Each fiber is surrounded by its own cladding, a glass or plastics coating that has optical properties those from core.
The outer most layer, surrounding one or a bundle of cladded fibers, is the jacket.
The jacket is composed of plastics and other material layered to protect against moisture, abrasion, crushing and other enviromental dangers.
Propogation mode
There are two modes of propogation of light in optical fiber:
Multi mode and Single mode.
Each mode requiere fiber with different characeristics.
Multimode can be implemented in two forms:
Step index and Graded index.
Multimode
Multimode is so named because multiple beams of light source move through the core in different paths.
How these beams moves within the cable depend on the structure of the core.
Multimode step index: in multiplexmode step index fiber, the densitof the core remaing constant from the centre to the edges.
A beam of light moves through this constant density ina streight line until it reaches the interface of the core and the cladding.
At the interface, there is an abrupt change to a lower density that angle of the beams motion.
The term step index to the suddenness of this change.
The core is the inner most section and consist of one or more very thin strands .Each fiber is surrounded by its own cladding, a glass or plastics coating that has optical properties those from core.The outer most layer, surrounding one or a bundle of cladded fibers, is the jacket.The jacket is composed of plastics and other material layered to protect against moisture, abrasion, crushing and other enviromental dangers.Propogation modeThere are two modes of propogation of light in optical fiber:Multi mode and Single mode.Each mode requiere fiber with different characeristics.Multimode can be implemented in two forms:Step index and Graded index.
MultimodeMultimode is so named because multiple beams of light source move through the core in different paths.How these beams moves within the cable depend on the structure of the core.Multimode step index: in multiplexmode step index fiber, the densitof the core remaing constant from the centre to the edges.A beam of light moves through this constant density ina streight line until it reaches the interface of the core and the cladding.At the interface, there is an abrupt change to a lower density that angle of the beams motion.The term step index to the suddenness of this change.
The light ray travelling the streight path through the centre and reaches the receiving and before the other rays, which follows a zigzag path.These different beams are recombined are recombined at the reciever, they result in a signal that is no longer an exact replica of the signal that was transmitted. This is known as dispersion.
