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(TECHNICAL ARTICLE) The technological challenges behind submarine optical networks

Manuel Andrade*

Cloud aplications, videos transmission in very high definition (4K and 8K), increased reality, 5G. All this points to the prospect of increasing traffic – and demand for bandwidth – increasing not only in terrestrial communications networks but also in submarine networks, responsible for ultra-long distance transmissions between continents and large urban centers separated by the oceans.

To meet the rapidly growing demand, at least nine new generation submarine cables have recently been built or are under construction to connect Brazil to other countries in the world. In addition to expanding the data transmission capabilities generated by the new IP and video applications, the goal is also to diversify the existing communication routes. The submarine cable being built by Angola Cables, linking Fortaleza to Luanda, for example, will be the first route connecting Latin America to Africa trough the South Atlantic.

However, despite the demand that has motivated several operators and over-the-top service providers (OTTs) to invest in the construction of new submarine networks, there are only six companies in the world (Padtec is one) capable of providing Solution in this area. After all, this is a great challenge, since the solution must offer high transmission capacity and, at the same time, meet the very high reliability, performance and robustness requirements to meet this market.

One of the most important – and critical – elements of the submarine long-distance network is the optical amplifier, the equipment responsible for the intermediate amplification of the signal along the submarine cable. In addition to using advanced optical components capable of ensuring high performance and high quality transmissions, this equipment must have complex mechanical protection to withstand corrosion and high seabed pressures – at depths of up to 8,000 meters – providing a longer service life (over 25 years). Robust electronics and optics with redundancy in the main components are essential features of the submarine optical repeater as well as optimized power consumption and heat dissipation. To overcome all the challenges that a transoceanic network presents, the equipment must undergo a complete set of tests in specialized laboratories – such as pressure and traction, simulating real conditions of the seabed.

A submarine optical network turnkey solution – both for regional applications and ultra- long distance systems – must also include passive and active Branching Units (BUs), which allow high flexibility and cost reduction in the deployment of new cables; External power supply equipment for optical amplifiers; Monitoring system, responsible for continuous monitoring of cable status and optical repeaters. In addition, part of the solution is the connection to the ground plant, the management of the implementation work and the maintenance services of the submarine plant, which requires highly specialized teams capable of acting quickly and accurately.

For existing submarine systems that do not yet fully exploit their capacity, the alien wavelength concept offers a flexible and non-disruptive expansion alternative. It is a solution that takes advantage of the entire structure of the existing submarine plant, protecting the investments already made, in the network capacity’s expansion.

All of these equipment and services that constitute a state-of-the-art submarine optical transmission platform are the result of a great research and development effort in technology – and also of some partnerships – that only a select group of companies in the world dared to do.

Manuel Andrade is Padtec’s CEO, a company that provides turnkey solutions for submarine optical networks.