Mode-competition phenomena among longitudinal modes in semiconductor lasers under the effect of external optical feedback

摘要

Comprehensive theoretical investigation of the influence of external optical feedback on the dynamics of semiconductor lasers are introduced. The analyses are based on numerical simulation of the multimode rate equations superposed by Langevin noise sources that are generated in such a way as to keep the correlation of the modal photon number with the injected electron number. The gain saturation effect which causes mode-competition phenomena among longitudinal modes are considered in our multimode rate equation model. The dynamics of modes and the characteristics of the output spectrum are investigated for strong external optical feedback strength. Numerically simulated results show that the mode-competition phenomena induce quasi-periodic hopping among several longitudinal modes which reveals multimode-like output spectra in lasers. This mode-hopping phenomena is described in terms of asymmetric gain saturation effect.