Patent ID: 8184990

Claim:
A light source wavelength control apparatus, comprising: a plurality of light sources; a multiplexer, which has a plurality of input ports, inputs lights from the plurality of light sources to the different input ports respectively and outputs a multiplexed light, and of which the plurality of input ports have mutually different transmissive wavelength characteristics; a plurality of reflection light generators, being equipped at the previous stage of the respective input ports of the multiplexer, to allow a pass or not to allow a pass according to the transmissive wavelength characteristics at the respective input ports corresponding to an incident light from a light source, specifically, to allow a pass if the incident light is a predetermined wavelength, or not to allow a pass if the incident light is other wavelengths, the incident light being not allowed to pass is reflected back to the light source from which the incident light is emitted; a wavelength setup circuit to set an output wavelength of the corresponding light source as the predetermined wavelength for the reflection light generator by detecting a reflection light from the plurality of reflection light generators; and an attenuator to attenuate a light incident to said multiplexer when a wavelength becomes the predetermined wavelength and to pass the light without attenuation when a wavelength is not the predetermined wavelength while said wavelength setup circuit sets a wavelength.