Infinera, TeliaSonera complete terabit field trial

Infinera Corp. (NASDAQ: INFN) and TeliaSonera International Carrier say they have successfully completed the world’s first terabit optical transmission based on 500-Gbps superchannels. The field trial covered a total distance of 1,105 km using a route between Los Angeles and San Jose.

Like every announcement of a field trial, this one contained enough qualifiers so that the company involved can claim a first. Infinera is not first to demonstrate terabit transmission, nor is it first to demonstrate superchannels – a large unit of optical capacity created by combining multiple optical carriers into a single managed entity.

What’s significant in this instance is that Infinera has demonstrated not one but two superchannels based on its 500G photonic integrated circuit (PIC) technology in a situation that closely mimics the real world using pre-production equipment over installed fiber that is carrying other traffic.

“Every time we do one of these field trials, there is a specific goal,” explains Geoff Bennett, director of solutions and technology at Infinera. “Because it costs a fair amount to do, the team has to demonstrate significant progress.”

Infinera had previously demonstrated a single 500G superchannel. Now it has scaled up to two superchannels by using pre-production boards from the DTN-X, the next-generation packet-optical platform that it unveiled in September (see “Infinera debuts DTN-X packet-optical transport platform with 500G PIC, OTN/MPLS support”).

Most field trials are still an experiment and vendors don’t have enough resources to build the equipment for more than one superchannel. Typically such experiments occupy multiple racks of equipment because they have to be built from discrete components. However, in Infinera’s case all they needed was two briefcase-sized line cards. “The big difference is that we’ve got enough kit to demonstrate more than one superchannel,” Bennett added. “We’re using pre-production equipment; stuff that’s going to start early shipping next year.”

Another important aspect of the field trial, he says, was that the fiber was carrying 300 Gbps of existing traffic encoded with non-return-to-zero (NRZ) modulation. In the past, people were worried that it wouldn’t be possible to mix coherent and non-coherent channels on the same optical fiber because of non-linear interactions between the different signals; this demonstration shows that vendors can manage the interaction.

Another high-profile demonstration of terabit transmission was described in a post-deadline paper at OFC/NFOEC earlier this year. Verizon and NEC transmitted 100 Gbps, 450 Gbps, and 1 Tbps superchannels simultaneously over a long-haul fiber link in the Dallas area (see “Verizon, NEC tout high-speed optical network trials”).

TeliaSonera has been using Infinera’s DTN system equipment on its US network since 2009, so it makes sense that it’s kicking the tires of the upcoming product, the DTN-X (see “TeliaSonera taps Infinera for US network”).

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