Determination of active-region leakage currents in ridge-waveguide strained-layer quantum-well lasers by varying the ridge width

This paper is concerned with the investigation of lateral current spreading in InGaAsP strained-layer, ridge-waveguide multiple-quantum-well (MQW) semiconductor lasers consisting of nine quantum wells (QWs) and having ridge widths varying from 1.5 to 5 /spl mu/m. By using a simple analytical model, it is possible to demonstrate that as much as 60% of the injected current escapes out of the active region of a 1.5-/spl mu/m laser at threshold. For the first time, such an analysis is extended into the above-threshold regime to examine the effects of lateral current spreading on the external differential efficiency.