US Patent 7623788 Optical wavelength division multiplexing transmitter

An optical transmitter for coupling and wavelength-multiplexing optical signals with a different wavelength has 3 or more light sources for emitting parallel optical signals with a different wavelength, and 2 kinds of optical components with a different optical signal reflectance arranged in an optical path of each light source for coupling into one the optical signals emitted from the light sources respectively. The reflectance or transmittance of each of the 2 kinds of optical components is set so that each optical signal has the same optical signal power when reflected off or transmitted through the optical components for being coupled together and output from the optical transmitter.