High resolution, fast response fiber-optic temperature sensor with reduced end conduction effect

We report a fiber-optic silicon Fabry-Perot temperature sensor with high speed by considering the end conduction effect, which refers to the unwanted heat transfer between the sensing element and the fiber stub delaying the sensor from reaching thermal equilibrium with the ambient environment. The sensor is constructed by connecting the narrow edge surface of a thin silicon plate to the edge of the microtube attached to the fiber tip. Compared to the traditional design where the silicon plate is attached to the fiber end face on its large plate surface, the new sensor design minimizes the heat transfer path to the fiber stub for improved sensor speed. It has the additional benefit of increased cavity length for improved resolution. We show that, compared with the sensor of traditional design, the sensor of the new design shortened the characteristic response time in still air from 83 ms to 13 ms and improved the sensor resolution by a factor of 12, from 0.15 K to 0.012 K.