TRANSVERSE MODEL CONTROLLED InGaAsP/InP LASERS AT 1. 5 mu m RANGE WITH BUFFER-LAYER LOADED PLANO-CONVEX WAVEGUIDE (BL-PCW) STRUCTURES.

A modified plano-convex waveguide structure is studied analytically and successfully applied to InGaAsP/InP lasers in the 1. 5-1. 6 mu m wavelength region to realize stable transverse mode operation. The structure of these lasers is characterized by a standard buffer layer between an active layer and an upper cladding layer and a waveguide layer of varying thickness between the active layer and the substrate. A theoretical analysis of this structure shows that, for a given channel depth, increases in buffer-layer thickness give rise to larger maximum channel widths of the substrate for fundamental transverse mode operation.