Fibre optic technology utilizes flexible, transparent glass fibers that transmit light for applications in telecommunications, medicine, and aviation. It offers advantages such as higher data capacity, signal security, and low loss, but requires careful installation and maintenance due to its fragility. The system works by converting electrical signals into optical signals for transmission and vice versa, with specific structures and processes in place to manage issues like attenuation and pulse spreading.

1. 5.10 FIBRE OPTIC

2. WHAT IS FIBRE OPTIC
• Flexible, transparent fiber made of a
pure glass (silica).
• It functions as light pipe, to transmit light
between the two ends of the fiber.
• It is an opto-electronic component (sensitive
to infrared, ultra violet that convert to
electrical signal)
• Use in medical, telecomunication and aviation
field.

4. ADVANTAGE
• Larger data carry – up to 3300MHz
• Low loss of signal
• Smaller diameter, lighter-weight cables
• Cross talk negligible – no effect to other cable(signal)
• Immunity to electromagnet interference
• Greater security – immune to wiretapping
• Greater safety – free from spark
• Low cost – material sand
• Long life span – double from conventional cable
• Greater reliability – resistance to corrotion and temp

5. DISADVANTAGE
• Installation cost high
• Fragile than wire
• Required special equipment for testing
• Required special skill and equipment to
splicing it

6. OPERATION
Receiver
Transmitter
Optical Coupling (Light
(Light Source)
Detector)
Transmitters: Light-emitting diodes (LED's) and Injected Lasers
Convert electrical signal to optical signal.
To send the optical signal over an optical fibre
Receivers: Photodiodes and Phototransistors.
To convert optical signal back to an electrical signal
Optical Coupling: Opto-isolators and Optical fibres

7. LIGHT
• Light wave more shorter than electromagnetic
wave (radio/radar).
• Velocity 3x108m/s, change depend on
medium.
• Propogation of light :
– Reflection
– Refraction
– Dispersion

8. REFLECTION
The light reflect back with same angle if surface is smooth
The light diffuse reflection if surface is irregular/rough

9. REFRACTION
Bending of light when passes through other medium
Air 1 00
Diamond 2 42
Ethyl Alcohol 1 36
Fused Quartz 1 46
Glass 1 55 - 1 9
Optical Fibre 15
Water 1 33
Index of refraction

10. DISPERSION
• Seperation of white light to the various color.
• Different color have a different
wavelength, different velocity and different
index of refraction.

11. CABLE STRUCTURE
High strength and tension resistance
Typically cable made in length of 1-3 km without splices.
Core - glass, polystyrene, polymethylmethacrylic.
Cladding - glass, silicon or Teflon.

12. TYPE OF CABLE
Wide graded index multimode
optical fibre
Single mode step index optical fibre
Large-core plastic-clad silica optical fibre

13. HOW IT WORK
Single Mode
Multimode

14. ACCEPTANCE ZONE

15. NUMERICAL APERTURE
• Its a colecting power of an optical fibre
• Its value from 0 to 1,
• Larger NA mean the greater amount light
accepted by fibre.
• NA is function of refractive index of the fibre.
• Define as NA = sin A

16. PULSE SPREADING
• The amount of acceptance signal have a limited
frequency due to the pulse(light) is being dispers inside
the cable.
• Dispersion tend to slow down the speed of the light.
• Two form of dispersion :
– Chromatic disepersion : Different speed due to
color
– Modal dispersion : Zigzag ray reach the end of cable
later than straight ray
• Total Dispersion = Chromatic + Modal

17. CONSEQUENCES
• The fastest the pulse travel, the worse
spreading its get.
• Need to limit the frequency of the signal travel

18. ATTENUATION
• Reduction of signal strength due to :
1. Atomic Absorption :
Atom of material absorb some of the light
2. Scatering by Flaw and Impurities :
Depend on size of scatering particle
inside the cable
3. Reflection by Splices and Conector :
Some light are reflected back even for perfect
splice or conector.

19. JOINING OPTICAL FIBRE
– Fusion Splicing
• Allign manually using micromanipulators and
microscope system.
• End of fibre are melt together using electric arc.
• Near perfect splice can lose as low 0.2dB
– Mechanical Splicing
• Two fibre end held together in splice equipment which
automatically allign the two fibre.
• Clamp it and expose to ultra-violet light to cures the
cement

20. SPLICING ERROR
• The end of fibre must be precisely line each
other to enable light pass from one fibre to
another.
• Typicall allignment error :

21. FIBRE OPTIC CONNECTOR
2 Type Conector A and B, both have :
- Allignment key and grooves
- Guide pin and cavities
- Color bands
- Three start threads
A type :
- 3 or 5 optical fibre
- Multichannel
- very low loss
B type :
- For LRU
- Multichannel
- For more frequent
conection and disconection

22. FIBRE OPTIC IN AIRCRAFT
• Advantage on aircraft :
– Can carry more data
– Less weight
– Immune to electromagnetic radiation
• Purpose:
– Network system: (OLAN),(AVLAN),(CABLAN)

23. AIRCRAFT NETWORK SYSTEM
• Flight attendent
– Keep sales data
– Enable and disable passenger functions
– Control the distribution of video entertainment
– Select boarding music
• Passenger
– Video and menu screen
– Games
– Inflight sales catalogue
– Instruction for telephone call
– Ground to airplane telephone pages
– Special video channel selection

24. ONBOARD LAN

25. CABIN LAN