A high sensitivity dual-parameter sensor based on glycerin filled fine-core polarization maintaining photonic crystal fiber

A high sensitivity dual-parameter sensor based on glycerin filled fine-core polarization maintaining photonic crystal fiber is proposed and verified experimentally. The sensor is fabricated by melting a fine-core photonic crystal fiber (PCF), which has a diameter of 80 µm and two single-mode fibers to form the interferometric structure. By observing the shift of the interference spectrum fringes, external strain and temperature changes can be obtained. Before the glycerin liquid is filled into the air hole, results suggest that sensitivity of the sensor in strain is 2.28 pm/με and sensor is temperature insensitive. At the same time, wavelength shift and dual-parameter change have a good linear relationship. Besides, sensitivity of proposed sensor can be improved by filling glycerin into PCF. When duty cycle N is equal 100%, linear response is also obtained and sensitivities increase to 2.98 pm/με and 237.57 pm/°C, respectively. The experiment also proved that the liquid filling duty ratio N will affect the sensitivity of the sensor. Proposed two-parameter matrix can effectively overcome the problem of sensor cross-sensitivity. The sensor has advantages of small volume, compact structure and high sensitivity.