基于飞秒激光制备的光纤Fabry-Perot折射率传感器

Optical fiber Fabry-Perot refractive-index sensor fabricated by femtosecond laser etching

在对光纤Fabry-Perot(F-P)传感器多光束干涉原理仿真分析的基础上,利用波长为800nm的飞秒激光脉冲在普通单模光纤(SMF)上制备微型传感器,并对其折射率响应性能进行了实验测试。理论分析表明,在低、高折射率区域,F-P传感器的反射谱对比度随着折射率的增加分别呈现先降低后增加的趋势(折射率高低分界点1.457)。飞秒激光的制备方法通过计算机控制腔长等可以进行参数可选择的微型光纤F-P传感器的制作。利用制备的传感器对一系列不同折射率的溶液进行了折射率响应测试实验,测试结果表明,传感器反射谱对比度对低折射率物质(折射率小于1.457)的灵敏度为27.65dB/RI,对高折射率物质(折射率大于1.457)的灵敏度为3.50dB/RI,且均具有良好的线性响应。

The optical fiber Fabry-Perot （F-P） sensor is simulated and analyzed based on multi-beam in- terference principle. Then the micro F-P sensor is fabricated by 800 nm femtosecond laser mechanism on the single mode fiber. And the refractive index （RI） response is experimentally tested. The fabrication parameters can be tunable through controlling the computer. Under different fabricated parameters, the different reflection spectra of the F-P sensor can be formed. According to the theoretical analysis, the fringe contrast of the micro F-P sensor will decrease within the low refractive index region,and it will in- crease within the high refractive index regioin （low region., refractive index is less than 1. 457~high re- gion.refractive index is more than 1. 457）. The refractive index responses to a variety of different solu- tions are carried out. The results show that the sensitivities of the sensor interference fringe contrast to low and high refractive index solutions are 27. 65 dB/RI and 3.50 dB/RI, respectively. And the experi- mental results of two refractive index regions both exhibit good linear response. This type of F-P sensor has advantages of high sensitivity, good reproducibility, anti-corrosion, and so on. It is easy to be fabrica- ted by femtosecond etching technique. Thus, it has a great potential application in the refractive index sensing field of optical fiber sensors.