Yield analysis of SLM DFB lasers with an axially-flattened internal field

The results of the yield analysis of distributed-feedback (DFB) lasers which can operate in a single longitudinal model (SLM) are presented. A DFB structure with two lambda /8 phase-shifters is analyzed, together with conventional structures with no shifters and a single shifter. The SLM yield is defined such that the lasers satisfy the criteria of both normalized threshold gain difference ( Delta alpha L) and a flatness factor of the internal field profile along the cavity direction. Flattening the field profile is indispensable to minimize the effect of spatial hold-burning. The SLM behaviour of the double lambda /8 shift DFB lasers with ideally zero reflectivity facets is also analyzed as a parameter of the distance between the shifters ( Delta L).>