History of Optical Fiber Communication

Study Notes

Optical Fiber Communication

In 1977, Bell installed an optical telephone communication system in Chicago, covering 1.5 miles, with each optical-fiber pair carrying the equivalent of 672 voice channels.
Today, over 80% of the world's long-distance voice and data traffic is carried over optical-fiber cables.
Optical fibers are thin, flexible, and transparent, acting as a waveguide to transmit light between two ends.
Fibers are used instead of metal wires because signals travel with less loss and are immune to electromagnetic interference.

Optical Fiber Types

OM1 Fibers, also known as 62.5/125 Multimode fibers, are popular in the United States.
OM2 and OM3 multimode fibers are also known as ITU-T G.651 fibers.
ITU-T G.652 Compliant Single Mode fibers are the most common type, designed to have minimum dispersion at around 1310nm.
G.652A, G.652B, G.652C, and G.652D fibers differ in attenuation and polarization mode dispersion.

Splicing

Splices are permanent connections between two fibers.
Mechanical splicing involves cutting and fixing fibers with epoxies or through fusion, but has worse insertion loss and back reflection than fusion splices.
Fusion splicing involves pre-aligned V-grooves, axial alignment, and electric arc firing to polish fiber ends.
The fusion process is critical to a good weld and is often automatically controlled by the fusion machine.

OTDR (Optical Time-Domain Reflectometer)

OTDR is a sophisticated measurement instrument that injects optical pulses into the fiber and analyzes the light scattering and reflection.
OTDR measures optical power loss, fiber length, and locates faults due to fiber breaks, splices, or connectors.
OTDR is used for maintaining fiber plant performance and provides advanced diagnostics to isolate points of failure.

Description

Explore the history and significance of optical fiber communication, from the first installations in Chicago to its present role in global long-distance voice and data traffic. Learn about the technology behind optical fibers and their importance in modern telecommunications.