Inverse design and fabrication tolerances of ultra-flattened dispersion holey fibers.

We employ a Genetic Algorithm for the dispersion optimization of a range of holey fibers (HF) with a small number of air holes but good confinement loss. We demonstrate that a dispersion of 0 +/- 0.1 ps/nm/km in the wavelength range between 1.5 and 1.6 microm is achievable for HFs with a range of different transversal structures, and discuss some of the trade-offs in terms of dispersion slope, nonlinearity and confinement loss. We then analyze the sensitivity of the total dispersion to small variations from the optimal value of specific structural parameters, and estimate the fabrication accuracy required for the reliable fabrication of such fibers.