Humidity and Temperature Measurement via Dual-Taper Based Michelson Interferometer

Relative humidity (RH) and temperature sensing is a vitally important research field due to its various applications in the environmental, industrial, and agricultural monitoring. In this article, dual-silica tapers are skillfully fused on the fiber end face to realize the Michelson interferometer (MI) and then used for the RH and temperature measurement. A polymeric microsphere is coated on one silica taper end to enhance the fiber-optic sensitivity. The humidity and temperature are measured sequentially, along with the sensitivities of 3.8 pm/%RH and 14.3 pm/°C, respectively. Furthermore, in order to eliminate the crosstalk between RH and temperature in the actual application, a hybrid structure of MI integrated with a fiber Bragg grating (FBG) is fabricated and measured, where FBG is used as the compensating element to demodulate the humidity information.