Patent ID: 7649916
Filing Date: 2010-01-19
Classification: H01S

Abstract:
1. A semiconductor laser for reducing a second order mode, the laser comprising: a substrate; an active region arranged over the substrate, wherein the active region includes one or more quantum wells that produce a primary mode and a second order mode; and a waveguide layer arranged over the substrate and having a thickness wherein a confinement of the second order mode in the active region is reduced by the waveguide layer more than a confinement of the primary mode in the active region so as to suppress the second order mode; wherein the waveguide layer and the active layer are part of the same epitaxial structure; and a semiconductor layer between the waveguide layer and the active region, wherein the materials of the active region, the waveguide layer, and the semiconductor layer and the thicknesses of the semiconductor layer and the waveguide layer are selected such that the modal index of waveguide layer for the secondary mode substantially matches the modal index of the active layer for the second order mode and the modal index of the waveguide layer for the fundamental mode does not match the modal index of the active layer for the primary mode such that the second order mode couples into the waveguide layer more than the first order mode.