- Multimode Fiber
- Monomode Fiber
Core:50μm
Cladding:125μm
50/125μm
Core:62.5μm
Cladding:125μm
62.5/125μm
Multimode fiber has two types
- Step Index
- Graded Index
Graded Index
In this type of fiber,there is no step change of refractive index between core and the cladding.The core has a refractive indexthat gradually decreases from the center to out words to outer surface of fiber.
The rays close to the center are slowed down because they travel smaller distance.The rays tarveling away from the axis are speed up using law refractive index than the center.There for they can catched up.Now all the rays will arrive at nearly same times at the Rx end.There for law dispersion-end high band width is achieved.Graded index just help to all the rays with entered to fiber with any angle through acceptance cone.
Monomode Fiber
To minimize dispersion we can reduce core diameter to very small valuves such as 5-10 μm
How ever cast of mono-mode fiber high due to manufacturing difficulties.For a multimode fiber 'NA' is between 0.2-0.3.But in a mono-mode fiber 'NA' is approximately 0.1 there for NA help us to identify the capability of the fiber.When the 'NA' is low the fiber is capable of transmitting higher bit rates.