title: Multistabilities and symmetry-broken one-color and two-color states in closely coupled single-mode lasers.
abstract: We theoretically investigate the dynamics of two mutually coupled, identical single-mode semi-conductor lasers. For small separation and large coupling between the lasers, symmetry-broken one-color states are shown to be stable. In this case the light outputs of the lasers have significantly different intensities while at the same time the lasers are locked to a single common frequency. For intermediate coupling we observe stable symmetry-broken two-color states, where both lasers lase simultaneously at two optical frequencies which are separated by up to 150 GHz. Using a five-dimensional model, we identify the bifurcation structure which is responsible for the appearance of symmetric and symmetry-broken one-color and two-color states. Several of these states give rise to multistabilities and therefore allow for the design of all-optical memory elements on the basis of two coupled single-mode lasers. The switching performance of selected designs of optical memory elements is studied numerically.
authors.affiliation: Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland and Department of Physics, University College Cork, Cork, Ireland.
authors.forename: Eoin
authors.initials: E
authors.lastname: Clerkin
authors.affiliation: Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland.
authors.forename: Stephen
authors.initials: S
authors.lastname: O'Brien
authors.affiliation: Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland and School of Mathematical Sciences, University College Cork, Cork, Ireland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Amann