Vladimir Shandarov

Observation of staggered surface solitary waves in one-dimensional waveguide arrays.

The observation of nonlinear staggered surface states at the interface between a substrate and a one-dimensional self-defocusing nonlinear waveguide array is reported. Launching of staggered input beams of different power in the first channel of the array results in formation of localized structures in different channels. Our experimental results are confirmed numerically.

Reconfigurable optical channel waveguides in lithium niobate crystals produced by combination of low-dose O 3+ ion implantation and selective white light illumination

We report on a new method to form reconfigurable channel waveguides in lithium niobate crystals, based on a combination of low-dose O(3+) ion implantation and selective white light illumination. The fabricated structures show low loss as well as rather high resistivity against optical erasure with red or infrared light, while at the same time reconfiguration of the structures remains possible using homogeneous white light illumination. The transmission properties of the channel waveguide modes can be well simulated numerically by the beam propagation method, which allows for the fabrication of tailored optical interconnections.

Beam interactions in one-dimensional saturable waveguide arrays.

The interaction between two parallel beams in one-dimensional discrete saturable systems has been investigated using lithium niobate nonlinear waveguide arrays. When the beams are separated by one channel and in phase it is possible to observe soliton fusion at low power levels. This result is confirmed numerically. By increasing the power, solitonlike propagation of weakly coupled beams occurs. When the beams are out-of-phase the most interesting numerically obtained result is the existence of oscillations which resemble the recently discovered Tamm oscillations.

Dark and bright blocker soliton interaction in defocusing waveguide arrays

We experimentally demonstrate the interaction of an optical probe beam with both bright and dark blocker solitons formed with low optical light power in a saturable defocusing waveguide array in photorefractive lithium niobate. A phase insensitive interaction of the beams is achieved by means of counterpropagating light waves. Partial and full reflection (blocking) of the probe beam on the positive or negative light-induced defect is obtained, respectively, in good agreement with numerical simulations.

Interaction of counterpropagating discrete solitons in a nonlinear one-dimensional waveguide array

We experimentally investigate the interaction of counterpropagating discrete solitons in a one-dimensional waveguide array in photorefractive lithium niobate. While for low input powers only weak interaction and formation of counterpropagating vector solitons are observed, for higher input powers a growing instability results in discrete lateral shifting of the formed discrete solitons. Numerical modeling shows the existence of three different regimes: stable propagation of vector solitons at low power, instability for intermediate power levels leading to discrete shifting of the two discrete solitons, and an irregular temporal dynamic behavior of the two beams for high input power.

One-dimensional bulk and planar photorefractive photonic superlattices in lithium niobate: features of linear and nonlinear discrete diffraction

The features of linear and nonlinear propagation of light beams in one-dimensional photorefractive photonic superlattices in bulk lithium niobate and in planar waveguides on this material are experimentally studied. The superlattices are optically induced in bulk samples and in planar waveguides using two-beam holographic recording method and optical projection scheme with coherent and incoherent light sources.

Dark spatial photovoltaic solitons and soliton-induced waveguide elements in ion-implanted planar lithium niobate waveguides

Formation of dark spatial optical solitons in planar waveguides produced by implantation of light ions into Fe- or Cudoped X cut lithium niobate wafers is experimentally studied. The implantation both of protons and O3+-ions results in the excellent waveguide layers with their thickness about 3 microns and optical losses less than 1 dB/cm. The soliton states at light wavelengths of 532 nm and 633 nm are developed due to the self-defocusing photorefractive-photovoltaic nonlinearity of lithium niobate. Extraordinarily polarized light beams are used in experiments to form dark solitons and to probe the soliton-induced waveguide channels. Steady-state dark photovoltaic spatial solitons have been realized in both, H+- implanted and O3+ - implanted planar waveguides at optical powers from 10 to 100 microwatts. The storage time of soliton-induced channel waveguides makes up at least some hours without special illumination of a planar waveguide and they may be erased within some seconds in a case of their permanent readout with stronger light beams. The possibility to form more complicated channel waveguide structures in regimes of dark spatial solitons is also demonstrated.

Optical formation of photonic waveguides and circuits in ferroelectric lithium niobate due to the contribution of pyroelectric effect

The pyroelectric nonlinear response of nominally undoped lithium niobate crystal is exploited to form within it as single waveguide channels as more complicated waveguide structures suitable for the photonic applications. The light wavelength of 532 nm with optical powers lower than 1 mW allowed their formation in experiments.

Self-induced diffraction patterns in nonlinear Fabry-Perot interferometer on lithium niobate

The effects of self-action of light fields within Fabry-Perot interferometers based on photorefractive lithium niobate plates both, of X- and Z- cuts are experimentally investigated. Formation of one-dimensional practically regular diffractive elements within the interferometers with slightly non-parallel input and output surfaces has been demonstrated at laser light wavelength of 532 nm. It has been found that these diffractive elements are formed due to the photorefractive response of the crystal to the steady-state optical interference patterns appeared within the interferometer at multiple reflections of light beam. From the Raman-Nath far field diffraction patterns the ordinary refractive index change within the interferometer on Z-cut crystal has been estimated.

Linear and nonlinear light localization within optically induced photonic superlattices in lithium niobate

We experimentally investigate effects of linear and nonlinear propagation of light beams within one-dimensional photonic superlattices fabricated in bulk photorefractive lithium niobate samples and in photorefractive planar waveguides by optical induction technique. In other case similar superlattices are formed by optical modulation of periodic waveguide arrays produced in lithium niobate by thermal diffusion of titanium and iron. The linear localization of light power is experimentally observed in superlattices of all kinds and proved using numerical simulations of light propagation within such structures. The features of nonlinear behavior of light at its propagation in superlattices is also experimentally demonstrated in a configuration of their single-channel excitation.