In this letter, a strain sensor with high sensitivity enhancement using a special case of Vernier effect is presented. The sensor configuration is composed of two-fiber loop mirrors in a cascaded configuration with opposite strain responses when individually characterized. Thus, the enhanced Vernier effect is explored, which is the most sensitive of three possible cases Vernier effect. Here, the Vernier response depends on the difference between the sensitivities of each Hi-Bi optical fiber. In addition to this, the fundamental and the first harmonic were also explored. The results obtained are a strain sensitivity of (13.3 ± 0.3) pm/με for the carrier, (80.0 ± 0.3) pm/με or the Vernier envelope of the fundamental case and (120 ± 1) pm/με for the Vernier envelope of the first harmonic. The first harmonic could achieve a magnification factor of 8. Considering that the optical interrogation system allows a minimum resolution of 0.02 nm, the minimum measurement step achievable is 0.2 με. This work proves the possibility of applying the concept of enhanced Vernier effect to fiber loop mirrors, obtaining higher sensitivity than a standard fiber loop mirror alone. Besides, the sensitivity can be increased through the usage of harmonics of the Vernier effect. Moreover, the use of large interferometers allows a better discretization of the envelope, which implies a greater ease of analysis.

中文翻译：

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使用 2 光纤环镜的基于游标效应的高增强应变传感器


在这封信中，提出了一种利用游标效应特殊情况提高灵敏度的应变传感器。传感器配置由级联配置的两光纤环镜组成，在单独表征时具有相反的应变响应。因此，探索了增强的游标效应，这是三种可能的游标效应中最敏感的。这里，游标响应取决于每根 Hi-Bi 光纤的灵敏度之间的差异。除此之外，还探讨了基波和一次谐波。获得的结果是载体的应变灵敏度为 (13.3 ± 0.3) pm/με，基本情况的游标包络为 (80.0 ± 0.3) pm/με 或基本情况的游标包络为 (120 ± 1) pm/με第一次谐波。一次谐波可实现 8 倍的放大倍数。考虑到光学询问系统允许的最小分辨率为 0.02 nm，可实现的最小测量步长为 0.2 με。这项工作证明了将增强游标效应概念应用于光纤环镜的可能性，获得比单独标准光纤环镜更高的灵敏度。此外，还可以通过利用游标效应的谐波来提高灵敏度。此外，使用大型干涉仪可以更好地离散化包络线，这意味着更容易分析。