A temperature sensor with high sensitivity based on the birefringence induced Vernier effect in a symmetrical metal-cladding waveguide (SMCW) structure is theoretically proposed. Due to the guiding layer of SMCW is extended to a sub-millimeter scale, the excited ultra-high order modes is highly sensitive to the variation of thermally modulated refractive index (RI) and the obtained comb-like resonance reflectivity spectrum shifts accordingly as changing the ambient temperature. There is a little difference between the RI of the ordinary light and the extraordinary light of the filled nematic liquid crystal (LC), the resulted slight different free spectral range of two orthogonal polarizations makes their superposition of reflectivity spectrum metamorphose into a period envelope with multiple sub-peaks. The dips in the fitting upper envelope possesses a much enhanced temperature dependent spectrum shift which can be measured by a low-cost integrated-type micro-spectrometer. Such a sensor has no reference resonant cavity and its sensing range can be easily controlled by filling with different kinds of LC.

中文翻译：

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基于对称金属包覆波导中双折射引起的游标效应的增强型温度传感

理论上提出了一种基于对称金属包覆波导（SMCW）结构中双折射引起的游标效应的高灵敏度温度传感器。由于SMCW的引导层扩展到亚毫米级，激发的超高阶模式对热调制折射率（RI）的变化高度敏感，并且获得的梳状共振反射率光谱随着变化而相应地移动环境温度。填充向列液晶（LC）的寻常光和非常光的折射率略有不同，导致两种正交偏振的自由光谱范围略有不同，使得它们的反射率光谱叠加变形为具有多个周期的包络线。子峰。拟合上包络中的下降具有大大增强的依赖于温度的光谱漂移，可以通过低成本集成型微型光谱仪进行测量。这种传感器没有参考谐振腔，其感应范围可以通过填充不同种类的 LC 来轻松控制。