That distance is twice as great as what current state-of-the-art equipment can transmit at the same capacity and is roughly equivalent to 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 Nokia Bell Labs and Nokia subsidiary Alcatel Submarine Networks (ASN), establishing a net throughput of 41 Tbps over 291 km using a C-band non-repeatable transmission system. C-band non-repeatable systems are commonly used to connect islands and offshore platforms to each other and to the mainland. The previous record for this type of system was 35 Tbps over the same distance. Nokia Bell Labs and ASN broke the record at ASN's research testbed, also in Paris-Saclay.

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

Lasers that blink faster
Nokia Bell Labs and Alcatel Submarine Networks achieved both world records thanks to innovations in higher-speed transmission technologies. Baud measures the number of times per second an optical laser switches on and off, or "flashes." A higher baud rate means greater data throughput and will allow future optical systems to transmit the same capacity per wavelength over much greater distances. For transoceanic systems, these higher baud rates will double the distance over which we could transmit the same amount of capacity, allowing us to effectively connect cities on opposite sides of the Atlantic and Pacific Oceans. For non-repeating C-band systems, a higher baud rate would allow service providers connecting islands or offshore platforms to achieve greater capacities with fewer transceivers and without the need to add new frequency bands.

The research behind these two records will have significant implications for the next generation of submarine optical transmission systems. While future submarine fiber deployments will leverage new fiber technologies, such as multimode and multicore, existing submarine fiber networks can benefit from next-generation transceivers with higher baud rates to improve performance and increase their long-term viability.