818 INDEX optical time division multiplexing ...
Trang 1810 INDEX
large effective area fiber (LEAF), 94-95
choosing, 342
dispersion profile, 94
distribution of power, 95, 96
refractive index profile, 95
See also optical fiber(s)
large electronic switches, 215-216
large optical switches, 201-207, 224
blocking characteristics, 202-203
build considerations, 201-203
loss uniformity, 202
number of crossovers, 202
number of switch elements, 202
See also optical switches
LARNET WRPON, 607-608
laser arrays, 185-186
lasers, 166-176
coherent output, 168
distributed-feedback (DFB), 37, 169-171
edge-emitting, 173
external cavity, 171-172
Fabry-Perot (FP), 168, 186
fiber, 166
grating coupler sampled reflector (GCSR),
183, 185, 186
local-oscillator, 263
longitudinal modes, 168-169
mode-locked, 174-176
multiple-longitudinal mode (MLM), 168, 169
principle of operation, 167-168
sampled grating (SG) DBR, 183, 184-185
semiconductor, 166, 526
single-longitudinal mode (SLM), 37, 168, 169
super-structure grating (SSG) DBR, 183,
184-185 tunable, 178-186
vertical cavity surface-emitting, 173-174
VGF, 183-184
lasing loops, 298-299
effects, 298
handling methods, 298
lasing threshold, 168
latching switches, 201
layered network architecture, 16-20
classical, 18-19
data flow between layers, 17
data link layer, 18-19
hierarchy illustration, 17
IP over ATM over SONET network, 20
IP over SONET network, 19-20 multiplexing example, 23 network layer, 19 physical layer, 18 SONET layer, 22, 23 transport layer, 19
See also optical layer L-band, 316
C-band vs., 689
EDFAs, 158-159, 289 positive chromatic dispersion fibers and, 97
See also C-band Lead service class, 567
light-emitting diodes (LEDs), 176-178 light output, 177
slicing, 177-178 lightpaths, 15,403,504 average lease time, 466
bandwidths, 502 circuit-switched, 428 dedicated, 447 full-duplex, 485 optical layer, 21 permanent, 21 protecting, 420, 428-429 protection routes per, 580 sets of, 475
setting up/taking down, 403
"single-hop," 443 undirected, 455 lightpath topologies, 405-406,
440, 442-443 all-optical, 442, 445-446 congestion vs node degree, 454 designing, 449, 453
hub design, 442, 444-445 PWDM ring, 442, 443 SONET rings, 454
of three-node network, 440 lightpath topology design (LTD) problem, 440, 449-454
bidirectional lightpath constraint, 451
congestion parameter, 450
degree constraints, 451 flow conservation at nodes, 450 flow control on logical link, 451 formulation, 449-450
LTD-LP, 452, 453 LTD-MILP, 452, 453
Trang 2nonnegativity and integer constraints, 451
objective function, 450
light propagation, 50-64
in dielectric waveguides, 63-64
geometrical optics approach, 50-55
wave theory approach, 55-64
limited wavelength conversion, 457-458
illustrated, 458
switch cost savings, 458
WA problem, 459
See also wavelength conversion
line amplifiers, 290
linear dielectric polarization, 82
linearity, 5 7-58
linear polarization, 61,742
linear program (LP), 452
LTD, 452, 453
relaxation, 452
linear susceptibility, 741
line coding, 241
line layer, 370
line network, 476
illustrated, 476
with N nodes, 481
line overhead
bytes, 374-375
illustrated, 373
See also SONET frame structure
line terminating equipment (LTE), 378
liquid crystal switches, 212-213,214
illustrated, 214
principle of operation, 213
lithium niobate external modulator, 188
with directional coupler configuration, 189
with MZI configuration, 190
livelock, 649
load imped~.~nce, 745
local-area networks (LANs), 4, 381
local-exchange carriers (LECs), 3
competitive (CLECs), 4
incumbent (ILECs), 3
locality of response, 56
local muhipoint distribution service (LMDS), 597
local-oscillator lasers, 263
logical AND operations, 625-630
nonlinear optical loop mirror (NOLM) for,
626-629
output, 623
soliton-trapping AND gate for, 629-630
long-haul interoffice connections, 377 long-haul networks, 4, 688-698 capabilities and costs, 691,694 case study, 689-696
C-band, 689 cost breakdown, 695 equipment and crossconnects, 691,695 handoff, 5
infrastructure, 5 link distances, 692 traffic mix, 690 transponders/amplifiers relative cost, 693,696 undersea, 697-698
WDM, 376, 689
See also ultra-long-haul (ULH) networks longitudinal component, 61
long-period fiber gratings, 127-132 fabrication, 127
principle of operation, 128-132 transmission spectrum, 129
See also fiber gratings; gratings loop mirror, 226
lOSS attenuation, as function of wavelength, 66 AWG, 140
bandwidth and, 65-68 bending, 67-68 differential, 641 due to Rayleigh scattering, 67 excessive, 110
insertion, 113,200-201,209 mechanisms, 65
in optical fiber, 31-32 optical power and, 31-32 parallel OADM architecture, 412 polarization-dependent (PDL), 110, 201 serial OADM architecture, 414-415 uniformity, 202
losslessness, 58 loss-of-signal (LOS) alarms, 507 low-loss transmission, 49 Mach-Zehnder interferometers, 109, 135-139, 188,220
crosstalk performance, 137 illustrated, 136
lithium niobate external modulator using, 190 multistage, 138-139
narrow band, 137
Trang 3812 INDEX
Mach-Zehnder interferometers (continued)
principle of operation, 137-139
transfer functions, 138,228
uses, 136, 137
magnetic flux density, 56
magnetic polarization, 56
management protocols, 500-501
CMIP, 501
SNMP, 501
management standards, 722-723
Manhattan Street network, 646, 647-648
diameter, 648
illustrated, 646
Markov chain, 466
master, 528
material absorption, 65-66
material dispersion, 68, 69
maximum load dimensioning models, 475-482
offline lightpath requests, 475-481
online RWA in rings, 475,481-482
shortcomings, 475
max-used algorithm, 474
Maxwell distribution, 753
Maxwell's equations, 55, 727-729
mechanical tuning, 179
media access control layer (MAC), 19
medium
homogeneous, 58
isotropic, 57
linear, 57-58
locality of response, 56
lossless, 58
mesh protection schemes, 576-581
centralized implementation, 580-581
complexity, 579
deployment issues, 579-580
distributed implementation, 581
past usage of, 478
resurrection of, 478
variations, 580-581
metro networks, 4-5, 698-703
access, 4-5, 698, 699
case study, 700-703
interoffice, 5,698-699
optical amplifiers in, 700
traffic distribution changes, 699
WDM deployment in, 699
See also networks
metropolitan-area networks (MANs), 4, 39, 381
micro-electro-mechanical system (MEMS) switches, 209-212
3D, 212 analog beam-steering mirror, 210 fabrication techniques, 211-212
n • n switch using mirrors, 211 two-state pop-up mirror, 209, 210
See also optical switches mid-span spectral inversion (MSSI), 319
midstage access, 408
mixed integer linear program (MILP), 452 LTD, 452, 453
value approximation, 453 mixing probability, 473 mode-locked lasers, 174-176 amplitude modulation illustration, 177 gain, 176
output oscillation, 175 time interval between pulses, 176
See also lasers modular OADM architecture, 412, 413 modulation, 186, 239-242, 272 cross-gain (CGM), 219-220 cross-phase (CPM), 83, 89-90, 220-223 design considerations, 343
direct, 38, 186-187 external, 38, 187-190 instability, 97 multilevel, 249 on-off keying (OOK), 186-190, 239-240 optical duobinary, 246-248
optical single sideband (SSB), 248-249 self-phase (SPM), 76, 83-88
subcarrier, 242-245 vestigial sideband (VSB), 249
See also demodulation monochromatic plane waves, 83 multicasting, 502
multichannel multipoint distribution service (MMDS), 597
multifiber rings, 480-481 multilayer thin-film filters, 743-750 cavities, 747
design, 747-750 single cavity, 749 three-cavity, 750 transfer functions, 746, 748, 749 two-cavity, 749
wave propagation and, 743-747
Trang 4multilevel modulation, 249
multilongitudinal mode (MLM) Fabry-Perot
lasers, 34-35, 36
multimode fiber, 33-35, 60
core diameters, 33
geometrical optics model, 33, 35
graded-index, 53
propagation modes, 60
step-index, 53
See also optical fiber
multiple-longitudinal mode (MLM) laser,
168, 169
multiplexers, 115
add/drop (ADMs), 378
high channel count architectures, 148-151
misalignment, 345
SONET, 365
stacked-up, 365
multiplexing, 618
asynchronous, 365
cost reduction, 365
frequency division (FDM), 13
illustrated, 13
optical time division (OTDM), 12-13
SONET/SDH, 364-366, 367-371
subcarrier (SCM), 243-245
techniques, 12-14
time division (TDM), 12-13, 41,603,
619-631
two-stage approach, 150
See also wavelength division multiplexing
(WDM)
multiplex section layer, 370
multiprotocol label switching (MPLS), 9,
392-394, 558
ATM and, 394-395
bandwidth reservation, 393
benefits, 393
design philosophy, 393
forwarding hardware optimization, 393
label-switched path (LSP), 392
paradigm, 393
VPN support, 394
multiservice platforms (MSPs), 679-681
development of, 679
ring configuration deployment, 681
service delivery, 680
multistage banding, 148-149
multistage interleaving, 149-151
multistage MZI, 138-139
multivendor interoperability, 5 0 5 - 5 0 7
narrowband DCS, 380
negative dispersion fibers, 95-98
network elements, 497 agents, 497-498 element management system (EMS), 497-499 types of, 497
network file system (NFS), 390 network interface units (NIUs), 593, 598 dedicated bandwidth, 594
illustrated, 594 optics/electronics, 594
shared bandwidth, 594, 595
in switched networks, 593 network layer, 19
network management accounting management, 497 adaptation management, 496, 524-526 configuration management, 496, 519-526 connection management, 496, 520-524 cost, 495, 530
equipment management, 519-520 fault management, 496, 503,507-519 framework, 497-499
function decentralization, 497 functions, 495-497
hierarchical performance of, 497 implementation, 497
information model (IM), 499-500 overview illustration, 498 performance management, 495-496, 507-519
protocols, 500-501 security management, 496-497 summary, 530-531
network management system (NMS), 499 networks
access, 4-5, 591-612 agile, 704
all-optical, 24-26 ATM, 9, 381 cable, 595 circuit-switched, 6-7 crosstalk in, 303 diameter, 647 distributed control, 496
distribution, 593
Trang 5814 INDEX
networks (continued)
ESCON, 12, 21
evolution, 667-681
hybrid fiber coax (HFC), 596
integrated services digital (ISDN), 597
interoffice, 5
IP over SONET, 19-20
line, 476
long-haul, 4, 5, 688-698
Manhattan Street, 646, 647-648
metro, 4-5, 698-703
next-generation, 673-681
nontransparent, 25
opaque, 704
packet-switched, 7-9
photonic packet-switched (PPS), 615-660
practical, 25
public, illustrated, 5
ring, 431,432, 473,478-479
scalable, 669
survivability, 537-587
telephone, 595
transparency, 24-26
twisted-pair, 596
ultra-long-haul, 690-691,694-695
undersea, 5, 697-698
wavelength-routing, 15,403,462-464
See also optical networks; SDH networks;
SONET; WDM systems network-to-network interface (NNI), 382,
385, 523
next-generation networks, 673-681
architectural choices, 673-681
illustrated, 680
nodes
failures, 538,553-554
Manhattan Street network, 646
PPS, 619
remote (RNs), 593, 594
routing, 616, 617
shufflenet, 646, 647
noise
amplifier, 760-762
APD, 255
ASE, 337
beat, 256
front-end amplifier, 254-255
shot, 253, 254, 759
signal-dependent, 288
thermal, 253,254
noise figure, 255 amplifier, 257 front-end amplifier, 255
input coupling loss and, 258 nonblocking switches, 202-203 noncompliant wavelength interface, 525
nonlinear amplifying loop mirror (NALM), 627
nonlinear dielectric polarization, 83 CPM, 89
four-wave mixing (FWM), 91, 92 SPM, 84, 85
nonlinear effects, 76-98, 323-335 categories, 76, 323
cross-phase modulation (CPM), 333-335 effective area, 77-79
effective length, 77-79, 323-325 four-wave mixing (FWM), 76, 329-333 limitations, 323-335
minimizing, 344
on pulse propagation, 735-738 peak transmit power limit, 288 propagation and, 81-83 role of chromatic dispersion management, 335 self-phase modulation (SPM), 76, 333-335 stimulated Brillouin scattering (SBS), 76, 77, 79-80, 325-326
stimulated Raman scattering (SRS), 76, 77, 80-81,326-329
transmit power and, 344 nonlinear index coefficient, 85 nonlinear length, 737 nonlinear optical loop mirror (NOLM), 623, 626-629
elements, 626
experiments, 627 illustrated, 627 nonlinear amplifying loop mirror (NALM) and, 627
terahertz optical asymmetric demultiplexer (TOAD), 627-628
nonlinear polarization, 741-742 nonlinear propagation coefficient, 736 nonlinear Schr6dinger equation (NLSE), 737 non-return-to-zero (NRZ) modulation, 240-242
advantages, 241 bit rate and, 312 chromatic dispersion limits, 309-311
Trang 6PMD and, 322
uses, 242
See also signal formats
nonrevertive protection, 540
nontransparent networks, 25
nonzero-dispersion fiber (NZ-DSF), 93-94
choosing, 342
chromatic dispersion, 93,316
dispersion slopes, 94
for submarine systems, 342
TeraLight, 93
for terrestrial systems, 342
See also optical fiber(s)
normalized propagation constant, 61
NP-complete problems, 461
OCh-Mesh protection, 576-581
OCh-SPRing protection, 575-576
offered load, 467
offline lightpath requests, 475-481
offline RWA problem, 462
OMS-DPRing protection, 571,572
illustrated, 572
implementations, 571
See also optical layer protection
OMS-SPRing protection, 571-573
after failure, 574
illustrated, 573
ring switching, 574
span switching, 574
two-fiber version, 573
See also optical layer protection
online RWA problem, 462-463,475,
481-482
on-off keying (OOK) modulation, 186-190,
239-240
DC balance, 241
direct, 186-187
external, 187-190
illustrated, 240
non-return-to-zero (NRZ) format, 240-242
return-to-zero (RZ) format, 240-242
signal formats, 240-242
See also modulation
opaque networks, 704
open fiber control (OFC) protocol, 528-530, 534
functioning of, 528-529
illustrated, 428
state machine run by each node for, 529
Open Shortest Path First (OSPF), 391
operations support system (OSS), 499
optical add/drop multiplexers (OADMs), 15, 40, 41,403, 408-419, 429-430, 679
architecture comparison, 414 architecture illustrations, 413 architectures, 411-4 16 band drop architecture, 413,416 benefits, 409 410
illustrated, 404 implementation, 15-16 inflexibility, 410 key attributes, 411-412 line ports, 15
in metro ring case study, 701 modular architecture, 412, 413 parallel architecture, 412, 413 reconfigurable, 417-419 role illustration, 409 serial architecture, 413, 414-416 single-channel OADM (SC-OADM), 414 use of, 403,408-409
in wavelength-routing network, 16 WDM ring using, 561
optical amplifiers, 151-165,289-299, 408 advantages, 151
block diagram, 408 cascades, 293-294 configurations, 290 drawbacks, 151 erbium-doped fiber amplifiers (EDFAs), 154-159
Fabry-Perot amplifier, 167 gain saturation, 291
in metro networks, 700 midstage access, 408 noise, 760-762
at periodic intervals, 100 Raman amplifiers, 159-161
semiconductor (SOAs), 161-165 spacing penalty, 294-296 spontaneous emission, 152, 153 stimulated emission, 152-153 types of, 151
See also line amplifiers; optical preamplifiers; power amplifiers
optical buffers, 28 optical channel (OCh) layer, 504-505 path (OCh-P), 505
section (OCh-S), 505 transparent section (OCh-TS), 505
Trang 7816 INDEX
optical channel-path trace, 509
optical channel-section trace, 509
optical channel-transparent section
trace, 509 optical crossconnects (OXCs), 15, 40, 41,380,
403, 430, 463 all-optical, 422, 424, 425-428
bit rate transparency, 420
configuration comparison, 423
configurations, 421-422
as cost-effective passthrough, 419
electrical core, 428
functions, 403-404
illustrated, 404
multiplexing and grooming, 421
network use illustration, 420
OLT system integration, 424-425
optical core, 428
performance monitoring, 420-421
port complex, 421
ports, 419, 422
protection, 420
reconfigurability and, 419
service provisioning, 420
size of, 463-464
switch core, 421,422, 423
test access, 421
wavelength conversion, 421
wavelength plane, 427-428
in wavelength-routing network, 16
optical duobinary modulation, 246-248
bandwidth advantage, 247
error propagation and, 247
ternary signaling scheme, 247
optical fiber(s), 10, 12
attenuation coefficient measurement, 349
bundles, 683
capacity limits, 249-250
choice, 341-342
cladding, 33
core material, 33
cross section, 50
in design consideration, 341-342
dispersion-shifted (DSF), 36, 75
graded-index, 53
LEAF, 94-95
light propagation in, 50-64
longitudinal section, 50
loss, 31-32
low-loss, 33 multimode, 33-35, 60 new types of, 93-98 nonzero-dispersion (NZ-DSF), 93-94 propagation of signals in, 49-104 pulse propagation in, 731-740 single-mode, 35-37, 54, 59 standards, 721
step-index, 53 transmission system evolution, 34 optical gating, 218-220
optical layer, 20-24 client layers of, 363-400 fault handling, 563 functions, 504 layers within, 504-505 lightpaths, 21 network-to-network interface (NNI), 523 optical channel (OCh) layer, 504-505 optical multiplex section (OMS) layer, 504-505
optical transmission section (OTS) layer, 504-505
services and interfacing, 502-504 user network interface (UNI), 523
See also layered network architecture optical layer overhead, 514-519 applications of, 515 digital wrapper overhead, 518-519 illustrated, 514
optical supervisory channel (OSC), 516-518
pilot tone, 516-517 rate-preserving overhead, 518 techniques, 514, 515-519 optical layer protection, 560-582, 584 1+10Ch, 569, 570, 574-575 1§ 569, 570 1:10MS, 571
I : N transponder, 573 bandwidth, 563 benefit, 562, 564 configuration illustration, 561,562 cost savings, 560
efficiency, 563 for enhancing SONET protection, 565 example, 564
OCh-Mesh, 576-581 OCh-SPRing, 575-576
Trang 8OMS-DPRing, 571,572
OMS-SPRing, 571-573
operating in optical channel layer, 568
operating in optical multiplex section (OMS)
layer, 568
for resilience, 563-564
routes, 566
schemes, 567-582
summary, 568
technique selection, 582
wavelength, 563
See also protection
optical line terminals (OLTs), 15, 41,403,
406-408, 429, 677
block diagram, 406
deployment, 15
functional elements, 406
illustrated, 404
optical amplifiers, 406
optical supervisory channel (OSC), 407-408
overhead, 407
OXC system integration, 424-425
transponders, 406-407
use of, 403
wavelength multiplexers, 406
in wavelength-routing network, 16
optical multiplex section (OMS), 504
optical networks
bandwidth, 10
deployment drivers, 1-2
evolution, 32-40
first generation, 12
introduction to, 1-42
passive (PONs), 600
problems solved by, 10
second generation, 14-16
See also networks
optical network units (ONUs), 599-607
different wavelength direction to, 606
performing NIU function, 599
specific time slot assignment to, 603
TDM approach and, 603
for upstream channel, 603
optical packet demultiplexers, 659
optical packet switching, 26-28
mission of, 27-28
nodes, 27, 28
optical path trace, 509
optical phase lock loop, 633-634
optical power, 31-32 optical preamplifiers, 255-258,290 design, 290
receivers with, 256
See also optical amplifiers optical safety, 526-530 optical single sideband (SSB) modulation, 248-249 implementation, 248
uses, 249 optical SNR (OSNR), 262-263 degradation, 293
measured, 263 obtaining, 263 optical supervisory channel (OSC), 407-408,
498, 516-518
illustrated, 516 location, 517 uses, 516, 518 wavelength choice, 516, 517
See also optical layer overhead optical switches, 199-216 applications, 199, 200 Bene~, 206-207 bubble-based waveguide, 212, 213 bulk mechanical, 207-209 Clos, 204-205
crossbar, 203-204 crosstalk, 201 electro-optic, 213-214 extinction ratio, 200 insertion loss, 200-201 large, 201-207 latching, 201 liquid crystal, 212-213,214 micro-electro-mechanical system (MEMS), 209-212
in packet-switched networks, 200 parameters, 200-201
reliability, 201 SOA, 214-215 Spanke, 205-206 Spanke-Bene~, 207 technologies, 207-215 technology comparison, 208 thermo-optic, 214
optical time division multiplexing (OTDM), 12-13,619-631
aggregate rate, 619 bit interleaving, 620-623
Trang 9818 INDEX
optical time division multiplexing (continued)
electronic TDM vs., 619
fixed, 27
framing pulses, 620
illustrated, 621
implementation, 12
packet interleaving, 623-625
statistical, 27
optical-to-electrical-to-optical (OEO)
converters, 27, 407 optical trace, 509
optical transmission section (OTS),
504-505 optimum decision rule, 258
optoelectronic regeneration, 217-218
output buffering, 637-639
with fiber delay lines, 642
with multiple wavelengths, 642
switches, 638
switching multiple input wavelengths, 644
See also buffering
overlay model, 523
overlay plus model, 523, 524
packet buffers, 638
packet interleaving, 623-625
demultiplexing operation, 625, 626
function illustration, 621
optical multiplexer, 624
packet layer, 616
packet-over-SONET (POS), 389
packets, 7
assured forwarding (AF), 392
buffered, 8
delay, 645-647
Diff-Serv packets, 392
expedited forwarding (EF), 392
flood, 390
link state, 390, 391
loss probability, 637
lost, 391,558
LSP, 393, 559
misrouted, 637, 645
queued, 8
sent by end node, 616
packet-switched networks, 7-9
best-effort service, 8
frame relay, 8
invention of, 7
optical, 26-28
packet header, 7 packets, 7 statistical multiplexing, 7-8 switches in, 200
parallel OADM architecture, 412, 413 fully tunable OADM with, 417, 418 illustrated, 413
loss, 412 partially tunable OADM with,
417, 418 parameters, this book, 717-719 passive optical networks (PONs), 600 architecture comparison, 601 evolution, 608-610
power budget calculation, 611 TPON, 603-604
wavelength-routed, 609-610 WDM components, 607 WPON, 595, 605
WRPON, 605-608
See also optical networks passive photonics loop (PPL), 606 path graph, 461
path layer, 370 path overhead bytes, 375 illustrated, 373
See also SONET frame structure peer model, 523, 524
performance management, 495-496, 507-519, 530
BER measurement, 509 impact of transparency, 508
See also network management performance monitoring, 420-421 permittivity of vacuum, 56 phase, 732
conjugation, 319 masks, 126 mismatch, 330 shifts, 118 phase lock loop (PLL), 266 phase-shift keying (PSK), 278 phase velocity
of pulse, 732
of wave, 732 photocurrent autocorrelation of, 758 autovariance, 759 spectral density, 759, 761
Trang 10photodetectors, 192-197, 250
avalanche (APD), 255, 275
efficiency, 193
materials, 192, 193-194
operating bandwidth, 194
photodiode, 195-197
principle, 192, 193
responsivity, 194
photodiodes, 195-197
avalanche, 197
bandwidth, 198
noise performance, 198
pin, 195-197
photonic packet-switched (PPS) networks,
615-660
block diagram, 617
buffering, 618, 635-649
burst switching, 649-650
feedback configuration, 636-637
feed-forward architecture, 636
functions, 618-619
header processing, 634-635
link speed, 617
nodes, 619
OTDM, 619-631
research, 619
summary, 657
synchronization, 618-619,
631-634
See also PPS testbeds
physical layer, 18
designing, 283-284
interfaces, 382
link initialization and take-down, 284
power penalty and, 284-287
SONET, 370
physical topology, 440
piezoelectric filters, 133
pilot tones, 516-517
advantages/disadvantages, 516
frequency, 515, 516
pinFET, 199
pin photodiodes, 195-197
illustrated, 197
receiver sensitivity, 261
structure, 196
See also photodiodes
plain old telephone service (POTS), 591
Planck's constant, 252
Platinum service class, 567
plesiochronous digital hierarchy (PDH), 364 problems, 364
SONET/SDH vs., 364-366
transmission rates, 365 pn-junctions, 163, 166, 195
forward-biased, 164 reverse-biased, 195, 196
PNNI (private network-to-network interface) routing, 387-388
goal, 388 signaling protocol, 388 points of presence (POPs), 4 point-to-point links, 351,403 OLTs in, 403
protection, 544-546
point-to-point protocol (PPP), 18, 388 point-to-point WDM (PWDM) ring, 442 architecture, 443
example, 443-444 illustrated, 442 number of wavelengths, 447 router ports, 447
See also lightpath topologies Poisson distribution, 753-754 Poisson random processes, 755-756
polarization, 61-63, 82 dielectric, 56, 82 induced electric, 56
interfering signals, 286 linear, 61,742 magnetic, 56
nonlinear, 741-742 orthogonal, 62 state of (SOP), 62, 113 transverse, 61 polarization-dependent loss (PDL), 63, 110, 322-323
bulk mechanical switches, 209 total, 323
polarization-mode dispersion (PMD), 62, 320-323
compensation, 321-322 distance limit due to, 684 effects, 62, 63
first-order, 322 illustrated, 63
as impediment, 308 imposed limitations, 320, 321 intersymbol interference (ISI), 321 NRZ modulation and, 322