A knotted shape core cladding optical fiber interferometer for simultaneous measurement of displacement and temperature

Abstract A novel composite structured all-fiber sensor was designed and experimentally demonstrated for simultaneous measurement of displacement and temperature. The sensor consists of a knotted shape core cladding optical fiber. The interferometer notch of a knotted shape fiber was found to be highly sensitive to the micro-displacement as well as environmental temperature, while the core-offset fiber was sensitive to temperature only. Thus the different features of these interferometer notchs of two parts can be used to measure the displacement and temperature. The experimental results showed that the sensor exhibited a high displacement sensitivity of −528.57 pm/μm ranges from 0 mm to 0.012 mm. And the temperature sensitivities of the knotted shape core cladding optical fiber were −114.86 pm/℃ and 31.66 pm/℃ ranges from 35 ℃ to 60℃, respectively. Due to the compact size and dual-parameters measurability, the sensor had a great potential in diverse sensing application.