Tailoring characteristics of DFB lasers with low- and high-reflection facets by using sampled gratings

Tailorability of distributed-feedback (DFB) laser characteristics by sampled grating has been pursued for DFB lasers with low- and high-reflection facets. This is based on the finding that there exists close correlation between the threshold gain difference and the axial photon distribution of the main and side modes. An effective-index transfer matrix method is used. This finding enables us to tailor DFB laser characteristics, and shows the futility of an attempt to relieve longitudinal spatial hole burning by making similar the axial photon distribution of the main and side modes. The threshold gain difference is shown to be improved by more than 15% by simple changing the arrangement of the sampled regions.