• Through the innovation of higher-baud-rate technologies, Nokia Bell Labs researchers have established two new world records in submarine optical communications
• The first record achieved a net data rate of 800 Gbps on a single optical wavelength at a distance of 7865 km – the distance between Tokyo and Seattle
• The second record, achieved by both Nokia Bell Labs and Alcatel Submarine Networks, established a net throughput of 41 Tbps over 291 km via a C-band unrepeated transmission system

Nokia  announced it has set two new world records in submarine optical transmission, both of which will shape the next generation of optical networking equipment.

The first sets a new optical speed record for transoceanic distances. Nokia Bell Labs researchers were able to demonstrate an 800-Gbps data rate at a distance of 7865 km using a single wavelength of light. That distance is two times greater than what current state-of-the-art equipment can transmit at the same capacity and is approximately the geographical distance between Seattle and Tokyo. Nokia Bell Labs achieved this milestone at its optical research testbed in Paris-Saclay, France.

The second record was achieved by both Nokia Bell Labs and Nokia subsidiary Alcatel Submarine Networks (ASN), establishing a net throughput of 41 Tbps over 291 km via a C-band unrepeated transmission system. C-band unrepeated systems are commonly used to connect islands and offshore platforms to each other and the mainland proper. The previous record for these kinds of systems is 35 Tbps over the same distance. Nokia Bell Labs and ASN broke the record at ASN’s research testbed facility, also in Paris-Saclay.

Nokia Bell Labs and ASN presented the scientific findings behind both records on the 4th and 5th of October at the European Conference on Optical Communications (ECOC), held in Glasgow, Scotland.

Making lasers that blink faster

Nokia Bell Labs and Alcatel Submarine Networks were able to achieve both world records through the innovation of higher-baud-rate technologies. “Baud” measures the number of times per second that an optical laser switches on and off, or “blinks”. Higher baud rates mean higher data throughput and will allow future optical systems to transmit the same capacities per wavelength over far greater distances. In the case of transoceanic systems, these increased baud rates will double the distance at which we could transmit the same amount of capacity, allowing us to efficiently bridge cities on opposite sides of the Atlantic and Pacific oceans. In the case of C-band unrepeated systems, higher baud would allow service providers connecting islands or off-shore platforms to achieve higher capacities with fewer transceivers and without the addition of new frequency bands.

The research behind these two records will have significant impact on the next generation of submarine optical transmission systems. While future deployments of submarine fiber will take advantage of new fiber technologies like multimode and multicore, the existing undersea fiber networks can take advantage of next-generation higher-baud-rate transceivers to boost their performance and increase their long-term viability.

Sylvain Almonacil, Research Engineer at Nokia Bell Labs, said: “With these higher baud rates, we can directly link most of the world’s continents with 800 Gbps of capacity over individual wavelengths. Previously, these distances were inconceivable for that capacity. Furthermore, we’re not resting on our achievement. This world record is the next step toward next-generation Terabit-per-second submarine transmissions over individual wavelengths.”

Hans Bissessur, Unrepeated Systems Group leader at ASN, said: “These research advances show that that we can achieve better performance over the existing fiber infrastructure. Whether these optical systems are crisscrossing the world or linking the islands of an archipelago, we can extend their lifespans.”