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Unlike the usual wavelength modulation principle of fiber Bragg grating (FBG) sensors, a novel weight sensor based on birefringence in FBG is proposed in this paper. The creation of the birefringence is based on the different stresses of the two orthogonal directions in the fiber core cross-section. If weight is applied on an FBG in the radial direction, two reflection spectra with different polarization states which can be observed by an optical spectrum analyzer will occur. An experimental prototype is set up and the measurement principle is described in this paper. Preliminary experimental results indicate that the proposed measurement method is very suitable for the application of heavy weight measurement in the range of 20 tons, especially for vehicle load monitoring in highway charge-by-weight systems. The sensitivity of weight measurement is be estimated to be about 5 kg. 相似文献
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L. Dong J.L. Cruz L. Reekie L. Archambault 《Photonics Technology Letters, IEEE》1995,7(12):1433-1435
We have demonstrated a new method for tuning and chirping fiber gratings. It relies on etching of a fiber down to very small cladding diameter, so that the propagating optical mode in the fiber interacts with the surrounding media. A tuning range of 4.5 nm has been demonstrated with a potential of much larger tuning range by optimization of fibers. Chirped gratings were also demonstrated with this technique. These chirped gratings are very important for use in fiber dispersion compensation and optical pulse shaping. 相似文献
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简单介绍了光纤布喇格光栅( F B G) 的原理及光学特性,详细阐述了 F B G 的制作技术。此外,详细地描述了采用 Kr F 激光器,利用位相掩模法光刻光纤形成 F B G 的实验。此种方法与其他方法相比,有很多的优点。给出和分析了实验的结果 相似文献
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Lightwave applications of fiber Bragg gratings 总被引:17,自引:0,他引:17
Fiber Bragg gratings (FBGs) have emerged as important components in a variety of lightwave applications. Their unique filtering properties and versatility as in-fiber devices is illustrated by their use in wavelength-stabilized lasers, fiber lasers, remotely pump amplifiers. Raman amplifiers, phase conjugators, wavelength converters, passive optical networks, wavelength division multiplexers (WDMs) demultiplexers, add/drop multiplexers, dispersion compensators, and gain equalizers 相似文献
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On the synthesis of fiber Bragg gratings by layer peeling 总被引:8,自引:0,他引:8
Two methods for grating synthesis which have appeared in the literature recently are compared directly. In particular, we point out the similarity between the two; both algorithms are based on propagation of the fields through the structure with simultaneous evaluation of the coupling coefficient according to simple causality arguments (layer-peeling algorithms). The first published method (the discrete layer-peeling algorithm) is reformulated in a simpler, more efficient way, and it is shown that its implementation can be made exact. For mathematical comparison, a derivation of the second method (the continuous layer-peeling algorithm) is presented. The methods are compared both mathematically and numerically. We find that the discrete layer-peeling algorithm is significantly faster and can be more stable than its continuous counterpart, whereas the continuous algorithm offers some advantages in flexibility 相似文献
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Bai-Ou Guan Hwa-Yaw Tam Xiao-Ming Tao Xiao-Yi Dong 《Photonics Technology Letters, IEEE》2000,12(10):1349-1351
We demonstrated that the thermal stability of fiber Bragg gratings written in hydrogen-loaded standard fibers can be significantly enhanced by preirradiating the fiber with UV beam before writing gratings. Our experimental result shows that these gratings maintained more than 60% of their initial index modulation after 10 hours at 605/spl deg/C. 相似文献
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A-Ping Zhang Bai-Ou Guan Xiao-Ming Tao Hwa-Yaw Tam 《Photonics Technology Letters, IEEE》2002,14(4):489-491
The spectral characteristics of superstructure fiber Bragg gratings are analyzed numerically based on the coupled mode theory, simultaneously taking into account the counterdirectional guided mode coupling, codirectional and counterdirectional claddings mode coupling. The theoretical results were compared with experimental data and very good agreement was obtained 相似文献
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Photodarkening and photobleaching in fiber optic Bragg gratings 总被引:1,自引:0,他引:1
A photobleaching effect is reported which reduces the broadband losses induced by the single-pulse writing of fiber Bragg gratings (FBGs). A primary application of the optical FBG reflector is as arrays of wavelength-encoded sensing elements for detecting mechanical strain. Instrumentation is being developed to interrogate >100 point sensors along a single fiber with FBGs and detectors operating in the 790-820 nm band. In this paper, we describe broadband absorptions induced by writing single-pulse FBGs which would impose a 10 dB power penalty with as few as 40 serialized FBGs. We have reduced these photo-induced losses more than seven-fold (measured near 800 nm) using a photobleaching process which minimally affects the FBG's reflectivities. After treatment, optical losses are sufficiently low to allow the interrogation of hundreds of FBGs along a single fiber. Photodarkening and photobleaching are measured in gratings prepared by single laser pulses, and by multiple pulses with and without hydrogen loading. Parasitic loss following photobleaching is lower for single-pulse FBGs operated near 800 nm than for FBGs written with multiple pulses in hydrogen loaded fibers and operated near 1300 nm 相似文献
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The transmission and polarization properties of Fiber Bragg Grating (FBG) with Faraday Effect are studied in this paper. The evolutions of transmission spectrum for different circular birefringence, grating parameter (physical length, index modulation) and input polarizations are simulated with Jones Matrix method. It is demonstrated that the monitoring of the 3rd normalized Stokes parameter peak values provide a new magnetic field measurement. The magnetic field strength sensitivity value is 1.482 × 10?5/Gs by using the optical vector analyzer whose precision is 10?5 in experiment and a very good agreement between theory and experience is reported. 相似文献
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Phase reconstruction from reflectivity in fiber Bragg gratings 总被引:3,自引:0,他引:3
We propose a method for phase, time delay, and impulse response reconstruction from the spectral power reflectance or reflectivity in fiber Bragg gratings (FBGs). This method is based on causality and stability conditions and uses the Hilbert and Wiener-Lee transforms. In order to obtain a complete study of the algorithm, we have applied it to uniform and nonuniform fiber Bragg gratings. Finally, we get a complete characterization of a experimental uniform fiber Bragg grating, from the measured reflectivity, by means of the phase reconstruction algorithm. Results show a good agreement between exact and reconstructed functions 相似文献
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Pureur D. Douay M. Bernage P. Niay P. Bayon J.F. 《Lightwave Technology, Journal of》1995,13(3):350-355
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Michael C. Emmons Hyungsuk K.D. Kim Gregory P. Carman W. Lance Richards 《Optical Fiber Technology》2012,18(3):157-160
A magnetic sensor utilizing direct magneto-optic field coupling in an optical fiber Bragg grating (FBG) is experimentally demonstrated. The FBG’s cladding is etched to expose the propagating evanescent light to the fiber’s surroundings. The etched FBG is surrounded with iron oxide nanoparticles and placed in a magnetic field perpendicular to the fiber. Measurements demonstrate that the λB shifts nonlinearly as a function of magnetic field, i.e. comparable to the magnetization versus magnetic field behavior of the nanoparticles measured by a SQUID magnetometer. This direct manipulation of light with magnetic fields provides an approach to develop future sensors relying on electromagnetic interactions. 相似文献
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In this paper we design a new kind of sinc-sampled fiber Bragg grating which is fabricated in high birefringence fiber (HBF). The sampled grating has two sets of reflection spectra along two perpendicular polarization directions. The grating’s channel number can be doubled approximately by designing the refractive index difference between the fast and slow axes of the fiber, which enhances the utilization ratio and reduces the claim for photosensitivity of the fiber. The group delay characteristics are theoretically studied and side-lobes are depressed by apodization as well to get the optimized spectra. The results show that the comb-like spectra of the grating have promising applications in both multi-wavelength polarized fiber lasers and fiber sensing networks. 相似文献