High sensitivity fiber temperature sensor based PDMS film on Mach-Zehnder interferometer

An optical fiber temperature sensor based on a Mach-Zehnder interferometer (MZI) coated with a film of polydimethylsiloxane (PDMS) was demonstrated. The MZI was fabricated by a fiber mismatch structure through core-offset fusion splicing method. The resonant dip wavelength of the MZI will shift with the changing of the environmental temperature own to the effects of expansion and thermo-optic of the PDMS. Experimental results showed that the proposed sensor shows the temperature sensitivity of 0.101 nm/°C under the temperature range of 20 °C to 100 °C, which is about 2 times of the existing similar temperature fiber sensors.