Dispersion flattened hybrid-core nonlinear photonic crystal fiber.

Photonic crystal fibers are highly attractive as nonlinear media as they combine a large nonlinear coefficient and a highly ustomizable zero dispersion wavelength - flexibility not found in any other medium. However, the high dispersion slope at the zero-dispersion wavelength demonstrated so far is very limiting to the useful bandwidth. We propose a new fiber design comprising a hybrid core-region with three-fold symmetry that enables unprecedented dispersion control while maintaining low loss and a high nonlinear coefficient. The lowest dispersion slope obtained is 1.10-3ps/(km.nm2) or one order of magnitude lower than for conventional slope reduced nonlinear fibers. The nonlinear coefficient is more than 11 (W.km)-1 and loss below 7.9 dB/km at 1.55 microm has been achieved.