title: Hopf bifurcation to square-wave switching in mutually coupled semiconductor lasers.
abstract: Using advanced continuation techniques for dynamical systems, we elucidate the bifurcations leading to asymptotically stable square-wave pulsing and polarization mode switching in semiconductor lasers with mutual time-delayed and polarization rotating coupling. We find that the increase of coupling strength leads to a cascade of Hopf bifurcations on a mixed-mode steady state up to a transcritical bifurcation on a so-called pure-mode steady state where both lasers emit with the injected polarization state. From these successive Hopf bifurcations emerge time-periodic solutions that have a period close to the laser relaxation oscillation for weak coupling but a period close to twice the time delay for large coupling strength. The wave form of the time-periodic solutions also evolves from harmonic pulsing up to square-wave pulsing as has been observed recently in experiments.
authors.affiliation: Supélec, OPTEL Research Group, Laboratoire Matériaux Optiques, Photonique et Systèmes, EA-4423, 2 rue Edouard Belin, F-57070 Metz, France. marc.sciamanna@supelec.fr
authors.forename: M
authors.initials: M
authors.lastname: Sciamanna
authors.forename: M
authors.initials: M
authors.lastname: Virte
authors.forename: C
authors.initials: C
authors.lastname: Masoller
authors.forename: A
authors.initials: A
authors.lastname: Gavrielides
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D019544:Equipment Failure Analysis; D005246:Feedback; D054023:Lasers, Semiconductor; D008962:Models, Theoretical; D009991:Oscillometry / Q000295:instrumentation* / Q000379:methods*