| 摘要 |
PURPOSE:To simplify structure, to eliminate the need for adjustment work requiring large workhours for optically coupling a photodetector for laser beams and to reduce manufacturing cost by unifying the photodetector for monitoring a laser optical output for fixed-output drive with a laser element. CONSTITUTION:With a semiconductor laser element, an n-type clad layer 2, an active layer 3, a p-type clad layer 4 and a cap layer 5 are superposed onto an n-type substrate 1. Electrode metals 6, 6', 7 are formed on the cap layer 5 side and the substrate side. A trench 10 reaching the substrate 1 is shaped through etching from the cap layer side in the dice-shaped semiconductor laser element, and the laser element is separated into two sections. Since a left section functions as the laser element 12 and a right section forms a p-n junction, the right section can be operated as a photodetector 13 by applying a DC bias in the opposite direction. Since laser beams 11 radiated toward the photodetector 13 from the laser element 12 are projected to the p-n junction section near the active layer in the photodetector 13, they can be received with excellent sensibility.
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