| 摘要 |
PURPOSE:To obtain a distributed feedback type semiconductor laser which can operate at a high output, has larger coupling constant and good sole mode property by specifying the mean thickness of a guide layer. CONSTITUTION:The compositions and the thicknesses of layers are fundamentally the same as those of a conventional example, but the mean thickness of a guide layer 7 is increased to 0.25-0.35mum as compared with the conventional one. In the principle of operation, when a current flows between electrodes 1 and 11, a light is generated in an active layer 5, confined in the active layers 5, 7 by upper and lower clad layers 8, 4, selectively amplified to the light of wavelength determined by the period of a diffraction grating provided in the layer 7 to generate a laser. When the mean thickness of the layer 7 is increased, most of the electric field in the laser is distributed in the layer 7. Thus, the rate of the electric field affected by Bragg's reflection by the diffraction grating is increased, and the value of the coupling constant is increased. |
