Novel Structures and Fabrication Techniques for the Observation of Solitons in AlGaAs

Novel structures and fabrication techniques applicable to the study of both spatial and temporal solitons in AlGaAs are investigated. A new and novel technique for suppressing the intermixing of GaAs/AlGaAs MQWs has been demonstrated. The technique relies on a hydrogen plasma discharge to produce a Ga2O3 layer from the native oxides on the GaAs surface and suppress vacancy formation. This method for suppressing intermixing has been shown to be free from damage, highly reproducible, can be made area selective using a patterned silica mask, does not introduce impurities and can be used to fabricate relatively long, low loss GaAs/AlGaAs MQW waveguides This technique was subsequently used to produce samples with approximately 40 nm shift in the band edge, which lead to a corresponding change in the nonresonant optical nonlinearity of in excess of 60%. This potentially opens the way for the production of many novel nonlinear optics devices which previously had no possible fabrication means. Also it has been experimentally shown that by using properly designed AlGaAs ARROW waveguides, the natural normal dispersion of the semiconductor can be overcome and waveguide modes can be made anomalous. This fact has been used to demonstrate solitonic compression of 1.51mum femtosecond pulses propagating in the guides, and the results are observed to correlate well with the theoretically predicted values