OPTICAL DEMULTIPLEXER

摘要

PROBLEM TO BE SOLVED: To obtain the optical demultiplexer in which signal light beams, that are wavelength multiplexed, are precisely and simply separated with a good sensitivity and taken out in a wavelength divided multiplex transmission type optical communication system. SOLUTION: The optical demultiplexer 10 radiates a multiplexed signal optical beam bm from an irradiating collimator 1 onto a transmission type interference filter 3 in which a tilt angle θ varies and at least a portion of the passed signal optical beams is received by a light receiving collimator 2. The collimator 2 is located at a position L1 which is parallel moved for a constant distance (d) in the direction approaching to a top part 3e of the filter 3 that is tilted from a reference alignment position L0 where the transmission loss of the beam bm becomes a minimum while the filter 3 is not inserted.