Dispersion Compensating Fiber Modules for Dispersion-Shifted Fiber

A dispersion-shifted fiber (DSF) is designed to have its zero dispersion wavelength in 1.55μm wavelength range. Since the dispersion of DSF is close to zero in the C-band, conditions for dense wavelength division multiplexing (DWDM) transmission using DSF are limited due to four wave mixing (FWM). In the L-band, however, the DSF has some dispersion values, so that the DWDM transmission using DSF is possible like non-zero dispersion-shifted fibers (NZDSF.) A DSF has a typical dispersion from 5 to 6ps/nm/km dispersion at the longest wavelength of the L-band, 1,625nm. The compensation of its accumulated dispersion is required in long-distance and high-speed transmission using DSF. For example, in 10-Gbit/s transmission systems, the accumulated dispersion is limited to 1,000ps/nm approximately 1). When the transmission distance of DSF is beyond 200km, its accumulated dispersion at 1,625nm exceeds 1,000ps/nm and dispersion compensation is required. Moreover, the difference of dispersion between 1,565nm and 1,625nm exceeds 1,000ps/nm when the distance of the transmission line is beyond 250km. In this case, dispersion slope compensation is necessary. There have been many reports on slope-compensating and dispersion compensating fibers (SC-DCF) and their modules for standard single-mode fibers (SSMF) and NZ-DSF 2) 3) 4) 5). There had been, however, no report on practical SC-DCF for DSF, which requires the highest relative dispersion slope (RDS) among various types of SC-DCFs, until we reported SC-DCF for DSF and its module 6). In this report, we present the optical characteristics, thermal coefficients of dispersion and nonlinearities of fabricated SC-DCF for DSF. In addition, we report on the performance and the reliability of SCDCF modules using the fibers.