基于匹配滤波解调的多芯Bragg光栅曲率传感器

Multicore Fiber Bragg Grating-Based Curvature Sensor Interrogated by Matched-Filter Technique

设计了一种多芯光纤Bragg光栅曲率传感器,并采用匹配滤波技术实现曲率解调。多芯光纤Bragg光栅曲率传感器是通过在多芯光纤的两个中心对称纤芯中写入Bragg光栅实现的。两个光纤Bragg光栅具有相似的反射谱和中心波长,当多芯光纤发生弯曲时,两个光纤Bragg光栅的反射谱叠加区域将发生改变。将两个光纤Bragg光栅构造成匹配滤波模式,则两个光纤Bragg光栅反射谱的叠加区域面积决定了输出信号的光强,而叠加区域的面积与光纤曲率有关。因此,通过测量匹配滤波信号的功率可以实现曲率解调。结果表明,匹配滤波技术能有效解调多芯光纤Bragg光栅曲率传感器,最大曲率解调灵敏度为0.78mW·m^(-1)。此外,测量了多芯光纤Bragg光栅曲率传感器在不同轴向应变和环境温度下的解调性能,结果表明,该曲率解调系统具有很强的抵抗外界环境波动的能力。

A multicore fiber Bragg grating （FBG）-based curvature sensor interrogated by a matched-filter technique is proposed and experimentally demonstrated, The multicore FBG-based fiber curvature sensor consists of two FBGs inscribed at two arbitrary outer cores arranged symmetrically to the center core. These two FBGs have almost same reflection spectrum and center wavelength. When the multi-core fiber is bent, the overlapping area of the reflection spectra of the two FBGs changes, which affects the matched-filter output power and is related to fiber curvature. Thus we can interrogate the curvature by monitoring output power. The proposed sensor with the sensitivity of 0.78 mW·m^-1 is achieved. In addition, the performances of the multicore FBG-based curvature sensor based on matched-filter interrogation under different externally applied axial strains and temperatures are also evaluated. The results show that the proposed sensor has strong ability to resist ambient fluctuations.