Jack knowledge about cable:knowledge of fiber optic cable

Front to introduce the the basics knowledge of the cable and power cable ! I think we all feel that the cable is made of metal as a conductor , in fact, with the development of technology, with its somewhat concentric cable has been widely used. Today ‘ll tell you about the history of fiber optic cables , structure, classification and install applications , and more!
An optical fiber cable is a cable containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed. Different types of cable are used for different applications, for example long distance telecommunication, or providing a high-speed data connection between different parts of a building.

Fiber Optic Cable History

In 1976, the American Institute in Atlanta Bell built the first experimental optical fiber communication system that uses a cable containing 144 fibers manufactured by Western Electric Company .
In 1980 , commercial multi-mode fiber optic cable is made from the beginning of the use of the trunk line between the city and a few long-distance Bureau .
Commercial single-mode fiber optic cable made ​​in the long line began to use in 1983 .
In 1988, the connection between the United States and Britain and France ‘s first successful transatlantic submarine cable laying , and soon built the first submarine cable across the Pacific .
China in 1978, developed a communications cable , using a multimode optical fiber, cable core structure for the layer stranded . Has worked in Shanghai , Beijing , Wuhan and other places to carry out field trials.
Soon after in the local telephone network as interoffice trunks trial , after 1984 , gradually for long-distance lines , and began using single-mode fiber .
Communications cable than copper cables with greater transmission capacity , long- distance relay , small size, light weight, no electromagnetic interference, has developed into a long haul since 1976 after the city’s relay , coastal and transoceanic submarine communications , as well as local area network, a private network , such as a wired backbone transmission lines and areas of the city began to subscriber loop wiring network development, FTTH , broadband integrated services digital network to provide transmission lines.

Fiber optic cable construction

The basic structure of the cable is normally provided by the cable core , strengthen steel , and sheathing filler composed of several parts , as well as needed in addition waterproof layer, a buffer layer , insulated wires and other metal components . Specifically refer to the following figure :

Fiber optic cable construction

Classification of fiber-optic cable

Fiber optic cables can also be in different ways performance , materials, structures, etc. There are many categories :
1 according to the different transmission performance , distance, and use , the cable can be divided into user- optic cable , telephone cable, fiber optic cable and long-distance submarine cable .
2 used according to the type of fiber optic cable within different cable can be divided into single-mode fiber and multimode fiber optic cable.
3 according to the number of core fiber optic cable , fiber optic cable can be divided into single , dual fiber optic cable .
4 reinforcement configuration according to different methods, the cable can be divided into central strength member fiber optic cable, fiber optic cable dispersed reinforcement member , the reinforcing member cable sheath and integrated cable outer sheath .
5 The transmission conductor , media situation is different, can be divided into non- metallic fiber optic cable , general cable, integrated cable ( mainly for railway network communication lines ) .
6 ways according to different laying , fiber optic cable can be divided into the pipe , buried cable, aerial and underwater fiber optic cable .
7 ways according to different structures , fiber optic cable can be divided into flat structure , Stranded cable , skeleton -type cable, armored fiber optic cable and high-density user .

Application of fiber optic cable installation

Long distance cable laying is most important to select a suitable path. Here is the shortest route is not necessarily the best , but also pay attention to the land use rights , the possibility of erecting or buried so on.
When the cable turn, its turning radius is 20 times greater than the diameter of the cable itself .

Buried cable depth standard
Laying lots and soil	Depth (m)
Ordinary clay, hard clay	≥1.2
Gravel, half stone soil, weathered stone	≥1.0
The stone, sand flow	≥0.8
The suburbs, towns and villages	≥1.2
The urban sidewalks	≥1.0
The road side ditch: Stone (stone, soft stone)	Side ditch design depth below 0.4
Other soil	Side ditch design depth below 0.8
Highway shoulder	≥0.8
Crossing the railway (from the road surface), highway (from the pavement basement)	≥1.2
The ditch, pond	≥1.2
Rivers	According to the requirements of submarine cable

Optical fibers are inherently very strong, but the strength is drastically reduced by unavoidable microscopic surface flaws inherent in the manufacturing process. The initial fiber strength, as well as its change with time, must be considered relative to the stress imposed on the fiber during handling ., cabling, and installation for a given set of environmental conditions There are three basic scenarios that can lead to strength degradation and failure by inducing flaw growth: dynamic fatigue, static fatigues, and zero-stress aging.
Telcordia GR-20, Generic Requirements for Optical Fiber and Optical Fiber Cable, contains reliability and quality criteria to protect optical fiber in all operating conditions.The criteria concentrate on conditions in an outside plant (OSP) environment. For the indoor plant, similar criteria are in Telcordia GR-409, Generic Requirements for Indoor Fiber Optic Cable.