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Submarine Networks – How Did We Get Here? Ciena Celebrates 25 Years
Submarine Cable NewsFeed - Technology
Sunday, 05 November 2017 15:57

By Brian Lavallée, Senior Director, Solutions Marketing at Ciena

Much has changed in the past 159 years since the first subsea cables delivered telegraph communications. These cables have been laid upon seabeds around the world, stitching together continental landmasses and resulting in the largest manmade construction feat ever created by size – the Internet. Subsea cables have gone from a relatively successful, albeit very low-speed telegraph communications medium, to today’s high-speed critical infrastructure. These cables now carry hundreds of terabits of data each second, over thousands of kilometers in the harshest environments on earth on glass strands no larger than a human hair. How can one not be impressed by this engineering marvel we use every day?

When Ciena was founded in 1992, the World Wide Web hadn’t even been born yet, but the evolution of submarine cables and networks since then has been immense, turning them into one of the most critical pieces of infrastructure in the modern world. From the advent of coherent networking to the rise of predictive analytics and maintenance, the technologies surrounding submarine networks are advancing ever rapidly, leading us toward new challenges and opportunities every day.

To celebrate this year’s 25th anniversary of Ciena, I would like to reflect on some of the notable trends and milestones that have impacted submarine networking since the company was first established. Here are several of the key developments that have changed, and continue to change, the submarine networking industry and, consequently, the entire connected world:

The Dawn of Coherent Networking

While it has only come within the last decade, coherent technology is one of the most significant advancements to submarine networks over the past 25 years. By allowing higher data rates (100 Gb/s and higher vs. 10 Gb/s) to be sent over extremely long-haul networks spanning thousands of kilometers, this enhanced performance and flexibility breathed new life into existing subsea assets by making it possible to transport significantly more information on the same fiber.

Planet of the Internet Content Providers

The bandwidth consumption boom of Internet Content Providers (ICP) presents a new set of challenges to traditional carriers in the modern networking landscape. Not only are ICPs generating the vast majority of data traffic today, but they are also putting it on their own cables in key regions, which is changing the industry’s entire business model. It is staggering to think that 60 percent of the transatlantic bandwidth going over submarine cables is produced by the data centers of a handful of ICP companies who are essentially talking to themselves. What’s more, that number was non-existent a decade ago. These data centers have completely changed the face of submarine networks as we know it.

Networks Open Up

For a variety of historical, political, geographic, and technological reasons, submarine networks were proprietary turnkey network solutions – in other words, closed. Over the past few years, with the advent of coherent detection modems originally developed for long-haul terrestrial networks, all that is changing.

Once these coherent modems were successfully tested across a 3rd party submarine cable, it became possible to upgrade wet plants deployed a decade or more earlier, from 10G (and sometimes even lower) to 40G and 100G, and even higher. This has allowed submarine cable operators to increase the capacity of their undersea assets to greatly extend the life of their investment, without having to lay costly new cables for quite some time.

The open movement is impacting submarine networking by aiming to remove the proprietary nature from networks to allow network operators to choose best-in-breed technologies from a much broader selection of vendors. Gone are the days of closed and proprietary submarine cable networks. The benefits and possibilities offered by open networks create new business opportunities through a transformational change in how networks are designed and operated.


Today, submarine cables carry more than $10 trillion worth of transactional value, each and every day. Over the last few years, Ciena and other vendors have focused intently on upgrading cables and being able to cram as much data as possible into new cables. However, the focus is now shifting towards determining how to best protect these capacity upgrades. It’s one thing to lose a few Gb/s of traffic, it’s quite another thing to lose multiple Tb/s of traffic!

There should be a healthy dose of concern associated with the threat of cable faults. While traffic can be rerouted to a new cable, that cable, and available capacity, must already be in place to maintain the flow of critical data communications. Today, cables are increasingly being pushed to full capacity with few alternative paths available to serve as backup. Were a major earthquake to happen in the wrong area, it could result in massive, wide-scale outages impacting entire continents. Fortunately, forward-looking cable operators are well-aware of the implications of cable cuts and are addressing these concerns via cable resiliency and diversity.

Shannon’s Limit Approaches

Submarine cables deployed years ago are today supporting a major increase in total information-carrying capacity. The exact total capacity of an upgraded cable depends upon its unique performance personality, but all capacity increases are astounding. Such cable upgrades have brought new life into existing subsea wet plants, some more than a decade old, and allow cable operators to maintain pace with over 40 percent CAGR in bandwidth demand in all regions of the world.

The introduction of coherent Submarine Line Terminating Equipment (SLTE) was a sea change milestone in the industry, with operators getting used to massive increases in capacity their subsea assets could support. However, there’s a looming limit to how many bits can be crammed into an existing optical fiber, known as the Shannon Limit – the hard, physical limit of how much data can be crammed onto a single fiber in the presence of noise. There are modem-centric advances and new wet plant designs that represent opportunities to challenge Shannon’s Limit, directly and indirectly, so it’s not all doom and gloom.

Analytics and Predictive Maintenance

Submarine cables have not been exempt from the big data and analytics adoption and the benefits they have brought. Most components of submarine networks show warning signs over time before they ultimately fail, and one of the biggest advantages of open northbound APIs is the ability to extract, consolidate, and analyze network data coming from the subsea network elements. They offer a variety of timely network performance and health data such as polarization mode dispersion, chromatic dispersion, transmitter power levels, receiver power levels, losses, bit error rates, and more. Much of this information is already being used to prevent, or at least minimize, the “miserable” days in the life of a submarine field technician. Proactive, predictive maintenance gives cable operators the opportunity to fix network faults before they occur and ultimately reduce network downtime.

Make Way for the Autonomous, Self-Driving Network

Who better to tell us about our networks’ health than the network itself? Imagining a scenario where our networks talk, tell us they are about to fail somewhere in the network, and decide to reroute traffic to prevent outages may sound like science fiction, but we are already close to this level of interaction with our networks. In fact, some of these capabilities are available right now, and the reason is the emergence of big data analytics, machine learning, and eventually, full-blown artificial intelligence in the future as the technology matures over time.

What started as a journey to be a hopeful technology provider for the cable industry, has led us to our current position as the leader in the submarine cable upgrade market. We have seen profound technological advancements and we are more connected now than ever before. Now we also have the ability to not only care for our networks but are close to giving them the ability to care for themselves. The future of our industry won’t be achieved through some major upgrade, but rather via a journey where we help our networks become the trusted partners we need them to be. To get there, as with any human relationship, the interface between us and them must also evolve as they get smarter and increasingly autonomous. Are you ready for the future?

Xtera® Executives Talk about Latest Contract Award
Submarine Cable NewsFeed - Technology
Thursday, 02 November 2017 07:15

In late September, submarine fiber optic systems supplier Xtera® announced that it had been awarded a turnkey contract from the Defense Information Systems Agency (DISA), an agency of the U.S. Department of Defense, to build a submarine cable system linking the U.S. Navy’s base at Guantanamo Bay to Puerto Rico. 

Xtera will deploy a full turnkey subsea system, including undersea optical repeaters, Nu-Wave Optima™ Submarine Line Terminal Equipment (SLTE), cable and all marine services.  The Nu-Wave Optima is Xtera’s optical Dense Wavelength Division Multiplexing (DWDM) transport that provides industry-leading capacity and ultra-long-reach capabilities configured to support all networking applications.

SubCableWorld recently had the opportunity to speak with Xtera’s Robert Richardson, Founder and Chief Sales Officer, and Tony Frisch, Chief Technical Officer, about this latest development.  Here are some of their comments:


Tell us something about this new contract award.


The project is a new cable running from the naval base at Guantanamo Bay to a military facility in Puerto Rico, the U.S. Army base at Fort Buchanan.  Xtera received the contract a few years ago from DISA for the first cable landing in Guantanamo Bay, which connected the base with Florida, and we’re happy to have been chosen for this second project.  This is our first turnkey contract since the acquisition by H.I.G. Capital and the team is really excited. 


I think it was a really nice project to work on last time.  We built up a good rapport with the guys from the government side and everyone is looking forward to getting in and making the new project happen.


The announcement came shortly after Hurricane Maria devastated Puerto Rico.  We have to ask if the damage from the hurricane will impact the project.


We don’t expect it to.  The military base that the cable will be landing at was not seriously damaged – those buildings are made to withstand a lot of punishment.  There obviously will be some logistical challenges in the short term in getting our people there to begin the process in terms of things like airline schedules and hotels, but the project itself should proceed on schedule.


The first cable landing at the base at Guantanamo Bay was completed in 2016.  What sort of impact did that cable have on Internet services at the base?


Guantanamo Bay is a functioning naval facility with a lot of people and their dependents living there.  I know from the interactions that we’ve had that since the first cable was placed in Guantanamo Bay that it has enabled a lot of things to be done in the naval facility -- not only for the Navy itself but also for the families and dependents.  They’ve been able to get Internet services that we normally take for granted here on the continent.  It’s been pretty exciting, from what I hear, what they’ve been able to do with the submarine cable from that perspective. 


Tony, are there any technological features of this new cable system that you would like to talk about?


The military likes to use equipment that they have tested and formally approved in the past, so this is essentially a rerun of the same technology.  Separately, Xtera continue to develop our technology and one of our latest products for regional systems such as this is a Branching Unit (BU). We developed the BU and completed the Qualification process last year.  The differentiating feature of Xtera’s BU it has interesting resiliency in that we can power the branching unit from a single cable, although in normal operation it will be powered from both ends. 

Now you say, “Well, if you’ve brought everything to the point where can only get the power from one cable, the branching unit’s not going anywhere else.”  But it turns out that in a lot of systems, if you’re unlucky with certain types of cable breaks, if you really need say two out of three cables to power a branching unit, it can make life a lot more difficult.  We had one very knowledgeable customer warn us about this some time back and they told us we need to really think about resilience when you are doing your design. 

So we’ve actually designed our system so that we can power it from a single cable and it turns out once we thought about that it is a great way to power up the system.  Essentially you start at one point and you just go from one branching unit to another to another.  I think it makes it much easier to re-power a system after a cable fault has occurred or while one is performing a repair.  With older cable systems, when they do have to make a repair it means a lot of coordination between stations.  We’ve had customers or potential customers complain that that they can sometimes spend hours powering up their systems because it is very complicated.  And people get very nervous when they’re doing this stuff because if anything goes wrong, it could be quite painful.


Looking ahead, what can we expect to see from Xtera?


Our chief focus is addressing the customer’s needs and working closely with customers to meet their requirements.  We’re making efforts to increase the capacity in our undersea systems.  We’re introducing more capacity and we have plans to expand to greater amounts of bandwidth in the undersea cables.  The current bandwidth is 55nm and it’s going to go up to 63nm and beyond. 


We’re definitely pushing the bandwidth because it is something that is practical for us to do, but also it is being driven by customers.  The other thing we’ve seen a lot recently is significant interest in open systems, disaggregation and virtualization.  These also are being driven by the industry.  We are seeing that from the people that we think are most likely to be either buying from us the first time or will be buying again.  And we’ll be looking hard to understand in a detailed way what is driving this.  We’re developing some new products and we’ve just been doing interoperation testing with another supplier as part of the support for being completely open and to help customers push the open systems model out.

Breakthrough optical fibers announced at OFC
Submarine Cable NewsFeed - Technology
Wednesday, 06 April 2016 18:55


Sumitomo fiber


It is worth noting that the Optical Fiber Communications (OFC) conference took place last month.  Although covering the entire range of optical fiber communications technologies, the conference is often the venue to announce new products related to submarine fiber optic technologies.  This year was no exception as there were two important announcements of new optical fibers with submarine cable applications. 

In a post-deadline paper, Sumitomo Electric announced that it has developed a coupled multi-core optical fiber suitable for ultra-long-haul transmission.  The fiber has set new records of the low attenuation and the low spatial mode dispersion in the optical fibers for space division multiplexing (see image above). 

In addition, OFS announced a breakthrough in ocean fiber technology with the introduction of TeraWave SCUBA Optical Fiber, offering a combination of the industry’s largest effective area, excellent cabling performance in the C- and L-bands, and low attenuation. These features enable reliable coherent transmission at 100 Gb/s and beyond over trans-oceanic distances at the highest channel counts.

For more information, check out our NewsFeed entries for OFS and Sumitomo (subscription required).

Submarine cable plant video
Submarine Cable NewsFeed - Technology
Monday, 22 February 2016 09:43

Swedish cable manufacturer Hexatronic has released a promotional video that includes some nice footage of its submarine cable-making operation.  The video is on YouTube at  The part showing the submarine cable works is in the last minute-and-a-half of the six-minute video.  It is brief, but for those who are not familiar with the process, it is an interesting introduction.

History of subsea telecom
Submarine Cable NewsFeed - Technology
Thursday, 27 August 2015 16:58

The following is a link to a nice booklet on the history of subsea telecommunications and its relation to Enderby House.  It is written by Stewart Ash and is located on the Atlantic Cable website at  The article was commissioned by the Enderby Group, which was recently been formed to promote Enderby House as a center for telling the story of its history and heritage.  A review of the booklet can be viewed at  


Suppliers extend reach of unrepeatered systems
Submarine Cable NewsFeed - Technology
Sunday, 17 May 2015 15:37

Last week during the recent International Telecoms Week (ITW) conference and gathering place for telecom professionals, Alcatel-Lucent Submarine Networks made an announcement regarding a new record for unrepeatered transmission over a submarine fiber optic cable system. This followed an Xtera announcement a few weeks earlier, also announcing record-breaking unrepeatered transmission distances.

Both records pushed the boundary for unrepeatered transmission past the 600 kilometer mark. As is the case with so many technologies, it was only a few years ago that the existing record was only half as much.

Unrepeatered systems is an often overlooked segment of the submarine fiber optic cable market. Projects that involve a few hundred kilometers of unrepeatered cable tend to be less dramatic than those connecting continents with many thousands of kilometers of repeatered cable. It is a segment, however, that has the potential to grow quickly in the coming years.

Unrepeatered systems are, due to the distance limitations, usually are reserved for domestic projects or point-to-point international links between countries separated by small bodies of water. They are considerably less expensive than repeatered systems, however. Increasing the transmission distance for unrepeatered systems can open up many new potential projects that are currently too costly to connect using repeatered cables.

At the same time, as we have noted many times in our annual Radar Screen Report, there is a growing desire to connect isolated populations – frequently islands – to deliver reliable and affordable broadband access. Not all that long ago, connecting small or underdeveloped populations would not be considered viable in terms of return on investment. Now, with broadband access being considered an economic development necessity and a basic human right, governments and NGOs are providing funding to isolated communities that wouldn’t have dared dream about not so long ago.

As unrepeatered distances increase, more islands are coming within range of the global submarine cable network. This is good news for the populations of those islands as well as for the submarine cable industry. More accessibility to affordable solutions means more projects will get financing.

Xtera to Deliver Tutorial on Raman Optical Amplification at OFC 2015 Conference
Submarine Cable NewsFeed - Technology
Sunday, 15 March 2015 19:00

Xtera Communications, Inc. will deliver the tutorial on Raman amplification technology at Optical Fiber Communication Conference (OFC) to be held in Los Angeles (22-26 March 2015). OFC is the largest global technical conference and exhibit for optical communications and networking professionals.

The tutorial will cover basics of Raman amplification, design rules for Raman amplifiers, control and dynamics, Raman in submarine systems, practical considerations, and examples demonstrating benefits from Raman.

Wise RamanTM is Xtera’s solution for Raman optical amplification that offers optical transmission performance, capacity overhead and operational excellence with a seamless integration of Raman amplification technology into optical networks. Wise RamanTM is a field-proven, future-proof solution to extend optical reach and expand the optical spectrum in long-haul optical transmission infrastructures. The Wise RamanTM solution enables 16QAM modulation format and channel rates exceeding 100G on long distances over existing fiber plants. This is validated by numerous worldwide commercial deployments, as well as by extensive lab and field trials, some of which were on a portion of Verizon’s network in the US (400G channels were transmitted on 1,500 km of aged fiber with high attenuation in summer 2013).

Using Xtera’s commercial Nu-Wave OptimaTM optical networking platform on existing fiber infrastructures, Wise RamanTM makes possible a [Capacity x Reach] metric that exceeds, by a factor of six, what is normally achievable by today’s 100G optical transport systems that use more conventional EDFA amplifiers. Xtera’s Wise RamanTM transmits 24 Tbit/s on more than 4,500 km, while 64 Tbit/s can be transmitted on more than 1,500 km in field conditions.

Wise RamanTM achieves both reach and capacity for today’s and tomorrow’s needs by enabling 100G/200G/400G/1T transmission over long all-optical paths and with long spans between sites in field conditions. Wise RamanTM solution is not only future-proofed for 64 Tbit/s backbone applications in field conditions but also future proofs existing fiber plants for higher capacities.

The tutorial to be delivered by Dr. Wayne Pelouch at the OFC 2015 conference is entitled “Raman Amplification: an Enabling Technology for High-Capacity, Long-Haul Transmission” and will take place at 09:00 on Wednesday 25 March, 2015 in Room 403B (Paper W1C.1). Don’t miss it if you want to gain a better knowledge of the key optical amplification technology enabling efficient 100G/200G/400/1T backbone networks.

Cool Submarine Cable Videos
Submarine Cable NewsFeed - Technology
Friday, 06 March 2015 12:28

Here are a couple of cool videos that you should check out.

Installation firm VBMS put together a five-minute time-lapse video on the landing of an offshore wind farm export cable in the Netherlands.  Click the following link to see the video:

In addition, Huawei Marine has released a video showing the sea trials of it innovative second-generation repeater and branching unit.  To view the video, go to

Xtera repeater video
Submarine Cable NewsFeed - Technology
Tuesday, 17 September 2013 09:48

Excellent video from Xtera highlighting their new repeater.  Beyond there, there is some nice footage of operations on a cable ship.  You can watch the video at

BBC Radio shows how submarine fiber cables carry Internet traffic
Submarine Cable NewsFeed - Technology
Wednesday, 21 August 2013 09:45

The BBC has always done a great job with documentaries on technology (remember James Burke's series "Connections").  Now BBC Radio continues the tradition with a fascinating description of how an email travels across the world.  It does extremely well in describing the role submarine fiber optic cables play in delivering Internet traffic.  Check it out at!.