Gap solitons in buried Bragg grating AlGaAs waveguides

Abstract

A balance of group velocity dispersion and nonlinear phase shift in AlGaAs waveguides with buried Bragg gratings is predicted to result in the propagation of gap solitons. Photonic gaps wide enough in wavelength to linearly reflect all Fourier components of the 0.5-ps input pulse being used in the initial experiments require a large modulation depth for the buried grating. Fabrication techniques include electron cyclotron etching and regrowth using MOCVD. The composition of the waveguide is at Al concentrations 0.2 so that the input pulse wavelength of 1.685 μm corresponds to excitation below half the energy gap. This reduces multiphoton absorption to levels where solitons can propagate without significant attenuation. Theoretical simulations and initial experimental results are described.