Highly Sensitive Optical Fiber Temperature Sensor Based on Microwave Photonic Filter With Enhanced Vernier Effect
Minghe Wang, Ailing Zhang, Honggang Pan, Fei Liu, Pengxiang Chang, Junfeng Wang, Rui Lin, Bo Wang
Abstract
A highly sensitive optical fiber temperature sensor based on microwave photonic filters (MPFs) with enhanced Vernier effect has been proposed and experimentally demonstrated. The enhanced Vernier effect is achieved through a parallel configuration structure that precisely controls the delay time difference and filter coefficient of two dual-tap MPFs with a common sensing arm. So, the free spectral range (FSR) of the two MPFs varies in opposite directions with temperature, which results in a more pronounced envelope shift and increased sensitivity. Experimental results demonstrate that the temperature sensitivity is improved to 902.51 kHz/°C by using the enhanced Vernier effect, which is around 69 and 71 times the individual MPFs, respectively.