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Type & applications
Voice, digital telegraphy Audio
Video conferencing
Data transfer, Ecommerce, Video entertainment Full-motion broadcast video HDTV
➢ Photonics reflects the importance of the photon nature of light. Photonics & electronics clearly overlap since electrons often control the flow of photons & conversely, photons control the flow of electrons.
➢ Optoelectronics: refers to devices & systems that are essentially electronics but involve lights, such as LED, liquid crystal displays & array photodetectors.
➢ Computer Simulations using Photonic software
- Over ten design exercises using Optiwave - Cover most linear and nonlinear phenomena - Excellent system design practice
wavelength of 1552.5 nm corresponds to a center frequency of 193.1 THz!) & consequently orders of magnitude increase in available transmission bandwidth & larger information capacity.
Department of Optical Engineering, 2008
From copper wire to optical fiber
➢ Carrier-signal freq. limit:
Copper wire 1MHz Coaxial cable 100 MHz Radio freq. 500KHz to 100 MHz Microwave: up to 100 GHz Light: 100-1000THz
As a result, new disciplines have emerged & new terms describing them have come into use, such as: - Electro-Optics: is generally reserved for optical devices in which electrical effects play a role, such as lasers, electro-optic modulators & switches.
➢ Photonics: in analogy withthe control of photons in free space and matter.
Department of Optical Engineering, 2008
Photonic Communications
Department of Optical Engineering, 2008
Department of Optical Engineering, 2008
Why Photonic Communications?
➢ Extremely wide bandwidth: high carrier frequency ( a
➢ Optical Fibers have small size & light weight. ➢ Optical Fibers are immune to electromagnetic interference (high
voltage transmission lines, radar systems, power electronic systems, airborne systems, …)
➢ Quantum Electronics: is used in connection with devices & systems that rely on the interaction of light with matter, such as lasers & nonlinear optical devices.
Department of Optical Engineering, 2008
History of Fiber Optical Communication
Department of Optical Engineering, 2008
BW demands in communication systems
Department of Optical Engineering, 2008
Introduction/definition
Telecommunications
What is it? Exchange of information over a distance
Net configurations: 1.point-to-point works: a) Mesh topology b) star topology c) ring topology d) bus topology
Department of Optical Engineering, 2008
Optoelectronic Technology in Our Life Everyday
Department of Optical Engineering, 2008
Introduction
➢ Why go digital?
Advantage: less misinterpretation
Disadvantage: requires more channel capacity
➢ Major demand
Higher capacity Lower cost
Department of Optical Engineering, 2008
- Single Mode Fiber - Fiber Materials & Fabrication Procedures
Signal Degradation in Optical Fibers Photonic Sources & Transmitters: LED & Laser Diodes
amplification, frequency conversion, …)
4- Detection of Light (coherent & incoherent) ➢ Photonic Communications: describes the applications
of photonic technology in communication devices & systems, such as transmitters, transmission media, receivers & signal processors.
systems WDM & Photonic Networks
Department of Optical Engineering, 2008
Lab & Computer Simulations
➢ Lab sessions
- Fiber Attenuation Measurement - Dispersion Measurement - Spectral Attenuation Measurements
➢ Lack of EMI cross talk between channels ➢ Availability of very low loss Fibers (0.25 to 0.3 dB/km),
high performance active & passive photonic components such as tunable lasers, very sensitive photodetectors, couplers, filters, ➢ Low cost systems for data rates in excess of Gbit/s.
Shannon-Hartley theorem
Capacity v.s. bandwidth (1948)
Capacity (bits/sec)=BW(Hz)xlog2(1+SNR)
Channel bandwidth v.s. Carrier-signal freq
Channel bandwidth (Hz) 0.1XCarrier-signal freq. (Hz)
Department of Optical Engineering, 2008
Enabling Technologies for Optic Comm.
➢ Three major developments are responsible for rejuvenation of optics & its application in modern technology: 1- Invention of Laser 2- Fabrication of low-loss optical Fiber 3- Development of Semiconductor Optical Device
