Longitudinal effects on SMSR in gain-coupled DFB lasers

Gain-coupled DFB lasers have a complicated modal interaction influenced by the effects of spatial hole burning (SHB) and nonlinear gain compression (NGC) because of the carrier dependent longitudinally distributed structures. In order to obtain a better understanding of the high single mode performance of gain-coupled DFB lasers, we perform a self-consistent multimode analysis using spatially dependent rate equations for the carrier density N and the modal photon number in a steady state.