基于微光纤布拉格光栅高阶模反射的折射率传感

Refractive index sensing based on higher-order mode reflection of a microfiber Bragg grating.

作者信息

Zhang Yu, Lin Bo, Tjin Swee Chuan, Zhang Han, Wang Guanghui, Shum Ping, Zhang Xinliang

机构信息

Wuhan National Laboratory for Optoelectronics and Institute of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.

出版信息

Opt Express. 2010 Dec 6;18(25):26345-50. doi: 10.1364/OE.18.026345.

DOI:10.1364/OE.18.026345

PMID:21164985

Abstract

A fiber Bragg grating written in a photosensitive microfiber using KrF excimer laser via a uniform phase mask is demonstrated. We have successfully fabricated two Bragg gratings in microfibers having different diameters. In the reflection spectrum of a microfiber Bragg grating (MFBG), we observed two reflection peaks,which agrees with our numerical simulation results. Compared with the fundamental mode reflection, the higher-order reflection mode is more sensitive to the refractive index (RI) variation of the surrounding fluid due to its larger evanescent field. The measured maximum sensitivity is ~102 nm/RIU (RI unit) at an RI value of 1.378 in an MFBG with a diameter of 6 μm.

摘要

展示了一种通过均匀相位掩模利用KrF准分子激光写入光敏微光纤中的光纤布拉格光栅。我们已成功在不同直径的微光纤中制作出两个布拉格光栅。在微光纤布拉格光栅（MFBG）的反射光谱中，我们观察到两个反射峰，这与我们的数值模拟结果相符。与基模反射相比，高阶反射模因其更大的倏逝场而对周围流体的折射率（RI）变化更为敏感。在直径为6μm的MFBG中，当RI值为1.378时，测得的最大灵敏度约为102 nm/RIU（RI单位）。