Semiconductor laser device

A semiconductor laser device comprising:

• a semiconductor laser element;
• a photodetector to receive laser light emitted from the semiconductor laser element;
• and
• a stem on which the semiconductor laser element and the photodetector are mounted, wherein
• the stem comprises a groove having an inclined face;
• the semiconductor laser element is disposed on the inclined face of the groove of the stem via a submount and the photodetector is disposed on an other submount on the stem except for the inclined face of the groove of the stem;
• an angle of the inclined face with respect to a stem front face of the stem is adjusted to an angle range in which the laser light emitted from the semiconductor laser element is received by the light receiving face of the photodetector;
• the semiconductor laser element is disposed on a side to the stem front face between the stem front face and a farthest portion of the photodetector farthest away from the stem front face of the stem on which the semiconductor laser element and the photodetector are mounted;
• and
• the photodetector has a light receiving face for receiving the laser light and a reflective film formed thereon in which part of the laser light is transmitted and the rest is reflected, and is a waveguide type light receiving element having an absorption layer that absorbs laser light and extends on a side to the light receiving face, the light receiving face being formed on a side facing the semiconductor laser element, wherein the light receiving face of the photodetector is an inclined face inclined with respect to a rear face of the photodetector facing the stem front face of the stem.