Multiple feedback effects in asymmetric external cavity semiconductor lasers

Detailed analysis of coherence collapse in semiconductor lasers

“…However, if we add optical feedback (or modulation, or light injection, or any of several other external stimuli) we have to expand the phase space, so the system can support many different rich dynamical phenomena. If the external cavity is weakly coupled so that it is sufficient to consider only one feedback delay term [29]- [31], the rate equations become:…”

<title>Reduction of spectral linewidth and FM noise in semiconductor lasers by application of optical feedback</title>

“…In this case the external cavity generally exerts a stabilizing influence, but it is still possible to observe self-pulsing instabilities and chaos [1 1]. The enhanced stability is probably due to the larger photon density in the external cavity, and because of the presence of multiple roundtrip feedback terms which impose more stringent phase filtering conditions [12]. For optimum linewidth narrowing with single longitudinal mode selection, however, a dispersive element may still be required in the external cavity [13][14][15].…”

Crisis route to chaos in semiconductor lasers subjected to external optical feedback

“…The PD and subharmonic routes were shown to exist for restricted ranges of operating parameters. For instance, to observe the subharmonic route, it is necessary to tilt the mirror [25,26] while adjusting injection current J [23]. This route to chaos was explained numerically using multiple reflections and was termed asymmetric feedback caused by the mirror's tilt [25,26].…”

“…For instance, to observe the subharmonic route, it is necessary to tilt the mirror [25,26] while adjusting injection current J [23]. This route to chaos was explained numerically using multiple reflections and was termed asymmetric feedback caused by the mirror's tilt [25,26]. The PD route was shown to exist if the ratio of f RO to f ECM is an integer multiple for low J ∼ 1.6J th with J th the threshold current at η = 0 [19].…”