Conference Paper

Nonlinear dynamics in directly modulated semiconductor ring lasers

DOI: 10.1117/12.921949 Conference: Proc. of SPIE, Volume: 8432

ABSTRACT In this paper, we have theoretically studied the dynamical behavior of current modulated semiconductor ring lasers (SRLs). As we vary the amplitude and frequency of the modulation around a fixed bias current, different dynamical states including periodic, quasi-periodic and chaotic states are found. As in other single mode semiconductor lasers, the modal intensities in a SRL present chaotic behavior for driving frequencies comparable to the relaxation oscillation frequency. In this regime the two counter-propagating modes vary in phase. However, for modulation frequencies significantly lower than the relaxation oscillation frequency, we reveal the existence of chaotic oscillations where the two counter-propagating modes are in anti-phase. In order to get a more complete understanding of the dynamics of SRLs at low modulation frequencies, we derive a reduced model using asymptotic methods. This reduced model uncovers a topological resemblance between current-modulated SRLs and the periodically driven Duffing-Van der Pol oscillator.