In this paper we demonstrate nonlinear optical properties of a channel waveguide made of E7 nematic liquid crystal infiltrated in a SiO2/Si V-groove. Light in C-Band (1530-1565 nm), fiber coupled to the core of the liquid crystal waveguide, was optically modulated by the optical beam itself, with a power below 25 mW. A bias voltage was applied to induce a liquid crystal orientation over the Freedericksz threshold and a further director reorientation was obtained by increasing the optical beam. The effect of optical modulation for different applied voltages obtained experimentally was modelled including both opto and electro-optical effects.