Design method of symmetrical biconical phase shift fiber grating and sensor system

The invention discloses a design method of a symmetric biconical phase-shifted fiber grating and a sensor system, and the method comprises the steps: obtaining a common phase-shifted fiber grating, and applying a high temperature to the common fiber grating until the common fiber grating approaches a molten state; applying an axial force to the common phase-shift fiber grating, changing the diameter distribution of the cladding and the fiber core of the common phase-shift fiber grating along the axial direction, and forming a symmetrical biconical phase-shift fiber grating; the symmetrical biconical phase shift fiber grating is axially chirped, the phase shift amount is increased, and simultaneous measurement of temperature and stress is realized. According to the sensing system provided by the invention, the simultaneous measurement of temperature and stress is realized, the central wavelength is positioned by reference to the Bragg fiber grating, and the variable quantity of the central wavelength is measur