Noting that the continued growth of cloud and explosion of artificial intelligence (AI) services is driving the need for greater subsea network capacity, which requires advanced coherent transmission systems that support higher performance, Cisco, in collaboration with Microsoft, has demonstrated an 800Gbps transmission trial on the Amitié transatlantic cable.
With a total length of 6,800km, 16 fibre pairs – more than traditional subsea cables – and a maximum capacity of 400Tbps, Amitié connects Lynn near Boston in the US with Le Porge near Bordeaux in France (6,234km) and Bude in the south-west of England. The result of almost four years of work between the two continents and the completion of validation tests, the cable is being managed by telcos and was ready for service in October 2023.
Amitié features space division multiplexing (SDM) technology with repeater power shared across the fibre pairs to deliver the highest cable capacity.
Cisco said the trial targeted improvements in subsea transmission to provide increased performance and capacity, citing exponential growth in cloud and AI services that requires increased subsea network capacity.
This real-time field trial exceeded any industry trial performance to date, with Dense Wavelength Division Multiplexing (DWDM) 800G in a 150GHz channel spacing, equivalent to a spectrum efficiency of 5.33bit/s/Hz and a maximum spectral efficiency of 5.6bit/s/Hz. In addition, 600G was transmitted over 12,469km for a transatlantic loopback configuration. This is said to be the first time a 140Gbaud single carrier signal was demonstrated live, and is the longest distance ever reported at single carrier 600G DWDM transmission on an SDM cable.
The trial was performed with the Cisco NCS 1014 platform enabled by Acacia’s Coherent Interconnect Module 8 (CIM 8), which is powered by its Jannu digital signal processor and advanced silicon photonics. Both products are available today and actively deployed in multiple networks.
“In the era of AI, reliable and fast network connections are more important than ever,” commented Bill Gartner, senior vice-president of optical systems and optics at Cisco. “Working with Microsoft on the Amitié cable to demonstrate the potential for improved overall network capacity with 800G at these distances is a significant milestone for an SDM cable, and we’re proud to drive the innovations that pave the way for ever-increasing network capacity needs.”
Amitié cable is also now part of Microsoft’s global network supporting all Microsoft services. “The transmission of 800G over 6,234km is a milestone that demonstrates SDM cables can deliver increased capacity over traditional subsea cables,” added Jamie Gaudette, general manager of cloud network engineering at Microsoft. “This field trial demonstrates what is now a commercial technology for subsea routes, and we can improve the network capacity and to help drive digital transformation for people, organisations and industries around the world.”
