Nonlinear analysis of a dielectric distributed feedback laser with complex coupling coefficient

An approximate analysis of the nonlinear operation of DFB a dielectric laser with complex coupling coefficient is presented, An expression relating the small signal gain to the output power and the system parameters, including the spatial hole burning effect, is obtained. It is shown that the gain grating, the loss grating, and the higher order Bragg grating all contribute to laser operation above the threshold in a different manner. Moreover, it is possible to achieve a "negative" gain effect in the partly gain-coupled structure operating above the threshold, which depends on the output power level, the distributed loss level and the spatial hole burning effect.