基于双环光电振荡器的频分复用光纤光栅传感系统  

Frequency Division Multiplexing Fiber Bragg Grating Sensing System Based on a Dual-Loop Optoelectronic Oscillator

作　　者：高玲歌 汪弋平[1] 田孝忠 朱丹[1] 肖云浩 葛嘉炜 陈莹莹[1] Gao Lingge;Wang Yiping;Tian Xiaozhong;Zhu Dan;Xiao Yunhao;Ge Jiawei;Chen Yingying(Jiangsu Key Lab on Opto-Electronic Technology,School of Computer and Electronic Information,Nanjing Normal University,Nanjing 210023,Jiangsu,China)

机构地区：[1]南京师范大学计算机与电子信息学院,江苏省光电技术重点实验室,江苏南京210023

出　　处：《光学学报》2023年第20期291-297,共7页Acta Optica Sinica

基　　金：国家自然科学基金(61975082,62205149)。

摘　　要：提出了一种基于双环光电振荡器(OEO)的频分复用光纤布拉格光栅(FBG)传感系统。在该传感系统中,从两个级联的FBG反射的光信号经马赫-曾德尔调制器调制后进入光路的双环结构,两路光信号经耦合后再通过波分复用分成两路,由光电探测器还原为电信号。该电信号分别通过两个不同中心频率的电带通滤波器后形成稳定的微波振荡,输出两路微波信号,分别对应两个FBG传感器。最后,通过对两路微波信号的频率漂移进行测量,最终实现传感解调。实验中对两个FBG分别施加应变和温度,结果表明:传感系统的应变灵敏度为0.100 kHz/με最大频率偏移0.035 kHz,对应0.35με的测量误差;温度灵敏度为1.135 kHz/℃,最大频率偏移0.072 kHz,对应0.06℃的测量误差。该系统借助双环OEO的结构,具有稳定性高、测量误差小的优点。Objective Fiber Bragg grating(FBG)sensors are widely studied due to their unique advantages of light weight,small size,and sound stability in harsh environments.Most of the conventional demodulation methods for FBG sensing such as the filtering method,wavelength swept laser method,and tunable F-P filter method are performed in the optical domain,and they have the disadvantages of slow demodulation speed and low resolution.Therefore,it is important to develop new demodulation techniques with fast demodulation speed and high resolution.With the development of microwave photonics(MWP),the FBG sensing demodulation techniques based on an optoelectronic oscillator(OEO)have attracted extensive research interest.Compared with optical signals,microwave signals have relatively low frequencies and can be detected more rapidly and accurately.However,most of the current OEO-based FBG sensors are single-loop structures with large frequency fluctuations and a small free spectrum range(FSR)of the microwave signal output from the OEO,which results in a small measurement range and large measurement errors.Most importantly,only single parameter measurement can be realized.To this end,our paper proposes a frequency division multiplexing FBG sensing system based on a dual-loop OEO.We construct an optical dual-loop structure in the OEO loop and then perform frequency division multiplexing by a wavelength division multiplexer(WDM)and two electrical bandpass filters(EBPFs)with different center frequencies.This not only realizes the simultaneous sensing of strain and temperature but also significantly improves the measurement range and sensor stability.Methods First,we employ two cascaded FBGs as the sensing heads for strain and temperature measurement respectively.Secondly,two optical loops 1 and 2 with great length differences are constructed to form a dual-loop structure to reduce the frequency fluctuation and increase the FSR of the output microwave signals.Then,the optical signal is divided into two paths by WDM and frequency divisi

关 键 词：传感器 光电振荡器 微波光子学 频分复用 光纤光栅 

分 类 号：TN29[电子电信—物理电子学]