Subpicosecond all optical switching in passive and active gallium arsenide/aluminum gallium arsenide nonlinear directional couplers.
Publisher
The University of Arizona.Rights
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.Abstract
Subpicosecond all optical switching device is pursued using a passive GaAs/AlGaAs multiple quantum well nonlinear directional coupler and an active GaAs/AlGaAs nonlinear directional coupler. A passive device showed all-optical switching from 2:1 contrast ratio to 2:3 with optical pulses detuned below the heavy hole exciton resonance. Underlying mechanism for the ultrafast switching is identified as an adiabatic following in semiconductors. With an active nonlinear directional coupler made of superlattice core, we demonstrated the lowest switching energy device (6pJ) with fast response of a few hundred femtoseconds. But no switching behavior is observed in an active nonlinear directional coupler which consists of well separated quantum wells. The importance of waveguide structure is emphasized while interpreting properties of waveguide core.Type
textDissertation-Reproduction (electronic)
Degree Name
Ph.D.Degree Level
doctoralDegree Program
PhysicsGraduate College