CALAIS — The Ile de Sein ship leaves the port of Calais this December day with precious cargo. No special escort accompanies the ship as it sets out into the channel. The boats traveling this route have an important mission: to foster communication by connecting people to the Internet. They travel the world to link continents via thousands of kilometers of telecommunications cables installed on the ocean floor.

Most people are unaware of how dependent our information society is on this subsea infrastructure. Nearly 99% of intercontinental traffic, such as Internet and telephone, passes through these cables.

If the boom of smartphones and mobile Internet has created the illusion of a wireless world, where everything is magically accessible, the reality is quite different. It is still by cables that the vast majority of telecommunication data is exchanged, and when it comes to connecting one continent with another, it happens at the bottom of the sea. As revealed by Edward Snowden in 2013, intelligence agencies also pay particular attention to the underwater network.

The Ile de Sein is part of the Alcatel-Lucent fleet and its specialized subsidiary ASN (Alcatel-Lucent Submarine Networks). The Franco-American group, which is about to be purchased by Nokia, is the world leader in underwater telecommunication cables — representing 40% of the market share. With a length of 140 meters, and a width of 23 meters, the ship is distinguished by the steel monster installed at the back: a huge industrial plow for digging trenches in the ocean floor. Inside, the tanks are specially designed to store up to 10,000 kilometers of telecommunications cables.

Weeks-long missions

The ship is on a mission for several weeks to install a part of the cable that will link France to Singapore. The system, called "Sea-Me-We 5" and controlled by a consortium of 15 telecom operators, spans 20,000 kilometers through the Mediterranean, the Red Sea and the Indian Ocean, with branches to Italy, Turkey, the UAE and India. ASN is responsible for the installations between France and Sri Lanka. This is where the Ile de Sein begins its mission. Destination: Djibouti. In between, there are 5,300 kilometers of cable to install.

The work is painstaking. Installing a fiber optic cable is not like throwing an anchor. The topography of the sea bed has been studied very closely to insure installations are optimal, and the data have been sent to the cable manufacturer who will custom design the cable. If the underwater terrain is rugged, the cable needs to be thicker to avoid risk of damage. The installation becomes more problematic closer to the coast, where the sea bed is more irregular and more exposed to external attacks such as fish bites, fishing and anchors.

Depth also affects the installation speed. "In the deep, we can install up to 200 kilometers a day, while in shallower waters, it's more like 20 kilometers a day," says Philippe Kervella, the young Ile de Sein captain. At just 34, Kervella has worked on cable ships for more than 10 years.

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The Ile de Sein ship in the port of Calais — Photo: Sergio77/GFDL

Before setting off for Sri Lanka, the Ile de Sein remained at Calais port for several days to load its precious cargo. The process takes a long time, as it is still done by hand. The cables are loaded in two huge tanks that are 7 meters high and 19 meters in diameter. Waiting for another load of cables to arrive, the workers have time to play a game of ping-pong or foosball. While the loading is done manually, the cables are shipped automatically through a 600-meter-long tunnel that connects the platform and the production site.

The majority of the world's communication cables are produced in Calais. The production site is the pride of the city, which these days is better known for the influx of migrants seeking to cross the channel into the UK. The "Jungle," a refugee camp that houses thousands of people, is located a few hundred meters away, and the surrounding roads are filled with patrol cars.

"Politicians visiting the area often make a detour to the cable factory," says Patricia Boulanger, ASN factory director. "It's a fine example of the industrial success for the region, where the economic situation remains complicated." With about 400 employees, the factory is one of the largest private employers in Calais, sustaining an entire ecosystem of subcontractors and suppliers.

Everything is recycled

The production site, situated at the edge of the city, was created in 1891 and has played an important part in the development of the industry over the decades. The first telegraph cables appeared in the 1850s between France and Britain, while the first underwater transatlantic telephone link wasn't installed until 1956. The first fiber optic cables were introduced in the mid-1980s.

Nexans is another telecommunication company with historical ties to ASN. The two companies used to be one — then owned by Cables de Lyon, CGE and finally Alcatel — but they separated in 2001.

Today, the ASN production site covers 16 hectares. The manufacturing process is divided into several steps. The first is the choice of the optical fiber that constitutes the raw material of the cable. "No fiber is identical. We test the optical performance of each one in order to meet customer needs," Boulanger says.

The coloring follows. One cable can contain a maximum 96 fibers, and to easier recognize the density, the cables are marked with color schemes. The next step is armoring the cable with a stainless steel tube to make it resistant to water pressure, and adding another copper layer to counter strong currents. The cables are divided into segments of 70 kilometers. In between the segments, electrical repeaters are installed to maintain the signal's intensity during its long journey. Finally, a last insulating layer is applied.

Before boarding, the material is tested and stored in huge tanks. Logistics are strategic: The cables should be stored in the order in which they will be deposited on the ocean floor. Part of the factory is dedicated to recycling old underwater cables. ASN has specialized in recycling for three years, and some older cables — as many as 40 years old — have been recovered and recycled. "Everything is recycled: plastic, steel, copper," Boulanger says. "The materials still work, the quality hasn't changed."

Submarine cables remain a niche market with three companies sharing the cake: ASN, TE SubCom (Tyco Electronics) and NEC. Orange is also present through its subsidiary Orange Marine, but only in installation and maintenance. The market activity remains limited, with a value estimated between 2 and 3 billion euros, marked by longer or shorter investment cycles.

"The current cycle is on the rise, as demand is fueled by the growth of mobile Internet, the use of video, the emergence of the Internet of Things, etc.," explains Leigh Frame, ASN's operations director. "We are witnessing an explosion of traffic, and this requires pipes to transport all the data."