Dynamic photovoltaic lenses in iron-doped optical waveguides on lithium niobate

Abstract The changes of intensity profile modification of light beams passed through optical waveguides in lithium niobate with special Fe - doping are experimentally investigated and discussed. Such changes are caused by arising of the dynamic lens - like elements due to the photorefractive effect. They are observed in waveguides tested at wavelength of 633 nm for the light intensity within them exceeding the level of 2 - 5 W/cm2. The time behavior features of beam shape distortions and therefore of lens profiles are explained by the inhomogeneity of intensity patterns in the waveguide plane and by the change of photorefractive parameters over the waveguide depth.