Much attention has been directed recently towards the need of national network operators to enhance the capacity of their long-haul networks in order to deliver data-heavy services, such as streaming high-definition video services to a large broadband subscriber base. A significant part of overcoming bottlenecks is the deployment of 100 Gb/s, and increasingly 200 Gb/s, transceivers employing coherent detection technology. However, it must not be overlooked that not every network operator is in exactly the same business.

Global IP traffic has increased fivefold since 2010 and there is no reason to think that this growth will stop anytime soon. Attempts to keep pace with such capacity demands have seen a dramatic increase in optical cable installations and installed optical fibre counts, causing unprecedented levels of congestion in carrier duct infrastructure. Soon, the large traditional cables installed in these ducts will reach capacity exhaust but, due to the high cost of civil works, many operators will be reluctant to invest in new duct and cable infrastructure.