A high-sensitivity temperature sensor based on liquid-infiltrated large lateral offset structure

Abstract

We demonstrated the high sensitivity and mechanical strength temperature and strain sensor based on liquid-infiltrated Fabry-Perot interferometer (FPI). The sensor is fabricated by splicing a short section of single-mode fiber (SMF) between two sections of SMF with a large intentional lateral offset forming open-cavity. For its high thermo-optic coefficient (TOC), isopropanol leads to a huge wavelength variation of the reflection spectrum while external temperature changes. The sensor was used to monitor the change of temperature and obtained a sensitivity of up to -655.0pm/°C in the range of 20 to 45 °C. In addition, the sensor presents a high sensitivity to a strain of 20.8pm/με. The sensor is expected to be used in high-sensitivity temperature and strain monitoring environments.