| 摘要 |
PURPOSE:To obtain a tunable single-axis mode semiconductor laser capable of an efficient wavelength control on a small wavelength controlling current by a method wherein a buffer layer with its energy gap larger than that of an optical waveguide layer is provided between the optical waveguide layer and a semiconductor substrate. CONSTITUTION:On a semiconductor substrate 1, an active region 21, consisting of an optical waveguide layer 3 and a light-emitting active layer 5 equipped with an energy gap smaller than that of the optical waveguide layer 3, and a distributed Bragg reflection region (DBR) 22 sharing the optical waveguide layer 3 with the active region 21 on the substrate 1, are provided. Current- applying means 31 and 32 are provided respectively for the active region 21 and the distributed Bragg reflection region (DBR) 22. In this semiconductor laser device, a buffer layer 30, with its energy gap larger than that of the optical waveguide layer 3, is provided between the waveguide layer 3 and the semiconductor substrate 1. For example, at a portion on an n-InP substrate 1, a diffraction grating 2 is built, after which an n-InGaAsP buffer layer 30, an n-InGaAsP optical waveguide layer 3, etc., are formed. |
