Because optical fibers are fragile, the optical fibers used in various environments must be processed into optical cables with corresponding mechanical properties to ensure that the optical fibers are not damaged by external forces during the process of laying, installation, use, and maintenance, so as to ensure the smooth flow of the network. . However, the outdoor optical cables and indoor optical cables that are widely used now do not give fundamental guarantees in terms of these performances in complex environments. Based on this, people have developed and designed armored optical cables.
What is armored fiber optic cable?
Armored fiber optic cable, as the name suggests, is a fiber optic cable wrapped with a layer of protective "armor". Its armor is mainly used to protect the fiber optic cable from animal bites, moisture erosion or other damage.
Why use armored fiber optic cable?
In the past, outdoor optical cables were usually laid in solid pipes to prevent the cables from being damaged by external forces. However, this fiber optic cable laying method is very complicated, and it will take a lot of time and labor costs. Therefore, some people design to add a layer of metal armor to protect the core of the optical cable, which is also known as armored optical cable. Armored optical cable has the functions of strong compression and tensile resistance, which can effectively adapt to harsh outdoor environments, and the wiring is much more flexible than pipe wiring. Now, armored optical cables have been widely used in the field of optical communication.
Construction of Armored Optical Cables
1. Outer sheath: In the design of armored optical cable, the outer sleeve can protect the cable from solvent and abrasion damage, usually the outer sleeve is made of plastic, such as polyethylene.
2. Metal armor: between the outer sleeve and the inner sheath is the armor, which is difficult to cut, bite and burn, and can also prevent the cable from stretching during the laying process. As shown in the figure below, the 12-core armored optical cable has 12 optical fibers and two inner and outer sheaths. The metal armor is located between the inner sheath and the outer sheath, and there is a layer of aramid yarn between the outer sheath and the metal armor. :
3. Inner Sheath: It is a protective and flame-retardant material that supports the inner cable harness. In simple terms, in armored fiber optic cables, the buffer conduit is surrounded by a layer of aramid yarn, a polyethylene jacket, and a corrugated steel plate armor.
Armored optical cables can be divided into indoor armored optical cables and outdoor armored optical cables according to the application of optical cables. In addition, armored optical cables can also be divided into interlocking armored optical cables and corrugated armored optical cables according to the type of metal armor.
Indoor armored optical cable: Indoor armored optical cable includes single-layer armored and double-layered armored optical cable. Among them, the double-layer armored cable is used in the shallow sea near the shore, and the single-layer armored cable is used in other occasions outside these extreme conditions.
Outdoor armored cable: Outdoor armored cable can be divided into light armored cable and heavy armored cable. Usually heavy armored cables are used on the bottom of rivers and submarines, so the price of light armored cables is cheaper than that of heavy armored cables.
Interlocking Armored Optical Cable: The interlocking armor is a twisted optical cable with aluminum armor, which is often used in indoor and outdoor general environments, with high durability and high pressure resistance.
Corrugated armored cable: Corrugated armor is formed by wrapping the longitudinal folds of the optical cable with steel tape. It is often used in outdoor environments. It has super mechanical properties and provides protection against rodent bites.
Application of Armored Optical Cable
According to different laying environments, armored optical cables can be divided into tight sheathed armored optical cables and loose sheathed armored optical cables. Loose sheathed armored cables are typically used in outdoor applications; tight sheathed armored cables can be used in indoor applications and indoor/outdoor applications.
The following figure is the structure diagram of indoor armored optical cable. Its metal armor is interlocking armor, and the sheath can be of riser type or low smoke halogen free type:
Indoor/outdoor armored fiber optic cables are widely used in modern telecommunication networks and are the link connecting two or more building networks. The following figure shows the internal structure of a common multi-core indoor/outdoor armored fiber optic cable:
The outdoor armored optical cable adopts corrugated armor, which has high tensile strength, high compression resistance and anti-rat bite. The following figure is the internal structure of the outdoor armored optical cable:
In the field of modern optical fiber communication, any optical fiber failure may cause significant loss of financial and material resources, so protecting the optical fiber is the top priority in the installation process of the optical fiber communication system. The armored optical fiber cable, which is wrapped with a layer of protective "armor" on the outside of the optical fiber, meets the requirements of people's anti-rat bite, anti-moisture, and anti-stretching.