Highly Sensitive Current Sensor Based on an Optical Microfiber Loop Resonator Incorporating Low Index Polymer Overlay

Abstract

A highly sensitive current sensor based on an optical microfiber loop resonator (MLR) incorporating low index polymer is proposed and experimentally demonstrated. The microfiber with a waist diameter of 2 m is wrapped around the nichrome wire with low index polymer overlay to realize the MLR as the highly sensitive current sensor. Low index polymer overlay can successfully reduce round-trip fractional loss resulting in the improvement of the Q-factor (Q) and the finesse (F) of the MLR around the nichrome wire. The use of the microfiber with a waist diameter of 2 m and low index polymer with high thermal property can effectively improve the current sensitivity of the proposed MLR to be 437.9 pm/A 2 . Index Terms-Fiber-optic sensors, microfiber, microfiber loop resonator, electric current sensors.0733-8724 (c)

Recent Developments in Micro-Structured Fiber Optic Sensors

“…An improved scheme was proposed by Wang et al in 2010 to make a free-standing microfiber closed-loop resonator by fusing two ends of a piece of microfiber [136]. The resonator was able to be tuned and had an extremely high W-factor of 110,500 with a finesse of 15.3. index polymer [139]. The microfiber was wrapped around the nichrome wire with low index polymer overlay, which is able to reduce the round-trip loss and improve the Q-factor and finesse of the MLR.…”

“…As the effective RI of the evanescent wave in the microfiber is modified by environmental humidity, the resonant wavelength of the resonator changes with RH level. In 2015, a highly sensitive current sensor was proposed and experimentally demonstrated based on an optical microfiber loop resonator (MLR) incorporating low index polymer [139]. The microfiber was wrapped around the nichrome wire with low index polymer overlay, which is able to reduce the round-trip loss and improve the Q-factor and finesse of the MLR.…”