OPTICAL COUPLING DEVICE

PROBLEM TO BE SOLVED: To provide a high speed, inexpensive and small optical signal recording and reproducing apparatus. SOLUTION: The optical coupling device comprises prisms (PBP 1, PBP 2) and deformable mirror devices (DMD 4, DMD 3). The PBP 1 and the PBP 2 have the same shape, and a bottom surface 1d and an upper surface 2b, and a bottom surface 2d and an upper surface 1b are arranged on the same plane to each other, and a slant face 1c and a slant face 2c are arranged in parallel. The DMD 4 is provided at the bottom surface 1d side. An angle θA formed by incident light L0 and a light beam L4, and an angle θB formed by the incident light L0 and emitted light L10 are 90 degrees, respectively, and a direction between the incident light L0 and the emitted light L10 differs by 90 degrees.