Patent ID: 6498337
Filing Date: 2002-12-24
Classification: G02B,H01L

Abstract:
A photodetector, comprising:a substrate having a principal surface; a photodetection part provided on a part of said principal surface of said substrate, said photodetection part comprising: an optical absorption layer of a semiconductor material extending parallel to said principal surface, said optical absorption layer causing excitation of carriers therein in response to an optical radiation supplied thereto; and an optical waveguide provided on said principal surface of said substrate, said optical waveguide guiding an optical beam in a direction parallel to said principal surface from a first end surface thereof to a second end surface thereof located adjacent to said photodetection part, such that said optical beam guided through said optical waveguide is injected into said optical absorption layer of said photodetection part, said optical waveguide comprising: a first tapered optical waveguide layer extending from said first end surface to said second end surface, said first tapered optical waveguide layer increasing a thickness thereof continuously from said first end surface to said second end surface; a second tapered optical waveguide layer provided on said first tapered optical waveguide layer with a separation therefrom, said second tapered optical waveguide layer increasing a thickness thereof continuously from said first end surface to said second end surface; and an intermediate layer having a refractive index smaller than a refractive index of any of said first and second tapered optical waveguide layers, said intermediate layer being interposed between said first and second tapered optical waveguide layers.