Fuji Electric Co., Ltd.

Takao Suyama

Shoji Kitamura

Yoichi Shindo

Shinji Ogino

Hiromi Mojikawa

Ken Komatsu

A semiconductor laser device is provided which includes a laser diode chip mounted on a sub-mount, a monitor photo diode incorporated in the sub-mount, for monitoring a laser beam emitted by the laser diode chip, a metallic main plate mounting the laser diode chip and the monitor photo diode, an end-face breaking protective layer covering the laser diode chip and the sub-mount; and a seal resin in which the laser diode chip, the monitor photo diode, the end-face breaking preventive layer and at least a portion of the metallic main plate are sealed. In this semiconductor device, a space is provided at a portion of an interface between the end-face breaking preventive layer and the seal resin, which portion is adapted to be irradiated with a monitor laser beam emitted by the laser diode chip, with a light intensity that is not higher than a half of a peak value of the intensity of the monitor laser beam.

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Saitama, Japan

Takao Suyama