| 摘要 |
PURPOSE:To stabilize the high speed responsiveness and the low threshold value operation of a distributed feedback semiconductor laser by reducing a sectional width perpendicular to the resonance axis direction of an active layer for a semiconductor laser smaller than that perpendicular to the same direction as that of an optical guide layer. CONSTITUTION:A diffraction grating 2 is provided on an N-type InP substrate 4, and no-added GaInAsP optical guide layer 1 is superposed thereon. An active layer 3, a P-type InP clad layer 5, and a P-type GaInAsP ohmic connection layer 6 are continuously crystal-grown thereon. These layers are mesalikeetched to form a guide moire of width Wb. A P-type InP layer 7, an N-type InP layer 8 and no-added GaInAsP cap layer 9 are grown at both sides of the mesalike moire. The oversaturation degree of the P-type InP solution of the layer 7 is selected to 15 deg., both sides of the layer 3 are melted back at 10 to narrow only the active layer. With this configuration, a confinement factor is increased, and a high speed response and low threshold value operation are stabilized due to the volume reduction of the active layer. |
