Applied Optoelectronics
(EEE – 436)
Spring 2020
Dr. Amir Haider
amirhaider@cuiatd.edu.pk
Course Plan
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Text Books:
1. G. P. Agrawal, ‘Fiber-Optic Comm Systems’ Wiley, 3/e
2. Gerd Keiser, “Optical Fiber Communications”,
McGraw–Hill, 3/e
3. Optoelectronics An Introduction by J Wilson –
J.F.B. Hawkes
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Grading Policy:
15%
10%
25%
50%
=
=
=
=
Assignments, Quizzes (1 for each week)
Course Project, Case study, Presentation etc.
Mid Semester Exam
End Semester Exam
2
Course Expectations
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Learning is a cooperative task and students must
participate actively.
The students are expected to listen to lectures and be
prepared to think and learn.
The lecture time period will be used to introduce and
establish fundamental concepts.
To get the most out of the lectures, you need to read
sections of the textbooks assigned in the tentative
schedule, and go over the examples and related exercise
problems. (will be given as assignment every week)
You are encouraged to work in online groups and
discuss the exercise problems. However, copying and
cheating is not allowed
3
Course Objectives
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This course addresses the physical
principles for important optical devices and
modules as well as their application in
photonic circuits and systems
The main application focus is
‘Optical fiber communication systems’
4
Course Expectations
◼
◼
◼
◼
◼
Learning is a cooperative task and students must
participate actively
The students are expected to come to lectures and be
prepared to think and learn
The lecture period will be used to introduce and establish
fundamental concepts
To get the most out of the lectures, you need to read
sections of the textbooks assigned in the tentative
schedule, and go over the examples and related exercise
Problems
You are encouraged to work in groups and discuss the
homework, However, copying and cheating is not allowed
5
Course Objectives
◼
◼
This course addresses the physical
principles for important optical devices and
modules as well as their application in
photonic circuits and systems
The main application focus is
‘Optoelectronics and Optical fiber
communication systems’
6
Topics to be Covered
1.
2.
Overview of Optical Communications
Optical Fiber: Wave guiding, Propagation Modes
o
o
o
3.
Photonic Sources & Transmitters:
o
4.
5.
6.
7.
Single Mode Fiber, Multimode and Specialty Fibers
Fiber Materials & Fabrication Procedures
Losses & Dispersion in Optical Fibers
LEDs & Laser Diodes
Photo detectors (PIN and ADP)
Power Launching & Coupling
Introduction to Optical Amplifiers
Introduction to Photonic Networks
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1
Overview
of
Optical Communications
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Optics is an old subject involving the
generation, propagation & detection of light.
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 SC Optical Devices
Electro-Optics: is generally reserved for optical
devices in which electrical effects play a role,
such as lasers, electro-optic modulators &
switches
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Optoelectronics: refers to devices & systems that are
essentially electronics but involve lights, such as
LED, liquid crystal displays & array photodetectors
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. It 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
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Optical Communication
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The Scope of Photonics:
1 – Generation of Light (coherent & incoherent)
2– Transmission of Light (through free space, fibers,
imaging systems, waveguides, … )
3– Detection of Light (coherent & incoherent)
4 – Processing of Light Signals (modulation,
switching, amplification, frequency conversion, …)
Photonic Communications: describes the applications
of photonic technology in communication devices &
systems, such as transmitters, transmission media,
receivers & signal processors.
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E = hν
c = λν = constant
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Note the relation between frequency & energy
c = λν
E = hν
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Wavelength Bands of Interest
50 nm (UV) – 100 μ m (IR)
400 nm – 700 nm (visible region)
800 nm – 1600 nm (1.55µm) range
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Attenuation Units
Ratio of optical output power Pout [P(z)] to optical
input power Pin [P(0)]
◼dB, dBm,
For Fibers
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Pz = P0 exp (− αp z)
where αp = (1/z) ln [(P(0)/P(z)], (per cm)
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α = attenuation coefficient, (dB/km)
= (10/z) log [(P(0)/P(z)] = 4.343 αp (/km)
(Hint: Log (e1) = 0.4343)
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Why Optical Communications?
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Extremely wide bandwidth: High carrier frequency ( a wavelength
of 1552.5 nm corresponds to a center frequency of 193.1 THz)
Small size & light weight
Immunity to Interference: Electromagnetic interference (high
voltage transmission lines, radar systems, power electronic systems,
airborne systems, …)
Signal Security
Lack of EMI cross talk between channels
Ruggedness and Flexibility
Low Transmission loss (0.25 to 0.3 dB/km)
System Reliability and Ease of Maintenance: high performance
active & passive photonic components such as tunable lasers, very
sensitive photodetectors, couplers, filters,
Low Cost systems for data rates in excess of Gbps
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Evolution of fiber optic systems
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1950s:
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1960s:
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1970s:
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1980s:
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1990s:
Imaging applications in medicine
& non-destructive testing, lighting
Research on lowering the fiber loss for
Telecom applications
Development of low loss fibers,
SC light sources & photodetectors
Single mode fibers (OC–3 to OC–48)
over repeater spacing of 40 km
Optical Amplifiers (e.g. EDFA), WDM
toward DWDM
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Optical Fiber Transmission Windows
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Operating range of 4 key components
1
Optical Fibers
2
Optical Sources
3
4
Optical Amplifiers
Optical Detectors
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Optical Fiber
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Major elements Of typical photonic comm link
?
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Installation of Fiber optics
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Submarine Systems
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Basic Communication & Digital Data Concepts
Analog Signal
Digital Signal
RZ & NRZ
Formats ?
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Basic Communication & Digital Data Concepts (cntd)
Analog Signal
Quantized Sample
Digital Stream
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Basic Communication & Digital Data Concepts (cntd)
TDM
FDM
5 Channels in 15 µSec
at their own turn
Multiple frequencies at the same time
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Concept of Wavelength Division Multiplexing
WDM
Multiple wavelengths at the same time
on a single fiber
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SONET & SDH Standards
Synchronous frame structure for sending multiplexed digital
traffic over fiber
◼ SONET (Synchronous Optical NETwork):
❑
❑
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used in North America
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 scrambled & converted to an Optical
Carrier Level N (OC-N) signal
SDH (Synchronous Digital Hierarchy):
❑
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 frames to form STM-N signal
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Standard Bit Rates
1 telephone call = 64 kbps
155 Mb/s
620 Mb/s
2.5 Gb/s
10 Gb/s
40 Gb/s
= 2000 telephone calls
= 8000 telephone calls
= 30,000 telephone calls
= 120,000 telephone calls
= 480,000 telephone calls
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Digital Transmission Hierarchy
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No of Audio Channels =
At a bit rate of 1% of the carrier
Bit rate vs Frequency ?
No of Photons
Sampling and Quantization in Digital Communication
C = λν
E = h ν (in Joules (watt x Sec))
1 eV = 1.6 x 10 − 19 Joule
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