基于多芯光纤级联布喇格光纤光栅的横向压力与温度同时测量

提出并制作了一种基于多芯光纤与单模光纤错位构成的马赫-曾德尔干涉仪,将其与光纤布喇格光栅级联,形成的全光纤传感系统可实现横向压力和温度双参量同时测量.马赫-曾德尔干涉仪是利用多芯光纤和单模光纤的模场不匹配而发生模间干涉,当外界横向压力直接作用在多芯光纤内部光场,干涉仪具有较高的灵敏度.实验结果表明:马赫-曾德尔干涉仪压力灵敏度为28.57nm/(N·mm~(-1)),线性度为0.997,而光纤布喇格光栅在一定范围内对压力变化不敏感;马赫-曾德干涉仪和光纤布喇格光栅对温度变化都具有较高的线性度,温度灵敏度分别为56.1pm/℃和11.3pm/℃.对于分辨率为0.02nm的光谱仪,传感器可实现的压力和温度测量分辨率分别为7.0×10~(-4)N/mm和0.03℃.马赫-曾德尔干涉仪的透射谱和光纤布拉光栅的谐振峰对横向压力和温度的变化有不同的光谱响应,利用光谱仪对传感器的透射谱实时监测,方便地实现了压力与温度双参量的测量.该传感器结构简单,灵敏度高,可用于不同领域的压力传感.

Simultaneous Measurement of Transverse Pressure and Temperature Based on Multi-core Fiber Cascaded with Fiber Bragg Grating

An all-fiber sensing system based on the Mach-Zehnder Interferometer (MZI) and Fiber Bragg Grating (FBG) was proposed for the measurement of transverse pressure and temperature simultaneously.The MZI was fabricated by splicing of a lateral-offset Multi-Core Fiber (MCF) with two single mode fibers, the modal interference was formed due to the mode field mismatch among MCF and Single Mode Fibers (SMFs), which made the external pressure directly acted on the light field inside of the multi-core fiber, thus a high pressure sensitivity of interferometer can be achieved.Experimental results show that the pressure sensitivity of the MZI is 28.57 nm/(N·mm-1), and the linearity is 0.997, while FBG is not sensitive to the pressure change.Both the MZI and the FBG show a good linearity between the wavelength shift and temperature, and the sensitivity is 56.1pm/℃ and 11.3pm/℃, respectively.For a spectrometer with a resolution of 0.02 nm, the proposed sensor can reach a resolution of 7.0×10-4N/mm for pressure and of 0.03℃ for temperature.The transmission spectrum of the MZI and the resonance peaks of the FBG have different spectral responses to pressure and temperature changes.By using optical spectrum analyzer to monitor the wavelength shift of the transmission spectrum of the sensor, so that the dual-parameters of pressure and temperature can be measured conveniently.The proposed sensor has a simple structure a high sensitivity, it can be well applied to transverse pressure measurement.