title: Tristability of a semiconductor laser due to time-delayed optical feedback.
abstract: We present an experimental and theoretical study of multistability of a single-mode laser subject to feedback through phase tuning and amplifier sections integrated on the same chip. Closely above threshold, a regime of tristability of continuous-wave (CW) states is found for multiple ranges of amplifier and phase currents. The separation between the tristable wavelengths agrees with the channel spacing of dense wavelength multiplexing in the C band of optical communication making the device interesting for ternary logic applications. Complementary theoretical investigations in the framework of the paradigmatic Lang-Kobayashi model provide a consistent understanding of the experimental findings and additionally yield an analytic formula expressing the maximum number of coexisting stable CW states by the linewidth-enhancement factor alpha . Tristability belongs to the alpha range from 5 to 8 in good agreement with experiment.
authors.affiliation: AG Photonik, Humboldt-Universität zu Berlin, Newtonstrasse 15, 12485 Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Loose
authors.forename: B K
authors.initials: BK
authors.lastname: Goswami
authors.forename: H-J
authors.initials: HJ
authors.lastname: Wünsche
authors.forename: F
authors.initials: F
authors.lastname: Henneberger