The 21.7 Tbps Fiber Trial

For the second year in a row, Verizon and NEC Corporation of America said they transmitted high bit-rate technologies over field fiber, with their latest trial sending 21.7 terabits per second (1 terabit equals 1,000 gigabits) – the highest capacity to date – under field conditions.??

The 2012 trial was performed earlier this year on 1,503 kilometers (934 miles) of standard single mode field fiber on Verizon’s network in the Dallas area.

This trial also used an approach that allowed for different modulation formats to be used to help ensure signal performance while carrying the highest total capacity. The two companies also specifically focused on transmission performance over a significant fiber distance; other experiments in this area, they say, have only been performed in a lab environment. ?

In 2011, Verizon and NEC transmitting high bit-rate technologies, including 100G, 450G and 1T, coexisting on the same fiber in a joint field trial. Verizon continues to deploy 100G on its global network.

The backstory: Network carriers are moving to ever-higher capacity rates to stay ahead of growing bandwidth demands from video services, wireless applications, large-scale data storage and increased IP services. By increasing modulation levels and by reducing optical carrier spacing using superchannels, the total capacity per fiber is increased by more than 100 percent as compared with the current standard 100G systems.

“Superchannels,” the two say, are the next evolution of optical technology that combines several optical carriers to create a signal with greater-than-100G capacity. The ability to use current field fiber to carry higher capacity rates enables carriers to avoid the need to deploy new fiber and, as a result, better use current network infrastructure. ?