@InProceedings{Supelec255,
author = {Krassimir Panajotov and Hugo Thienpont and Marc Sciamanna},
title = {{Interplay of optical feedback and polarization dynamics in VCSELs}},
year = {2006},
booktitle = {{NOLTA 2006}},
publisher = {Research Society of Nonlinear Theory and its Applications},
month = {sep},
note = {invited},
address = {Bologna (Italy)},
abstract = {We present experimental and theoretical studies of nonlinear
dynamics induced by optical feedback in vertical cavity surface
emitting lasers (VCSELs) focusing on the impact of polarization
mode competition. We unveil the bifurcation mechanism leading to
multiple channels of interchanging linearly polarized (LP) steady
states, study the way of their destabilization and the role of
the external cavity modes and the polarization of light in this
process. We distinguish two situations depending on the dichroism
present in the VCSEL. In the first one, as typical for
semiconductor lasers, with increasing the optical feedback
strength the VCSEL exhibits a Hopf bifurcation from steady state
to a limit cycle followed by a torus bifurcation to quasiperiodic
behavior and then can become chaotic. Bistability between
different single polarization dynamics: steady-state, periodic,
quasi-periodic and chaotic dynamics is possible, however, the
suppressed polarization mode is never excited. In the second
case, when the VCSEL is biased in the region of polarization
bistability, increasing the feedback strength can not only cause
polarization switching but can also lead to chaotic emission in
the two LP modes. Polarization switching can happen from a limit
cycle in the x-LP mode to a steady state in the y-LP mode which
then undergoes consecutive Hopf and torus bifurcations and
becomes chaotic. Bistability between chaotic two LP mode emission
and periodic single LP mode emission is demonstrated. We also
consider the case of polarization selective optical feedback and
the influence of the spontaneous emission noise or external noise
in the system. For the last situation we demonstrate slow
antiphase hopping between the two LP modes together with rapid
anticorrelated oscillations in the LP intensities at the
external-cavity frequency. These last dynamics can be strongly
enhanced by the noise leading to the phenomenon of coherence
resonance. Finally, we consider the transition from long to short
external cavity and show that the typical low-frequency
fluctuation chaotic dynamics is anticipated by a regime of
regular dynamics - fast pulses at the delay time modulated by a
slow time periodic envelope. We discuss the interplay of optical
feedback and polarization dynamics in this regime, too.},
hal = {hal-00212983}
}