Highly nonlinear fiber with dispersive characteristic invariant to fabrication fluctuations.

New class of highly nonlinear fibers possessing dispersive characteristics invariant to transverse geometry fluctuations is described. The sensitivity to stochastic core fluctuations is reduced by order of magnitude while maintaining the fiber nonlinear coefficient. The effectiveness of the new highly nonlinear fiber type is demonstrated on stochastically perturbed distant-band mixer that could not be previously constructed with high-confinement fiber. The new fiber design offers a unique platform for ideally phase matched parametric exchange with significantly increased Brillouin threshold.