| 摘要 |
PURPOSE:To simplify the structure and stabilize the light output, by installing on the same axis a photo emission region and a P-N junction part of a photo detecting part in the quantum well-type structure layer sandwiched between semiconductor layers whose composition are larger than the mean composition of two kinds of compound semiconductor constituting the quantum well-type structure layer. CONSTITUTION:When the electron current and the positive hole current are supplied to the N-side electrode 8 of the laser part 11 and the back side electrode 10 of the substrate 1, respectively, the current concentrates to the impurity non-diffusion region 4a in the quantum well-type structure layer 4, and the single mode oscillation of the laser light occurs in the transverse direction. The most part of laser light emitted from the oscillation region 4a is reflected at the boundary of the impurity diffusion layer 4c, and emitted from the cleavage face. A part of the light which has penetrated through the boundary is introduced into the impurity non-diffusion layer 4b. In the photo detecting part 12, the P-N junction is inversely biased to form the depletion layer. When the light is introduced, electrons and holes generated according to the light intensity are accelerated to the N-type layer 3 and the P-type layer 2, respectively. The electromotive force is taken out as the electric signal from the electrodes 9 and 10, and is fed back to the input side of the laser part 11 to control the output light. |
