Highly Sensitive Temperature Sensor Based on All-Fiber Polarization Interference Filter With Vernier Effect

A novel highly sensitive temperature sensor based on all-fiber polarization interference filter with Vernier effect is proposed and experimentally demonstrated in this article. The all-fiber polarization interference filter, namely Lyot filter, is simply consisted of a section of polarization-maintaining fiber positioned between two linear fiber polarizers. Vernier effect is introduced by simply cascading a Fabry–Perot interference with the Lyot filter. The temperature characteristics of the Lyot filter without and with Vernier effect are experimentally investigated, respectively. The experimental results show that with Vernier effect, the temperature sensitivity of Lyot filter can be improved from −1.752 nm/°C to −25.289 nm/°C. To the best of our knowledge, this is the first demonstration of Lyot filter based temperature sensor combining with Vernier effect. The good performance of the Lyot filter with Vernier effect in temperature sensing not only provides a new option for the optical fiber temperature sensor, but also further broadens the application of Lyot filter in the sensing field.