| 摘要 |
PURPOSE:To make it possible to set a coupling constant to a designed value with excellent reproducibility, by providing both surfaces of a diffraction grating layer with a semiconductor layer having a large energy gap, and forming parallel stripe trenches with a specified period. CONSTITUTION:On an active layer 3, the following are grown in order; a first semiconductor layer 4 whose energy gap is larger than the active layer 3, a diffraction grating layer 5 whose energy gap is larger than the active layer 3 and smaller than the first semiconductor layer 4, and a second semiconductor layer 6 whose composition is identical to the first semiconductor layer 4. On the whole surface of the above layer, parallel stripe trenches with a specified period are formed so as to reach the first semiconductor layer 4. Then a clad layer 7 is grown and a diffraction grating 11 is formed. As the photo coupling constant of the diffraction grating is determined by the thickness of the first semiconductor layer 4 and the diffraction grating layer 5, a semiconductor laser having a diffraction grating whose light coupling constant is set by a designed value can be obtained with excellent reproducibility. |
