Guiding light by soliton waveguides in photorefractive lithium niobate crystals

In this paper, we demonstrate guiding of c.w. and femtosecond laser beams in waveguides induced by bright spatial solitons in lithium niobate crystals. Bright spatial solitons were written with low-power c.w. and pulsed laser beams in photorefractive lithium niobate crystals.

The soliton beams can create single-mode waveguides into the propagating materials. These waveguides have also important features as: re-writable, 3D orientation in the bulk materials and adaptive graded index profile (to the laser fundamental mode). The soliton generation process shows serious advantages in the competition with the other methods for light waveguide writing, as proton exchange, titanium in-diffusion, direct writing with UV lasers, which are irreversible, superficial and with a refractive index profile dependent on chemical processes.