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 Applications 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.