Temperature sensing characteristics of borosilicate capillary sensitized low-finesse fiber extrinsic Fabry-Perot interference sensor

A low-finesse fiber extrinsic Fabry-Perot interference (EFPI) temperature sensor with high sensitivity, large dynamic range and high repeatability for marine applications is designed, and demonstrated. The use of borosilicate glass as the cavity sensitizing material improves the sensitivity of the sensor. In order to achieve temperature measurement with a large dynamic range and high repeatability, sensor samples with three common coupling methods of hydrogen-oxygen flame (HO), epoxy glue (EG) and glass solder (GS) welding were fabricated and the repeatability in a large temperature range were tested. The sensor fabricated by HO has the best repeatability. A sensitivity of 1.5 nm/°≅ in the temperature range of 10°≅~to 100 °≅, with a repeatability of 0.07 °≅ was demonstrated. The theoretical resolution can reach 0.000667°≅. The sensor has a good application prospect in ocean temperature monitoring.