Large measurement range and high sensitivity temperature sensor with FBG cascaded Mach-Zehnder interferometer

A high sensitivity and wide measurement range temperature sensor with Mach-Zehnder interferometer (MZI) and fiber Bragg grating (FBG) cascaded is proposed and experimentally implemented. The proposed MZI is fabricated by inserting a section of single mode fiber between two sections of single mode fibers with 62 μm core-offset, where the length of the inserted fiber is 300 μm. Polydimethylsiloxane (PDMS), as a kind of thermo-sensitive material, is covered on core-offset region. Meanwhile, FBG is adopted to enlarge the measurement range. Temperature experiment results turn out to be fruitful for improving the performance of sensitivity and measurement range, and the sensitivity of proposed sensor is up to 10.389 nm/°C from 10 °C to 59.4 °C with good linearity. Moreover, the exhaustively comparison with other optical fiber interferometers reveals that the proposed sensor is simple making, miniature size, good reproducibility, high sensitivity and large measurement range, which has tempting commercial prospect.