Abstract: In a resin-sealed laser diode device, in order to prevent the sealing resin on the front light-emitting end face of the laser diode chip from being deteriorated by the laser beam, a thermosetting rubber-like organic silicone resin layer is formed on the front light-emitting end face to a thickness of at least 50 &mgr;m on the extension of the surface of the active layer. On the side of the rear light-emitting end-face of the laser diode chip, the rubber-like organic silicone resin layer on the photo-diode is curved upwardly with respect to the light receiving surface of the latter. Furthermore, in order to prevent the far field pattern of the laser beam from being made irregular, at least the surface of the end-face protecting film on the light-emitting end face essentially contains silicon dioxide.

Abstract: 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.