Showing papers in "Fibers in 1993"
TL;DR: In this article, the authors present a review of distributed optical fiber sensors, where measurements may be taken along the length of a continuous section of optical fiber and thus the information can be obtained from a single instrument and hence the cost per sensing point can be more acceptable.
Abstract: This review paper covers the field of distributed optical fiber sensors, where measurements may be taken along the length of a continuous section of optical fiber. Such a feature greatly increases the information that can be obtained from a single instrument and hence the cost per sensing point can be more acceptable. The review does not attempt to cover all methods, but gives a selection of some of the more interesting theoretical concepts, describes the current status of research, and indicates where optical sensing methods are being applied in commercial instruments.
94 citations
TL;DR: Latency and synchronization issues are discussed, and an integrated system, Tactus, is described, which facilitates the implementation of interactive multimedia computer programs by managing latency and synchronization in the framework of an object-oriented graphical user interface toolkit.
Abstract: Digital interactive media augments interactive computing with video, audio, computer graphics and text, allowing multimedia presentations to be individually and dynamically tailored to the user. Multimedia, and particularly continuous media pose interesting problems for system designers, including those of latency and synchronization. These problems are especially evident when multimedia data is remote and must be accessed via networks. Latency and synchronization issues are discussed, and an integrated system, Tactus, is described. Tactus facilitates the implementation of interactive multimedia computer programs by managing latency and synchronization in the framework of an object-oriented graphical user interface toolkit.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
63 citations
TL;DR: In this article, a micromachined cantilever beam accelerometer is described in which beam deflection is determined optically by the decrease of light coupled across the gap between the waveguide sections.
Abstract: A micromachined cantilever beam accelerometer is described in which beam deflection is determined optically. A diving board structure is anisotropically etched into a silicon wafer. This diving board structure is patterned from the wafer backside so as to leave a small gap between the tip of the diving board and the opposite fixed edge on the front side of the wafer. In order to sense a realistic range of accelerations, a foot mass incorporated onto the end of the beam is found to provide design flexibility. A silicon nitride optical waveguide is then deposited by low pressure chemical vapor deposition (LPCVD) onto the sample. Beam deflection is measured by the decrease of light coupled across the gap between the waveguide sections. In order to investigate sensor response and simulate deflection of the beam, we utilized a separate beam and waveguide section which could be displaced from one another in a precisely controlled manner. Measurements were performed on samples with gaps of 4.0, 6.0, and 8.0 micron and the variation of the fraction of light coupled across the gap as a function of displacement and gap spacing was found to agree with overlap integral calculations.
57 citations
TL;DR: In this paper, an expression describing the relationship of the strain to relative spectral shift was derived from the phase index of refraction of the waveguide and it was experimentally verified.
Abstract: Fiber optic Bragg gratings were used and evaluated as strain gauges. An expression describing the relationship of the strain to relative spectral shift was derived from the phase index of refraction of the waveguide and it was experimentally verified. The application of these sensors in large scale concrete structures was evaluated.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
55 citations
TL;DR: In this article, the survivability of optical fibers for data bus and gyroscope applications in the natural space radiation environment has been analyzed using radiation-induced loss data of single mode, multimode, and polarization-maintaining fibers.
Abstract: The survivability of optical fibers for data bus and gyroscope applications in the natural space radiation environment has been analyzed using radiation-induced loss data of single mode, multimode, and polarization-maintaining fibers. Since it is virtually impossible to simulate the dynamic conditions of space, extrapolations have been made from measurements at dose rates, temperatures, and total doses different from those onboard spacecraft. The anticipated degradation of most Ge-doped silica core fibers and all pure silica core fibers appears to be well within allowable margins in fibers for data bus applications, while the radiation sensitivity of polarization-maintaining fibers could result in a significant decrease in fiber gyro performance.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
52 citations
TL;DR: In this article, the effects of potential loss mechanisms on the performance of erbium-doped resonant fiber lasers and superfluorescent fiber sources were explored via computer simulations, and the rate equations for paired ions were used to understand their saturation behavior and their effect on the slope and threshold of fiber sources.
Abstract: To explain the sub-optimal performance of erbium-doped resonant fiber lasers and superfluorescent fiber sources observed experimentally, the effects of potential loss mechanisms are explored via computer simulations. Pump excited-state absorption (ESA) at 980 nm and 1.48 micrometers , and signal ESA are unable to explain the dependence of the observed effects on concentration. Cooperative upconversion among uniformly distributed erbium ions fails to explain the observed reduction in source slope efficiency with increasing concentration. On the other hand, rapid cross-relaxation between paired ions, which might form in high concentration fibers, can produce the observed dependences. Rate equations for paired ions are used to understand their saturation behavior and their effect on the slope and threshold of fiber sources. Methods to assess the fraction of paired ions are discussed. Measurements suggest that about 18% of the ions in an aluminum co-doped silica fiber with 5 X 10 19 Er 3+ /cm 3 are paired. The effects of paired ions on the gain of Er-doped fiber amplifiers are also briefly discussed.
49 citations
TL;DR: Deformable mirror devices (DMDs) have been under development at Texas Instruments for several years, primarily as spatial light modulators for free-space optical applications such as analog phase modulation and digital projection imaging.
Abstract: Deformable Mirror Devices (DMDs) have been under development at Texas Instruments for several years, primarily as spatial light modulators for free-space optical applications such as analog phase modulation and digital projection imaging. A DMD consists of one or more electrostatically deflectable micromechanical aluminum mirror elements, including both micromirrors suspended from thin flexible hinges and membranes. These devices are fabricated using low temperature silicon-compatible semiconductor processing techniques, and thus can be monolithically fabricated over any addressing circuitry. In the last few years DMDs have been integrated into optical fiber switching systems, and efforts are underway to integrate them as routing switches onto optical waveguides. The DMDs used for optical fiber switching are torsion-hinged devices similar to those used for projection imaging. These devices have been integrated with multimode fibers to construct a 4 X 4 multimode optical fiber cross-bar switch with a 19 dB optical (80:1) extinction ratio for all 16 channels. Extinction ratios of 73 dB optical (20 X 106) have been achieved for single point single mode switches. The waveguide switches currently under development are deformable membranes which are monolithically fabricated on silicon wafers with phosphosilicate glass (PSG) waveguide directional couplers to form optical time delay path selection switches. In this paper we describe the fabrication of deformable mirrors, their integration with optical fibers and waveguides, and the resulting system performance.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
49 citations
TL;DR: In this paper, the authors describe the principles and recent development of a new technique for measuring temperature and strain distribution using Brillouin backscattering rather than Rayleigh and Raman backscatter.
Abstract: This paper describes the principles and recent development of a new technique for measuring temperature and strain distribution using Brillouin backscatteringrather than Rayleigh and Raman backscattering. The technique is based ontemperature- and strain-induced changes in the Brillouin frequency shift. Experimental sensitivities of 1.2 MHz/K and 5.8 MHz/104 strain are demonstrated at awavelength of 1.32 rim. Two approaches for measuring the weak Brillouin line arediscussed. 1 . INTRODUCTION Fiber-optic sensor systems which can explore the distributed measurand over a wide range are categorized as being distributed or quasi-distributed1. Thedistributed fiber sensor systems usually utilize scattering in an optical fiber astheir sensing mechanism, while the quasi-distributed sensor systems or multi-pointsensor systems only employ a fiber as an optical transmission line and have discrete sensors arranged in the fiber or more complicated fiber networks. Of these, thedistributed fiber sensor systems are very attractive since they can operate over
49 citations
TL;DR: A wide range of multiplexing techniques for fiber optic sensors have been proposed and demonstrated over the past 10 years as mentioned in this paper, and systems utilizing multiplexed sensors have undergone field trials which have successfully proven the technology.
Abstract: A wide range of multiplexing techniques for fiber optic sensors have been proposed and demonstrated over the past 10 years. In many cases, systems utilizing multiplexed sensors have undergone field trials which have successfully proven the technology. This paper reviews this technology and discusses recent research efforts in the area.
47 citations
TL;DR: In this paper, an impact detection and location system using fiber optic extrinsic Fizeau interferontric sensors embedded in a graphite/epoxy composite laminate is presented.
Abstract: We present an impact detection and location system which uses fiber optic extrinsic Fizeau interferontric sensors embedded in a graphite/epoxy composite laminate. The acoustic signals generated by the impact events are detected by four fiber optic sensors. The fiber sensor and the embedding process are described. Also developed are a mathematical method and computer program that allow calculations of unambiguous impact location from the sensor data. The impact location can be determined with a 0.5 millimeter resolution and an accuracy typically less than five millimeters.
39 citations
TL;DR: In this article, an analysis is presented on the use of embedded optical fiber sensors in concrete elements and structures for the non-destructive measurement of internal stress and strain as well as for the assessment of structural integrity.
Abstract: In this paper an analysis is presented on the use of embedded optical fiber sensors in concrete elements and structures for the non-destructive measurement of internal stress and strain as well as for the assessment of structural integrity. A discussion of the fundamental materials and micro-mechanical aspects regarding the fiber/matrix interaction is given. In addition, a summary of the experimental results obtained to date is made along with the applications sought for this new technology.
TL;DR: In this article, a PZT actuator-based fiber-optic switches are introduced as low loss, high interchannel optical isolation 1 X 2 and 2 X 2 fiber-Optic switches.
Abstract: Piezoelectric thin film actuator-based fiber-optic switches are introduced as low loss, high interchannel optical isolation 1 X 2 and 2 X 2 fiber-optic switches. A macroscale PZT actuator is built and tested. Preliminary results from a microscale actuator are given. Optical switch configurations and fabrication procedures are highlighted.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this paper, the bridge and cantilever structures have been analyzed and experimental results on sound measurement are presented, where they are applied in acoustic signal detection and noise monitoring, respectively.
Abstract: Micromechanical bridges and cantilevers sensitive to external forces have been fabricated upon Si substrates. They are used as optical waveguides and part of sensor circuits. The waveguides consist of sandwiched layers of an SiO2 buffer, an Al2O3 waveguide and an SiO2 cover. The bridges and cantilevers with very small dimensions such as 100 micrometers in length, 5 micrometers in width and 2.5 micrometers in thickness have been successfully produced. Such bridge- or cantilever-shaped waveguide structures have been applied in acoustic signal detection and noise monitoring. In this paper, the bridge and cantilever structures will be analyzed and experimental results on sound measurement will be presented.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, excited-state absorption measurements performed at 980 nm in erbium-doped silica fibers provide evidence that Er 3+ ions undergo clustering to varying degrees, depending on glass composition.
Abstract: Excited-state absorption measurements performed at 980 nm in erbium-doped silica fibers provide evidence that Er 3+ ions undergo clustering to varying degrees, depending on glass composition. The technique employed allows a quantitative characterization of the degree of clustering. It is found that the smallest degree of clustering occurs in silica fibers co- doped with aluminum, and those prepared by the sol-gel method.
TL;DR: In this article, high purity, high-OH, silica optical fibers were irradiated in a hydrogen atmosphere to explore hydrogen binding into defects created by the ionizing radiation, and significant improvements in subsequent measurements of steady state radiation-induced attenuation were observed.
Abstract: High purity, high-OH, silica optical fibers were irradiated in a hydrogen atmosphere to explore hydrogen binding into defects created by the ionizing radiation. Significant improvements in subsequent measurements of steady state radiation-induced attenuation were observed. Transient and steady state radiation-induced attenuations and long term stability of the phenomena were evaluated.
TL;DR: In this paper, a novel error compensation technique capable of significantly improving the gyroscope performance by reducing the polarization related bias errors of a polarization-rotating (PR) resonator is presented.
Abstract: A novel error compensation technique capable of significantly improving the gyroscope performance by reducing the polarization related bias errors of a polarization-rotating (PR) resonator is presented. It is shown that the PR-resonator has residual errors which depend on the polarization-dependent losses and coupling ratios of the resonator output coupler and on the polarization crosstalk within the ring. A bias error reduction by a factor of 50 or more is achieved by employing the technique which involves periodical switching of the resonance tracking operation between adjacent resonators.
TL;DR: In this article, a two-channel fiber optic grating sensor system using interferometric determination of strain-induced Bragg-wavelength shifts is described, which provides high resolution to quasi-static and dynamic strain perturbations of the gratings in the system.
Abstract: We describe results obtained with a two-channel fiber optic grating sensor system using interferometric determination of strain-induced Bragg-wavelength shifts. The system provides high resolution to quasi-static and dynamic strain perturbations of the gratings in the system. Results demonstrating the detection of low frequency (about 1 Hz) strain levels of about 6 nanostrain/sq rt Hz in a 3-point bending flexural beam experiment are presented.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, a review of optical reflectometry techniques that are capable of achieving spatial resolutions of less than 1 cm is presented, and a white light interferometry technique known as optical low-coherence reflectometry is emphasized.
Abstract: This paper reviews optical reflectometry techniques that are capable of achieving spatial resolutions of less than 1 cm. Advantages and disadvantages of these techniques are discussed. A white light interferometry technique known as optical low-coherence reflectometry is emphasized. This technique has been used to obtain spatial resolutions on the order of tens of microns and reflection sensitivities as low as -148 dB.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this paper, the authors describe an ATM-based passive optical network (APON) and present the results of feasibility tests for the most critical parts of the system: high-speed medium access protocol for upstream transmission (TDMA), burst mode clock synchronisation technique, and high speed electro-optic transceivers applicable to burst mode transmission.
Abstract: Passive Optical Networks (PONs) have been demonstrated to be a cost-attractive approach for the deployment of Fiber- In-The-Loop systems (FITL) having POTS services capability. In the future these systems must be able to carry broadband services in ATM format as defined by CCITT. The present paper describes an ATM-based PON (APON) and presents the results of feasibility tests for the most critical parts of the system: high-speed medium access protocol for upstream transmission(TDMA), burst mode clock synchronisation technique and high-speed electro-optic transceivers applicable to burst mode transmission. System design options such as the downstream and upstream bit rates, the sharing factor and the multiplexingtechnique used for the bidirectional transport of ATM cells are discussed. Issues such as analog CATV services delivery andthe provision of digital video-on-demand (VOD) are covered as well.1. INTRODUCTIONDeployment of fiber in the local loop has become of major interest during the last years. A large number of papers 1..6
TL;DR: First results confirm the exceptional capabilities of the novel monobeam distributed laser Doppler velocimeter (DLDV), which permits the continuous recovery of the flow velocity at any point belonging to the light beam, without moving the collimating optics.
Abstract: Classical LDV techniques permit the recovering of the flow profile at the expense of the movement of projection and recovery optics. This operation limits the performances of the LDV and extends the measurement time. The aim of this communication is to present a novel monobeam distributed laser Doppler velocimeter (DLDV) which permits the continuous recovery of the flow velocity at any point belonging to the light beam, without moving the collimating optics. The DLDV applies the low-coherence multiplexing technique to a backscattering reference-beam LDV scheme. The DLDV uses a very-short coherence source (a superluminescent diode) which feeds an unbalanced interferometer. The sensing arm of the interferometer is launched in the flow while the remote reference arm permits the user to interrogate different flow volumes. The scheme has been implemented by all-fiber components. Preliminary measurements were given on a laboratory hydraulic circuit. The DLDV can be used as a conventional LDV, to measure with high accuracy a flow velocity component in a point of the duct, or in a distributed mode, to recover the flow velocity profile along a duct cross-section. Profiles of the flow were recovered at different average velocity and the first results confirm the exceptional capabilities of the novel instrument.
TL;DR: In this article, an integrated-optic channel waveguide device is configured as a biosensor, which measures a refractive index change on the waveguide surface, so it is called a biorefractometer.
Abstract: An integrated-optic channel waveguide device is configured as a biosensor. The device measures a refractive index change on the waveguide surface, so it is called a biorefractometer. With an appropriate overlay or selective coating, the device can monitor proteins in blood or pollutants and bio-warfare agents in water. We describe the design, fabrication, and testing of a sensor employing a waveguide Mach-Zehnder interferometer configuration. The device is fabricated in a glass substrate using potassium ion exchange. A patterned glass buffer layer defines the sensing and reference arms of the interferometer. A silicone-rubber macro-flow cell confines the liquid above the integrated-optical waveguide device. Salt solution data show that the biorefractometer has a sensitivity ((Delta) neff/(Delta) nLiquid) of 2 X 10-3 and can measure refractive index changes of about 0.005. Data obtained for antigen-antibody binding of the protein IgG indicate that a 10 percent signal change occurs in approximately 1 minute for a 10 (mu) g/ml concentration level.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, the radiation-induced coloring of erbium-doped optical fibers (EDF's) is reported and the radiation hardness of the EDF's is observed to be strongly dependent on composition.
Abstract: The radiation-induced coloring of erbium-doped optical fibers (EDF's) is reported. The radiation hardness of the EDF's is observed to be strongly dependent on composition. The implications for erbium-doped fiber amplifier (EDFA) performance is modelled.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: This paper derives a condition on the utilization factor for ensuring timely delivery of all synchronous messages, and shows that 33% utilization is the tight lower bound, regardless of the number of nodes, message lengths, periods, etc.
Abstract: Timely delivery of multimedia data is one of the key requirements in a distributed multimedia system. In a token ring network, this can be achieved by a proper control of channel access. FDDI uses a timed token MAC protocol to control the token rotation time. During network initialization, a protocol parameter called target token rotation time (TTRT) is determined. Its value indicates the expected token rotation time. Each node is assigned a fraction of the TTRT, known as synchronous bandwidth, for transmitting its synchronous messages which may be deadline constrained. In this paper, we study methods used for setting the protocol parameters such as TTRT and synchronous bandwidth. The goal is to satisfy the message deadlines. In particular, we discuss the use of the normalized proportional scheme for allocating the synchronous bandwidth. We derive a condition on the utilization factor for ensuring timely delivery of all synchronous messages, and show that 33% utilization is the tight lower bound, regardless of the number of nodes, message lengths, periods, etc. Based on this scheme, we address proper selection of TTRT and trade-off between buffer size and the capability of meeting message deadlines.
TL;DR: In this article, a planar waveguide structure can be used simultaneously for beam splitting and generation of phase shifted interference signals, which are necessary for decoding the direction of motion and for interpolation procedures to increase resolution and accuracy.
Abstract: A miniature integrated optical Michelson interferometer in glass based on a 3 X 3 directional coupler for high precision displacement measuring is presented. The planar waveguide structure can be used simultaneously for beam splitting and generation of phase shifted interference signals. The latter are necessary for decoding the direction of motion and for interpolation procedures to increase resolution and accuracy. The basic process for fabricating the waveguides in the integrated optical chip is a double thermal ion exchange of silver and sodium in special glass BGG31. It allows to produce buried waveguides with low loss and modefield dimensions adjusted to standard silica fibers.
TL;DR: In this article, the authors describe bend enhanced fiber (BEF) sensors used to make continuous, linear, real-time measurements of curvatures, which often relate more directly than strains to the control of vibration and position.
Abstract: This paper describes novel bend enhanced fiber (BEF) sensors used to make continuous, linear, real-time measurements of curvatures, which often relate more directly than strains to the control of vibration and position. BEF sensors are made by treating optical fibers to have an optically absorptive zone along a thin axial stripe a few millimeters long. Light transmission through the fiber past this zone then becomes a robust function of curvature, three orders of magnitude more sensitive to bending than in the untreated fiber. Directionality and polarity of curvature are preserved in the transmission function, over a linear range covering five orders of magnitude, centered about zero curvature. Thus, BEF sensors are curvature-measuring optical analogs of elongation-measuring resistance strain gauges, with similar sensitivity. BEF sensors add little or no thickness to the fiber, can be instrumented with simple analog electronics, and have been successfully embedded in composites. Results of dynamic curvature measurements are included, along with characterization data for BEF sensors made with plastic and silica fibers as small as 125 microns.
TL;DR: In this paper, a time delay-based, transmit-receive mode, remotely located, optical control system for wide instantaneous bandwidth phased arrays is introduced, where high channel isolation, low insertion loss optical switching between delayed and undelayed paths is based on polarization switching using the low cost nematic liquid crystal arrays and polarizing beam splitters.
Abstract: We introduce a novel, time delay-based, transmit-receive mode, remotely located, optical control system for wide instantaneous bandwidth phased arrays. Time delays are achieved using a cascade of free-space and fiber-based optical delay lines using bulk imaging optics for low complexity, two dimensional, free-space optical interconnects. High channel isolation, low insertion loss optical switching between delayed and undelayed paths is based on polarization switching using the low cost nematic liquid crystal arrays and polarizing beam splitters. The system allows for noise reduction via spatial and polarization filtering. A dual- channel time-multiplexed system arrangement is used to implement the fast (e.g., 200 beams/s) radar scan rates using the several millisecond response time nematic liquid crystals.
TL;DR: The number of models is reduced to only 1 basic model, based on a power law to describe the stress-induced crack growth, and a choice of 3 testing methods to obtain information about the weak-flaw distribution is given.
Abstract: More than 10 existing lifetime models for optical fibers, based on a power law to describe the stress-induced crack growth, are studied and compared. The number of models is reduced to only 1 basic model. This model is taking into account the effects of proof test. An alternative model, to be used when proof testing is performed on-line, is given as a worst-case limit of the basic model. A choice of 3 testing methods to obtain information about the weak-flaw distribution is given: dynamic-fatigue and variable screen-testing of long lengths or using the failure number during proof test. The models can also be used for titanium-doped fibers, but then a correction must be made for the compressive surface-stress. The lifetime models cannot be used for carbon-coated fibers and for fibers in water without further study.
TL;DR: In this paper, active integrated optical (IO) devices based on the IO nanomechanical effect can be actuated by electrostatic forces, and an intensity modulator, deflection, and focusing and defocusing of a guided wave in a planar waveguide are demonstrated.
Abstract: We demonstrated that active integrated optical (IO) devices based on the IO nanomechanical effect can be actuated by electrostatic forces. In particular, we demonstrated: (1) an intensity modulator, (2) the deflection, and (3) the focusing and defocusing of a guided wave in a planar waveguide.
TL;DR: In this paper, a brief report on an ongoing study concerned with the responses of acousto-optic modulators (AOMs) and deflectors (AODs) exposed to linearly accelerated electrons, gamma rays, and X rays is presented.
Abstract: A brief report on an ongoing study concerned with the responses of acousto-optic modulators (AOMs)and deflectors (AODs) exposed to linearly accelerated electrons, gamma rays, and X rays is presented.The diffracted spatial intensities of PbMoO4, Te02, and InP devices were observed to undergodisplacements and attenuation. Discussions of radiation-induced temperature gradients and color centerformation believed to be responsible for these effects are included.2. INTRODUCTIONThe interests in Optical Computing'3, Optical Processing4, and Optical Correlators5 have raised questionsconcerning the abilities of certain optical components, which are integral to these technologies, to performin space environments.Some components generic to this technology, such as optical fibers, sources, and detectors, have beenstudied for radiation and temperature cycling degradation over prolonged time periods in low earth orbit.The Phillips Laboratory's "Space Environineiit Effects On Fiber
TL;DR: In this paper, the authors report the results of a series of experiments undertaken to quantitatively evaluate the accuracy of a fiber optic Fabry-Perot strain sensor embedded in a material system.
Abstract: In this paper, we report the results of a series of experiments undertaken to quantitatively evaluate the accuracy of a fiber optic Fabry-Perot strain sensor embedded in a material system. The optical fiber sensor is embedded in three material systems containing different physical attributes to simulate a variety of local stress fields. The material systems, which included a homogeneous material, a model system, and a composite laminate, are subjected to tensile and compressive loads to evaluate the performance of the sensor under each of these conditions. In each test, the data obtained from the optical fiber sensor is compared to data from externally attached resistance strain gages for validation purposes. Results demonstrate that optical fiber sensors provide highly accurate results if sufficient chemical and/or mechanical load transfer mechanisms are present.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.