Waveguides Induced by Screening-Photovoltaic Solitons inBiased Photorefractive–Photovoltaic Crystals

Abstract

We investigate theoretically waveguides induced byscreening-photovoltaic solitons in biased photorefractive–photovoltaiccrystals. We show that the number of guided modes in a waveguide inducedby a bright screening-photovoltaic soliton increases monotonically withthe increasing intensity ratio of the soliton, which is the ratiobetween the peak intensity of the soliton and the dark irradiance. Onthe other hand, waveguides induced by dark screening-photovoltaicsolitons are always single mode for all intensity ratios and theconfined energy near the centre of a dark screening-photovoltaic solitonincreases monotonically with the increasing intensity ratio. When thebulk photovoltaic effect is neglectable, these waveguides are thoseinduced by screening solitons. When the external field is absent, thesewaveguides predict those induced by photovoltaic solitons.