Mitsubishi Denki Kabushiki Kaisha

Kisuke Matsumoto

Tatsuya Kimura

Akira Takemoto

A semiconductor laser includes a semiconductor substrate of a first conductivity type having opposite front and rear surfaces, a double-heterojunction structure including a first conductivity type lower cladding layer, an undoped active layer, and an upper cladding layer of a second conductivity type, opposite the first conductivity type, successively disposed on the front surface of the semiconductor substrate wherein the double-heterojunction structure is a mesa having opposite sides, and a light and current confinement structure disposed on the opposite sides of the mesa for confining laser light and laser driving current within the mesa. The confinement structure includes a first conductivity type mesa embedding layer, a second conductivity type mesa embedding layer, and a semi-insulating InP layer which are successively disposed on the semiconductor substrate contacting the opposite sides of the mesa. In this structure, since the semi-insulating semiconductor layer is not in contact with the active layer, unfavorable diffusion of impurities contained in the semi-insulating layer into the active layer is prevented.

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Itami, Japan

Kisuke Matsumoto