WAVELENGTH VARIABLE FILTER AND OPTICAL BRANCHING FILTER

摘要

PROBLEM TO BE SOLVED: To separate a multiplexed luminous flux without complicated assembly and adjustment by providing a filter having the distribution of a transmitted wavelength and a means changing the incident point of light which is made incident on the filter. SOLUTION: The transmission wavelength is set to be variable by changing the incident point of light into the filter having the distribution of the transmitted wavelength. The means changing the incident point is constituted by a means making light incident on the filter and a means changing a relative position with the filter. Namely, only the light of the wavelength corresponding to the thickness of a wedge in light which is made incident on a wedge-type interference film filter 403 from an optical fiber 401 through a rod lens 405 is interfered and is transmitted. Transmitted light is made incident on a fiber 402 through a rod lens 406 and is guided to a photodetector 404. Here, the transmitted wavelength can continuously be changed by moving the wedge-type interference film filter 403 to right and left.