Ultra-longer fiber cantilever taper for simultaneous measurement of temperature and relative humidity* *Project supported by the Scientific Research Project of Institutions of Higher Learning in Inner Mongolia Autonomous Region, China (Grant No. NJZY19214), the Natural Science Foundation of Inner Mongolia Autonomous Region, China (Grant No. 2018MS05064), the Education and Teaching Research Project of Chifeng College (Grant No. JYXMY202025), the Applied

Abstract

An ultra-longer fiber cantilever taper for simultaneous measurement of the temperature and relative humidity (RH) with high sensitivities was proposed. The structure was fabricated by using the simple and cost-effective method only including fiber cleaving, splicing, and tapering. The length of the cantilever taper is about 1.5 mm. The dip A and dip B were measured simultaneously, owing to the ultra-long length and super-fine size, the temperature sensitivities of the dip A and dip B reached as high as 127.3 pm/°C and 0 pm/°C between 25 °C and 50 °C, and the RH sensitivities are –31.2 pm/% RH and –29.2 pm/% RH with a broad RH interval ranging from 20% RH to 70% RH. Besides, the proposed structure showed good linearity in the sensing process and small temperature crosstalk. It will be found in wide applications in environmental monitoring, food processing, and industries.