An interview with Brian Lavallée, Ciena Senior Director of Portfolio Marketing

Editor’s Note: The use of submarine fiber optic cables for scientific research is often overlooked.  Submarine cables are very expensive to build and install, so the number of dedicated submarine cable based scientific systems is small compared with their use in the global telecom network.  But what if you could use transoceanic cables to collect data from the ocean floor with disrupting their commercial use?  That’s the concept of SMART cables. 

SubCableWorld recently spoke with Brian Lavallée, Ciena Senior Director of Portfolio Marketing, to get his view of SMART cables.  The following are his comments. 

Mr. Lavallée: The concept of Scientific Monitoring and Reliable Telecommunications (SMART) cables, or Green Cables as they are sometimes called, has been around for many years.  The basic concept is to use dedicated or commercial submarine fiber optic cables to collect ocean data continuously and have that data transmitted to shore quickly and inexpensively where it can be used for subsea earthquake monitoring for tsunami early warning purposes, as one example.  It would involve placing sensors in the repeaters of submarine cables and using the built-in transmission capacity of the cable itself, say a fiber pair or a wavelength, to deliver that data to those who need it. 

I think on a personal level that SMART cables are a great idea.  Most of the data we use for environmental and climate science is done either by floating buoys or land-based coastal stations.  The deep-ocean parts of our planet are essentially not being monitored.  We all know that the ocean has a huge impact -- the tides, the currents, temperature – on the global climate.  So being able to collect potentially vast amounts of real-time data from the ocean floor would help to improve our ongoing understanding of oceans, which cover over two thirds of our planet. 

The technology itself is not too complex.  Whether you’re measuring pressure, temperature, seismic movements, etc., we’re basically talking about similar sensors that today are floating in buoys and communicating with satellites, and putting them on the submarine cables themselves.  Then we can use the transport medium of the cables to relay that information to the coast, in one way or another.  One of the big advantages of the submarine cables, compared to the existing ocean data collection methods, is that you’re measuring environmental metrics at the bottom of the ocean.  We would be able to measure a lot more of the ocean that we really can’t measure today.

The best place to put the sensors is in the repeaters.  There you would have the power feeds come into the repeaters and while you’re powering the optical amplifiers you can siphon off some of the electrical power for the sensors. Then you could run that data from one end of the submarine cable to the other.  You could put the sensors in between the repeaters but that would be likely be more complex.  I think its more logical to host them in the repeaters themselves.

There are onging discussions regarding retrofitting existing cables to become SMART cables.  You could do it, but there are major issues.  You would have to lift the cable off the ocean floor and anytime you do that you risk damaging it.  Obviously, you have to do that if the cable suffered an outage, but you try to avoid it.  Then there’s the fact that the cable, which is probably carrying many Terabits of commercial Internet traffic, would have to be taken out of service while the retrofitting is taking place.  Clearly that’s not desirable or feasible.  The applicability for SMART cables is thus primarily for new builds. 

One of the concerns with this concept is how do you relay the information to from all these sensors in the cable to the endpoints.  At the extreme, you could consume an entire fiber pair, which translates to a loss of revenue for the cable operator, unless the company or academic institution is paying the service provider for that pair’s use.  You could use a dedicated wavelength, instead, but would have to find a way to incorporate it along with the rest of the commercial traffic-carrying wavelengths.  You wouldn’t necessarily need the entire fiber pair, but you would need to have the access to it. 

The development of Spatial Division Multiplexing (SDM) could provide new opportunities.  When we talk about ocean sensors, we’re not talking about a lot of data by the standards of Internet traffic that we are used to in the submarine cable industry.  The amount of scientific data that you’re transmitting back to the cable station is relatively small.  With SDM cables, you’ll have a lot more fiber pairs and more cables, which means more opportunities.  But as we all know, there’s roughly 40% bandwidth growth compounded each year in all regions of the world.  The spare capacity for carrying scientific data may be available today, but in a few years you’ll probably need that space to turn up business services, so some kind of commercial agreement h the organization that is actually asking for the capabilities to be put onto that cable. Unless there is somebody with a whole lot of money who cares about the environment and builds a cable and is willing to give up a wavelength, as one way of carryng the sensor data, for free.  That’s always a possibility.  Probably not a big one.

The other thing about SDM is that the technology will require the industry to look at the traditional or classic repeater designs that we’ve been using for well over 10 years.  If they’re looking at redesigning the repeaters for SDM -- mechanically, optically, electrically -- then now is the time to at least take SMART cables and sensor hosting into consideration. 

Then the question is, “Who pays for that R&D?”  And it’s not just the R&D per se, but also who is liable if something goes wrong.  One of the reason the wet plants are so reliable for 25 years is that they pick and choose very pristine parts, the designs are excellent, and there is redundancy built into them.  They are also relatively simple meaning fewer things to go wrong.  When you start adding stuff to it, the risk that something could go wrong is an increased probability.  What that probability is, who knows, because nobody has built them yet.  If they will be looking at updating the repeater designs for SDM cables, then now is the time to at least look at SMART cable technology.  I don’t think they would look at redesigning the repeaters just for sensor support, simply due to the economics involved.

Submarine cables that are put on the bottom of the ocean typically have a lifespan of 25 years.  Every time people want to mess around with the technology, there’s always a bit of hesitance and rightfully so.  You don’t want to put a whole bunch of new technology on the bottom of the ocean that may not be generating a lot of revenue but you’re risking the lifespan of that cable or at least the meantime between failures. 

Then you run into all of the geopolitical issues if you have sensors on a cable near somebody’s shoreline and you’re measuring movements and vibrations.  Is that vibration a ship?  A warship?  A submarine? A commercial ship?  I’ve heard those discussions in a variety of groups.  That’s another thing that would have to be taken into account for sure. 

When it comes to SMART cables, the same discussions always come up.  “Who’s paying for it,” Who will design it into the cable?” “What are we going to do with this data?”  All these type of questions and the whole geopolitical scene is often hotly debated.  I think what’s happening now is that more and more emphasis is being placed on climate change in general, and that’s a good thing.  The average citizen of Earth is more focused on the environment and the oceans have a huge say in what kind of short-term weather and long-term climate we have.  This is just the time to start talking about SMART cables.  And when you look at how many new cables will be going into the water, people are starting to ask the questions, “Well, if we’re going to be putting in 10-15 transoceanic cables in the next 10 years, why aren’t we considering this?”  Because don’t forget when we went from 10 Gbps per channel to 40 Gbps to 100 Gbps, there were already existing submarine cables.  With these cables, before the content providers came on board, we were upgrading the capacity to the point where new cables were not required.  So the discussion was rather moot.

Now that we’re starting to max several legacy cables as we’re getting very close to Shannon’s Limit, we have a whole slew of new cables coming in, meaning it’s a good time to talk about actually building in SMART cable technology on these cables and not just in such respected organizations as the International Telecommunication Union, Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization (UNESCO/IOC), and World Meteorological Organization (WMO), but moreso in commercial circles as well.