Optical communications technology vendor Opnext Inc. (NASDAQ:OPXT) and Dutch research and education network SURFnet say they have successfully tested Opnext’s new 100-Gbps coherent subsystems. The field trial over SURFnet’s network saw Opnext’s OTS-100FLX digital coherent subsystem transmit 100-Gbps signals between the National Supercomputing Center, SARA, in Amsterdam and CERN (Conseil Européen pour la Recherche Nucléaire - European Organization for Nuclear Research) in Geneva, a round-trip distance of 3300 km.
Opnext, which is in the process of finalizing its merger with Oclaro, unveiled its OTS-100FLX 100-Gbps digital coherent subsystem at OFC/NFOEC last March. The system pairs dual-polarization quadrature phase-shift keying (DP-QPSK) with coherent detection as well as soft-decision forward error correction (SD-FEC). The subsystem consists of a suite of OTS-100FLX 100-Gbps flexponder line cards and a newly released OTS-mini ETSI shelf with a 4RU form factor.
The embedded fiber link comprised a combination of the relatively high-nonlinear TW+ and TWRS fibers, augmented with EDFAs. The transmission circuit was optically looped back in Geneva, thus creating the 3,300-km full run. The looped-back link operated error-free for more than 23 hours (BER<10-15) over the entire C-band and over a range of launch powers, the parties say. The trial demonstrated the ability of the link to support 8 Tbps via 100-Gbps coherent transponders.
SURFnet installed coherent 100-Gbps technology from Ciena Corp. in its network last year (see “SURFnet adds 100 Gbps, ROADM, packet-optical transport via Ciena gear”). However, that hasn’t stopped it from taking technology from other vendors for a test drive. For example, a field trial of 100-Gbps equipment from Cisco using the same route as the Opnext trial was revealed this past March (see “SURFnet demos Cisco 100G DWDM between Amsterdam and Geneva”).
“This trial is another clear demonstration that coherent 100-Gbps PM-QPSK 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 systems from multiple vendors,” said 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.”
“It is great to see the results of our 100-Gbps coherent product development deliver both the capacity and reach needed to scale next-generation optical networks around the world,” said Mike Chan, president of Opnext’s subsystems business unit. “SURFnet’s 3,300-km field trial really pushed us, and our 100-Gbps coherent technology met the challenge.”