Bell Labs Displays 4000-km, 2.56-Tb Transmission

Bell Labs scientists in Holmdel and Murray Hill, both in New Jersey, have transmitted 64 40-Gb/s channels over 4000 km of fiber without regeneration. They reported the work in a postdeadline session at OFC 2002 in Anaheim, Calif., in March.

The team employed return-to-zero differential-phase-shift keying to improve transmission over the 100-km spans of nonzero dispersion-shifted fiber. The method yielded a 3-dB reduction in the signal-to-noise ratio. The setup, which incorporated 1554.6- to 1607.0-nm distributed feedback laser sources, also used counterpropagating Raman amplification and forward error correction.