Active TM mode envelope soliton propagation in a nonlinear nematic waveguide

In this note the propagation of an envelope optical soliton in a nematic waveguide is examined. The waveguide is subject to an elastic distortion and this distortion propagates as a front, which in turn influences the propagation of the soliton. It is found that the re-orientation of the optical director can produce either defocusing or focusing of the soliton, thus influencing its motion. Both approximate equations and numerical solutions show that a modulation in the defocusing optical regime can catch up with the re-orientation front and then form an envelope soliton in the focusing region ahead of the front. Furthermore, numerical solutions show that slow modulations in the defocusing region disintegrate into radiation. A limiting solution of a coherent optical soliton locked onto the front also exists, but it is meta-stable and eventually disintegrates.