Research on simultaneous temperature and relative humidity measurement based on tapered PCF Mach-Zehnder interferometer

Abstract A Mach-Zehnder interferometer (MZI) based on tapered photonic crystal fiber (PCF) for simultaneous temperature and relative humidity (RH) is proposed. It consists of two sections of single-mode fiber (SMF) fused with a section of tapered PCF. The temperature and RH sensitivities are improved by adding a taper in the middle of the PCF. The experimental results show that the temperature sensitivities are 0.061 nm/°C and 0.028 nm/°C from 30 °C to 90 °C, respectively. The RH sensitivities are 0.039 nm/%RH and 0.032 nm/%RH from 30%RH to 70%RH, respectively. The simultaneous measurement of temperature and RH can be achieved by calculating the sensitivity coefficients matrix. This MZI has the superiorities of high sensitivity, good repeatability, simple fabrication, and compact size.