The business of subsea cabling

This Q&A with our Chief Evangelist, Mattias Fridström was originally published by Telecoms.com. 

When you look at the industry, what is your assessment of where we are on sustainability in subsea cabling?

I think, as an industry, we can all honestly say that we are not where we want to be, but progress is being made and there are some great opportunities coming along.  The vessels that are used for laying and repairing cables remain the biggest contributor by far to building a true blue ocean economy, and they need to become much more sustainable.  Ships are improving all the time and we, as an organisation, certainly work hard to make sure we are partnering with groups such as Baltic Offshore, who are making great progress.

But there is much more to it than the vessels.  On land we operate within legal requirements for a biodiversity net gain, and the same needs to happen at sea.  Where we choose to land cables for example and how they are landed is a big part of that given the fragility of all coastlines.  Progress is being made here, with operators thinking more carefully about the landing sites used and landing methods.  Other advances include improvements on the drilling side with the ability to undertake much longer stretches of under seabed drilling, leaving the bed unaffected.

Finally, one of the big challenges with subsea cabling has been power, and in particular how to provide power mid-cable for repeater equipment.  At a conference I recently attended, there was a lot of excitement around using buoys and wave power to provide the energy needed for this equipment in a way that is both environmentally friendly and low maintenance.

SMART Systems seem to be gathering momentum, what is your take on how viable these are?

I think the idea of using subsea technology to support a range of needs outside connectivity is a very exciting one.  The idea we just talked about, of using wave-based power at repeater stations, is a real enabler for this as it means there can be more capacity.  With a sustainable, low-maintenance power source, there is no reason why additional projects cannot be supported – these could range from seismic measurements to testing sea water and emergency early warning systems for events, such as a tsunami.

These systems also create an opportunity to partner with third parties and governments, which can lower the cost of implementing mid-sea repeater stations.  A great example is CAM-2 between Portugal’s mainland, Madeira and the Azores. Almost wholly financed by the Portuguese government, once live it will provide early warnings of 10-30 min for Tsunamis etc.  This may change the game plan completely for new cables and specifically in the Pacific. If governments start investing in cables, then capacity may end up being very cheap.

Are you seeing anything that is exciting you on the cable front?

There are a couple of things we have discussed already in terms of the SMART devices, and the possibility of wave power at repeater stations, but the way cables themselves are developing is going to make a big difference to the economics of subsea.

Density is increasing greatly, thanks to smaller fibres.  Whilst these individual fibres may be less efficient and have lower throughput than their predecessors, the fact that they can be more tightly packed is changing the economics across the supply chain.  A boat can go out and lay far more fibre pairs than it could five years ago – it actually makes more sense to lay as many fibres as possible in a core, and then bring those pairs online as they are needed, or trade them on the open market.

This is being made possible by Spatial Division Multiplexing fibres and repeaters. There is less capacity per fibre pair, but many more fibres in the cable. SDM fibres have a smaller effective area (80-100 µm²) compared to the normal (125-150 µm²), so the repeaters need less power to support more fibres. One laser pump can also be used for many more fibres. Combine this with the ability to supply power mid-sea, as described earlier, and it is a very powerful proposition.  SDM does not currently support the C and L bands, but arguably this is a fair sacrifice for increased fibre density, and it may well change in the future.

SDM could bring down the cost of acquiring fibre pairs by a factor of 10, and is going to make for a very interesting market moving forward, particularly if densities of 64 fibre pairs are being achieved.

Do cable consortiums still have a place in the market?

I think they do, but not in the way they had been working for a long time.  The traditional way of building a cable would involve a consortium of 10-15 members.  For any project, that would be a complicated process of meetings, negotiations, and compromise that can take years to agree, before any soil is broken.

Whilst there are a few companies that could build a subsea cable of their own, few would choose to take on the risks and cost, and it would take a very long time to see a return on the investment.  Today’s consortiums are much smaller than those of old, consisting of three to six partners, who agree how the fibre pairs will be shared out.  The hyperscale companies from across tech and telecoms are coming together to create these cables.  Rather than taking years to get to a contract, these smaller consortiums can reach agreement much more quickly and move (relatively) faster to dry ink on the page and spades in the ground!