Abstract

There is considerable interest in the optical Kerr effect, described by the nonlinear refractive index n₂, as it can be employed to perform high-speed, all-optical switching. Semiconductor waveguides offer an attractive media for compact, integrated all-optical switching.^1,2 The dispersion of n₂ in direct-gap, zinc- blende semiconductors was recently accurately calculated using a four-band Kane model.³ In this paper the polarisation dependence of nonlinear refraction in zinc-blende semiconductors will be addressed. This dependence has two aspects to it: (1) an optical polarisation dependence which provides a variation in n₂ for linear and circular polarisations.⁴ This variation can occur even for isotropic media. The same dependence also gives a different value for the cross-phase-modulation using parallel and perpendicular polarisations (orthogonal cross-phase-modulation was employed in a demonstration of all-optical demultiplexing⁵). (2) a material polarisation dependence which provides a variation in n₂ depending on how the optical polarisation is orientated with respect to the crystalline axes.

© 1995 Optical Society of America