OPTICAL SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To constitute a negative feedback loop which realizes a stable optical output by economically and efficiently receiving a backward beam from a semiconductor laser. SOLUTION: The optical semiconductor device comprises the semiconductor laser 1 which propagates the backward beam 3 of the laser 1 incident from the front end side face of a photodetector 4 in the photodetector 4, and reflects the beam on the rear end side face 7 of the photodetector 4 opposed to the front end side face of the photodetector 4, in such a manner that the part or the overall of the rear end side face 7 is inclined so as to direct the backward beam 3 toward the photodetecting surface 5 of the photodetector 4.