Nonlinear dynamics of current-modulated vertical-cavity surface-emitting lasers

Abstract

A numerical analysis of the nonlinear dynamics of weakly index-guided vertical-cavity surface-emitting lasers (VCSELs) subject to high-frequency current modulation is performed. Chaotic behavior appears in the multi-mode regime due to transverse-mode competition. Chaotic operation is such that multi-stability of the chaos–chaos type is observed. Injection of appropriate optical pulses can switch between different chaotic solutions. The analysis of the nonlinear dynamics of high-frequency current-modulated single-mode VCSELs indicates that the chaotic behavior is not present for the considered range of current modulation amplitudes and frequencies. Only periodic behaviors are observed in such a way that multi-stability of different periodic solutions is also observed. Switching between different stable periodic solutions can be obtained by injecting external optical pulses. Finally, we show that spontaneous emission noise increases the number of available channels in chaotic optical communication systems in which frequency division multiplexing with multi-transverse-mode VCSELs is used.