为了实现高精度、低成本的液体折射率测量, 采用飞秒激光水辅助微加工技术, 制备出一种基于微孔结构的单模光纤液体折射率传感器。研究了传感器的传输损耗与孔内液体折射率及微孔长度的关系, 利用射线理论分析了传感的机理, 讨论了温度对传感器性能的影响。结果表明, 该传感器在折射率1.333~1.413区间具有良好的线性响应, 灵敏度达到157.48dB/RIU, 且不易受温度串扰。该传感器具有结构紧凑、制备简单、高灵敏度、温度不敏感和低成本等优点, 在生物化学测量领域中有着广泛的应用前景。

In order to measure refractive index of liquid with high-precision and low-cost, a liquid refractive index sensor based on a micro-hole in the single-mode fiber was fabricated by means of water-assisted femtosecond laser ablation method. The responses of transmission loss of the sensor to the refractive index and micro-hole length were investigated. Based on the ray theory, the sensing mechanism was analyzed. The effect of temperature disturbance on the sensor performance was also discussed. The experiment results show that the sensor has a good linear response in the refractive index range of 1.333~1.413, the sensitivity of the sensor can achieve 157.48dB/RIU and it is less susceptible to temperature change. Compared with other fiber refractive index sensors, optical fiber micro-hole sensors have the outstanding advantages, including compact, easy to fabricate, high sensitivity insensitive to temperature and low cost, etc. Therefore optical fiber micro-hole sensors can have extensive application in the fields of biochemical measurement.