Transcript Fiber Optics Technology

Fiber Optics Technology
Introduction to Optical Fibers.
Fibers of glass
Usually 120 micrometers in diameter
Used to carry signals in the form of light
over distances up to 50 km.
No repeaters needed.
Introduction (Cont…)
Core – thin glass center of the fiber
where light travels.
Cladding – outer optical material
surrounding the core
Buffer Coating – plastic
coating that protects
the fiber.
Evolution of Fiber
1880 – Alexander Graham Bell
1930 – Patents on tubing
1950 – Patent for two-layer glass wave-guide
1960 – Laser first used as light source
1965 – High loss of light discovered
1970s – Refining of manufacturing process
1980s – OF technology becomes backbone of
long distance telephone networks in NA.
Advantages of Optical Fibre
Thinner
Less Expensive
Higher Carrying Capacity
Less Signal Degradation& Digital Signals
Light Signals
Non-Flammable
Light Weight
Areas of Application
Telecommunications
Local Area Networks
Cable TV
CCTV
Optical Fiber Sensors
Type of Fibers
Optical fibers come in two types:
Single-mode fibers – used to transmit one signal
per fiber (used in telephone and cable TV). They
have small cores(9 microns in diameter) and
transmit infra-red light from laser.
Multi-mode fibers – used to transmit many
signals per fiber (used in computer networks). They
have larger cores(62.5 microns in diameter) and
transmit infra-red light from LED.
How Does Optical Fibre
Transmit Light??
Total Internal Reflection.
Fibre Optics Relay Systems has
-Transmitter
-Optical Fibre
-Optical Regenerator
-Optical Receiver
Total Internal Reflection in Fiber
How are Optical Fibre’s made??
Three Steps are Involved
-Making a Preform Glass Cylinder
-Drawing the Fibre’s from the preform
-Testing the Fibre
Testing of Optical Fiber
Tensile Strength
Refractive Index Profile
Fiber Geometry
Information Carrying Capacity
Operating temperature/humidity range
Ability to conduct light under water
Attenuation
Optical Fiber Laying
Mechanical Linking
Includes coupling of two connectors end to end
Optical distribution frames allow cross connect fibers
from by means of connection leads and optical
connectors
Soldering:
• This operation is done with automatic soldering machine that
ensures:
– Alignment of fiber’s core along the 3 axis
– Visual display in real-time of the fibers soldering
– Traction test after soldering (50 g to 500 g)
Optical Fiber Laying (Cont…)
Blowing
Used in laying optical cables in roadways.
Cables can be blown in a tube high density
Poly Ethylene
Optical fiber is then blown in the tube
using an air compressor which can propel it
up to 2 kilometers away.
Tools of Trade
Cleaning fluid and rags
Buffer tube cutter
Reagent-grade isopropyl alcohol
Canned air
Tape (masking or scotch)
Coating strip
Microscope or cleaver checker
Splicer
Connector supplies
Fiber Optics Test Kit
Features
Includes Smart FO Power Meter and Mini LED or
laser source
FO test lite software for data logging
Tests all networks and cable plants
New versions of Gigabit Ethernet
Low Cost
Applications
Measure optical power or loss
Trouble shooting networks
Protecting Fibers
Tougher than copper wires
Designed in three concentric layers
Core – Cladding – Buffer
Two basic buffer types
• Tight buffer
• Loose tubes
Implementation of Different LANs
IEEE 802.3
FOIRL
• Fiber optic inter repeater link
• Defines remote repeaters using fiber optics
• Maximum length – 1000 meters between any two
repeaters.
IEEE 802.3 (Cont…)
10BASEF
• Star topology with hub in the center
• Passive hub:
– Short cables
– No cascading
– Reliable
• Active hum:
– Synchronous
– May be cascaded
– Do not count as one repeater
– Any 10BASEF active hub must have at least
two FOIRL ports
Token Ring
Advantages
Long range
Immunity to EMI/RFI
Reliability
Security
Suitability to outdoor applications
Small size
Compatible with future bandwidth
requirements and future LAN standards
Token Ring (Cont…)
Disadvantages
Relatively expensive cable cost and installation cost
Requires specialist knowledge and test equipment
No IEEE 802.5 standard published yet
Relatively small installed base.
Fiber Distributed Data Interface
Stations are connected in a dual ring
Transmission rate is 100 mbps
Total ring length up to 100s of kms.
Conclusion
This concludes our study of Fiber Optics. We have
looked at how they work and how they are made. We have
examined the properties of fibers, and how fibers are
joined together. Although this presentation does not
cover all the aspects of optical fiber work it will have
equipped you knowledge and skills essential to the fiber
optic industry.