Abstract

AlGaAs is an attractive material system for the study of the dynamics of Kerr spatial solitons, having a nonlinear coefficient around 1000 times that of silica around the communication wavelength of 1.55 µm. However there are a number of differences between AlGaAs and silica when the polarisation dependence of nonlinear refraction is considered. Cubic semiconductors can display an anisotropic third-order nonlinearity¹ (although in terms of linear optics they are non-birefringent) and are also usually exploited in the vicinity of an optical resonance (e.g. just below the half-bandgap) so Kleinmann symmetry cannot be assumed. On considering the propagation of two orthogonal polarisation components in such a medium, one obtains not only self-phase-modulation, cross-phase-modulation and four-wave-mixing but now with a orientation dependence, but an additional three terms which only contribute in anisotropic media.²

© 1998 Optical Society of America