SEMICONDUCTOR LIGHT EMITTING DEVICE AND ITS MANUFACTURE

PURPOSE:To increase the chirping width of laser, restrain deterioration of CNR at the time of fiber transmission, improve current concentration to an active layer, and reduce strain, regarding a laser for analog transmission. CONSTITUTION:The impurity concentration of a clad layer on an active layer is ununiformly distributed in the surface of the clad layer, and the refractive index distribution in a waveguide is ununiformly formed. A semiconductor layer whose concentration is higher than that of the clad layer is stuck on the clad layer, and impurities are ununiformly introduced from the semiconductor layer by solid phase diffusion. An optical guide layer 3, an active layer 4, a first clad layer 5 composed of P-InP, and a cap layer 6 composed of P InGaAsP are grown in order on a substrate 1 composed of N-InP, and impurities are subjected to solid phase diffusion from the cap layer to the first clad layer. Instead of P InGaAsP, P InGaAs is used as the cap layer 6.