Variable lateral shearing Sagnac interferometer with dove prism

Sagnac interferometer is an important structure of lateral shearing interferometer. The shearing distance of the interferometer affects the measurement sensitivity of the interferometer and the stripe density of the fringes. A Sagnac interferometer with dove prism with variable lateral shearing distance is proposed. A dove prism is placed in the traditional optical path between the two mirrors in the Sagnac interferometer. The shearing distance of the interferometer can be adjusted by rotating the dove prism continuously. This structure can get the shearing distance over a wide range and reduce the influence of vibration on the system in the Sagnac interferometer during adjustment. The availability of this interferometer was confirmed after simulation and experiment.