基于温度补偿高双折射光纤环镜的边缘滤波解调方法

提出了一种光纤光栅传感解调新方法。系统由1个3dB耦合器、1个传感光纤布喇格光栅、1个双折射光纤环镜和1个探测器构成,高双折射光纤环镜作为边缘滤波器。光纤光栅波长的线性解调带宽为3．6nm。对双折射光纤环镜的温度补偿进行了实验研究,实验表明,封装的高双折射光纤环镜能够补偿高双折射光纤环镜的温度漂移。补偿前的高双折射光纤环镜波长随温度漂移为2．3nm／℃,补偿后的双折射光纤环镜波长随温度漂移为0．005nm／℃,远小于未补偿的双折射光纤环镜波长随温度漂移。     

一种新颖的双边缘滤波光纤布拉格光栅解调技术

设计了一种基于机械感生长周期光纤光栅(MI-LPG)的双边缘滤波光纤布拉格光栅(FBG)传感解调方案。采用不同写制参数制作了谐振边带对称交迭,谐振峰值和带宽相同的两个MI-LPG作为滤波器,利用反射FBG信号通过不同光谱特性的滤波器时输出不同光强的比值对数算法确定被测波长。实验表明,本解调方法能够精确、稳定地实现FBG传感信号的解调,动态范围可达5 nm,解调系统线性拟合计算值和光谱仪所测波长值的均方差为6 pm,线性度好,精度高。     

基于双LPFG解调的高灵敏度振动检测系统

基于边缘滤波解调原理,提出了一种利用双长周期光纤光栅（LPFG）解调光纤布拉格光栅（FBG）振动传感信号的新方法。利用传输光谱叠加后的双LPFG作为边缘滤波器,增大了FBG传感信号解调灵敏度。静态实验结果表明,利用单、双LPFG作为滤波器解调的灵敏度分别为-1．1965dB／nm和-2．4836dB／nm,双LPFG解...     

FBG光纤传感器的同步探测技术

光纤光栅传感解调系统的波长校准技术是人们关注的焦点,通常是将固定波长的FBG固定在恒温箱中,以此作为光纤光栅传感解调系统的参考元件．此方法占用了宽带光源的某个波长范围,从而制约了解调系统的波长扫描范围．构建的光纤光栅传感解调系统,将FP滤波器的驱动锯齿信号转变为方波信号,以此作为同步处理所需参考信号,省去了这个固定波长的FBG传感器,充分地利用了宽带光源的波长范围,并使得解调技术简单,同时提高了外接FBG传感器的数量．     

基于光纤Sagnac环滤波器的高稳定光纤布拉格光栅传感解调技术

光纤Sagnac环滤波器用于光纤布拉格光栅(FBG)传感器波长解调时受环境温度影响很大,为此提出一种可消除温度影响的高稳定解调新方法,介绍了系统光路和解调器的工作原理。将带有一段保偏光纤的Sagnac环作为边缘滤波器,分布反馈(DFB)激光器的单波长激光作为参考光,对FBG波长信号和参考光信号同时进行滤波。在同一时间探测经Sagnac环滤波器输出的透射光强度和反射光强度,进行光强信号归一化处理并采用差动检测方法分析。理论分析和实验结果表明,该解调方法基本消除了Sagnac环滤波器的温度效应,提高了解调系统的稳定性。在1302~1318nm波长范围内,解调装置的温度漂移为2.4×10-4 nm/℃,是未封装补偿无参考光的Sagnac环滤波器透射谱温度漂移的1.8×10-4倍。     

基于环型腔掺Er光纤激光器的FBG传感系统

提出并实验了一种基于可调谐环型腔掺Er光纤激光器的光纤光栅（FBG）传感解调系统。传感FBG与受一维调节器调节控制的匹配FBG共同构成环型腔掺Er光纤激光器的窄带滤波器。一维调节器与步进电机相连,步进电机由PC通过可编程逻辑控制器（PLC）进行控制,一维调节器通过调节匹配FBG的周期以匹配传感FBG的周期从而滤除激光的输出,由激光的输出特性来判断2个FBG周期的匹配性并完成对传感FBG周期的测量。调节器控制系统、激光信号检测电路与数据处理模块共同完成传感信号的解调。实验测得,在4．04nm范围内,系统的波长探测精度为0．02nm。     

基于F-P腔滤波器的FBG温度传感器解调技术

近些年来,光纤光栅传感器成了传感领域的研究热点.对高精度的波长编码信号解调是实现光纤光栅传感的关键技术.介绍了光纤布拉格光栅(FBG)传感器的工作原理,同时对F-P腔滤波器的工作原理进行了分析,阐述了光纤光栅传感器解调技术的发展趋势,并提出了光纤光栅传感器解调技术需要解决的技术问题.     

用可调谐F-P滤波器实现分布式应变与温度同时测量系统

理论分析了FBG光纤光栅和长周期光纤光栅应变与温度同时测量的传感原理.在分析实现光纤光栅传感技术解调的基础上,重点研究了可调谐光纤F.P滤波器解调法.提出采用可调F-P滤波器实现分布式应变与温度同时测量系统的解调方案,较好地实现了多点应变与温度的同时测量.这种方法的测量精度较高,其中测量应变的灵敏度可以达到9με,测量应变的灵敏度为15℃.     

光纤光栅传感系统信号解调技术的研究

光纤光栅传感是光纤光栅的重要应用之一,波长信号的解调是实现光纤光栅传感网络的关键。介绍了布喇格光纤光栅(FBG)传感的基本原理,对比FBG说明了长周期光纤光栅(LPG)的特点。阐述了基于长周期光栅的布喇格光纤光栅的解调技术,详细阐述了用长周期光纤光栅来解调布喇格光纤光栅的具体方案及技术。     

基于线型腔拉曼光纤激光器的长距离光纤布拉格光栅传感

提出了一种基于线型腔拉曼光纤激光器的长距离分布式光纤布拉格光栅(FBG)传感解调系统,并进行了理论分析和实验验证。传感光纤布拉格光栅构成拉曼光纤激光器腔镜的一端,受一维调节器调节控制的匹配光纤布拉格光栅构成腔镜的另一端。一维调节器与步进电机相连,步进电机由计算机(PC)通过可编程逻辑控制器(PLC)进行控制,一维调节器通过调节匹配光纤布拉格光栅的周期来控制激光器的输出。实验结果表明,传感解调系统能很好地实现长距离分布式传感及传感信号的检测。30 km非归零色散位移光纤(NZDSF)用于拉曼增益可以产生信噪比大于40 dB的稳定拉曼激光输出,在4.2 nm范围内系统解调精度为0.05 nm。     

MZI-based wavelength interrogation system with tunable-FBG

We proposed a scheme of fiber Bragg grating (FBG) sensor interrogation system based on all fiber Mach-Zehnder Interfer- ometer (MZI) edge filter and tunable-FBG. The equal power signals from FBG sensor and tunable FBG are coupled into port 1 and port 2 of MZI respectively. The experimental results show that the interrogation precision of the proposed system is 0.02 nm in a range of 1nm. Furthermore, the precision can be improved by adjusting the two interference arms of the filter.     

Dynamic Temperature Compensating Interrogation Technique for Strain Sensors With Tilted Fiber Bragg Gratings

In this letter, we propose a novel method of edge filter linear demodulation using tilted fiber Bragg gratings (TFBGs) in a fiber sensor system. Based on the filter characteristics of TFBGs and the same temperature characteristics as the FBG, the strain sensor demodulation system with dynamic temperature compensation can be achieved. An experimental system is built up to achieve one or multichannels of sensor demodulation. The experimental results were analyzed in detail. Using this method based on intensity, linear demodulation with a bandwidth of 6 nm can be achieved. The advantages of this system are an all-fiber design, quasi-static and dynamic operation, and potential high-speed demodulation.     

Linear edge and temperature characteristic of tilted fiber Bragg gratings cladding-mode envelope

In this paper, a system of linear edge filter demodulation based on weakly tilted fiber Bragg gratings in fiber sensor was proposed. The linear edge of the cladding-mode envelope and temperature characteristic between cladding modes and core mode of tilted fiber Bragg grating (TFBG) were experimentally investigated. The results show that falling edge (1505–1535 nm) and rising edge (1545–1565 nm) of the cladding-mode envelope is approximately linear and can be used as an edge filter. Moreover, the temperature characteristics of the core mode and cladding modes are similar to FBG’s. It can dynamically compensate the temperature induced wavelength shift of the FBG and the effect of temperature on the demodulated sensing signals is minimized. The advantages of this simple system are an all-fiber design, quasi static and dynamic operation, high stability and lower cost.     

光纤光栅传感器阵列化与温度补偿研究

利用啁啾光纤Bragg光栅（FBG）反射和长周期FBG边沿滤波，提出并实现了一种综合的FBG传感快速解调方案。封装1对FBG进行应变差动传感、同时消除温度影响，不增加波长资源占用并使应变灵敏度得到有效提高，温度影响在很大范围内几乎为0。在全光纤化解调温度补偿型传感的基础上，研究了两路时分复用的设计方法，给出了时分链路间延迟光纤与光脉冲和解调端时分选通门的关系，实验结果与理论分析吻合。     

一种新的光纤布拉格光栅波长移位检测技术

提出了一种利用全光纤非平衡Mach Zehnder干涉仪作为边缘滤波器进行光纤布拉格光栅 (FBG)波长移位检测的方案。这种边沿滤波器具有梳状的滤波特性 ,且其两输出臂滤波特性互补。利用其一对滤波边沿 ,可以将被测光栅的波长信息转化为功率信息进行检测。在制作时 ,通过适当改变干涉臂长差可方便地调整测量范围和检测分辨率 ,具有较大的灵活性。以两种不同的比较运算的方法消除系统功率起伏对测量结果的影响 ,都得到了较好的结果。采用该检测方案进行了光纤布拉格光栅温度传感实验 ,得到了± 10 pm的波长测量精度。     

Chirped-pulsed frequency modulation (C-PFM) for fiber Bragg grating sensors multiplexing

In this paper, we present experimental demonstration of using chirped-pulsed frequency modulation technique (C-PFM) in order to increase the multiplexing capability of a multipoint fiber Bragg grating (FBG) sensor network without increasing the hardware complexity of the acquisition system. This technique, extensively used in radar applications, is based on the amplitude modulation of the emitted signal (pulsed) by a chirped frequency signal and on the use of an adaptive filter for the demodulation of the reflected signals. Here, the same principle has been used to develop a FBG multisensor interrogation system by employing a proper frequency chirped modulation. The optical signals reflected from the FBG sensors are first interrogated by using an in-fiber edge filter and discriminated by a novel adaptive numerical filtering. The potentiality and limitation of such technique are discussed. Preliminary experimental results are presented.     

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℃.     

Modeling and performance analysis of a fiber Bragg gratinginterrogation system using an acousto-optic tunable filter

The performance of a fiber grating interrogation system using an acousto-optic tunable filter (AOTF) is analyzed. An equivalent linear circuit is presented to describe the system, which tracks the wavelength of a fiber Bragg grating (FBG) sensor in a FBG sensor array. From the model, the tracking resolution of a shot-noise-limited system has been determined for both transmissive and reflective interrogation of FBGs. An optimum ratio between the bandwidths of the FBG and the AOTF has been derived. Experimental results of a tracking system are presented to validate the theoretical predictions. The theory should also be suitable for interrogation systems using other forms of tunable bandpass filters for tracking the FBG wavelength     

FFP边带滤波技术研究

以双光束干涉原理为基础,推导了光纤法布里-珀罗腔(FFP)边带滤波器的反射率方程,讨论了端面反射率对其特性的影响;通过与光纤迈克尔逊、M-Z解调方法比较分析了FFP边带滤波器的热稳定性问题;对FFP在光纤光栅传感解调中的应用,采用泰勒展开方法进行了一阶线性近似,用线性边带滤波方法实现了布拉格光纤光栅传感器的应变测量,最大测量误差为3.8个微应,满量程测量精度为6‰,能满足一般工业测量应用.