Fiber optic cable material

Materials are used for optical fiber :

The material requirement of fiber optic cable for glass and plastic. They offer widely different characteristics and therefore fibers made from the two different substances and find uses in very different applications.

The main requirement of fiber optic material to be given below :

• Fiber material must be required with compatible the cladding material
• It must be possible to draw long thin fiber from the material used
• The material must be used to be transparent for efficient transmission of light

Glass and plastics materials have fulfilled this requirement:

Most fiber consists of silica or silicate. Various types of low loss and high loss glass fiber are available to suit the requirement. Plastic fibers are not too much popular because of its high attenuation so they have better mechanical strength.

Glass fiber :

Glass fiber made by materials fusing mixtures of metal oxides having a refractive index of 1458 at 850 nm. For changing the refractive index different oxides like B₂O₃, GeO₂ and P₂O₅ are added as dopants. 

One important criterion is that the refractive index of the core is greater than that of the cladding, hence some important composition is used such as given below :

Composition :

1 : Core type -  GeO₂ - SiO₂  Cladding type - SiO₂ 

2 : Core type  -  P₂O₅  - SiO₂  Cladding type - SiO₂ 

3 : Core type - SiO₂  Cladding - B₂O_{3 -} SiO₂ 

4 : Core type - GeO₂ - B₂O₃ -  SiO₂  Cladding type - B₂O_{3  -} SiO₂ 

The principal raw material for silica is sand and glass materials. The fiber materials composed of pure silica is called as silica glass. The desirable properties of silica glass are given below:

• Resistance to deformation even at high temperatures.
• Good chemical durability. 
• Better transparency.
• Resistance to breakage from chemical thermal shocks.

Other types of glass fibers are :

• Halide glass fibers.
• Active glass fiber.
• Chalcogenide glass fiber.
• plastic optical fibers.