Effects of multiple quantum well nonlinearities on coupling coefficient and wavelength detuning in distributed-feedback laser structures

Abstract

Using a finite element formalism, the effects of an intensity dependent refractive index nonlinearity on the coupling coefficient and wavelength detuning of an index coupled multiple quantum well distributed-feedback laser structure are modeled. The associated nonlinear 1D guided wave equation is numerically solved for the effective index (eigenvalue) and the transverse field profile (eigenvector). Results are obtained for varying numbers of quantum wells and grating thickness. Changes in wavelength detuning and coupling coefficient for a given laser structure are shown to change linearly with increasing optical power.