Ultrasensitive Temperature Sensor Based on Fiber-Optic Fabry–Pérot Interferometer with Vernier Effect

Resumo

We propose and demonstrate an ultrasensitive temperature sensor based on a fiber-optic Fabry–Pérot interferometer (FPI) with the Vernier effect. The sensor is prepared by splicing a section of silica tube and single-mode fiber (SMF) to a section of SMF in sequence, which formed two-cascaded FPIs. Their superimposed spectrum can produce the Vernier effect and form the interference spectrum envelope due to a similar free spectrum range (FSR). The shift of the interference spectrum envelope is much larger than that of a single FPI, when the temperature changes. Experimental results show that the designed sensor can provide a high temperature sensitivity of 183.99 pm/°C, which is almost 220 times higher than that of a single air cavity (0.86 pm/°C) and about 20 times higher than that of a single silica cavity (9.14 pm/°C). The sensor designed has compact structure (< 1 mm) and high sensitivity, providing a prospect for successful applications.