Efficient photonic crystal fiber dynamic coupling device

The invention discloses an efficient photonic crystal fiber dynamic coupling device which comprises a shell, an input fiber group, an output fiber group, a collimating lens group, a Dammann grating phase plate, a transparent shell, a medium cavity, a converging lens, an air bag, a medium suction pump and a medium bag. After an optical signal is input through the input optical fiber set on the shell, the optical signal is divided into multiple paths of optical signals through the diffraction effect of the Dammann grating phase plate, the optical signals fall onto the output optical fiber set after being converged through the converging lens, and then the beam splitting effect is achieved; further, a medium cavity between the transparent shell and the Dammann grating phase plate is filled, so that the diffraction effect of the Dammann grating phase plate disappears; an optical signal of the input optical fiber group is collimated by the collimating lens group, linearly penetrates through the Dammann grating pha