Displacement and deflection of optical beams by nonlinear planar waveguide

In this paper we investigate the propagation characteristics of an end fired Gaussian optical beam through a planar nonlinear waveguide. Using variational formalism we have derived three coupled second order dynamical equations for the beam widths and centre of gravity of the propagating optical beam. Using these equations, we have investigated numerically the beam deflection, displacement and their possible control by nonlinearity. We have shown that intensity dependent control is possible only when the waveguide core possesses nonlinearity and the substrate is linear. In addition, we have demonstrated that such control is not possible in bulk media. We have further established that setting an appropriate length of the waveguide one can achieve maximum displacement with minimum deflection or minimum displacement with maximum deflection. Possible application of our investigation in optical communication and signal processing are highlighted.