Two closely coupled lasers, dynamics & applications

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dc.contributor.advisor Amann, Andreas en
dc.contributor.advisor O'Reilly, Eoin P. en Clerkin, Eoin 2015-11-03T12:47:40Z 2014 2014
dc.identifier.citation Clerkin, E. 2014. Two closely coupled lasers, dynamics & applications. PhD Thesis, University College Cork. en
dc.description.abstract The dynamics of two mutually coupled identical single-mode semi-conductor lasers are theoretically investigated. For small separation and large coupling between the lasers, symmetry-broken one-colour states are shown to be stable. In this case the light output of the lasers have significantly different intensities whilst at the same time the lasers are locked to a single common frequency. For intermediate coupling we observe stable two-colour states, where both single-mode lasers lase simultaneously at two optical frequencies which are separated by up to 150 GHz. For low coupling but possibly large separation, the frequency of the relaxation oscillations of the freerunning lasers defines the dynamics. Chaotic and quasi-periodic states are identified and shown to be stable. For weak coupling undamped relaxation oscillations dominate where each laser is locked to three or more odd number of colours spaced by the relaxation oscillation frequency. It is shown that the instabilities that lead to these states are directly connected to the two colour mechanism where the change in the number of optical colours due to a change in the plane of oscillation. At initial coupling, in-phase and anti-phase one colour states are shown to emerge from “on” uncoupled lasers using a perturbation method. Similarly symmetry-broken one-colour states come from considering one free-running laser initially “on” and the other laser initially “off”. The mechanism that leads to a bi-stability between in-phase and anti-phase one-colour states is understood. Due to an equivariant phase space symmetry of being able to exchange the identical lasers, a symmetric and symmetry-broken variant of all states mentioned above exists and is shown to be stable. Using a five dimensional model we identify the bifurcation structure which is responsible for the appearance of symmetric and symmetry-broken one-colour, symmetric and symmetry-broken two-colour, symmetric and symmetry-broken undamped relaxation oscillations, symmetric and symmetry-broken quasi-periodic, and symmetric and symmetry-broken chaotic states. As symmetry-broken states always exist in pairs, they naturally give rise to bi-stability. Several of these states show multistabilities between symmetric and symmetry-broken variants and among states. Three memory elements on the basis of bi-stabilities in one and two colour states for two coupled single-mode lasers are proposed. The switching performance of selected designs of optical memory elements is studied numerically. en
dc.description.sponsorship Science Foundation Ireland (SFI Grant 09/SIRG/I1615) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Eoin Clerkin. en
dc.rights.uri en
dc.subject Mutually coupled lasers en
dc.subject Laser dynamics en
dc.subject Semiconductor lasers en
dc.subject Laser diodes en
dc.subject Closely coupled lasers en
dc.subject Weakly coupled lasers en
dc.title Two closely coupled lasers, dynamics & applications en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text not available en Indefinite en 10000-01-01
dc.description.version Accepted Version
dc.contributor.funder Science Foundation Ireland en
dc.description.status Not peer reviewed en Physics en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Yes en
dc.thesis.opt-out true
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat E-thesis on CORA only en
dc.internal.conferring Spring Conferring 2015

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© 2014, Eoin Clerkin. Except where otherwise noted, this item's license is described as © 2014, Eoin Clerkin.
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