Institute of Photonics Technology, Jinan University, Guangzhou 510632, China.
Opt Lett. 2012 Jul 1;37(13):2703-5. doi: 10.1364/OL.37.002703.
A directional vibration sensor based on polarization-controlled cladding-to-core recoupling is demonstrated. A compact structure in which a short section of multi-mode fiber (MMF) stub containing a weakly tilted fiber Bragg grating (TFBG) is spliced to another single-mode fiber without any lateral offset. Multiple core modes of the MMF are coupled at the junction and appear as well defined resonances in reflection from the TFBG. Some of those resonances exhibit a strong polarization and bending dependence. Both the orientation and the amplitude of the vibrations can be determined unambiguously via dual-path power detection of the orthogonal-polarimetric lowest order LP(1n) modes. Meanwhile, the unwanted power fluctuations and temperature perturbations can be referenced out by monitoring the fundamental LP(01) mode resonance.
基于偏振控制包层-芯重新耦合的定向振动传感器得到了演示。该传感器采用了一种紧凑的结构，其中一小段含有弱倾斜光纤布拉格光栅（TFBG）的多模光纤（MMF）短节与另一段单模光纤熔接，没有任何横向偏移。MMF 的多个芯模在连接处耦合，并在 TFBG 的反射中呈现出明确定义的共振。其中一些共振表现出强烈的偏振和弯曲依赖性。通过对正交偏振最低阶 LP(1n)模式的双通道功率检测，可以明确确定振动的方向和幅度。同时，通过监测基本 LP(01)模式共振，可以参考消除不需要的功率波动和温度干扰。
