Fiber optic cables transmit digital information over long distances using thin strands of glass. Light signals travel through the core of the fiber due to total internal reflection off the cladding. A fiber optic system includes a transmitter that encodes light signals, the optical fiber that conducts the signals, and a receiver that decodes the signals. Optical fibers have advantages over copper wires like being thinner, having higher carrying capacity, and causing less signal degradation over long distances.

1. 1.introduction of How Fiber Optics Work
● The telephone system,the cable TV system or the
Internet are related to fiber-optic cables.
● Fiber-optic lines are strands of optically pure glass as
thin as a human hair.
● The strands carry digital information over long
distances.
● Fiver-optic lines are also used in medical imaging and
mechanical engineering inspection.
In this article, we will show you how these tiny strands of glass
transmit light and the fascinating way that these strands.

2. 2.What are Fiber Optics?
・Feature
Made by pure glass, which is very thin as long as a human hair.
It called optical cable, it transmit light signals over long distance.
・Contexture
Core - Thin glass center of the fiber where the light travels
Cladding - Outer optical material surrounding the core that
reflects the light back into the core
Buffer coating - Plastic coating that protects the fiber from
outside
・Type
Single-mode fibers - have small cores and transmit infrared laser
light
Multi-mode fibers - have larger cores and transmit infrared light
of LED

3. 3.How Does an Optical Fiber Transmit Light?
● The light in a fiber-optic cable travels through
the core (hallway) by constantly bouncing from
the cladding (mirror-lined walls), a principle
called total internal reflection.
● Because the cladding does not absorb any
light from the core, the light wave can travel
great distances.
● And, light finally reaches a target place.

4. 4.A Fiber-Optic Relay System?
・Device to communicate
(1)Transmitter-Produces and encodes the light signals.
It receives and directs the optical device to turn the light
"on" and "off", and then it produces a light signal.
(2)Optical fiber - Conducts the light signals over a distance.
It is core communicate device.
(3)Optical regenerator - May be necessary to boost the light
signal.
It produces a new stronger light signal. This device task is a
laser amplifier for the incoming signal.
(4)Optical receiver - Receives and decodes the light signals.
It gets the incoming digital light signals, and then decodes
them. They are sends the electrical signals to the various

5. 5.How Fiber Optics Work
・Advantages points – compared to copper wire
(1) Less expensive (5) Light signals
Cheaper than copper wire. Optical fibers are not interfered
from other fibers.
(2) Thinner
(6) Low power
Smaller diameters than
Optical fibers uses lower-power
copper wire.
transmitters.
(3) High carrying capacity (7) Digital signals
Optical fibers cab be bundled Optical fibers are suited to
fibers than copper wire. carry digital information over
(4) Less signal degradation internet.
The loss signal is less than in (8) Non-flammable
copper wire. No electricity, therefore is not
caused fire hazard.
These are only part, more points exist.

6. 6.How Are Optical Fibers Made?
Optical fibers are made of extremely pure
optical glass. Then, how are they made?
Making optical fibers requires the following
steps:
1. Making a preform glass cylinder
2. Drawing the fibers from the preform
3. Testing the fibers