| 摘要 |
PROBLEM TO BE SOLVED: To obtain satisfactory light-off ratio by forming at least one part of an optical waveguide into a curved shape in a photosemiconductor device that has the optical waveguide for outputting light which is inputted from one end to the other and functions as a photo amplifying medium, where light is amplified by at least one part of the optical waveguide. SOLUTION: An activation layer 3 for forming an optical waveguide of a photosemiconductor device (SOA) 1 is formed in an S-shaped curved shape, linear light input and output parts 11 and 12 are provided in one piece at the both ends, and the light input and output parts 11 and 12 are offset in parallel and are formed in a tapered structure, where the thickness of the layer is gradually thinned toward an end part. Then, the size of a light spot on an end face is enlarged, thus obtaining a satisfactory optical coupling. Also, a pair of element end faces opposite each other is positioned in parallel, and an AR coat 13 is formed as non-reflecting covering by an SiON film, thus quenching signal light being inputted for preventing it from being outputted. |
