Underwater and submarine fiber optic cables are used to transmit voice and data traffic internationally by laying fiber optic cables on the ocean floor, connecting different landing points. There are several types of submarine cables suited to different depths, including single armor, double armor, and lightweight cables. Submarine cables are composed of optical fibers that carry data and conductive materials that power optical amplifiers along the cable. They offer benefits like high reliability, security, capacity and cost-effectiveness over long distances.

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Underwater/Submarine fiber optic cable dominate international voice and data traffic, due largely to the
advantages offered in terms of high reliability, security and capacity, and cost-effectiveness on major
routes. This article will provide some knowledge of underwater/submarine fiber optic cables.
What is Underwater and Submarine Fiber Optic Cable?
Underwater cable is a fiber optic cable laid underwater across rivers, lakes, beaches, and other
places.This cable laying environment condition is much worse than pipeline laying and direct
burial laying.

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A submarine cable (or subsea/undersea fiber optic cable) is a fiber optic cable laid in the ocean,
connecting two or more landing points, which is used for optical signal, network signal
transmission, and connection.
Cable Types
According to the application, submarine fiber optic cables can be divided into submarine single
armor (SA), submarine double armor (DA), submarine light-weight protected (LWP), submarine
light-weight (LW), and submarine light-weight armor (LWA) fiber cable.
 SA cable is suitable for deployment, burial, construction, and recycling in areas with a water

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depth of more than 20 meters and at least 1500 meters deep.
 DA cable is suitable for deployment, burial, construction, and recycling in areas reaching a
depth of 500 meters, provides the protection required within this depth, and should have a
certain weight to prevent tides waves from moving submarine cables.
 LWP cable is suitable for deployment, construction, and recycling in areas with a water depth
of more than 1000 meters and at least 8000 meters deep, but it has certain anti-wear and
anti-fish bite capabilities.
 LW cable is suitable for deployment, construction, and recycling in areas with a water depth of
more than 1000 meters and at least 8000 meters deep.
 LWA cable is suitable for the deployment, burial, construction, and recycling in areas with a
water depth of 20 meters and 1500 meters, and 2000m water depth when not buried.
How Does Underwater/ Submarine Fiber Optic Cable Work?
Underwater fiber optic cable has layers of steel wire or steel tape armored structure. The structure
of the inner sheath and outer sheath are also needed to take into consideration , according to the

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hydro-geological situation of the river. For example, in the stony soil, scouring seasonal riverbed,
fiber optic cable suffers from wear and tear and high tension, not only thick steel wire is needed
for armoring, but even a double layer of armor is required. The method of construction should
also be selected according to the river width, water depth, flow rate, river bed, flow speed, river
bed soil, and so on.
Submarine fiber optic cable is made up of two key components: optical fibers that carry the data
and a conductive material that transmits the current used to feed the optical amplifiers located
along the subsea cable. Additionally, cables are coated with several layers of protective materials
to guard and protect them against water and corrosion.
Benefits
Most fiber optic cables are installed by an aerial, duct, and direct buried. But when it comes to
places with rivers, lakes, and beaches, the traditional fiber cable laying method would require a lot
of fiber optic cables and installation costs. An underwater fiber optic cable perfectly solves this
issue by connecting both ends with underwater laying. It saves lots of fiber cables, and the laying
is also simplified. Other than that, with the fiber optic cable under the rivers and lakes, it won’t
be affected by wind and most animals above ground. In addition, underwater/submarine cables
provide high-transmission capacity, high reliability, high security, long service life, and low
maintenance effort.Submarine cables have excellent crush resistance because of the heavy
armoring, and provide better tensile strength, strong anti-interference ability, and good
confidentiality performance for the cable.
Applications
Underwater/submarine fiber optic cables are used in the telecommunications industry, offshore

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oil and gas industry, ocean observation network, local area networks(LAN),video, data, CATV, and
inter-office communication applications.
Conclusion
Underwater/submarine fiber optic cables provide good transmission quality, high reliability, long
service life, low maintenance effort, and high maintenance capacity communication. Sun
Telecom provides a wide range of options for high-quality underwater/submarine cable products
to the global market.