CHAOTIC DYNAMICS OF SEMICONDUCTOR-LASERS WITH PHASE-CONJUGATE FEEDBACK

This paper considers the chaotic dynamics of semiconductor lasers in the presence of phase-conjugate feedback (PCF). Bifurcation diagrams are used to explore the chaotic dynamics and show the difference between the conventional feedback and the PCF. In general, semiconductor lasers display richer chaotic dynamics in the case of PCF. Period-doubling, quasiperiodic, and intermittency routes to chaos are observed in numerical simulations performed by using realistic parameter values. For weak values of PCF, the laser can be phase locked to the phase provided by the phase-conjugate mirror, resulting in dramatic narrowing of the laser linewidth. Higher values of feedback result in periodic output, as the laser relaxation oscillations become destabilized. At a critical value of feedback, the laser enters the chaotic regime, resulting in increased low-frequency intensity noise and substantial broadening of the laser line. Finally, the effect of detuning between the solitary-laser frequency and the frequency of the phase-conjugate-mirror pump laser is explored.