PC481 Fiber OpticsPC481 Fiber Optics
Fall 2010Fall 2010Instructor: Dapeng ZhouInstructor: Dapeng Zhou
Lecture 1Lecture 1
Introduction to PC481
Chapter 1:Overview of Optical Fiber Communications
Introduction to PC481Introduction to PC481Course Description:Types of optical fibers. Basic theory: characteristics, numerical aperture, losses, dispersion, modes. Passive fiber devices: couplers, connectors, splices. Light sources: LED, solid and semiconductor lasers. Modulators. Detectors. Systems design. The major emphasis is on fundamentals and on individual devices which make up the system rather than on detailed design of optical communication networks.
Contents:1. Overview of optical fiber communications (Chapter 1)2. Optical fibers: structures, waveguiding, fabrication and optical cable
(Chapter 2)3. Signal degradation in optical fibers (Chapter 3)4. Optical sourses: Laser diodes and LEDs (Chapter 4)5. Power launching and coupling (Chapter 5)6. Photodetectors (Chapter 6)7. Photonic transmission systems (Chapter 7) 8. Wavelength-division multiplexing (Chapter 8)
InstructorsInstructors
Lecture instructor:Dapeng Zhou, Science Building, Room N2079(519)884-0710, ext. [email protected] hour: Fridays 13:00 pm-15:00 pm
Lab instructor:Hasan Shodiev, Science Building, Room N2086(519)884-0710, ext. [email protected]
Text BookText Book
Optical fiber communications, by Gerd Keiser, 4th edition, McGraw Hill, 2011. (The 3rd edition is no long in print; it is OK if you already have it.)
EvaluationEvaluation
Assignment: 20%Lab: 25% (At least 12.5% to pass)Midterm: 20% (End of October 2010)Final exam: 35%
Chapter 1Chapter 1Overview of Optical Fiber CommunicationsOverview of Optical Fiber Communications
OpticsOpticsOptics is an old subject involving the generation, propagation & detection of light.Optical theory development:Ray optics: short wavelength
↓
Wave optics: scalar approximation ↓
Electromagnetic optics: complete classical treatment ↓
Quantum optics: explanation of all optical phenomena
Quantum Optics
Electromagnetic OpticsWaveOptics
Ray Optics
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
PhotonicsPhotonicsOptoelectronics: refers to devices & systems that are essentially electronics but involve lights, such as LED, liquid crystal displays & array photodetectors.Quantum Electronics: is used in connection with devices & systems that rely on the interaction of light with matter, such as lasers & nonlinear optical devices.Quantum Optics: Studies quantum & coherence properties of light.Lightwave Technology: describes systems & devices that are used in optical communication & signal processing.Photonics: in analogy with electronics, involves the control of photons in free space and matter.
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
The Scope of Photonics:The Scope of Photonics:1- Generation of Light (coherent & incoherent)
2- Transmission of Light (through free space, fibers, imaging systems, waveguides, … ) 3- Processing of Light Signals (modulation, switching,
amplification, frequency conversion, …)
4- Detection of Light (coherent & incoherent)
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
At sending end: Data are transferred over the communication channel by superimposing the information onto an EM wave ( known as Carrier)
At the destination, the information is removed from the carrier wave and processed as desired
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Basic components of optical fiber linkBasic components of optical fiber linkOptical fibersStep/Graded-index; single-mode/multimodeSources for optical transmittersSemiconductor/fiber lasers; LEDsDetectors for optical receiversPin photodetector/Avalanche photdiodesSignal processing equipmentsModulators; multiplexer/demultiplexer; couplersOptical amplifiersErbium-doped fiber amplifier (EDFA)
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Elements of an optical fiber transmission link
MilestonesMilestonesThree major developments are responsible for rejuvenation of optics & its application in modern technology:
1- Invention of Laser2- Fabrication of low-loss optical Fiber3- Development of Semiconductor
Optical Device
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Evolution of fiberEvolution of fiber--optic systemsoptic systems
1950s:Imaging applications in medicine & non-destructive testing, lighting1960s:Research on lowering the fiber loss for telecom. applications.1970s:Development of low loss fibers, semiconductor light sources & photodetectors1980s:single mode fibers (OC-3 to OC-48) over repeater spacings of 40 km.1990s:Optical amplifiers (e.g. EDFA), WDM (wavelength division multiplexing) toward dense-WDM.
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
UnitUnitDecibels (dB) – ratios or relative unitsIn designing and implementing an optical fiber link, it is convenient to reference the signal level either to some absolutevalue or to a noise level.
Power ratio in dB =
and are optical powers in mW
2
1
10 log PP
1P 2P
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
UnitUnit
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
The dBm – absolute valueDecibel power level referred to 1 mW
Power level = 110log1
PmW
ExamplesExamples
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
3dB loss
200 µW in dBm unit
2
1
3 10 log( )PdBP
− =
3/102
1
10 0.5PP
−= ≈
6
3
( ) 200 1010log[ ] 10log[ ] 7.01 1 10P W WP dBmmW W
−
−
×= = = −
×
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Basic fiber optic system modelBasic fiber optic system model
System performanceSystem performance
Bit Error Rate (BER)Probability of error per bitReceiver SensitivityMinimum number of photons per bit necessary to guarantee that the BER is smaller than a prescribed rateDesign StrategyAttenuation/dispersion-limited performance
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
WDM: wavelength-division multiplexingWDM technology: The technology of combining a number of wavelegnth onto the same fiber is known as WDM
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
TX1
TX2
TXn
MUX
RX1
RX2
RXn
DeMUXOA
OAOA
SMF
components for today’s typicaloptical fiber communication
TX: optical transmitter e.g. laser, modulator etc…RX: optical receiver e.g. photodiode etc…OA: optical amplifier e.g. EDFA, SOA etc…SMF: single mode fiberMUX: optical wavelength multiplexerDeMUX: optical wavelength demultiplexer
Conceptual WDM systems
Optical NetworksOptical NetworksPoint-to-point links VS Complex networks
Basic Topologies: Logical manner in which nodes are linked together
Standards (SONET/SDH) : Specify formats for optical signals so they can be shared between networks
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Early application of fiber optic communicationEarly application of fiber optic communicationDigital link consisting of time-division-multiplexing (TDM) of 64 kbps voice channels (early 1980).
The fundamental building block is a 1.544 Mb/s transmission rate known as a T1 rate. At any level, a signal at the designated input rate is multiplexed with other input signals at the same rate.
Digital transmission hierarchy used in the North American telephone network
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
SONET & SDH StandardsSONET & SDH StandardsSONET (Synchronous Optical NETwork) is the network standard used in north America & SDH (Synchronous Digital Hierarchy) is used in other parts of the world. These define a synchronous frame structure for sending multiplexed digital traffic over fiber optic trunk lines.
The basic building block of SONET is called STS-1 (Synchronous Transport Signal) with 51.84 Mbps data rate. Higher-rate SONET signals are obtained by byte-interleaving N STS-1 frames, which are scramble & converted to an Optical Carrier Level N (OC-N) signal.
The basic building block of SDH is called STM-1 (Synchronous Transport Module) with 155.52 Mbps data rate. Higher-rate SDH signals are achieved by synchronously multiplexing N different STM-1 to form STM-N signal.
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
STM-649953.28STS-192OC-192
STM-324976.64STS-96OC-96
STM-162488.32STS-48OC-48
STM-81244.16STS-24OC-24
STM-4622.08STS-12OC-12
STM-1155.52STS-3OC-3
-51.84STS-1OC-1
SDH equivalentLine rate (Mb/s)Electrical levelSONET level
SONET & SDH transmission ratesSONET & SDH transmission rates
SONET multiplex hierarchySONET multiplex hierarchy
STS: Synchronous transport signalSPE: Synchronous payload envelopeVT: Virtual tributary
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
DWDM employmentDWDM employment
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
Chapter 1 Overview of Optical Fiber CommunicationsChapter 1 Overview of Optical Fiber Communications
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