Semicondutor laser device

Claim 1

A semiconductor laser device comprising: a substrate having a first semiconductor layer of a first conductivity type; and a semiconductor laser element and an auxiliary mechanism, provided side by side on said substrate; said semiconductor laser element including: a mesa portion having a second semiconductor layer provided above said first semiconductor layer and of a second conductivity type; an active region consisting of a semiconductor formed between said first and second semiconductor layers, having a predetermined width and having an energy gap smaller than the energy gap of said first and second semiconductor layers, said active region having opposed edge surfaces serving as reflecting mirrors for oscillating a laser beam between said opposed edge surfaces and emitting a laser beam from one of said edge surfaces, thereby contributing to light emission; a pair of buried portions consisting of a semiconductor formed on and contiguous to opposite sides of said active region in the width direction thereof and having a greater forbidden band width than the energy gap of said active region; electric insulating regions formed on the opposite sides of said buried portions and between said first and second semiconductor layers; and first and second electrodes for supplying current to said active region; and said auxiliary mechanism including: a third semiconductor later made of the same material as the buried portions; a high resistivity layer provided on said third semiconductor layer; and an electrode take-out pad portion provided on said high resistivity layer and electrically connected to said first electrode of said semiconductor laser element.