Modeling and analysis of narrow-linewidth distributed feedback lasers based on apodized laterally coupled gratings

A physical model is demonstrated to optimize narrow-linewidth distributed feedback lasers based on apodized laterally coupled gratings (AG-DFB). The structure can effectively suppress the longitudinal spatial hole burning as well as remove the regrowth process during fabrication by using the apodized grating geometry. The studies include numerical simulations of the AG-DFB laser for its static and dynamic behaviors at different cavity lengths and facet coating conditions. The results show that the proposed device can achieve narrow linewidth, high slope efficiency, and broad modulation bandwidth, as compared to λ/4 phase-shifted DFB lasers.