| 摘要 |
PURPOSE:To enable the wavelength to be electrically controlled precisely in a DBR (distribution reflection) type semiconductor laser, by providing dual diffraction gratings. CONSTITUTION:On an N type GaAs substrate 11, are layered an N type Ga0.7Al0.3 As clad layer 12, a P type GaAs active layer 13, and P type Ga0.7Al0.3As waveguide layer 14. The first diffraction grating 15 with a period T1 is formed at both ends, and a thin N type GaAs gas layer 16 is grown on the entire surface. A stripe shaped P<+> type layer 171 is formed on an active region. On the first diffraction grating 15, is formed the second diffraction grating 18, wherein the N type layer 16 and a P<+> type layer 172 are alternately arranged, and which is characterized by the perturbation of the gain or loss of a period T2 which is different from the period T1 of the first diffraction grating. |
