the fine tracking system is more than 5 kHz using an off-the-shelf miniature Galvano mirror actuator and an analog PID controller.

  19. Hot Springs-Garrison Fiber Optic Project

    SciTech Connect

    Not Available

    1994-10-01

    Bonneville Power Administration (BPA) is proposing to upgrade its operational telecommunications system between the Hot Springs Substation and the Garrison Substation using a fiber optic system. The project would primarily involve installing 190 kilometers (120 miles) of fiber optic cable on existing transmission structures and installing new fiber optic equipment in BPA`s substation yards and control houses. BPA prepared an environmental assessment (EA) evaluating the proposed action. This EA was published in October 1994. The EA identifies a number of minor impacts that might occur as a result of the proposed action, as well as some recommended mitigation measures. This Mitigation Action Plan (MAP) identifies specific measures to avoid, minimize, or compensate for impacts identified in the EA.

  20. Quantum cryptography over underground optical fibers

    SciTech Connect

    Hughes, R.J.; Luther, G.G.; Morgan, G.L.; Peterson, C.G.; Simmons, C.

    1996-05-01

    Quantum cryptography is an emerging technology in which two parties may simultaneously generated shared, secret cryptographic key material using the transmission of quantum states of light whose security is based on the inviolability of the laws of quantum mechanics. An adversary can neither successfully tap the key transmissions, nor evade detection, owing to Heisenberg`s uncertainty principle. In this paper the authors describe the theory of quantum cryptography, and the most recent results from their experimental system with which they are generating key material over 14-km of underground optical fiber. These results show that optical-fiber based quantum cryptography could allow secure, real-time key generation over ``open`` multi-km node-to-node optical fiber communications links between secure ``islands.``