Two-dimensional single-channel and multichannel optically induced waveguide structures formed in a lithium niobate crystal with the pyroelectric effect

Formation of single two-dimensional waveguides and multi-element (3 and 5 waveguides) of such waveguides within a bulk of undoped lithium niobate has been experimentally demonstarated. Waveguide structures with a channel size of 8, 12, 23 μm have been formed by the bright spatial solitons obtained at the compensation of the diffraction divergence of light beams in the crystal due to the contribution of the pyroelectric effect into the nonlinear response. The light wavelength were 532 and 633 nm and the optical power was ranged from 50 to 200 μW in experiments. The total compensation of the diffraction divergence at uniform heating of the crystal sample to the temperature from 35 to 55 degrees Celsius.