Tailoring single-mode DFB laser with integrated passive feedback section for direct modulation applications

This paper discusses the main requirements on the active distributed feedback (DFB) section of the passive feedback laser (PFL). The discussion is based on the numerical simulations and analysis of the travelling wave (partial differential equation) model of multisection semiconductor lasers. For illustration, the PFL with the same passive integrated feedback (IFB) section, but with different types of the index-or gain-coupled gratings in the active DFB section is considered.