Wavelength
Multiplexing
(Dense)
Wavelength Division Multiplexing
WDM
is typically-8 or less channels operating on the same fiberoptic waveguide.
Each channel has it's own optical carrier, within the low-loss IR region,
separated by 10s to 100s of nanometers in wavelength.
Converge Digest: WDM -- new WDM
Lightwave: Optical Networking and WDM Q&A
All-optical wdm packet networks
Channel
allocation
Linewidths,
stability, modes,
Allows
wider range of laser sources, simpler filters/receivers
General
issues
Power
and distortion budgets, ISI (interchannel crosstalk, skew, ...),
passive/amplifier effects
WDM in the Access Network and Key Components
WEST: WDM/electronic Switching Technology
Bell Atlantic / ATDNet WDM White Paper
WEST-- 40 Gb/s WDM + electronic switching technology
WDM Testing for Service Providers: A Product and Vendor Survey
FILTERING/SWITCHING,
CONVERSION, WADM
WADM -- ASE Noise Accumulation
DWDM (Dense WDM) The
new spectrum battle begins
("dark
fiber" -> "dark wavelength")
A
set of wavelengths has been allocated by the ITU committee establishing more
than 50 Optical Channels ("lambdas") within the wavelength range of
1.520 - 1.570 um (roughly 196-191 THz), with channel spacings nominally 100 GHz
(~0.80 nm.) The dense multiplexing scheme requires precise and stable laser
sources and highly-discriminating low-loss filters.
STATUS -- Overview / Tutorial Testbeds
Overviews /
Links
Context Issue on Optical Networking
Links to sites regarding Wavelength Division Multiplexing
DWDM from Hitachi Telecom (USA), Inc.
LIGHTWAVE MICROSYSTEMS ANNOUNCES BREAKTHROUGH ON NEW DENSE WAVELENGTH DIVISION MULTIPLEXER
DWDM and New Switching Architectures
North American DWDM Market To Reach $3.2 Billion by 2002
http://www.photonicsonline.com/profile.html
Standards:
ITU-T "The ITU Grid" on 1510-1568
1547.72 (red
band)
Tutorials Lucent Tutorial
Transmission
Paper
on ultimate bandwidth of standard singlemode fiber, including nonlinearities:
Optical
Transmitters:
Nortel High-stability wavelength-controlled DFB laser sources for Dense WDM applications
Nortel
LCM155-64N, strained-layer MQW DFB laser emitter + III-V MZI modulator chip --
OC-192 (10Gbps) long-distance apps. TE heatpumps, NTC thermistor monitor,
optical isolator, back-facet monitor diode. 0.9mW @1557nm, for <1500ps/nm
links.
TR_-NWT-000468
Nortel
LCM155W-20A Etalon Stabilized Laser (to +/-0.10nm lifetime) + III-V MZI
modulator, for very long haul STM16/OC-48 2.5Gbps on 12800ps/nm links with low
dispersion penalty. ITU wavelengths 1530-1560, 1.0 mW.
Ganged
sources vs. tunable sources
Modulation
issues, int/ext, chirp, extinction,
Channel
Wavelength/Power,
Bandwidth, Latency Allocations
|
Type |
CH |
Channel Spacing |
Channel width (.5dB) |
I.L. |
Isol. |
PDL |
Tdrift nm/° C |
|
WAVESPLITTER Fused Cascaded Fiber
(FCF), Unbalanced MZI |
8 |
.8nm (100 GHz) 1.6nm (200 GHz) |
.25 .5 |
<4dB |
>30demux >18mux |
<.2 |
<.005 0-50 |
|
|
16 |
.8nm (100 GHz) |
.25 |
<6dB <3dB |
>30demux >18mux |
<.2 |
<.005 0-50 |
|
NORTEL |
4 |
200 GHz |
|
|
|
|
|
|
JDS-Fitel |
|
|
|
|
|
|
|
http://www.wavesplitter.com/images/colorgraph.gif
OCLI / JDS-Fitel (wdm product catalog)
Fiber
/ Passives
Connectors [1]
AllWave™, wider wavelength range fiber
Couplers: Fiber Bragg Gratings, Graded-index Lenses, planar waveguide Ics, Arrayed Waveguide Gratings (AWG)
Switches,
converters
Repeaters,
Optical
Amplifiers: EDFAs, PrDFAs ...
EDFA:
Nortel Optoelectronics Metro WDM EDFA, single 980 pump
PDFA: Galileo E/O FluoroAmp
Noise
Figure
Pump
Channels: multi-pump
coupler 974, 977, 980, 983
or 1060, 1480
BW
0.6nm/3.0 channel spacing, >15dB isolation, >55dB directivity
ASE
Reflections
-- [1]
ISI,
nonlinearities: SPM, PMD, crosstalk, Raman/Brillouin scattering [1]
Reception
Fixed
vs. tunable filters, agile receivers
Arrayed-Waveguide Grating (AWG) DWDM Module
Limitations
The limiting factors are amplifier noise,
chromatic dispersion, self phase modulation (SPM), polarization mode dispersion
(PMD), crosstalk, and the optical frequency fluctuations of all components. Transparent Optical
Networks, Bachus et. al.,
Heinrich-Hertz Institut
[1]
Problems and
Considerations for WDM and Very High Bit Rate Transmission Systems -- Bell Atlantic
Futures:
Capacity -- Bell Labs Terabit experiments
NTONC National Transparent Optical Network Consortium (Bay Area)
Generic
Crosspoint
Wavelength
conversion
OADM
System
Issues
Standardization
/ Interoperability
Management
High-Speed Network Traffic Management: Automatic Control Approach
Allocation
Switching
" AT&T Corp. plans to use a very high-capacity fiber-optic network technology from Lucent Technologies Inc. The WaveStar Optical Line System can put up to 80 different signals - each as much as 2.5 Gbps - onto a single fiber-optic strand. With eight strands per system, it offers an astounding 3.2 terabits per second in capacity. "
Lucent: Optical Networking Today, June 8, 1998
Lucent statement
SONET
Bell Atlantic / ATDNet SONET over WDM White Paper
SONET DCC --Focal Communications Corporation
FTTC/HFC/LMDS --CICTR: Broadband Access Networks Systems
CDMA
rr24.rtf cdma, dark signalling
July 1, 1998 -- Bar-coding fiber
CTC: Delivering an all-optical cdma network solution
AF2025 v1c9-1 | Brilliant Force and the Expert... | (Ch 3)
Related
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