Xtera and UCL demonstrate a record 74.38 Tbit/s per fiber transmission over transoceanic distances

February 28th, 2019 – Xtera®, a provider of innovative subsea fiber optic technology, today demonstrates the benefits of its advanced and novel approach to subsea line design by transmitting 74.38 Tbit/s over a transatlantic distance on Single Mode Fiber. This result gives a record-breaking spectral efficiency of 6.86 b/s/Hz over 6,300km, across the C and L bands. The experiment, which was performed in collaboration with University College London (UCL), used a hybrid distributed-Raman / EDFA amplifier with a bandwidth of 91 nm.  This is an adaptation of the technology which Xtera currently deploys in its subsea repeaters, with a new Geometric Shaped DP-64 QAM constellation and adaptive FEC expertise coming from UCL, and hybrid Sumitomo Z+150 and Z Fiber.

Increasing the bandwidth is the best way to get more capacity from a given fiber and the combination of a C-band and an L-band amplifier has been used commercially to achieve bandwidths of approximately 70 nm, but Raman amplification used by Xtera can offer even greater bandwidth while also offering very low noise. The experiment was performed on a recirculating loop comprised of 9 spans, each with 70 km of Single Mode Fiber and a hybrid distributed-Raman / EDFA amplifier.

Full details will be presented by Xtera’s Maria Ionescu at OFC 2019 in the Wideband Transmission session (Tu3F) on Tuesday the 5th March, and findings are also available on arXiv.  This experiment builds on the work of Xtera and UCL earlier this year, Xtera and UCL smash a Transmission World Record, where 120 Tbit/s was transmitted over 9 spans (630 km) using DP-256 QAM signals, and comprising the same Sumitomo hybrid fiber types.

Leigh Frame, Xtera’s Chief Operating Officer, states “This exceptional result demonstrates the value of Xtera’s and UCL’s innovative research. The ability to achieve capacities of this scale over transoceanic distances is truly ground breaking, and although this result was produced in the laboratory it was achieved with a simple extension of Xtera’s already industrialised products.  Xtera continues to invest heavily in R&D and as such will remain at the forefront of the telecoms subsea transmission market when it comes to producing high bandwidth, high capacity technology”.

“The collaboration with Xtera has proved extremely valuable in allowing the application of a number of techniques developed by UCL in an advanced undersea system and highlights that these techniques are of prime importance in the quest to maximise optical fiber capacity, essential to ensuring the growth of the digital economy,” adds Professor Polina Bayvel, CBE FRS FREng.

About Xtera®

Xtera is an innovative provider of subsea systems and telecoms technology. We supply both unrepeatered and repeatered networks, delivering traffic directly inland to data centers and cities. Xtera consistently challenges industry norms and creates novel solutions that are tailored to each individual customer whether that be for the provision of a system, an open architecture

design or individual network elements. Xtera’s turnkey project management expertise and system integration capability is offered in combination with solid industry partnerships and provides operators with the confidence for Xtera to design, build and commission submarine cable solutions that deliver high performance, capacity and end-to-end capability.

Xtera’s product offering is underpinned by leading-edge research and development, often in collaboration with universities, resulting in an enviable patent portfolio and a series of industry technology firsts. Xtera’s objective is to deliver submarine cable solutions that maximize optical capacity and network capability from seabed to city through outstanding expertise, know-how and technology innovation.