Abstract

Purely index-coupled distributed feedback (DFB) lasers are well-known components with practical application as optical sources in telecommunication networks using wavelength division multiplexing. Unfortunately, spatial hole burning makes them somewhat problematic above-threshold so that more complicated multisection structures (with multiple phase shifts, phase adjustment region or distributed coupling coefficient for example) have to be designed. On the other hand, gain coupling mechanisms in Bragg gratings attract attention from many research groups and promising devices are expected. Such complex-coupled DFB (CC-DFB) structures have already been studied through the relative amount of gain and index couplings, assuming a fixed phase difference between the two contributions (generally 0 or π) [1]. On the other hand, by lifting the restriction of this fixed phase difference, conventional CC-DFBs have been found to exhibit various interesting and useful properties [2] but, to date, nonuniformly complex-coupled (NCC-DFB) devices have not been addressed.

© 1998 IEEE