Semiconductor laser device and method of manufacturing the same

A method for manufacturing an air ridge type semiconductor laser device, comprising the steps of:

• a step of forming a multi-layer structure by forming a first cladding layer, an active layer, a second cladding layer and a contact layer, each comprising a compound semiconductor layer, on a compound semiconductor substrate, using the epitaxial growth method;
• a step of etching said contact layer and said second cladding layer in said multi-layer structure to form a ridge stripe comprising said contact layer and an upper layer of said second cladding layer, and a lower layer of said second cladding layer, which extends outwardly from both lower ends of the upper layer;
• a step of epitaxially growing a protection layer comprising a compound semiconductor layer having a different conductivity type from said second cladding layer on an upper surface of said second cladding layer other than an upper surface of said contact layer and on side planes of said ridge stripe using the selective area growth method;
• and
• a step of forming a metal film on an upper surface of said contact layer to form an electrode for ohmic contact with said contact layer.