DETERMINATION OF ACTIVE-REGION LEAKAGE CURRENTS IN RIDGE-WAVE-GUIDE STRAINED-LAYER QUANTUM-WELL LASERS BY VARYING THE RIDGE WIDTH

This paper is concerned with the investigation of lateral current spre ading in InGaAsP strained-layer, ridge-waveguide multiple-quantum-well (MQW) semiconductor lasers consisting of nine quantum wells (QW's) an d having ridge widths varying from 1.5 to 5 mu m. By using a simple an alytical model, it is possible to demonstrate that as much as 60% of t he injected current escapes out of the active region of a 1.5-mu m las er 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.