Bell Labs discloses 100-G Ethernet over optical

COLORADO SPRINGS, Colo. — Lucent Bell Labs presented two papers at the European Conference on Optical Communication detailing work on optical transmission using the emerging 100-Gbit Ethernet standard.

While Ethernet framing has been used in 40-Gbit Sonet backbones, and the IEEE has discussed a 100-Gbit follow-on, the work described at the conference in Glasgow, Scotland, is the first to allow 100-Gbit transmission over optical fiber.

The first paper covers duobinary optical modulation, a technique that forms the basis of a new multisource agreement on transponders. In the methodology, three electrical signal levels are used to represent a traditional binary signal, allowing a transmission to require less bandwidth than nonreturn-to-zero (NRZ) coding. Bell Labs employees used a 40-Gbit optical modulator with duobinary to achieve a 107-Gbit/s serial data stream.

The second paper described a single-chip optical equalizer that compensates for all intersymbol interference encountered in a 107-Gbit NRZ electronic time-division multiplexing transmitter. As with the duobinary device, the equalizer allowed the use of a commercial 40-Gbit modulator to general a 107-Gbit optical NRZ signal.