Multi-parameter sensor with high sensitivity based on a long-period fiber grating prepared by a polarization-maintaining fiber

We propose what we believe to be a novel long-period fiber grating (LPFG) based on a polarization-maintaining fiber (PMF) and single-mode fiber. Due to the principal axis of stress, the resonance peak is strongly dependent on the polarization state of the input light. Under different polarization states, the response of the resonance peak to the change of the external environment is different. A single resonance peak can measure several physical quantities without wavelength overlap using polarization multiplexing. The experimental results show that the PMF-LPFG realizes a high sensitivity torsion and bending measurement under different polarization states (-3.27 nm/rad*m and -13.38 nm/m) and can also measure the ambient temperature (84.10 pm/°C). The PMF-LPFG unit has the advantages of small size, high sensitivity, and multi-parameter measurement. The design scheme of the sensor provides a new idea for a multi-parameter sensor.