1. INTRODUCTION TO OPTICAL COMMUNICATION TECHNOLOGY

2. Table of Content The learning outcomes
Elements in Telecommunication System
Optical Communication System Components
Light : The characteristic and behavior
The advantages of optical communication

3. The Learning Outcomes
At the end of the module, student should able to :
Explain the basic elements of optical communication
Explain the behavior of light
Describe the advantages optical communication technologies
Application of optical communication

4. Elements in Telecommunication
the part where the message is processed, modulated and sent as signal.
Transmitter
where the signal sent through
Transmission Medium
the part where signal is received, demodulated and converted to original message.
Receiver
Transmitter
Receiver
Medium

5. Optical Communication System
Light source
The transmitter
Optical Fiber Optic
Transmission medium
Photodetector
The receiver
Light source
Photodetector
Optical Fiber

6. What is Light?
Light is electromagnetic radiation that can be detect by the human eye ( nm).
In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not.
Wavelength Range (nanometers)
Perceived Color
Near Ultraviolet (UV; Invisible)
Violet
Blue
Green
Yellow to Orange
Orange to Red
Over 700
Near Infrared (IR; Invisible)

8. Understanding of light
Near Infrared
Frequency
Wavelength
1.6
229
1.0
0.8 µm
0.6
0.4
1.8
1.4 UV
(vacuum)
1.2
THz
193
461
0.2
353
Longhaul Telecom
Regional Telecom
Local Area Networks
850 nm
1550 nm
1310 nm
CD Players
780 nm
HeNe Lasers
633 nm

9. Characteristics of Light
Speed: 3x108 m/s
Power (Watts,dBm) or Energy (Joules)
Wavelength (m) or Frequency (Hz)
Spectrum bandwidth (nm,Hz)
Beam profile (shape)
Phase (angle: degree or radiance)
Polarization (angle: degree)

11. Understanding Light: The Behavior
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Understanding Light: The Behavior
An EM wave with quantized energy
Travels in straight line
Transmits through media
Reflects off different media
Chargeless - does not interact with other light- can go through each other
Interact with materials (media)
Can be visible/invisible
2-Dimesional; carries image

12. When a light wave hits an object, what happens to it depends on the:
Energy
Frequency at which electrons vibrate in the material
Strength with which the atoms in the material hold on to their electrons.
Based on these three factors, four different things can happen when light hits an object:
Reflected or scattered
Absorbed
Refracted
Pass through

13. TOTAL INTERNAL REFLECTION
When the critical angle is exceeded for a particular light wave, it exhibits total internal reflection back into the medium.
Usually the higher index medium is considered the internal medium, because air (having a refractive index of 1.0) is in most cases the surrounding, or external medium
If the incident angle increases past a specific value (dependent upon the refractive index of the two media), it reaches a point at which the angle is so large that no light is refracted into the medium of lower refractive index, as illustrated in Figure 1. In this figure, individual light rays are represented by either red or yellow colored arrows moving from a medium of higher refractive index (n(2)) to one of lower refractive index (n(1)). The angle of incidence for each individual light ray is denoted by the value i and the angle of refraction by the variable r. The four yellow light rays all have an angle of incidence (i) low enough to allow them to pass through the interface between the two media. However, the two red light rays have incident angles that exceed the critical angle of reflection (approximately 41 degrees for the water and air examples) and are reflected either into the boundary between the media or back into the higher refractive index medium.

14. Total Internal Reflection
Apply for light propagation inside fiber optic

15. Advantages for Communications
Low cost/bandwidth
High Speed
Low Power Operations
No Electromagnetic Interference (EMI)
No Grounding
Secure
Simple Modulation and Detection
Real Full Duplex transmission (bi-directional)

16. Communication Link Performance

17. Advantages of Optical communication
Immunity to EMI
High bandwidth
Immunity to crosstalk
Low attenuation
Safety
Size and capacity
Immunity to EMI
Because it carries light rather than electrical signals, it cannot be affected by electromagnetic interference from power, radio or microwaves sources.
High bandwidth
Increase information carrying capacity over long distance.
Fiber optic – 10 Gb/s for 300 meters
Copper – 1 Gb/s for 100 meters
Immunity to crosstalk
The structure of optical fiber is such that the light energy is essentially completely constrained within the core of the fiber and, hence signals cannot couple between fibers in a cable.
Low attenuation
Attenuation is proportional to cable length, hence, fiber’s lower attenuation enables much longer link distances than copper.
Safety
Fiber does not conduct electricity, hence no lightning strikes.
Size & Capacity
A single fiber can replace several copper conductors.
Fiber: Capacity of a 1/2 inch diameter cable (144fibers) = 65,000 simultaneous conversations on each fiber… million total calls on the entire cable
Copper: Capacity of a 4 1/2 inch diameter cable = 40,300 calls (and for shorter distances ) Weight
Fiber: A typical single-fiber cable weighs 9 lbs./1000 feet
Copper: A comparable coaxial cable weighs 80 lbs./1000 feet

18. Copper VS Optical Fiber

19. Q&A? murnisigtech@gmail.com HP: 0192695157 Thank You

20. Next Module : Optical Fibers and Cables Termination and Connectors
Measurements and test gears
Optical Cable Installation