A team of researchers from Infinera has achieved new benchmarks for efficiency for transatlantic fiber optic cables. By employing 16QAM modulation on the MAREA transatlantic cable, the researchers generated signal speeds topping out at 26.2 terabits per second, a 20 percent increase over what the cable designers originally thought feasible. By comparison, the most common way signals are modulated for MAREA today only reaches 9.5 terabits per second. The test marked the first time PM-16QAM signals were sent such distances.
The 6,605-km MAREA cable came online last year and is made of eight pairs of optic fibers, with each pair designed to carry 20 Tbps.
The paper will be presented at the upcoming Optical Fiber Conference and Exposition, held 3-7 March in San Diego, Calif., U.S.A.
“In an optical fiber, it’s desirable to carry more data per second, which we call the fiber capacity, and also to be able to send the signal over longer distances, which we call the optical reach,” said Dr. Pierre Mertz, an author on the study. “In simple terms, if you try to push the limits of fiber capacity you will reduce the reach. The biggest challenge is that the system was operating very close to the Shannon Limit, or the theoretical maximum information transfer rate for a communications channel, according to Mertz. "That means that every gain we make becomes harder and harder,” he said.
Authors: Stephen Grubb, Pierre Mertz, Ales Kumpera, Lee Dardis, Jeffrey Rahn, James O’Connor, Matthew Mitchell
