Semiconductor photodetector having an optical attenuator

摘要

A waveguide type semiconductor photodetector device comprises a photosensitive section including a photo-absorption layer for converting a signal light into an electric signal, and an optical attenuation section including an optical attenuation layer made of a bulk crystal for attenuating incident light. Assuming that Eg.ATT and Ein are bandgap energy of the optical attenuation layer and optical energy of the incident light signal, respectively, Ein+50 meV