Abstract

For recent years various kinds of optical fibers for WDM transmission have been developed and new types of fibers and hybrid fiber links has been developed. Recently, new non-zero dispersion shifted fibers (NZ-DSF) for WDM transmission not only in the C- and L-bands but also in the S-band were proposed for terrestrial transmission.^1,2 The chromatic dispersions of these fibers at 1550 nm are about +8 ps/nm/km which we call medium dispersion in this paper. The dispersion is larger than those of conventional NZ-DSFs and effective to reduce dispersion-related nonlinear impairment. On the other hand, dispersion-flattened hybrid optical fiber links using a positive dispersion fiber (PDF) and a negative dispersion fiber (NDF) for long-haul transmission systems have been developed. For 20- or 40-Gb/s transmission, however, nonlinear intra-channel phenomena due to a large accumulated dispersion through a PDF impair the system performance.³ The medium dispersion is also effective to reduce this impairment.⁴ In both applications, a medium-dispersion fiber (MDF) is attractive and a large effective area and a low dispersion slope are preferable for the fiber as well as for a conventional NZ-DSF.

© 2002 Optical Society of America