FEATURE: SUBMARINE NETWORKS
THERE’S A HUGE AMOUNT OF INDUSTRY CHAT ABOUT “HOW DO WE CONNECT TO AFRICA?”
so we’re deploying fully a reconfigurable optical add-drop multiplexer (ROADM). It’s a known technology in terrestrial systems, but just making its way into under-sea systems now, and providing more flexibility in terms of traffic routing over the life of the system. We’re also starting to implement optical switches in undersea systems where you can now get more complex switch matrices. Tere’s no longer just a bypass switch, you can decide which fibre pair to drop onto a branch, to a switch matrix in branching nodes. Tere are a lot of technology advances happening to support these higher fibre-count systems, where we’re basically making cables with a count up to 24 or even 32-fibre.’
changing with the drive for higher capacity. ‘We see a sustained and continued drive for more capacity in undersea systems,’ he said. ‘Tere are a number of advances that we’re taking advantage of, in order to drive this higher capacity on the cables, like SDM. What we see is a drive to increase capacity on the cable and we’re moving away from maximising the capacity per fibre pair, rather maximising the capacity for fibre on the cable. ‘One of the enablers for that is by making
smarter use of the pump power that’s available. Te pump power is what feasibly drives the amplifiers, the repeaters in the system. So, we’re making use of this more efficiently by spliting it onto multiple fibre pairs. Terefore, we get a litle bit less capacity per fibre pair, but now we have more fibre pairs and therefore also the capacity on the cable increases and improves.’ Tis shiſt in technology, believes Mohs, is
changing the way cables are built. ‘It’s driving more fibre pairs from the cable and more amplifiers in the repeaters,’ he said, ‘so there’s a drive towards almost an explosion, in terms of the number of fibre pairs. ‘Te systems in the past have been around
six, maybe eight sets of fibre pairs and now we’re seeing demand for systems that are 12 fibre pairs, with the expectation to go even higher. ‘Tese other technologies we’re using are optical add-drop multiplexing (OADM) based,
www.fibre-systems.com @fibresystemsmag
Supply and demand Te company has further optimised its production processes to enable these higher fibre-counts and for its repeaters to increase the density of amplifiers. ‘Tere’s a challenge associated with that,’ Mohs said, ‘to fit more components and treat the higher density and the repeaters. It’s an evolution of the product line. It’s not really radically different, but we’re evolving the product to accommodate these higher fibre counts. We’re the supplier, so we’re meeting the demand.’ Clarke concurs on the technological evolution. ‘In terrestrial land, we’ve had
ROADMs for 20 years,’ he said. ‘But only just now we’re starting to put ROADMs on the sea bed.’ Tis, he said, is because of the concern of what might happen if it goes wrong, but also because it takes longer to qualify the components for an extra period of time. ‘While there is a reactive environment on the terrestrial land, it’s very much slower and more methodical in subsea,’ he said. ‘So, we’re reluctant to change. But the change in our eco-system, the ideas of the tier one carriers of this world being superseded by the content providers who, if you look at the tele-geographies, certainly show that most of the traffic is content driven. Ten, just our consumer experience, moving from voice to VoIP in terms of WhatsApp and Facetime and Facebook live, every possible thing is driven to require a completely different network.’
Centre stage Te other big change affecting submarine networks, highlights Clarke, is building into data centres, rather than cities. ‘[Instead] of going New York to London, which all of the North Atlantic cables used to go to because they were the VoIP centres. Now we’re going to data centres like Virginia Beach, or to Dublin, because that’s where they’re building data centres. Once the data centre location has been picked, people try to work out how to get a cable there because it has to be connected. We’ve been driven to change because of our eco system around us. Wherever you look, there’s a data centre being built. You can track where they are and as they get announced, they will clearly have to be connected. Tat’s a key indicator. Look at the data centres and then know that in some way, shape or form, there’s a cable to be announced.’ For Mohs, another trend worth mentioning
is coherent transmission. ‘We have extended the reach of trans-oceanic systems, now we are really creating systems and connecting Hong Kong to the west coast of the US directly. Tese
The Equiano cable will start in western Europe and run along the west coast of Africa, between Portugal and South Africa
Issue 25 n Autumn 2019 n FiBRE SYSTEMS 19
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