DYNAMIC PHOTOVOLTAIC LENSES IN IRON-DOPED OPTICAL WAVE-GUIDES ON LITHIUM-NIOBATE

The changes of intensity profile modification of light beams passed th rough optical waveguides in lithium niobate with special Fe - doping a re experimentally investigated and discussed. Such changes are caused by arising of the dynamic lens - like elements due to the photorefract ive effect. They are observed in waveguides tested at wavelength of 63 3 nm for the light intensity within them exceeding the level of 2 - 5 W/cm(2). The time behavior features of beam shape distortions and ther efore 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.