Heterodyne interference measuring system convenient in splitting ratio adjustment

The invention provides a heterodyne interference measuring system convenient in splitting ratio adjustment. The heterodyne interference measuring system comprises a laser, a polarization splitting prism and a photoelectric detector. An acousto-optic frequency shifter is arranged in front of the laser. Zero-order light generated by the acousto-optic frequency shifter is used as measuring light, and first-order diffraction light is used as reference light. The measuring light is irradiated to a measured object successively through the polarization splitting prism and a quarter-wave plate. The reflected measuring light is transmitted through the quarter-wave plate and then is irradiated to a convex lens after being reflected by the polarization splitting prism. The reference light is irradiated to a convex lens successively through the reflection of a reflector, and a half-wave plate. According to the invention, the zero-order light and the first-order diffraction light generated by the acousto-optic frequency shifter are respectively used as the measuring light and the reference light, a beam splitting device is not needed, the splitting ratio can be conveniently changed by the adjustment of a acousto-optic frequency shifter driving circuit, the intensity of the reference light is enabled to be close to the intensity of the measuring light, a relatively good interference effect is obtained, the measuring precision is improved, the adopted optical member are fewer, and the beneficial effect is substantial.