高分辨率光纤光栅温度传感器的研究

报道了一种具有高分辨率和高效且价廉的解调系统的光纤布拉格光栅(FBG)温度传感器.提出了光纤光栅的金属槽封装技术,以提高传感光栅的温度灵敏性.研究了金属槽封装光栅的温度灵敏性,理论分析和实验结果表明,封装光栅的温度灵敏系数比普通裸光栅提高了3.6倍.系统利用一长周期光栅(LPG)作为线性滤波器,宽带光源经此长周期光栅调制后入射到传感光栅,可解调布拉格传感光栅的波长位移.理论分析与实验结果一致,系统可达到的温度分辨率为0.02℃.     

Interrogating a Fiber Bragg Grating Vibration Sensor by Narrow Line Width Light

A method to interrogate fiber Bragg grating vibration sensor by narrow line width light is demonstrated. The interrogation scheme takes advantage of the intensity modulation of narrow spectral bandwidth light, such as distributed feedback laser, when a reflection or transmission spectrum curve of an fiber Bragg grating （FBG） moves due to the strain which is applied on the sensor. The sensor＇s response to accelerating frequency and amplitude is measured by experiment. The factors which have impacts on the sensitivity of the interrogation system are also discussed.     

Strain and Temperature Characteristics of a Long-Period Grating Written in a Photonic Crystal Fiber and Its Application as a Temperature-Insensitive Strain Sensor

Strain and temperature characteristics of a long-period grating (LPG) written in an endless-single-mode photonic crystal fiber (ESM-PCF) are investigated theoretically and experimentally. By use of a dispersion factor , a deeper understanding of the behavior of LPG in the ESM-PCF is achieved. The negative strain sensitivity of the LPG is explained by the negative value of the dispersion factor . Our analysis clearly reveals the significant effect of the waveguide dispersive characteristics of the cladding modes on the strain and temperature characteristics of the LPG in the ESM-PCF. By selecting an appropriate grating period, a simple, low-cost LPG sensor with approximately zero temperature sensitivity but large strain sensitivity is realized.     

AWG-based large dynamic range fiber Bragg grating interrogation system

Arrayed waveguide gratings(AWGs) are extensively employed in fiber Bragg grating(FBG) interrogation systems due to their compact size, lightweight nature, and excellent interrogation performance. The resolution and total measurement range of AWG-based FBG interrogation systems are constrained by the output properties of AWG. We proposed an AWG-based large dynamic range interrogation system. The temperature dependence of AWG is exploited to achieve continuous interrogation. The test results show ...     

Fiber Grating Sensor Interrogation Using a Double-Pass Mach–Zehnder Interferometer

We propose an advanced quadrature sampling method for a fiber grating sensor interrogation. A Mach–Zehnder interferometer output is sampled at internal triggers which are generated at the zero-crossing points of a double-pass Mach–Zehnder interferometer output. Due to the phase relationship, the internal trigger signals assure a 90$^{circ}$ phase difference between the sampled signals even in the presence of environmental disturbances. Also, no parameter adjustment is required when the frequency and/or shape of the phase modulation signal changes, which makes it a very practical technique for fiber grating sensor demodulation. From the preliminary experiments, we could obtain a measurement resolution of $sim $ 8 pm.      

箱型光谱响应聚合物阵列波导光栅的研制

通过减少奇数阵列波导的芯宽度,同时增加偶数阵列波导的芯宽度的技术,构造了箱型光谱. 选用氟化聚芳醚FPE聚合物材料,设计并制备了17×17信道箱型光谱响应阵列波导光栅（AWG）波分复用器. 测试结果表明,器件的中心波长为1550.87nm,波长间隔为0.8nm, 3dB带宽约为0.476nm,串扰低于-21dB,插入损耗为13~15dB.     

箱型光谱响应聚合物阵列波导光栅的研制

通过减少奇数阵列波导的芯宽度,同时增加偶数阵列波导的芯宽度的技术,构造了箱型光谱-选用氟化聚芳醚FPE聚合物材料,设计并制备了17×17信道箱型光谱响应阵列波导光栅(AWG)波分复用器.测试结果表明,器件的中心波长为1550.87nm,波长间隔为0.8nm,3dB带宽约为0.476nm,串扰低于-21dB,插入损耗为13～15dB.     

阵列波导光栅器件及应用

简述阵列波导光栅(AWG)复用／解复用器的原理，总结和分析AWG器件性能的一些改进措施，并综述了AWG在当今光通信中的多种应用。     

Athermalized Polymeric Arrayed‐Waveguide Grating by Partial Detachment from a Si Substrate

We demonstrate a new fabrication method for adjusting the temperature dependence of a polymeric arrayed‐waveguide grating (AWG) on a Si substrate. A temperature‐dependent wavelength shift of ?0.1 nm/°C in a polymeric AWG on a Si substrate is reduced to +0.01 nm/°C by detaching part of the polymer film, including the grating channel region of the AWG, from the Si substrate while the other parts remain fixed on the substrate.     

氟化聚合物光谱响应平坦化阵列波导光栅的优化设计和制备

本文基于阵列波导光栅(AWG)的传输理论,利用含氟聚合物(PFS-co-GMA)共聚物材料,对17×17信道光谱响应平坦化AWG波分复用器进行了参数优化.由于在聚合物阵列波导光栅器件的制备过程中,选用了反应离子刻蚀(RIE)工艺和蒸汽回溶技术,形成的梯形截面波导芯,使AWG传输的光产生相位移,导致传输光谱移动,引起串扰...     

基于长周期光纤光栅的液位传感研究

基于简化的光纤三层模型,从折射率传感和长周期光纤光栅级联特性两方面对应用长周期光纤光栅作液位传感器进行了研究,当以峰值损耗为传感参量进行测量时,在没有发生过耦合的情况下,在一个较宽的范围内,光栅峰值损耗与进入液体的百分比成很好的线性关系;而当有过耦合发生时,光栅峰值损耗与进入液体的百分比不再一一对应.     

Novel Distributed Fiber Bragg Grating Sensing System Based on M-Z Interferometer

One of the problems in using grating sensors is how to measure a small Bragg wavelength shift accurately. Nowadays demodulation techniques are mainly based on the edge filter, tunable filter, or interferometric scanning methods. Interferometric demodulation is widely accepted as the technology which can provide the high sensitivity. An interrogation system using the interferometric scanning method is presented, in which an unbalanced fiber M-Z interferometer is used as the wavelength scanner for temperature measurement. A novel fiber Bragg grating sensor system based on M-Z interferometric demodulation technique is presented in this paper. The temperature sensitivity measured in the experiment is almost consistent with that obtained from the theoretic calculation.     

阵列波导光栅复用/解复用器研究进展

综述了阵列波导光栅(AWG)复用/解复用器的最新研究进展,并对该种器件的前景进行了展望.     

基于F-P扫描干涉仪的长周期光纤光栅传感解调系统研究

利用F-P扫描干涉仪的滤波特性,提出了一种可应用于长周期光纤光栅传感解调的新方法.即利用F-P扫描干涉仪对长周期光纤光栅的某一级透射谱进行波长扫描,通过探测器实现光电转换,电压比较器对滤波光束电压进行比较,检测最小电压,借助F-P驱动电压进行定标确定传感元的波长,实现信号解调.通过与光谱仪监测值进行对比,得到实验结果与监测值基本吻合,且具有很好的重复性.     

面向光接入网的光纤光栅传感数据数字化系统

利用现有的光纤通信网实现对光纤光栅传感网络的远程监控,既可以避免重新铺设传感信道,节约成本,又可以增加传感网组网的灵活性。提出了一种基于阵列波导光栅(AWG)的面向光接入网的光纤布拉格光栅(FBG)传感网传感数据数字化系统,系统能够快速实现对携带传感信息的FBG反射波长的数字化。分析了系统的工作原理及主要误差来源,并设计了传感数据成帧模块的结构及适于在光接入网中传输的传感数据帧结构。采用OptiSystem/Matlab协同仿真的方法对一个3×3光纤光栅传感网络进行了仿真实验,实现了在-50℃～100℃范围内精度为1℃的温度监测,能够满足日常温度监控需要。实验结果表明了该方案的可行性。     

光纤光栅传感器干涉型解调仪的稳定性分析和改进

提出了一种利用两种不同温度系数的光纤光栅对来对解调仪的不稳定性进行改进的方法,并进行了理论分析,研究了影响该解调仪稳定性的几个因素.将所研制的传感器布设在东海大桥上,组成传感网络,并用改进后的光纤光栅解调系统对传感器的信号进行解调.在大桥竣工测试时,该传感解调系统表现出较好的性能.     

基于阵列波导光栅的单纤三重波分复用器

利用阵列波导光栅实现单纤三重波分复用器是一种具有很多优点的方法.ITU G.983标准规定了无源光网络的三个波长为1310,1490和1550nm,由于这三个波长的间距相差很大,光谱范围也大,用普通的AWG设计方法不能达到理想的效果.文中提出了一种基于阵列波导光栅的单纤三重波分复用器的新型设计,利用衍射光栅的频谱周期性,使离第二、三波长较远的第一波长工作在不同的衍射级次,并将第一波长映射到与第二、三波长形成几乎等间距信道的第四波长,从而减小了对光栅自由光谱范围的要求,同时使对应这三个工作信道的输入/输出波导几乎等间距,解决了传统设计方法导致的衍射级次小、器件尺寸大、制作困难等问题.     

A Calibration Method Based on Linear InGaAs in Fiber Grating Sensors Interrogation System

In accordance with the characteristics of wavelength shift detection in fiber grating sensor interrogation system, the wavelength interrogation system which uses linear InGaAs as the spectrum receiver is proposed. Orientation of optic spectrum line affects the silt of volume phase grating and size of InGaAs photosensitive unit, thus the calibration method is needed. Based on an analysis of InGaAs imaging model, least square curve fitting method is proposed to detect spectrum wavelength and InGaAs photosensitive unit position. The experimental results show that the methods are effective and the demodulation system precision is improved.     

基于熔融拉锥过耦合器的光纤光栅解调系统

提出了一种基于光纤熔融拉锥过耦合器进行解调的方法,实验制作了一个特殊的熔融拉锥过耦合器,对其输出的两路光功率进行了测试,并论证了用该耦合器进行解调的原理.利用该过耦合器组成的检测系统对光纤光栅传感器进行解调,得到了较好的响应.该解调方法成本低,结构简单,解调范围大,线性范围可达10 nm以上.     

Low‐Loss Compact Arrayed Waveguide Grating with Spot‐Size Converter Fabricated by a Shadow‐Mask Etching Technique

This paper describes a low‐loss, compact, 40‐channel arrayed waveguide grating (AWG) which utilizes a monolithically integrated spot‐size converter (SSC) for lowering the coupling loss between silica waveguides and standard single‐mode fibers. The SSC is a simple waveguide structure that is tapered in both the vertical and horizontal directions. The vertically tapered structure was realized using a shadow‐mask etching technique. By employing this technique, the fabricated, 40‐channel, 100 GHz‐spaced AWG with silica waveguides of 1.5% relative index‐contrast showed an insertion‐loss figure of 2.8 dB without degrading other optical performance.