END-FACE PHOTODETECTING-TYPE PHOTODIODE

摘要

PURPOSE:To guide the incident light from an end part of a device to a photodetecting part efficiently by a method wherein a heterostructure light waveguide route composed of a clad part and a core part which have a forbidden band width bigger than the photodetecting part is formed as a window part at an end part on the incident side of the photodetecting part. CONSTITUTION:A core layer 47 has a forbidden band width which is smaller than a lower-part clad layer 46 and an upper-part clad layer 49, i.e. has a refractive index which is bigger than these layers. Because these three layers have the forbidden band width which is bigger than the energy corresponding to the wavelength of the incident light, they constitute a plasma waveguide route which is transparent with reference to the incident light 52. The core layer 47 forms a core part; the lower-part clad layer 46 and the upper-part clad layer 49 form clad parts. The incident light 52 is guided to a photodetecting part by the planar waveguide route composed of the core layer and the clad layers and is photodetected at a photodetecting part 51.