Intelligent transport network provider Infinera Corp. has completed a series of record-breaking submarine field trials over MAREA, a 6600-km submarine cable between Virginia Beach, Virginia, and Bilbao, Spain. The trials used Infinera’s fourth-generation Infinite Capacity Engine (ICE4) advanced coherent technology to achieve new records for trans-Atlantic real-time spectral efficiency, producing 6.21 bits/s/Hz over 6644 km, translating to a fiber capacity of 26.2 Tb/s; and 4.46 b/s/Hz over 13,210 km for 18.6 Tb/s fiber capacity. To achieve the record-breaking results, Infinera employed several advanced technologies, including precision, multicarrier common wavelocking based on Infinera’s large-scale photonic integrated circuit (PIC), and digitally synthesized subcarriers with near-Nyquist pulse shaping, enabled by the ICE4 real-time coherent digital signal processor, and operation over a high-optical power, large-area optical fiber cable. Bandwidth-hungry applications and cloud-scale architectures are driving the need for dramatically increased subsea network capacity. Historically, trans-Atlantic cables have not been able to use higher order modulations, such as 16QAM, to achieve higher capacity. Several technology advances helped overcome this limitation, including modern, large effective area subsea cables that improve the reach for higher order modulations. Combining this with a range of advanced coherent technologies and unique properties of a PIC implementation, Infinera successfully validated 16QAM over unusually long distances using exceptionally tight channel spacing. “We were thrilled to have an opportunity to work with a major internet content provider to demonstrate Infinera’s leading innovation in spectral efficiency over the MAREA cable system,” said David Welch, co-founder and chief strategy and technology officer at Infinera. “Infinera’s ICE4 technology has continually delivered in optical performance for our customers over the past year. This latest example, in a production platform, allowed upward of more than 30 percent increased spectral capacity over other supplier technologies that are available today.” Infinera’s end-to-end packet-optical portfolio is designed for long-haul, subsea, data center interconnect, and metro applications.