Enhanced dynamics of QWS-DFB lasers by longitudinal variation of their coupling coefficient

Time-domain simulations performed on quarter-wave-shifted (QWS) distributed-feedback (DFB) lasers show that large-signal dynamics of such structures can be greatly enhanced by adequate longitudinal variation of their coupling coefficient K. Indeed, mode instabilities induced by spatial hole burning (SHE) can be less disastrous on the performance of distributed-coupling-coefficient QWS-DFB (QWS-DCC-DFB) lasers with respect to their conventional QWS-DFB (uniform coupling profile) counterparts.