The invention discloses an annular
fiber grating manufacturing method and
system for a high-order
mode coupling fundamental mode, and the method comprises the steps: starting a
femtosecond laser and corresponding equipment, and enabling the
femtosecond laser and corresponding equipment to be in a standby state, so as to guarantee the stability of
laser processing; a
coating layer at the
optical fiber processing position is stripped, the relative distance and height of the electric rotating clamps on the two sides are adjusted, so that the exposed part of the
optical fiber is located between the electric rotating clamps on the two sides, and the
horizontal and vertical positions of the electric displacement platform are adjusted; the
grating period
lambda, the rotating speed of the electric rotating clamp, the
moving speed of the electric displacement platform, the interval time of opening and closing of the laser valve and the period number are preset on the computer; and executing a preset program, and forming annular
fiber gratings periodically distributed along the
fiber axis on the interface of the fiber core and the cladding. The annular
fiber bragg grating inscribed by the method has
circular symmetry performance, and the problem that
mode coupling is influenced by random
azimuth angles of a
transverse mode field in a high-order mode influenced by non-uniform fiber
refractive index distribution and external environment disturbance can be effectively avoided.