Incoherently coupled gray-gray soliton pairs in biased photorefractive-photovoltaic crystals

We show that incoherently coupled gray-gray soliton pairs and multicomponent gray solitons are possible in biased photorefractive-photovoltaic crystals under steady-state conditions. These soliton pairs and multicomponent solitons can be obtained provided that the carrier beams share the same polarization, wavelength, and are incoherent with one another. When the bulk photovoltaic effect is neglectable, these soliton pairs and multicomponent solitons predict incoherently coupled gray-gray soliton pairs and multicomponent gray solitons for screening solitons. When the external field is absent, these soliton pairs and multicomponent solitons predict incoherently coupled gray-gray soliton pairs and multicomponent gray solitons for photovoltaic solitons.