Nonlinear dynamics of optically injected self-pulsating laser diodes

The behavior of a 1.55-/spl mu/m InGaAsP distributed feedback (DFB) self-pulsating (SP) laser diode (LD) when injected with either unmodulated or modulated light from an external LD is investigated numerically. When subjected to weak injection of unmodulated light, the SP-LD exhibits mostly chaotic behavior with some regions of self-sustained-pulsations and multiple-peak periodic oscillations. As the strength of optical injection increases, the SP-LD transits from chaos to multiple-peak periodic oscillations followed by high-frequency self-oscillations before reaching an equilibrium state (i.e., a steady level). When injected with modulated light, the output of the SP-LD is dominated by either quasi-periodicity or chaos depending on the modulation current of the injected optical signal.