Pulsed beams in a nonlinear nematic fiber

A model for a cylindrical fiber whose cladding is an initially homogeneous nematic liquid crystal is presented. We construct a narrow wavepacket of transverse magnetic modes propagating through the fiber taking into account the dispersion, self-focusing and diffraction in the nematic. Then a nonlinear Schrِdinger equation for the time evolution of its envelope is derived. The speed, time- and length-scales and nonlinear index of refraction of the optical solitons are estimated by using typical experimental values for some of the parameters.