高灵敏度光纤MZI折射率传感器

High-sensibility Fiber MZI Refractive Index Sensor

首次在实芯光子晶体光纤中制备了横向大偏置结构光纤马赫-曾德尔干涉仪折射率传感器,并理论分析了此种干涉仪的干涉机制和折射率传感特性,以及影响折射率传感特性的各种因素;搭建实验系统,测试了折射率传感特性。结果表明,腔长330μm传感器的干涉谱对外部环境折射率变化的响应成线性,透射谱随环境介质折射率增大而向短波方向移动,灵敏度超过-15 100 nm/RIU,灵敏度与腔长长度无关,光子晶体光纤的气孔对折射率传感特性影响很小。此种高灵敏度的光纤微腔折射率传感器适用于液体或气体的快速检测领域。

It is the first time that a large lateral offset structure Mach- Zehnder interferometer refractive index sensor is fabricated in photonic crystal fiber with solid core. The intefference prin- ciple and refractive index sensing characteristics of this kind of intefferometer are theoretically studied, and all kind of factors affecting the refractive index sensing characteristics are also studied. The experiment measuring system is set up, and the refractive index sensing characteristics are experimentally tested. Results show that, the interference spectrum of 330μm- length refractive index sensor shows linear response to the variation of external refractive index, transmis- sion spectral shifts toward the short wavelength with the increasing of refractive index of external medium, refractive index sensitivity exceeds -15100nm/RIU, sensitivity has nothing to do with the length of cavity length, and air holes of photonic crystal fiber have little effect on the refracrive index sensing characteristics. This high - sensitivity fiber micro - cavity refractive index sensor is suitable for fast detecting gas or liquid.