Nonlinear Refraction and Absorption in Semiconductor Waveguides

We have an extensive track record of studying and exploiting ultrafast third-order optical nonlinearities in semiconductor waveguides, such as nonlinear refraction (optical Kerr effect) and two-photon absorption. Using the AlGaAs waveguide platform we have demonstrated spectral broadening, all-optical switching, spatial solitons, vector (polarisation) solitons and discrete spatial solitons. Our earlier research is available under Nonlinear Optics in AlGaAs (1990s). We have also investigated the effective third-order nonlinearity arising from cascading optical rectification and Pockel's electro-optic modulation.

More recently we have been studying the AlGaAs superlattice waveguides and using quantum-well intermixing to provide a spatial variation in the nonlinear coefficients.


Much of this research has been undertaken in collaboration with Prof. Stewart Aitchison, Prof. Amr Saher Helmy and Dr. Sean Wagner, University of Toronto. The contributions of the EPSRC National Facilties are acknowledged: III-V Technologies, University of Sheffield and University of Surrey Ion Beam Centre.