Phase-slip induced distributed feedback resonator modes with tilted modulation

Transversely bounded lambda /4 distributed feedback (DFB) resonator with ti lted index modulation is considered. By treating the modulation as a weak p erturbation and averaging the wave equation with respect to the transverse field distribution we obtain an effective coupled-wave equations with spati ally varying coupling constant. We analyze these equations both analyticall y and numerically for a specific case of transverse confinement. The evolut ion of the frequency of the lowest threshold laser mode with the tilt angle is studied. It is demonstrated that the dependence of the frequency of the intra-gap localized mode on the tilt angle originates from the mode-conver sion mechanism in the DFB process. (C) 2001 Published by Elsevier Science B .V.