Anti-drop polarization maintaining optical fiber coupler

The utility model relates to the technical field of couplers, in particular to an anti-drop polarization-maintaining optical fiber coupler, which comprises an optical fiber, a sleeve is sleeved on the outer wall of the optical fiber, the top end of the sleeve is fixedly connected with a limiting plate, the sleeve is connected with a gear through a thread structure, the gear is connected with a bevel gear, and the bevel gear is connected with the optical fiber. A transmission shaft is fixedly connected to the top end of the bevel gear, a rotary knob is fixedly connected to the top end of the transmission shaft, the transmission shaft is rotationally connected with an upper protective sleeve, and the upper protective sleeve is connected with a lower protective sleeve through a limiting structure. According to the utility model, through the connection between the round cap and the sleeve, the diameter of the bottom end of the sleeve is reduced to realize tight clamping of an optical fiber, the risk that the opti