基于游标效应增敏的全光纤液体折射率传感器

A Sensitivity-enhanced All-fiber-optic Liquid Refractive Index Sensor Based on Vernier Effect

为了实现液体折射率的高灵敏度测量,提出并制备了一种基于游标效应增敏的全光纤液体折射率传感器.该传感器由法布里-珀罗传感腔和法布里-珀罗参考腔并联构成,其中,传感腔为开放腔,由单模光纤错位熔接制得,参考腔为封闭腔,由单模光纤与空芯光纤熔接制得.传感腔和参考腔的自由光谱范围相近,但不相等,双腔反射光经光纤耦合器后叠加产生游标效应,达到增敏的效果.实验结果表明,该传感器的折射率灵敏度约为9048.78 nm/RIU,约是单个传感腔的8倍.该传感器具有灵敏度高、结构简单、易于制备、成本低廉的优点,在生物医疗、环境检测等领域有潜在的应用前景.

In order to realize the high sensitivity measurement of the liquid refractive index,a sensitivity-enhanced all-fiber-optic liquid refractive index sensor based on vernier effect is proposed and demonstrated.The sensor is composed of a Fabry-Perot sensing cavity and a Fabry-Perot reference cavity in parallel.The sensing cavity is an open cavity made by offset splicing of single mode fiber,and the reference cavity is a sealed cavity,which is fabricated by fusion splicing of single mode fiber and hollow optical fiber.The free spectral ranges of the two Fabry-Perot cavities are similar,but not equal.Vernier effect is generated when the beams are superimposed via a fiber coupler to achieve the sensitization effect.Experimental results show that the refractive index sensitivity of the proposed sensor is about 9048.78 nm/RIU,which is about 8 times that of a single sensing cavity.Due to the advantages of high sensitivity,simple structure,easy preparation and low cost,the sensor has potential application foreground in chemical and biomedical domain.