A high temperature sensor based on a peanut structure-based Michelson interferometer

A novel fiber temperature sensor with high sensitivity based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a peanut-shape structure and we demonstrated that the peanut-shape structure can couple the light energy of the core mode into the cladding and re-couple the light in the cladding into the core. The experimental results show that the device can be heated up to 900 degrees C with the sensitive of 0.096nm/degrees C when the sensor length L is similar to 21mm. Such kind of simple, low-cost, and highly sensitive fiber-optic temperature sensor would find applications in sensing fields.