Abstract
This paper introduces a theoretical study on the influence of intermodal asymmetric gain suppression (AGS) on dynamics and output of multimode semiconductor lasers. The study includes comprehensive and intensive simulations of the dynamics of 21-oscillating longitudinal modes taking account of the self- and cross-modal gain suppression mechanisms. AGS is varied in terms of a pre-defined parameter, H(c )that combines the linewidth enhancement factor and differential gain as controlling parameters of AGS. We classify laser oscillation into four types, namely, single mode oscillation (SMO), symmetric steady-state multimode oscillation (SSMMO), asymmetric steady-state multimode oscillation (ASMMO) and hopping multimode oscillation (HMMO) depending on the values of H-c and injection current. We allocate the operating regime of each of these classes over a mapping diagram of H-c versus current. SMO is attained when the current increases beyond the threshold and H-c has small values. Jumping of the oscillating mode on the long-wavelength side is noticed by increasing H(c. )When H-c increases and violates AGS, HMMO is induced among a number of modes, and asymmetric output spectra are obtained. In this case the mode-hopping frequency ranges between 36 and 392 MHz and the hopping modes are anti-correlated with correlation coefficient exceeding - 0.25.