How Google, Facebook put thousands of miles of fiber optic cable under the sea floor?

The process of completing an undersea cable route can take up to several years, using a dedicated cable laying vessel with a pre-explored route.

Google and Facebook have laid thousands of miles of fiber optic cables to the bottom of the sea, spreading across continents to bring the Internet to the whole world.

Normally, Google and Facebook will jointly invest with some other companies for undersea fiber optic cable projects although they also have their own projects. In total, Google invests in 19 projects, and owns 5 of its own.

Meanwhile, Facebook has invested in two active undersea fiber optic cable projects, and it has also invested in five other projects under construction, according to a company representative.

To install the fiber optic cable to the seabed, they first need to plan the route the fiber optic cable will take. This could take years, according to Jayne Stonel, Google's global infrastructure strategy negotiator.

Facebook told Insider that it will perform geophysical and depth surveys along the planned route of the cable, allowing for meter-accurate planning. To do this, the airline has to send in state-of-the-art vessels to probe the seabed, looking for risks such as high currents, underwater landslides, and unexploded bombs or mines.

The cable itself is about the thickness of a garden hose.

They are encased in a copper shell to conduct electricity. 'A plastic and steel shell is then added to make it waterproof, making it resistant to potentially adverse ocean conditions such as high currents, earthquakes or interference from fishing boats. ,' Stowell said.

As for Facebook's 2Africa cable, it uses aluminum instead of copper to reduce production costs. The 2Africa project is under construction, which is 37,000km long - just slightly shorter than the circumference of the Earth.

After fabricating the cable and marking the route, the cable is placed on a dedicated laying vessel. Google's Stowell says the company uses a fleet of 50 to 55 dedicated vessels, with capacity for up to 100 crew members. Just loading the cables on board can take four weeks.

Meanwhile, the crew on Facebook's cable-laying ship has about 30-50 people.

The ship left the port, laying the cable reel behind. When it gets into deep water, it uses an underwater plow to dig a trench along the seabed on which it lays cables. Ocean waves will quickly fill the trench once the cable is placed on the seabed.

'A plow at sea doesn't look too different from a plow a farmer might use in the field, except it's much larger - about the height of a two-story building,' says Stowell. This plow can only be used at a depth of 1,500 - 2,000m.

This is the safest depth for marine fiber optic cables, avoiding potential damage that can be caused by fishing boats or ships anchored to avoid storms. Basically, the undersea fiber optic cable will be laid naturally, with no additional protection measures.

With long cables, the manufacturer will add a component called an amplifier every 100 meters to keep the signal stable.

Although fiber optic cables are made of the purest glass, over long distances the intensity of the light beam begins to wane. The amplifier enhances the light intensity of the beam.

Upon reaching its destination, the cable-laying vessel could not reach the shore.

The buoy will be used to guide the fiber optic cable to the shore, floating on the sea surface. Divers, smaller boats will be mobilized to carry out this work.

Finally, the cable is pulled up the beach to a ready-made trench, where it is connected to a manhole on the beach, a container buried where the undersea cable is joined to the terrestrial cable - which in turn connects to cable station.