Incoherently coupled grey–grey spatial soliton pairs due to two-photon photorefractive media

The coupling of two mutually incoherent optical beams with the same polarization and wavelength in two-photon photorefractive media is studied; it is shown that incoherently coupled grey–grey spatial soliton pairs are possible due to two-photon photorefractive effect under appropriate bias conditions. The relevant example is presented. The grey–grey spatial soliton pairs reduce to dark–dark spatial soliton pairs when the greyness is zero.