The Selection Of Fiber Cable

The selection of fiber optic cable is a difficult task due to various which are to be finalized. These are:

1. Use of fiber cable indoor/outdoor or offshore/inshore
2. Operating temperature and other atmospheric conditions
3. Selection of loose buffer or tight buffer cable
4. Safety from rodents/bird attack
5. Mechanical strength of cable
6. Transmission characteristics wavelength, attenuation, single mode or multimode, bandwidth, etc.
7. Selection of bend radius of fiber cable during installation.

The survey of land or sea is required before optical fiber communication is planned and fiber cable is procured. The above selection parameters are important to decide choice of a fiber cable for a particular application. Indoor cable requires less temperature and mechanical strength as compared to outdoor cable but the indoor fiber cable should be fire retardant and emits a very low level of smoke if there is any firing. The cable allows smaller bend radius for installation purpose. The cable is based on tight buffer design so that it can be mounted both horizontally and vertically. The handling of fiber cable is easy and the fibers in the cables should be in multiples of 4, 6, 8, 12, 16, 32 numbers for various types of buildings or offices.

Outdoor cable covers a large number of applications starting from laying of fiber cables on ocean beds to connecting various cities in (WAN application) or any two buildings (LAN application). This type of cable has high temperature characteristics as well as high mechanical strength. Th will be loose buffer type so that drawing inside the ducts, trench, pipes under each surface is easy. It allows slightly more bend radius as compared to indoor cable and is generally mounted in horizontal position. These cables contain steel rod of diameter 2-2.5 mm as strength member and weight is approximately 20-25 kg/km. Other strength members are high strength kevlar materials and copper wires.

Indoor/outdoor fiber cable is usually used in LAN application so that the same cable can be used for transmission link between the buildings and inside the premises. However, offshore cables are of different types and are described separately. The offshore cables may be single or double armoured depending on whether the buried area is shallow or normal.

Some standards have been developed for indoor or outdoor cables so that necessary quality and safety is maintained in the fiber cable. For example, in case of indoor cable installation, the cable must adhere to National Electric Code (NEC) of USA, Similarly, for outdoor applications of fiber cable, Telecom industry Association of USA have devised various tests and regulations to qualify the cable for outdoor use. These cables are tested by manufacturer as per regulations for telecommunication application, Fiber Telecommunication Optics standard 96 (FTOP 96) qualifies the fiber cable for outdoor use. Such cables are operating at high temperature under abverse weather conditions.