Opt Lett. 2019 Jan 15;44(2):379-382. doi: 10.1364/OL.44.000379.
A real-time random grating sensor array for quasi-distributed sensing based on spectral-shaping and wavelength-to-time (SS-WTT) mapping and time-division multiplexing is proposed and experimentally demonstrated. The sensor array consists of multiple random gratings written in a single-mode fiber (SMF) at different physical locations. When the temperature or strain applied to a particular random grating is changed, the central wavelength of the reflection spectrum of the random grating will change, which is converted to the time domain as a time shift based on SS-WTT using a linearly chirped fiber Bragg grating. After detection at a photodetector, an electrical waveform with the time shift information encoded in the random waveform is obtained, which is further compressed by correlation to increase the time resolution. As a demonstration, a real-time quasi-distributed sensing system based on a two-random-grating array is implemented. The results show that the sensing resolutions for temperature and strain are 0.23°C and 2.5 μϵ, respectively, and the accuracies for temperature and strain are 0.11°C and 1.2 μϵ, respectively. Compared with a conventional quasi-distributed sensor, our proposed sensing system has key advantages, including real-time sensing, high-resolution interrogation, and large scalability.
提出并实验演示了一种基于光谱整形和波长至时间（SS-WTT）映射和时分复用的用于准分布式传感的实时随机光栅传感器阵列。该传感器阵列由在不同物理位置写入单模光纤（SMF）中的多个随机光栅组成。当施加到特定随机光栅的温度或应变发生变化时，随机光栅的反射光谱的中心波长将发生变化，该变化基于 SS-WTT 转换为时间域中的时间位移，使用线性啁啾光纤布拉格光栅。在光电探测器处检测后，获得了在随机波形中编码有时间位移信息的电波形，该电波形通过相关进一步压缩以提高时间分辨率。作为演示，实现了基于双随机光栅阵列的实时准分布式传感系统。结果表明，温度和应变的传感分辨率分别为 0.23°C 和 2.5 μϵ，温度和应变的精度分别为 0.11°C 和 1.2 μϵ。与传统的准分布式传感器相比，我们提出的传感系统具有实时传感、高分辨率询问和大可扩展性等关键优势。
