A Few Mode Fiber Temperature Sensor Filled With PDMS Based on Vernier Effect

A few mode fiber temperature sensor filled with PDMS based on vernier effect is proposed. It uses single mode fiber(SMF), few mode fiber(FMF), and polydimethylsiloxane(PDMS) to form the SMF-air microcavity-FMF-PDMS-FMF structure. The PDMS is used as a sensing microcavity. When the temperature changes, the length and refractive index of the PDMS microcavity will change accordingly, which will cause a change in the interference spectrum of the sensor. And because the vernier effect is formed by the superposition of the two microcavities, the temperature sensitivity can be obviously amplified and the temperature can be measured with high sensitivity. The experimental results show that in the range of 40~56C, the transmission spectrum of the sensor appears red shift with the increase of temperature, and the temperature sensitivity can reach 3.89nm/C. The sensor is simple to manufacture, has high sensitivity, and has good application prospects in various survey environments