Polarization and configuration dependence of beam self-focusing in photorefractive LiNbO_3

Abstract

International audienceWe present numerical and experimental analyses showing the formation of (2+1D) spatial photorefractive solitons at visible wavelengths in electrically biased lithium niobate crystals for ordinary and extraordinary light polarizations. Similarly sized self-trapped beams are observed for both polarizations, despite the polarizationdependent electro-optic coefficients. The tensorial character of the photovoltaic effect is shown to play a key role. The soliton-induced waveguides are able to properly guide telecommunication wavelengths. Finally, a higher degree of anisotropy is observed for ordinary polarized solitons for specific electro-optic configurations, which reveals the presence of the photorefractive field component perpendicular to the applied field. Experimental results are confirmed by a time-dependent numerical model

High aspect ratio lithium niobate ridge waveguides fabricated by optical grade dicing

“…Even if this performance is not needed for the implementation of optical waveguides with low losses, it provides nevertheless an idea of the enormous capability of the method, and opens appealing alternatives towards the development of thin LiNbO 3 layers. As an example, the thin films may be exploited for the implementation of tridimensional optical circuits by means of bright spatial solitons [20]: thanks to the high index contrast provided by the deep ridge, the photorefractive effect is expected to be enhanced and to lead to an increased confinement of self trapped waveguides. The deep grooves provided by optical grade dicing may also be very appealing for ensuring hybrid integration of LiNbO 3 components, or for guiding fibres toward the optical waveguides.…”

High intensity behavior of pyroelectric photorefractive self-focusing in LiNbO3

“…Moreover, the two spots possess different power and they are not aligned with the z-axis contrary to the prediction of the numerical calculations. These two differences may be explained by photorefractive charge saturation that forms an asymmetric index variation [18] and by an additional photovoltaic component that tilts the splitting beam [19]. These features were not taken into account in our numerical computation, which explains the discrepancies.…”