CROSS POLARIZATION TYPE OPTICAL FREQUENCY SHIFTER

PURPOSE:To reduce the number of constituting parts and to reduce the cost by interposing an optical deviding means and an optical coupling means between bottom faces of first and second acoustooptic mediums and using upper faces of these mediums as reflecting means to eliminate a need of positional adjustment for synthesis of two orthogonal frequency laser light beams on one optical path. CONSTITUTION:An optical divider 9 as a first deflecting film is brought into contact with bottom faces 29 and 32 of first and second acoustooptic mediums 1 and 2 and are interposed between these bottom faces 29 and 32 in the vicinity of an incidence face 11, and first linearly polarized light of laser light 14 made incident through the incidence face 11 is transmitted through as transmitted laser light 15, and second linearly polarized light is reflected as reflected laser light 16. An optical coupler 10 is provided as a second deflecting film in the vicinity of an exit face 12, and shifted laser light 18 and 20 are coupled and are emitted as the exit laser light from the exit face 12. Thus, a position adjusting mechanism to synthesize two orthogonal frequency laser light on the same optical path is not required, and two orthogonal frequency laser light are obtained by an inexpensive and small-sized device of small loss.