Elimination of mode grouping in InGaAsP/InP ridge waveguide laser using quantum-well intermixing.

In this letter, we report the observation of the longitudinal mode grouping effect in the InGaAsP/InP multiquantum-well ridge waveguide laser. Two mode groups were observed and showed different behaviors with the changing of the injection current. The higher order lateral modes and the current spreading in the ridge waveguide structure is proposed to be responsible for this mode grouping phenomena. A one-step quantum-well intermixing process using the SiO₂ electrical isolation layer itself was introduced and proved to be effective in improving the lateral electrical and optical confinement in a ridge waveguide laser structure as well as eliminating the mode grouping. [ABSTRACT FROM AUTHOR]