Infinera and Telstra successfully demonstrate PM-8QAM across submarine cable between Japan and South Korea

The test, which was conducted across 2,200 kilometers of Segment F of the Reach North Asia Loop (RNAL), included Polarization Multiplexed 8 Quadrature Amplitude Modulation (PM-8QAM), and a range of advanced FlexCoherent™ modulation formats, along with transmitter and receiver-based signal processing technologies. Segment F runs between Wada in Japan and Pusan in South Korea.

PM-8QAM is a key technology for the optimization of the capacity of a fiber, in order to increase the value of established submarine cable systems around the world. PM-8QAM is designed to deliver a 50% increase in capacity compared to the most common coherent modulation technique, PM-QPSK, in a typical installation under the same conditions.

Steve Grubb, Infinera Fellow and the architect behind the RNAL demonstrations, said, “This trial demonstrates the potential of a full suite of FlexCoherent modulation formats on a single line card and the ability to precisely trade capacity for reach and margin. It also highlights the emergence of next generation coherent processing that works with existing coherent 100 Gigabit per second technologies, which are now firmly entrenched in modern submarine terminating line equipment, such as the Infinera DTN-X platform.”

“When regeneration within the submerged cable is simply not an option, the ability to trade margin for additional capacity can be crucial in submarine networks. Having the full suite of modulation formats on a single card can also dramatically lower inventory costs, while allowing the service provider to maximize cable capacity,” Grubb said.

In addition to showcasing these advanced modulation techniques, the RNAL trial included demonstrations of advanced coherent transmitter-based Nyquist DWDM pulse shaping, and both transmitter and receiver-based non-linear compensation technologies.

“We’re delighted to collaborate with Infinera to push technology boundaries when it comes to advanced super-channel techniques,” said Telstra’s Andrew Hankins, Head of Engineering, Global Enterprise & Services.

“We believe that the current and future capabilities of the DTN-X platform and our use of the newest technologies will continue to give Telstra a clear advantage in the Pacific region, both in terms of capacity and the ability to help deliver reliable services quickly to meet customer demand.”

As part of a larger showcase of submarine super-channel capabilities between Telstra and Infinera, one of the world’s first demonstrations of PM-3QAM modulation on a 4,250 km link between California and Hawaii was also completed.