SELF-TAPERING OF ELLIPTIC GAUSSIAN BEAMS IN AN ELLIPTIC-CORE NONLINEAR FIBER

We show stable modes (stationary self-trapped beams) of elliptic cross section in an elliptic-core nonlinear fiber. These stable modes can b e tapered in the presence of absorption or gain. Ellipticity of the be am can be controlled by induced tapering. Another interesting feature is the possibility of conversion of an elliptic Gaussian laser beam in to a circular Gaussian laser beam. A stationary self-trapped beam plus an elliptic-core nonlinear fiber form an elliptic-core Linear fiber f or a low-power signal beam, and hence one can induce an elliptic-core linear fiber of optically tunable parameters for a low-power signal be am. (C) 1995 Optical Society of America