Optical
Fiber Communications Principles and Practice Third Edition
JOHN M.
SENIOR
Contents
Chapter 1: Introduction 1
1.1
Historical development 1
1.2
The general system 5
1.3
Advantages of optical fiber communication 7
References
10
Chapter 2: Optical fiber waveguides 12
2.1
Introduction 12
2.2
Ray theory transmission 14
2.2.1
Total internal reflection 14
2.2.2
Acceptance angle 16
2.2.3
Numerical aperture 17
2.2.4
Skew rays 20
2.3
Electromagnetic mode theory for optical propagation 24
2.3.1
Electromagnetic waves 24
2.3.2
Modes in a planar guide 26
2.3.3
Phase and group velocity 28
2.3.4
Phase shift with total internal reflection and the
evanescent
field 30
2.3.5
Goos–Haenchen shift 35
2.4
Cylindrical fiber 35
2.4.1
Modes 35
2.4.2
Mode coupling 42
2.4.3
Step index fibers 43
2.4.4
Graded index fibers 46
2.5
Single-mode fibers 54
2.5.1
Cutoff wavelength 59
2.5.2
Mode-field diameter and spot size 60
2.5.3
Effective refractive index 61
2.5.4
Group delay and mode delay factor 64
2.5.5
The Gaussian approximation 65
2.5.6
Equivalent step index methods 71
2.6
Photonic crystal fibers 75
2.6.1
Index-guided microstructures 75
2.6.2
Photonic bandgap fibers 77
Problems
78
References
82
Chapter 3: Transmission characteristics of
optical fibers 86
3.1
Introduction 87
3.2
Attenuation 88
3.3
Material absorption losses in silica glass fibers 90
3.3.1
Intrinsic absorption 90
3.3.2
Extrinsic absorption 91
3.4
Linear scattering losses 95
3.4.1
Rayleigh scattering 95
3.4.2
Mie scattering 97
3.5
Nonlinear scattering losses 98
3.5.1
Stimulated Brillouin scattering 98
3.5.2
Stimulated Raman scattering 99
3.6
Fiber bend loss 100
3.7
Mid-infrared and far-infrared transmission 102
3.8
Dispersion 105
3.9
Chromatic dispersion 109
3.9.1
Material dispersion 110
3.9.2
Waveguide dispersion 113
3.10
Intermodal dispersion 113
3.10.1
Multimode step index fiber 114
3.10.2
Multimode graded index fiber 119
3.10.3
Modal noise 122
3.11
Overall fiber dispersion 124
3.11.1
Multimode fibers 124
3.11.2
Single-mode fibers 125
3.12
Dispersion-modified single-mode fibers 132
3.12.1
Dispersion-shifted fibers 133
3.12.2
Dispersion-flattened fibers 137
3.12.3
Nonzero-dispersion-shifted fibers 137
viii Contents
3.13
Polarization 140
3.13.1
Fiber birefringence 141
3.13.2
Polarization mode dispersion 144
3.13.3
Polarization-maintaining fibers 147
3.14
Nonlinear effects 151
3.14.1
Scattering effects 151
3.14.2
Kerr effects 154
3.15
Soliton propagation 155
Problems
158
References
163
Chapter 4: Optical fibers and cables 169
4.1
Introduction 169
4.2
Preparation of optical fibers 170
4.3
Liquid-phase (melting) techniques 171
4.3.1
Fiber drawing 172
4.4
Vapor-phase deposition techniques 175
4.4.1
Outside vapor-phase oxidation process 176
4.4.2
Vapor axial deposition (VAD) 178
4.4.3
Modified chemical vapor deposition 180
4.4.4
Plasma-activated chemical vapor deposition
(PCVD)
181
4.4.5
Summary of vapor-phase deposition
techniques
182
4.5
Optical fibers 183
4.5.1
Multimode step index fibers 184
4.5.2
Multimode graded index fibers 185
4.5.3
Single-mode fibers 187
4.5.4
Plastic-clad fibers 190
4.5.5
Plastic optical fibers 191
4.6
Optical fiber cables 194
4.6.1
Fiber strength and durability 195
4.7
Stability of the fiber transmission characteristics 199
4.7.1
Microbending 199
4.7.2
Hydrogen absorption 200
4.7.3
Nuclear radiation exposure 201
4.8
Cable design 203
4.8.1
Fiber buffering 203
4.8.2
Cable structural and strength members 204
Contents
ix
4.8.3
Cable sheath, water barrier and cable core 206
4.8.4
Examples of fiber cables 207
Problems
212
References
213
Chapter 5: Optical fiber connections: joints,
couplers and isolators 217
5.1
Introduction 217
5.2
Fiber alignment and joint loss 219
5.2.1
Multimode fiber joints 222
5.2.2
Single-mode fiber joints 230
5.3
Fiber splices 233
5.3.1
Fusion splices 234
5.3.2
Mechanical splices 236
5.3.3
Multiple splices 241
5.4
Fiber connectors 243
5.4.1
Cylindrical ferrule connectors 244
5.4.2
Duplex and multiple-fiber connectors 247
5.4.3
Fiber connector-type summary 249
5.5
Expanded beam connectors 251
5.5.1
GRIN-rod lenses 254
5.6
Fiber couplers 256
5.6.1
Three- and four-port couplers 259
5.6.2
Star couplers 264
5.6.3
Wavelength division multiplexing
couplers
269
5.7
Optical isolators and circulators 280
Problems
283
References
287
Chapter 6: Optical sources 1: the laser 294
6.1
Introduction 294
6.2
Basic concepts 297
6.2.1
Absorption and emission of radiation 297
6.2.2
The Einstein relations 299
6.2.3
Population inversion 302
6.2.4
Optical feedback and laser oscillation 303
6.2.5
Threshold condition for laser oscillation 307
x Contents
6.3
Optical emission from semiconductors 309
6.3.1
The p–n junction 309
6.3.2
Spontaneous emission 311
6.3.3
Carrier recombination 313
6.3.4
Stimulated emission and lasing 317
6.3.5
Heterojunctions 323
6.3.6
Semiconductor materials 325
6.4
The semiconductor injection laser 327
6.4.1
Efficiency 328
6.4.2
Stripe geometry 330
6.4.3
Laser modes 332
6.4.4
Single-mode operation 333
6.5
Some injection laser structures 334
6.5.1
Gain-guided lasers 334
6.5.2
Index-guided lasers 336
6.5.3
Quantum-well lasers 339
6.5.4
Quantum-dot lasers 339
6.6
Single-frequency injection lasers 342
6.6.1
Short- and couple-cavity lasers 342
6.6.2
Distributed feedback lasers 344
6.6.3
Vertical cavity surface-emitting lasers 347
6.7
Injection laser characteristics 350
6.7.1
Threshold current temperature dependence 350
6.7.2
Dynamic response 354
6.7.3
Frequency chirp 355
6.7.4
Noise 356
6.7.5
Mode hopping 360
6.7.6
Reliability 361
6.8
Injection laser to fiber coupling 362
6.9
Nonsemiconductor lasers 364
6.9.1
The Nd:YAG laser 364
6.9.2
Glass fiber lasers 366
6.10
Narrow-linewidth and wavelength-tunable lasers 369
6.10.1
Long external cavity lasers 371
6.10.2
Integrated external cavity lasers 372
6.10.3
Fiber lasers 376
6.11
Mid-infrared and far-infrared lasers 378
6.11.1
Quantum cascade lasers 381
Problems
383
References
386
Contents
xi
Chapter 7: Optical sources 2: the light-emitting diode 396
7.1
Introduction 396
7.2
LED power and efficiency 398
7.2.1
The double-heterojunction LED 405
7.3
LED structures 406
7.3.1
Planar LED 407
7.3.2
Dome LED 407
7.3.3
Surface emitter LEDs 407
7.3.4
Edge emitter LEDs 411
7.3.5
Superluminescent LEDs 414
7.3.6
Resonant cavity and quantum-dot LEDs 416
7.3.7
Lens coupling to fiber 419
7.4
LED characteristics 422
7.4.1
Optical output power 422
7.4.2
Output spectrum 425
7.4.3
Modulation bandwidth 428
7.4.4
Reliability 433
7.5
Modulation 435
Problems
436
References
439
Chapter 8: Optical detectors 444
8.1
Introduction 444
8.2
Device types 446
8.3
Optical detection principles 447
8.4
Absorption 448
8.4.1
Absorption coefficient 448
8.4.2
Direct and indirect absorption: silicon and
germanium
449
8.4.3
III–V alloys 450
8.5
Quantum efficiency 451
8.6
Responsivity 451
8.7
Long-wavelength cutoff 455
8.8
Semiconductor photodiodes without internal gain 456
8.8.1
The p–n photodiode 456
8.8.2
The p–i–n photodiode 457
8.8.3
Speed of response and traveling-wave photodiodes 462
8.8.4
Noise 468
xii Contents
8.9
Semiconductor photodiodes with internal gain 470
8.9.1
Avalanche photodiodes 470
8.9.2
Silicon reach through avalanche photodiodes 472
8.9.3
Germanium avalanche photodiodes 473
8.9.4
III–V alloy avalanche photodiodes 474
8.9.5
Benefits and drawbacks with the avalanche photodiode 480
8.9.6
Multiplication factor 482
8.10
Mid-infrared and far-infrared photodiodes 482
8.10.1
Quantum-dot photodetectors 484
8.11
Phototransistors 485
8.12
Metal–semiconductor–metal photodetectors 489
Problems
493
References
496
Chapter 9: Direct detection receiver performance
considerations 502
9.1
Introduction 502
9.2
Noise 503
9.2.1
Thermal noise 503
9.2.2
Dark current noise 504
9.2.3
Quantum noise 504
9.2.4
Digital signaling quantum noise 505
9.2.5
Analog transmission quantum noise 508
9.3
Receiver noise 510
9.3.1
The p–n and p–i–n photodiode receiver 511
9.3.2
Receiver capacitance and bandwidth 515
9.3.3
Avalanche photodiode (APD) receiver 516
9.3.4
Excess avalanche noise factor 522
9.3.5
Gain–bandwidth product 523
9.4
Receiver structures 524
9.4.1
Low-impedance front-end 525
9.4.2
High-impedance (integrating) front-end 526
9.4.3
The transimpedance front-end 526
9.5
FET preamplifiers 530
9.5.1
Gallium arsenide MESFETs 531
9.5.2
PIN–FET hybrid receivers 532
9.6
High-performance receivers 534
Problems
542
References
545
Contents
xiii
Chapter 10: Optical amplification, wavelength
conversion and regeneration 549
10.1
Introduction 549
10.2
Optical amplifiers 550
10.3
Semiconductor optical amplifiers 552
10.3.1
Theory 554
10.3.2
Performance characteristics 559
10.3.3
Gain clamping 563
10.3.4
Quantum dots 565
10.4
Fiber and waveguide amplifiers 567
10.4.1
Rare-earth-doped fiber amplifiers 568
10.4.2
Raman and Brillouin fiber amplifiers 571
10.4.3
Waveguide amplifiers and fiber amplets 575
10.4.4
Optical parametric amplifiers 578
10.4.5
Wideband fiber amplifiers 581
10.5
Wavelength conversion 583
10.5.1
Cross-gain modulation wavelength converter 584
10.5.2
Cross-phase modulation wavelength converter 586
10.5.3
Cross-absorption modulation wavelength converters 592
10.5.4
Coherent wavelength converters 593
10.6
Optical regeneration 595
Problems
598
References
600
Chapter 11: Integrated optics and photonics 606
11.1
Introduction 606
11.2
Integrated optics and photonics technologies 607
11.3
Planar waveguides 610
11.4
Some integrated optical devices 615
11.4.1
Beam splitters, directional couplers and switches 616
11.4.2
Modulators 623
11.4.3
Periodic structures for filters and injection lasers 627
11.4.4
Polarization transformers and wavelength converters 634
11.5
Optoelectronic integration 636
11.6
Photonic integrated circuits 643
11.7
Optical bistability and digital optics 648
11.8
Optical computation 656
Problems
663
References
665
xiv Contents
Chapter 12: Optical fiber systems 1: intensity
modulation/direct detection 673
12.1
Introduction 673
12.2
The optical transmitter circuit 675
12.2.1
Source limitations 676
12.2.2
LED drive circuits 679
12.2.3
Laser drive circuits 686
12.3
The optical receiver circuit 690
12.3.1
The preamplifier 691
12.3.2
Automatic gain control 694
12.3.3
Equalization 697
12.4
System design considerations 700
12.4.1
Component choice 701
12.4.2
Multiplexing 702
12.5
Digital systems 703
12.6
Digital system planning considerations 708
12.6.1
The optoelectronic regenerative repeater 708
12.6.2
The optical transmitter and modulation formats 711
12.6.3
The optical receiver 715
12.6.4
Channel losses 725
12.6.5
Temporal response 726
12.6.6
Optical power budgeting 731
12.6.7
Line coding and forward error correction 734
12.7
Analog systems 739
12.7.1
Direct intensity modulation (D–IM) 742
12.7.2
System planning 748
12.7.3
Subcarrier intensity modulation 750
12.7.4
Subcarrier double-sideband modulation (DSB–IM) 752
12.7.5
Subcarrier frequency modulation (FM–IM) 754
12.7.6
Subcarrier phase modulation (PM–IM) 756
12.7.7
Pulse analog techniques 758
12.8
Distribution systems 760
12.9
Multiplexing strategies 765
12.9.1
Optical time division multiplexing 765
12.9.2
Subcarrier multiplexing 766
12.9.3
Orthogonal frequency division multiplexing 768
12.9.4
Wavelength division multiplexing 771
12.9.5
Optical code division multiplexing 777
12.9.6
Hybrid multiplexing 778
Contents
xv
12.10
Application of optical amplifiers 778
12.11
Dispersion management 786
12.12
Soliton systems 792
Problems
802
References
811
Chapter 13: Optical fiber systems 2: coherent and
phase modulated 823
13.1
Introduction 823
13.2
Basic coherent system 827
13.3
Coherent detection principles 830
13.4
Practical constraints of coherent transmission 835
13.4.1
Injection laser linewidth 835
13.4.2
State of polarization 836
13.4.3
Local oscillator power 840
13.4.4
Transmission medium limitations 843
13.5
Modulation formats 845
13.5.1
Amplitude shift keying 845
13.5.2
Frequency shift keying 846
13.5.3
Phase shift keying 847
13.5.4
Polarization shift keying 850
13.6
Demodulation schemes 851
13.6.1
Heterodyne synchronous detection 853
13.6.2
Heterodyne asynchronous detection 855
13.6.3
Homodyne detection 856
13.6.4
Intradyne detection 859
13.6.5
Phase diversity reception 860
13.6.6
Polarization diversity reception and polarization
scrambling
863
13.7
Differential phase shift keying 864
13.8
Receiver sensitivities 868
13.8.1
ASK heterodyne detection 868
13.8.2
FSK heterodyne detection 871
13.8.3
PSK heterodyne detection 873
13.8.4
ASK and PSK homodyne detection 874
13.8.5
Dual-filter direct detection FSK 875
13.8.6
Interferometric direct detection DPSK 876
13.8.7
Comparison of sensitivities 877
xvi Contents
13.9
Multicarrier systems 886
13.9.1
Polarization multiplexing 889
13.9.2
High-capacity transmission 890
Problems
894
References
897
Chapter 14: Optical fiber measurements 905
14.1
Introduction 905
14.2
Fiber attenuation measurements 909
14.2.1
Total fiber attenuation 910
14.2.2
Fiber absorption loss measurement 914
14.2.3
Fiber scattering loss measurement 917
14.3
Fiber dispersion measurements 919
14.3.1
Time domain measurement 920
14.3.2
Frequency domain measurement 923
14.4
Fiber refractive index profile measurements 926
14.4.1
Interferometric methods 927
14.4.2
Near-field scanning method 930
14.4.3
Refracted near-field method 932
14.5
Fiber cutoff wavelength measurements 934
14.6
Fiber numerical aperture measurements 938
14.7
Fiber diameter measurements 941
14.7.1
Outer diameter 941
14.7.2
Core diameter 943
14.8
Mode-field diameter for single-mode fiber 943
14.9
Reflectance and optical return loss 946
14.10
Field measurements 948
14.10.1
Optical time domain reflectometry 952
Problems
958
References
962
Chapter 15: Optical networks 967
15.1
Introduction 967
15.2
Optical network concepts 969
15.2.1
Optical networking terminology 970
15.2.2
Optical network node and switching elements 974
15.2.3
Wavelength division multiplexed networks 976
15.2.4
Public telecommunications network overview 978
Contents
xvii
15.3
Optical network transmission modes, layers and protocols 979
15.3.1
Synchronous networks 980
15.3.2
Asynchronous transfer mode 985
15.3.3
Open Systems Interconnection reference model 985
15.3.4
Optical transport network 987
15.3.5
Internet Protocol 989
15.4
Wavelength routing networks 992
15.4.1
Wavelength routing and assignment 996
15.5
Optical switching networks 998
15.5.1
Optical circuit-switched networks 998
15.5.2
Optical packet-switched networks 1000
15.5.3
Multiprotocol Label Switching 1002
15.5.4
Optical burst switching networks 1004
15.6
Optical network deployment 1007
15.6.1
Long-haul networks 1008
15.6.2
Metropolitan area networks 1011
15.6.3
Access networks 1013
15.6.4
Local area networks 1023
15.7
Optical Ethernet 1028
15.8
Network protection, restoration and survivability 1034
Problems
1038
References
1041
Appendix A The field
relations in a planar guide 1051
Appendix B Gaussian
pulse response 1052
Appendix C Variance
of a random variable 1053
Appendix D Variance
of the sum of independent random variables 1055
