基于拉锥多模光纤的高灵敏度光纤折射率传感器

Using oxy-hydrogen flame to taper 62.5/125 μm multimode fiber, a tapered fiber with 30 mm taper length and 3.5532 μm waist diameter is obtained. Based on the tapered multimode fiber, a single mode-tapered multimode-single mode (STMS) fiber refractive index (RI) sensor structure is made, which has strong evanescent field and high sensitivity to the outside refractive index. In the liquid refractive index sensing experiment, the tapered multimode fiber is maintained straight and hung in the air at room temperature 25℃.The RI liquids are placed around the taper using a dropper. Experimental results show that this refractive index sensor structure offers RI sensitivity as 1009.9nm/RIU within the RI range of 1.3414 to 1.3586. The change of liquid refractive index can be accurately monitored by the proposed sensor.