Patent ID: 7620090

Claim:
A semiconductor laser device comprising: a supporting substrate having a wiring pattern on a surface thereof; a semiconductor laser element fixed on the surface of said supporting substrate, the semiconductor laser element having a signal output section at a first surface that emits signal laser light and a monitoring output section at a second surface that emits monitoring laser light; and a monitoring photodiode fixed on said supporting substrate, wherein said monitoring photodiode has a semiconductor substrate transparent to a wavelength of said monitoring laser light, and a light receiving section for photoelectric conversion on a surface of said semiconductor substrate, said monitoring photodiode having a side surface that is an exterior incident surface of said semiconductor substrate and that is arranged at a position so that said monitoring laser light is incident thereon, said light receiving section is arranged at a position higher than said monitoring output section, and a back surface of said semiconductor substrate opposite said exterior incident surface is arranged to oppose said wiring pattern, the surface of said supporting substrate is substantially a flat plane, and said semiconductor laser element and said monitoring photodiode are arranged on said flat plane with both the second surface and the exterior incident surface extending in a perpendicular direction from the flat plane, and the second surface and the exterior incident surface are arranged to be non-parallel with respect to each other.