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September 12, 2017

The Future of the Cloud Lies Under the Sea

By Pravin Mahajan
Director of Product Marketing

Today marks a milestone in Infinera’s journey of continuing to push the boundaries of optical networking. Seaborn Networks announced the deployment of the Infinera XTS-3300 meshponder on their Seabras-1 subsea cable. Seabras-1 is one of the longest uncompensated subsea fiber cables in the world, connecting New York and São Paulo. So how does this deployment break boundaries?

Let’s begin with business requirements. Subsea fiber optic cables may not be the trendiest topic in networking, but while they lack the glitz of the cloud, they support around $10 trillion worth of business every day (source: NYT), including from financial institutions that settle transactions on them every second. Seabras-1 is the first cable to link the financial centers of the U.S. and Brazil directly, with ultra-low latency of 106.6 milliseconds round trip.  The 10,600-kilometer (km) cable is one project among many in a market that is thriving – investments totaling approximately $7.5 billion are being poured into subsea cable construction around the world this year and next. These investments are fueled by demand from cloud providers, which are increasingly dominating traffic volume on subsea cables – some 70 percent of trans-Atlantic subsea cable traffic is now content related. Clearly, as the cloud soars, the importance of subsea cables continues to grow. As they invest, submarine network operators should choose the best-in-class optical equipment available to enhance performance and maximize the return on their very expensive subsea cable assets.

Next, let’s turn to technical requirements. Seabras-1 is a new build using uncompensated fiber cables. Traditionally, subsea cables have compensated for optical dispersion and other penalties due to the terminals at the ends of the cables performing only basic transponder and transmission functions. As terminal technologies have improved, particularly in coherent modulation using digital signal processors (DSPs), there is no longer a need for new cables to compensate for optical penalties. This requires a new breed of terminal equipment that is purpose-built for the job. At PTC 2017, we announced the world’s first subsea meshponder – a new category of platforms enabled by the Infinite Capacity Engine (ICE4) that are motivated by web-scale disaggregation principles and support sophisticated coherent techniques. The XTS-3300 combines super-channel scalability with sliceable photonics in an ultra-compact form factor, without the complexity of integrated switching. At just one rack unit with one fiber pair and a maximum of 1.2 terabits per second (1.2T) of line-side capacity across six channels, and installed in just one operational motion, it combines rack-and stack form factor, operational simplicity and mesh optical functionality.

The XTS-3300 supports the Infinera Advanced Coherent Toolkit (ACT), which includes many industry-first performance-enhancing technologies, such as:

  • Nyquist subcarriers: Infinera pioneered super-channels, which allow the provisioning of several carriers in one operational cycle, vastly simplifying optical communications. Now Infinera is advancing super-channels with digitally synthesized Nyquist subcarriers. By using the cutting-edge functions of Infinera’s dual-channel FlexCoherent DSP, each optical carrier can be further synthesized into multiple subcarriers that are closely spaced to each other, dramatically improving tolerance of non-linear impairments.
  • SD-FEC gain sharing: With software-decision forward error correction (SD-FEC) gain sharing, the FEC output from two channels can be mathematically combined so that the stronger channel can be used to enhance the quality factor of the weaker channel. This is only possible using a dual-channel DSP like Infinera’s. The rest of the industry uses single-channel DSPs, which prohibit the use of gain sharing.

These industry-unique implementations within ACT allow Infinera to tightly space channels, helping deliver the highest spectral efficiency on the fiber. ACT was first validated on the 9000-km Endeavour trans-Pacific cable and the compensation techniques enabled the maximization of overall reach and capacity. This past July, Infinera showcased 19T of capacity on a Trans-Atlantic route, delivering the highest spectral efficiency with a stable, commercial-ready performance margin. This trial also validated ICE4’s transmission of an 8QAM (quadrature amplitude modulation) 600 gigabits per second (600G) super-channel in 140 gigahertz of spectrum.

This industry-leading performance was one of several reasons why Seaborn chose the XTS-3300 for their Seabras-1 link. The simplicity of the rack-and-stack design allowed the XTS-3300 to be deployed within half an hour on the 10,600-km link, faster than ordering pizza. The Instant Bandwidth capability on the XTS-3300 provides Seaborn with superior economic agility, enabling cloud scale capacity to be delivered in 100G increments in minutes using just few mouse clicks. This capacity is paid for only when activated, instantly matching end-customer demand. Finally, Seaborn is able to unify services across subsea, long-haul and metro networks because they use Infinera’s XTS Series, XTC Series and XTM Series platforms, resulting in a truly seamless experience from end to end. Seaborn’s deployment of the XTS-3300 enables scalability up to 11.8T* on the fiber, with comfortable margin.

Subsea cables are the lifeblood of global electronic communications and commerce. While the world’s attention is on the cloud, let’s take a moment to reflect on the underlying network of fiber optic cables wiring the globe. These workhorses are driving content connectivity and new business. The future of the cloud truly lies under the sea, and Infinera is constantly putting our technology through its paces to enhance subsea network performance even further – stay tuned for more.

*Oct 2017 Update: Infinera validated even higher scalability, exceeding Seaborn’s initial target of 11.8T on the fiber. Andy Bax, of COO of Seaborn Networks, discusses how a new industry benchmark for capacity-reach was achieved, by verifying up to 18.2T on a Seaborn’s fiber pair using 8QAM with the Infinera XTS-3300.

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