| 摘要 |
PURPOSE:To couple a photosemiconductor element or optical fiber with low loss by small-sized constitution by setting the spot diameter of a light wave, which is propagated in an input/output waveguide, larger than the spot diameter of a light wave which is propagated in a waveguide which has an optical processing function. CONSTITUTION:The parts of input/output optical waveguides 22 and 24 which are connected to optical elements such as semiconductor laser diodes and optical fibers are formed in such a waveguide structure that a spot diameter close to the light spot diameter of the waveguide of the photosemiconductor or optical fiber is obtained. Independently of above waveguide structure, the waveguide part which has the optical processing function is formed in a waveguide struc ture which determines the spot diameter of light propagated there so that the propagation loss of the waveguide and the loss of coupling with the optical fiber go to small and the best efficiency of the optical processing function is obtained. Consequently, even when the photosemiconductor element is joined directly, low-loss coupling becomes possible and a high-efficiency, small-sized optical communication device is realized. |
