In this article, we present comparative study on the transmission and the sensing characteristics of an all-fiber Sagnac loop interferometer (SLI) made by different kinds of the highly-birefringent (HB) two-core photonic crystal fiber (TCPCF), respectively for strain, torsion, and temperature sensing. The fiber device is analyzed theoretically and experimentally. Transmission spectrum of the SLI using the HB TCPCF shows six spatial frequencies due to superposition of multiple two-beam interferences originating from the intra-core and the inter-core interactions between the fundamental polarization modes propagating in the two birefringent cores. Our results reveal that the transmission characteristics of the fiber device and the sensing features of its multiplexed interferences are strongly dependent on the optical and the structural properties of the two birefringent cores such as their intrinsic birefringences, the effective index contrast between them, and the relative orientation between the (slow) birefringence axes. Finally, the application of the SLI made by the specific HB TCPCF is discussed in the simultaneous measurement of three parameters.

中文翻译：

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基于高双折射两芯 PCF 的萨格纳克干涉仪：理论、实验和传感特性


在本文中，我们对由不同种类的高双折射（HB）二芯光子晶体光纤（TCPCF）制成的全光纤萨尼亚克环路干涉仪（SLI）的传输和传感特性进行了比较研究，分别用于应变、扭转和温度传感。对光纤装置进行了理论和实验分析。使用 HB TCPCF 的 SLI 的传输频谱显示出六个空间频率，这是由于源自纤芯内的多个两光束干涉以及在两个双折射纤芯中传播的基本偏振模式之间的纤芯间相互作用的叠加。我们的结果表明，光纤器件的传输特性及其复用干涉的传感特性在很大程度上取决于两个双折射芯的光学和结构特性，例如它们的固有双折射、它们之间的有效折射率对比度以及相对折射率。 （慢）双折射轴之间的方向。最后讨论了特定HB TCPCF的SLI在三个参数同时测量中的应用。