9 July 2012

Opnext demos record 3300km transmission distance using 100G coherent PM-QPSK subsystem on SURFnet DWDM infrastructure

Optical module and component maker Opnext Inc of Fremont, CA, USA and SURFnet, the National Research and Education Network (NREN) in The Netherlands, have announced a successful 100Gbps coherent field trial between the National Supercomputing Center (SARA) in Amsterdam and CERN (Conseil Européen pour la Recherche Nucléaire - European Organization for Nuclear Research) in Geneva. Opnext used its OTS-100FLX 100Gbps digital coherent subsystem for the field trial, utilizing next-generation 100Gbps single-carrier technology and soft-decision forward error correction (SD-FEC) to optically link Amsterdam to Geneva with a transmission distance of 1650km using only erbium-doped fiber amplifiers (EDFAs).

To further demonstrate the subsystem’s performance, the embedded fiber link consisted of a combination of the relatively high-nonlinear TW+ and TWRS fibers. Furthermore, the circuit was optically looped back in Geneva, creating a 3300km circuit. The looped-back 3300km link operated error-free for more than 23 hours (bit-error rate, BER < 10-15) over the entire C-band and over a range of launch powers, highlighting the upgrade potential of the link to 8Tbps in the future using 100Gbps coherent transponders.

“This trial is another clear demonstration that coherent 100Gbps PM-QPSK [polarization multiplexed quadrature phase-shift keying] transmission technology is tolerant to a very large range of impairments (i.e. chromatic dispersion, polarization mode dispersion, noise) and allows the use of alien wavelengths in research networks over DWDM [dense wavelength division multiplexing] systems from multiple vendors,” says Roeland Nuijts, Optical Network Architect for SURFnet. “Transmission distance and tolerance against different impairments will be critical going forward as we look to build out international networks across geographic and administrative borders in order to realize a global facility for research networking,” he adds.

The Opnext subsystem consists of a suite of OTS-100FLX 100Gbps flexponder line cards and a newly released OTS-mini ETSI shelf with a 4RU small form factor.

“It is great to see the results of our 100Gbps coherent product development deliver both the capacity and reach needed to scale next-generation optical networks around the world,” says Mike Chan, president of Opnext’s subsystems business unit.

Tags: Opnext

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