title: Square-wave self-modulation in diode lasers with polarization-rotated optical feedback.
abstract: The square-wave response of edge-emitting diode lasers subject to a delayed polarization-rotated optical feedback is studied in detail. Specifically, the polarization state of the feedback is rotated such that the natural laser mode is coupled into the orthogonal, unsupported mode. Square-wave self-modulated polarization intensities oscillating in antiphase are observed experimentally. We find numerically that these oscillations naturally appear for a broad range of values of parameters, provided that the feedback is sufficiently strong and the differential losses in the normally unsupported polarization mode are small. We then investigate the laser equations analytically and find that the square-wave oscillations are the result of a bifurcation phenomenon.
authors.affiliation: Air Force Research Laboratory, Directed Energy Directorate AFRL/DELO, Kirtland AFB, New Mexico 87117, USA.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Gavrielides
authors.forename: Thomas
authors.initials: T
authors.lastname: Erneux
authors.forename: David W
authors.initials: DW
authors.lastname: Sukow
authors.forename: Guinevere
authors.initials: G
authors.lastname: Burner
authors.forename: Taylor
authors.initials: T
authors.lastname: McLachlan
authors.forename: John
authors.initials: J
authors.lastname: Miller
authors.forename: Jake
authors.initials: J
authors.lastname: Amonette