Soliton self-frequency shift in a short tapered air-silica microstructure fiber

We report a soliton self-frequency shift of more than 20% of the optical fr equency in a tapered air-silica microstructure fiber that exhibits a widely flattened large anomalous dispersion in the near infrared. Remarkably, the large frequency shift was realized in a fiber of length as short as 15 cm, 2 orders of magnitude shorter than those reported previously with similar input pulse duration and pulse energies, owing to the small mode size and t he large and uniform dispersion in the tapered fiber. By varying the power of the input pulses, we generated compressed sub-100-fs soliton pulses of s imilar to1-nJ pulse energy tunable from 1.3 to 1.65 mum with greater than 6 0% conversion efficiency. (C) 2001 Optical Society of America.