Abstract

We report a theoretical study of an all- optical long-distance soliton-based lightwave system using single-mode heavy metal fluoride (HMF) fibers at 2.55 μm, where the minimum loss is projected to be ~0.03 dB/km. Mollenauer has experimentally demonstrated soliton transmission over more than 6000 km in single-mode silica fibers at ~1.6 μm, with loss periodically compensated by Raman gain by using a pump at ~1.47 μm. Our motivation was to investigate what can be possible in future when single-mode HMF fibers become a practical reality. Since the peak Raman gain shift in HMF fibers is 580 cm^-1, the pump will be at 2.22 μm, with 0.06-dB/km loss. A simple step-index HMF fiber with good dispersion flattening was used in this study and its properties are as follows: core diameter 6 μm; relative index difference 0.95%; zero dispersion wavelength is 2.48 μm, with a slope of 0.008 ps/nm²/km; dispersion at 2.55 μm is 0.6 ps/nm/km, with negative group velocity dispersion as required and small manufacturing tolerances will still preserve this. The band width length (Gordon-Haus) limit was calculated to be ~120,000 GHz·km.

© 1989 Optical Society of America