ADVA touts 400 Gbps over 100 km via PAM4 for data center interconnect

ADVA Optical Networking and the Technical University of Denmark say they have transmitted 400 Gbps over 100 km via PAM4 optical modulation. The transmission, which comprised eight channels of 50 Gbps apiece, could have implications for low-cost data center interconnect as an alternative to approaches based on coherent transmission.

ADVA Optical Networking and the Technical University of Denmark say they have transmitted 400 Gbps over 100 km via PAM4 optical modulation. The transmission, which comprised eight channels of 50 Gbps apiece, could have implications for low-cost data center interconnect as an alternative to approaches based on coherent transmission.

The work was funded by the EU Marie Curie projects ABACUS and CEEOALAN. The collaborators will provide details of the demonstration during a presentation at OFC 2016 in Anaheim, CA, "First Real-Time 400G PAM4 Demonstration for Inter-Data Center Transmission over 100 km of SSMF at 1550nm," by Nicklas Eiselt, Jinlong Wei, Helmut Griesser, Annika Dochhan, Michael H. Eiselt, Joerg-Peter Elbers, Juan José Vegas Olmos and Idelfonso Tafur Monroy.

The work features a prototype transceiver with an equalizer on the transmitting and on the receiving side to compensate for limited bandwidth and residual dispersion. The researchers emulated a data center interconnect transmission link using 80 km and 100 km of standard single-mode fiber, a multiplexer and de-multiplexer, and optical amplifiers.

"The uniqueness of our PAM4 setup is that it enables a cost-effective and low-power high-speed data center interconnect solution by significantly extending the reach of short-reach 400G PAM4 solutions, which are currently under standardization at IEEE 802.3bs," said Nicklas Eiselt, a PhD candidate, Department of Photonics Engineering, at the Technical University of Denmark.

Eiselt suggests the concept could be extended to support a link capacity greater than 4 Tbps at distances up to 100 km. Future research could focus on increasing transmission speeds up to 56 GBaud, while tightening integration at the component level to lower power consumption and cost.

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