OFS Highly Non-Linear Fiber (HNLF) combines a high non-linear coefficient with numerical small group velocity dispersion. The fiber design includes a high delta core, doped with either GeO2or Al, surrounded by a deeply depressed ring doped with fluorine. The HNLF is available in four versions: a version with a slope of 0.019 ps/(nm2?km), a zero dispersion slope version, a PM version, and a version with aluminum-doped core for increased SBS threshold. All types are available with a wide range of dispersion values. The PM-HNLF is based on an elliptical core. It doesn’t have any stress rods.