OPTICAL PATH LENGTH CORRECTION MODULE

PROBLEM TO BE SOLVED: To provide a compact optical path length correction module which easily adjusts an optical path length. SOLUTION: A movable mirror 5 and fixed mirrors 6, 7 are disposed in the optical path from collimator units 1, 3 in which a collimator lens is connected to the end of each input side optical fiber to a collimator units 2, 4 in which a collimator lens is connected to the end of each output side optical fiber. The movable mirror 5 commonly used for respective optical fibers is positioned at the center of the optical path, movable in the optical axis direction, and reflects by 180° and folds back incident light so as not to interfere with each other of light. The fixed mirrors 6, 7 which correspond the optical fibers to one-to-one are positioned between the movable mirror and the collimator unit and reflects by 180° and folds back incident light so as not to interfere with each other of light. COPYRIGHT: (C)2010,JPO&INPIT