ANALYSIS OF DISTRIBUTED-FEEDBACK SEMICONDUCTOR LASER-ELECTROABSORPTION MODULATOR INTEGRATED LIGHT-SOURCE, INCLUDING GAIN-COUPLED STRUCTURE

Taking into consideration of gain coupling, characteristics such as single-mode selectivity, chirping and light output efficiency of photonic integrated circuits (PIG) integrating distributed feedback (DFB) semiconductor lasers and electroabsorption modulators are analyzed for the first time. Devices with conventional index-coupled (IC), quarter-wave-shifted (QWS) and gain-coupled (GC) DFB laser sections are calculated and compared. The chirping of GC-PIC is nearly the same as that of IC-PIC and QWS-PIC, hut the single-mode selectivity of GC-PIC is much better. With a [HR-AR] coating, which is advantageous for high-power operation, GC-PIC shows a much higher probability of single-mode operation than IC-PIC, while QWS-PIC does not function at all.