Abstract: A method of manufacturing an avalanche photodiode capable of effectively preventing edge breakdown is disclosed. First, so as to manufacture an avalanche photodiode an absorption layer, a grading layer, a charge sheet layer of a first conductivity type and a multiplying layer are formed in sequence on a compound semiconductor substrate of the first conductivity type. Then, a concave portion is formed within multiplying layer at the central portion thereof. A first diffusion layer of the second conductivity type is formed to a first thickness within the multiplying layer so as to surround the concave portion. Next, a second diffusion layer of second conductivity type is formed within the multiplying layer to a second depth deeper than the first depth by extending the first diffusion layer and simultaneously a floating guard-ring, separated from the second diffusion with a selected distance is formed within the multiplying layer.

Abstract: A ridge wavegide laser diode, with an inverse mesa structure, resistant to heat and improved in the adhesion of a contact metal to a contact layer, which can be obtained by forming a polyimide spacer in such a way that polyimide remains only at the lower part of the corner of the inverse mesa structure. In the diode, the contact metal is minimally broken off at the opposite sides of the mesa structure.