| 摘要 |
PURPOSE:To efficiently receive backward emitting beams from a semiconductor laser by providing a monitoring photodetector on a substrate made into an optical IC. CONSTITUTION:A luminous flux emitted from a semiconductor laser 4 is condensed on an information recording medium surface 6 by a light condensing grating coupler 5, and the reflected luminous flux is received and detected by a photodetector 10. Backward emitting beams 14 of the semiconductor laser 4 are received and detected by a monitoring photodetector 17 provided on a substrate 1, whether or not the semiconductor laser 14 emits the beams at a prescribed optical output is decided by a semiconductor laser driving circuit 15, and the driving current I of the semiconductor laser 4 is supplied so as to emit the prescribed beams. Thus the backward emitting means of the semiconductor laser being the light source can be efficiently detected. |
