What is Fiber Optic Cable? Types of Fiber Optic Cables
What is Fiber Optic Cable? Types of Fiber Optic Cables
Blog Article
What is fiber optic cable? Optical fiber cable mainly composed of optical fiber (optical fiber) and plastic protective sleeve and plastic outer skin. It is a communication line in which a certain number of optical fibers are formed into a cable core in a certain way and covered with a sheath. Some also covered with an outer sheath to achieve optical signal transmission.
Types of Optical Cables
There are many types of optical cables, and there are even more ways to classify them. There are different classifications according to different standards:
1.According to transmission performance, distance and purpose
It divided into urban optical cable, long-distance optical cable, submarine optical cable and user optical cable.
2.According to the type of optical fiber
It divided into single-mode optical cable and multi-mode optical cable.
3.According to the method of plastic sheathing of optical fiber
It divided into tight-tube optical cable, loose-tube optical cable, bundled tube optical cable and ribbon optical cable.
4.According to the number of optical fiber cores
It divided into single-core, double-core, four-core and six-core.
5.According to the configuration method of reinforcement components
It divided into central reinforcement component cable. Such as layer-stranded optical cable, skeleton optical cable, dispersed reinforcement component cable. And such as bundle tube both sides reinforcement optical cable and flat optical cable, sheath reinforcement component cable. Such as bundle tube steel wire armored optical cable, and PE outer sheath plus a certain number of fine steel wires PE fine steel wire comprehensive outer sheath optical cable.
6. According to the laying method
It divided into pipeline optical cable, direct buried optical cable, aerial optical cable and underwater optical cable.
7. According to the properties of the sheath material
It divided into polyethylene sheath ordinary optical cable, polyvinyl chloride sheath flame-retardant optical cable and nylon anti-ant and anti-rat optical cable.
8. According to the transmission conductor and medium conditions
It divided into metal-free optical cable, ordinary optical cable, and optoelectronic composite cable.
9.Classification by structure
It divided into flat structure optical cable, layer-twisted structure optical cable, skeleton structure optical cable, armored structure optical cable (including single-layer and double-layer armor), etc.
10.At present, optical cables for communication can divided into
(1) Indoor (field) optical cables, which used for outdoor direct burial, pipelines, troughs, tunnels, overhead and underwater laying.
(2) Soft optical cables, which are movable optical cables with excellent bending performance.
(3) Indoor (office) optical cables, which are suitable for indoor laying.
(5) Submarine optical cables, which used for laying across the ocean.
(6) Special optical cables, which are optical cables for special purposes in addition to the above categories.
Other Properties of Fiber Optic Cables
The requirements for the performance of optical cables are based on the transmission performance, environmental conditions and laying methods of their use.
(1) The transmission performance of optical cables mainly depends on the characteristics of the optical fiber selected for the optical cable.
(2) The mechanical properties of optical cables include stretching, flattening, impact, repeated bending, torsion, and gunshot.
(3) The environmental performance of optical cables includes attenuation temperature characteristics, drip performance, sheath integrity, water permeability and flame retardancy.
The life of optical fiber depends on the stress on the optical fiber and the humidity in the environment. Generally speaking, optical fiber is afraid of moisture and force. In addition, the attenuation of quartz optical fiber will increase under a certain hydrogen pressure. Therefore, optical fiber is also afraid of hydrogen.
Two Common Optical fiber Cables
The commonly used optical cables produced by various manufacturers divided into two types: loose tube layer twisted type and central bundle tube type.
Water Blocking Problem of Fiber Optic Cable
Because the optical fiber is afraid of moisture and water, the optical cable must have good waterproof performance. Waterproofing divided into transverse and longitudinal water blocking.
(1) Transverse water blocking
Due to the vapor pressure gradient inside and outside the optical cable. In a humid environment, moisture or water outside the optical cable will penetrate and migrate into the optical cable. Strictly speaking, the plastic sheath of the optical cable cannot prevent the intrusion of tides for a long time. Once moisture invades the optical fiber, it will cause rust on the metal accessories. Then electrochemical hydrogen evolution. Not only will it corrode the metal parts, it will also cause an increase in optical fiber loss. Affect the stability of the long-term transmission performance of the optical fiber. In order to prevent the transverse water seepage of the optical fiber, longitudinal aluminum strips (steel strips) usually used to complete it.
(2) Longitudinal water blocking
During the laying process of optical cables, due to local damage to the protective layer of the optical cable or accidental water seepage at the connection of the optical cable, moisture will penetrate into the optical cable and penetrate along the longitudinal direction. This will not only affect the performance of the optical cable. The accumulated water will also enter the junction box and terminal equipment, destroying the operation of the entire communication line.
The traditional method of longitudinal water blocking of optical cables is to use optical cable grease to block the gaps in the optical cable structure to prevent water from flowing in the optical cable. In addition, filling fiber grease, wrapping water blocking tape or winding water blocking yarn, and applying hot melt adhesive at the overlap of steel belts can also play a certain longitudinal water blocking role.
Differences and Standards of A (S) Sheaths of Optical Cables
(1) A (S) sheath standards
A (S) sheathed optical cables should apply a longitudinally overlapped aluminum (steel) plastic composite tape moisture barrier layer outside the cable core, and at the same time extrude a layer of black polyethylene sheath to make the polyethylene sheath and the composite tape and the tapes at the overlap of the two edges of the composite tape bonded to each other.
If necessary, adhesive can applied at the overlap to improve the bonding strength. The overlap width of the composite tape shall not be less than 6 mm or not less than 20% of the circumference of the cable core when the cable core diameter is less than 9.5 mm. The nominal value of the polyethylene sheath thickness is 1.8 mm, the minimum value shall not be less than 1.5 mm, and the average value on any cross section shall not be less than 1.6 mm.
The nominal thickness of the aluminum (steel) tape is 0.15 mm, and the nominal thickness of the composite film is 0.05 mm. A small number of composite tape joints allowed in the manufacturing length of the optical cable, and the distance between the joints shall not less than 350m. The joints shall be electrically conductive and the plastic composite layer shall be restored. The strength of the composite tape with joints shall not be less than 80% of the strength of the adjacent section without joints.
(2) A (S) sheath difference
The sheath of the optical cable provides further protection for the optical cable. It enables the optical cable to have better mechanical properties such as resistance to lateral pressure, impact resistance, and bending resistance. The sheath varies according to the purpose of the optical cable. (A) Aluminum tape longitudinal sheath mainly used for moisture and water resistance, (S) corrugated steel tape mainly used to improve lateral pressure and impact resistance. 5.1.2 Water blocking of optical cable Since optical fiber is afraid of moisture and water, optical cable must have good waterproof performance. Waterproof divided into horizontal and vertical water blocking. Report this page