semiconductor devices and opto-electronics meint smit leon kaufmann xaveer leijtens opto-electronic...
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Semiconductor devices and opto-electronics
Meint Smit
Leon Kaufmann
Xaveer Leijtens
Opto-Electronic Devices GroupEindhoven University of Technology
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Course information
• Opto-electronics:– Book: Gerd Keiser, Optical Fiber Communications
3rd edition, McGraw-Hill, obligatory!– Contact: Xaveer Leijtens
[email protected] – 247 5112
• Electronic devices:– Book: Linda Edwards-Shea, The Essence of Solid-
State Electronics, Prentice Hall, obligatory!– Contact: Leon Kaufmann
[email protected] – 247 5801
• Website: http://oed.ele.tue.nl (education)
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Course overview
Week Mon 1,2 Tue 1,2 Wed 2,3 Fri 2 (vko) Fri 3,4
49 Lect o Lect e Instr o Lect e Lect o
50 Lect e Instr e Instr o Lect e Lect o
51 Lect e Instr e Instr o Lect e Lect o
2 Lect e Instr e Instr o Lect e Lect o
3 Lect e Instr e Instr o Lect e Instr e
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Contents semiconductor devices
• Recapitulation: electrons in atoms, introduction to quantum mechanics
• Solid state materials: crystal structures, energy band diagrams of insulators, metals and (un)doped semiconductors
• Semiconductors and carrier transport• Principle of operation of pn junction diodes• Fundamentals of MOSFETs• CMOS technology (incl. video demonstration)
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OGO3.2Free space optical communication
Kickoff Meeting Dec 1 in MA1.41 13:30h
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Contents Opto-Electronics
Lecture Chapter About
1 1 Introduction
2 Optical fibers
2 3 Fiber transmission properties
5 Power launching and coupling
3 4 Light sources
4 6 Light detectors
5 7 Optical receivers + guest lecture
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Examination
• Closed-book examination, formula sheet will be provided• Electronic devices: Edwards-Shea, chapter 1-8• Opto-electronics: Keiser
Chapter # pages
1 not: 1.4 and 1.5 15
2 not: 2.3.5, 2.4.3-9, 2.7.2-4, 2.8-10 30
3 3.1.2-3.1.4: no formula’s, only mechanismsnot: 3.1.5, 3.3, 3.4, 3.5.4-5
28
4 not: 4.4 and 4.5 44
5 not: 5.1.3, 5.2.1-end, with p 212, 218 8
6
7
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Optical communication
+ ––
TRANSMITTER FIBRE
+ –
RECEIVER
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Electromagnetic spectrum
• Optical communication wavelength: = 1500 nmcorresponds to = c/ 200 THz = 200.000 GHz
• 1% = 2 THz = 2000 GHz• EDFA-bandwidth 30 nm 4 THz
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Standard Single-Mode (SM) Fiber
Fiber coreSiO2+ GeO2
Ø 10 mn 1.443
SiO2 Cladding
Ø 125 mn 1.44
Primary coating (soft)Ø 400 m
Secondary coating (hard)Ø 1 mm
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Optical source
+ ––
TRANSMITTER
FIBER
Performance
Modulation speedFiber-coupled power
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–
Light Emitting Diode (LED)
Typical performance data
Power in MM-fiber: 100 W
Power in SM-fiber: 1 W
Direct Modulation Bandwidth: 100 MHz
+
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Laser
Typical performance
Power (in fiber): 5-10 mWMax: 100-300 mWDirect Modulation Bandwidth: 1-10 GHz
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Photodiode detector
Typical performance data
Responsivity: ~1 mA / mWBandwidth: 1-20 GHz
+ –
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Optical communication systems
First Generation, ~1975, 0.8 mMM-fiber, GaAs-laser or LED
Second Generation, ~1980, 1.3 m, MM & SM-fiberInGaAsP FP-laser or LED
Third Generation, ~1985, 1.55 m, SM-fiberInGaAsP DFB-laser, ~ 1990 Optical amplifiers
Fourth Generation, 1996, 1.55 mWDM-systems
1.80.8 1.0 1.2 1.4 1.60.9 1.1 1.3 1.5 1.7Wavelength (m)
Att
en
ua
tion
2 dB/cm
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WDM-transmission
MultiwavelengthTransmitter
MUX
MultiwavelengthReceiver
DMX
opticaltransmitter
opticalreceiver
optical fiber
+ –
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Erbium-Doped Fiber Amplifier (EDFA)
PUMP LASER 0.98 m or 1.48 m
Er-doped fiber
MUX FILTER
-10
0
10
20
30
1520 1530 1540 1550 1560 1570
wavelength (nm)
ED
FA
ga
in (
dB
)
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Synchronous Digital Hierarchy
Data rate SDH
Europe
SONET
US & Japan
52 Mb/s OC-1
155 Mb/s STM-1 OC-3
622 Mb/s STM-4 OC-12
2.5 Gb/s STM-16 OC-48
10 Gb/s STM-64 OC-192
40 Gb/s STM-256 OC-768
EuropeSDH: Synchronous
Digital Hierarchy
STM: SynchronousTransport Module
US & JapanSONET: Synchronous
Optical Network
OC: OpticalCarriers
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WDM experiments
Si electronics
ETDM
installed(10x / 6 yrs)
(10x / 2.5 yrs)
5 yrs
0.01
0.1
1
10
100
1000
10000
1980 1985 1990 1995 2000
Cap
acit
y (G
b/s
)
Trunk transmission capacity
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# W
DM
-cha
nnel
s
4
16
64
256
0.01 0.1 1 10 100
Channel bitrate (Gb/s)
1
Trunk transmission capacity
•‘97
10 Gb/s
1 Tb/s
0.1 Gb/s
1 Gb/s
100 Gb/s
•‘98
•‘98•
‘99
•‘00
•‘04?
•‘86
•‘96
•‘89
•‘83
•‘80
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Undersea cables
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Undersea cable
Cable Capacity fully upgraded (Gbps)
2,400
Fiber Pairs 6
Wavelengths per Fiber Pair 40
Gbps per Wavelength 10
Cable Length (km) 14,500
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Optical Transport Network
Global Network
Wide Area Network
Metropolitan/Regional Area Optical Network
Corporate/Enterprise Clients
Cable modemNetworks
Client/Access Networks
FTTHMobile
SDH/SONET
ATM
PSTN/IP
ISPGigabit Ethernet
Cable
FTTB
ATM
< 10000 km< 10 Tbit/s
< 100 km< 1 Tbit/s
< 20 km100M - 10 Gbit/s
Courtesy: A.M.J. Koonen
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O X C
1
2
1
2
in out
X
X
X
X
Integrated optical cross-connect
Dimensions: 8x12 mm2
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Fibre propagation
n1
n2
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Fiber performance
z=0 z=L
Dispersion
z=0 z=L
Attenuation
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Optical attenuation in glass
1960
Att
enua
tion
(dB
/km
)
1
10
100
1000
0.11970 1980 1990 2000
20 dB/km (Corning)
0.16 dB/km
CVD (Chemical Vapor Deposition)
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1.80.8 1.0 1.2 1.4 1.60.9 1.1 1.3 1.5 1.7
Wavelength (m)
Att
enua
tion
(dB
/km
)
0.2
0.5
1.0
1.5
0.16 dB/km
Rayleighscattering
IR band edge
OH--peak
UVabsorption
0.70.6
Fiber attenuation (SiO2)
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A note on dB and dBm
• dB– optical signals:
– electrical signals:
–
• dBm– absolute power value (with 1 mW as reference)
– power level in dBm:
2
1log10P
P
22
11
2
1
2
1 log10log20log20IV
IV
I
I
V
V
mW
P
1log10
elelopt PIP electrical dB = 2 x optical dB
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Reflection & refraction
n2<n1
n1
1 1
1
2
2
Snell’s law
2211 sinsin nn
2211 coscos nn
n2<n1
n1
1= c
c
Critical angle
1
2sinn
nc
1
2cosn
nc
n2<n1
n1
1 >c
Total internal reflection
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Numerical Aperture
1
2cosn
nc Critical angle:
Maximum entrance angle:
cn
n sinsin0
1max,0
Multimode fiber
n1
n2
0
c
n0
n0
22
21
211max,00 cos1sinsin nnnnnNA cc
Numerical aperture:
n
n
n
nn
n
nn
nnn
1
212
1
22
21
21
2
: if 222
22
1 nnnnnNA
61.0 max,0NA
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L
n1
n2
Dispersion (intermodal)
c
t
c
n
n
nL
T
2
1
c
nLT 1
min
cc
nLT
cos1
max
1
2cosn
nc
c
n
c
n
n
nL
T
2
1
nc
NA
c
n
c
n
n
nL
T2
2
2
1
T
LLB
2
2
NA
nc
T
LLB
kmnsnc
NA
c
n
c
n
n
nL
T /2
2
2
1
kmsMbNA
nc
T
LLB )/(
22
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Bandwidth and bit rate
tT
FWHM
dBo
0
1.5
3
oe
dBe
0
3
6
oe
e
CCT
B
22
1120
Rule of thumb:
(incoherent)
Bandwidth
Cross talk
opteldet PPI
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refractiveindex
SM Single-Mode
Fiber types
MM-SIMulti-ModeStep Index
MM-GIMulti-ModeGraded Index
2/1
1 21
a
rnrn
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Fiber classification (1)
Core diameter 50 - 400 m
Cladding 125 (500) m
2nd coating 250 - 1000 m
NA 0.16 - 0.5
Attenuation 1 - 4 dB/km
Bandwidth 6 - 25 MHz.km
Application Short distance, low cost
limited bandwidth
MM-SI: Multi Mode - Step Index fiber
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Fiber classification (2)
Core diameter 50 m standard
Cladding 125 m
2nd coating 200-1000 m
NA 0.2 - 0.3
Attenuation 1 dB/km (1300 nm)
Bandwidth 150 MHz.km - 2 GHz.km
Application Medium distance communication
LED/Laser sources
MM-GI: Multi Mode - Graded Index fiber
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Fiber classification (3)
Core diameter 3-10 m
Cladding 50-125 m
2nd coating 200-1000 m
NA ~0.1 (not used)
Attenuation 0.20@1550 - 0.4@1300 dB/km
Bandwidth >> 500 MHz.km
Application Long distance communication
Lasers, standard fiber
SM-SI: Single Mode - Step Index fiber
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The wave equation
Plane wave:
Spherical wave:rjkeE
R
eE
Rjk
Solutions to Maxwell’s equations:
2
kn
knk
/0
0
r
rr
n
kk
0000
phase fronts
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Wave vector and decomposition
kz
kx
kkx
kz
z
x
z
x
zjkxjk zx eezxE ),(
zz
xx
k
k
2
2
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Interference
x
x
z
z
phase frontsabsorber
metallic plates
kz
kx
k+
kx+
kz
+
kx-
k-
-
zjkx
zjkxjkxjk
rkjrkj
z
zxx
exk
eee
eezxE
cos2
,
xx
xz
k
nkk
kkk
2
0
22
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The metallic waveguide
metallic plates
d
z
x
kz zj
x exkzxE cos,
dx 2x
xk 2
220
2xz kknk
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Modes & Rays
waveguide
d
2 1 0
m=0 m=2m=1
d
mk mx
1,
0
,arcsinnk
k mxm
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Optical waveguide modes
m=0 m=4m=3m=2m=1
n2
n1
n0
k
z
m=0m=1
m=2m=3
m=4
kx
n1k0
c2
c0
substrate modes
superstrate modes
guided modes
n0k0n2k0 n1k0
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Mode intensity profiles
• Optical modes:
• Excitation of modes:
0 1 2
d
a
Planar:
Single-mode if V
Fiber:
Single-mode if V 2.405
22
21
2nn
dV
22
21
2nn
aV
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V-parameter
• V number: determines how many modes a fiber supports
• Lowest order mode HE11 has no cut-off
• Single-mode fiber:
NAa
nna
V
22 2
22
1
405.2V
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Number of modes
• Number of modes in step-index fiber
• Optical power in the cladding
2
2
2
1 22
22
1
2V
nna
M
MP
Pcladding3
4 for large values of V
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Step index fiber modes (2)
Effective index /k as a function of
Single-mode fiber: V 2.405
NAa
nna
V
22 2/12
22
1
HE11
TE01TM01
EH11
HE12
HE31
0 1 2 4 53 6
n1
n2
k
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Birefringence
• HE11:
• Birefringence: difference in effective refractive indices between two polarization modes
• Fiber beat length: phase difference between the two polarization modes is
xyf nnB
xyp nnk
L
0
Horizontal modeVertical mode
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Fiber materials
• Silica glass fiber– starting material: pure silica (SiO2) in the form of fused quartz
(amorphous)– modification of refractive index by addition of impurities
• lowering refractive index : B2O3, F• raising refractive index : P2O5, GeO2
• Polymer optical fiber (POF)– large core (multimode)– large refractive index difference between core and cladding– easy handling– relatively high losses
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Losses in polymer optical fiber
• Absorption loss in POF >>> Absorption loss in Silica fiber search for low loss polymers
• PMMA (Poly Methyl Metacrylate)• PS (Polystyrene)• FA (Fluoro acrylate)
– Typical absorption levels: 100 dB/km– Low loss windows: several windows in the range 500-800 nm
• New material development: perfluorinated polymer 50 dB/km from visible to 1600 nm
• Core type• Step index• Graded index
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Advantages of Optical communication
Huge bandwidth
Small and light
Low loss
Electrical isolation
No EMI (Lightning, interference)
Security (no tapping)
Reliability
Low cost per bit