Grating pitch angle centering fine adjustment device

The invention belongs to the technical field of semiconductors, and relates to a grating pitch angle centering fine tuning device in an external cavity type tunable laser light source. The grating pitch angle centering fine adjustment device comprises an adjustment support and piezoelectric ceramics. The piezoelectric ceramic is vertically arranged in the adjusting bracket; a flexible hinge structure is arranged between the upper part and the lower part of the adjusting bracket; the rotation center of the flexible hinge structure coincides with the grating plane and the light path plane. According to the device, the rotation center of the grating plane, the rotation center of the light path plane and the rotation center of the flexible hinge coincide, so that when the pitching angle of the grating is adjusted, the position of the grating in the light path is not changed, and the cavity length of the light path of the external cavity cannot be changed. The grating does not need to be adjusted before being glue