LIGHT CONFINING STRUCTURE AND PHOTODETECTOR USING STRUCTURE THEREOF

摘要

PURPOSE:To provide a light confining structure, which can decrease surface reflection and can perform the light confinement effectively. CONSTITUTION:A transition layer 2 having the recess parts and protruding parts is provided on the surface of the a substrate 3. The repeating width of the recess part and the protruding part is made to be the wavelength or less of main light 5, which is to be confined. It is preferable to provide recess parts and protruding parts 8 and 9 at the rear surface of the substrate 3. The refractive index of the transition layer 2 is changed so as to approach the refractive index of the substrate toward the side of the substrate from the reverse side of the substrate.