Patent ID: 7136409
Filing Date: 2006-11-14
Classification: G02B,G11B,H01S

Abstract:
1. A semiconductor laser device comprising: a laser emission part for emitting a laser beam; laser reception parts for receiving a backward beam of the laser beam reflected by an irradiation object; a polarization hologram for transmitting the laser beam directed from the laser emission part to the irradiation object as a forward beam without diffracting the laser beam, and diffracting the backward beam of the laser beam, which is a return beam of the forward beam that has been reflected by the irradiation object, and dividing the backward beam into plural holographic diffracted beams so that the holographic diffracted beams are deflected from a direction directed toward the laser emission part and further directed toward the laser reception parts; a three-beam diffraction grating for dividing one of the holographic diffracted beams, which result from the diffraction of the backward beam by the polarization hologram, into three beams and for letting the three beams incident on the laser reception part; and wherein the three-beam diffraction grating is not located in a forward path of the forward beam between the laser emission part and the polarization hologram, and wherein the three-beam diffraction grating is located only in a backward path of one of the holographic diffracted beams.