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I n t e r n a t i o n a l Te l e c o m m u n i c a t i o n U n i o n
ITU-T The leader in
means
Recommendations
•
G.694.1 "Spectral grids for WDM applications: DWDM frequency
grid" specifies a frequency grid which supports a variety of DWDM
channel spacings ranging from 12.5 GHz to 100 GHz (and wider)
Cost-effective applications, through the use of a great
number of optical channels on a single optical fibre pair
•
Granularity in the capacity with the possibility of adding
new optical channels, also operating at different bit rates,
to the same optical fibre pair, as additional capacity is
required
•
Modularity in the reach of the systems, with possible link
length from a few to more than one thousand kilometres
•
Flexibility in link configuration [linear, ring with or without
optical add drop multiplexing (OADM)]
G.696.1 "Longitudinally compatible intra-domain DWDM applications" specifies long-haul DWDM systems primarily intended for
backbone applications
G.698.1 "Multichannel DWDM applications with single channel
optical interfaces" specifies DWDM systems primarily intended for
metro applications with channel bit rates up to 10 Gbit/s
G.698.2 "Amplified multichannel DWDM applications with single
channel optical interfaces" specifies DWDM systems primarily intended for core metro/regional applications that include line optical
amplifiers with channel bit rates up to 10 Gbit/s
G.959.1 "Optical transport networks physical layer interfaces"
specifies DWDM optical systems with 32 channels for different bit
rate classes up to 10 Gbit/s
DENSE WAVELENGTH
DIVISION MULTIPLEXING
For more information on activities related to optical
transmission Recommendations, please check the ITU-T Study
Group 15 website at:
www.itu.int/ITU-T/com15
G.973 "Characteristics of repeaterless optical fibre submarine
cable systems" deals with submarine DWDM systems without line
optical amplifiers
G.977 "Characteristics of optically amplified optical fibre submarine cable systems" deals with submarine DWDM systems with
line optical amplifiers
tsbpromo@itu.int
05.2008
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ITU-T
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Highlights
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100 GHz, 50 GHz, 25 GHz channel spacing
(G.694.1)
Unidirectional
Up to forty 10 Gbit/s optical channels 100 GHz
spaced per DWDM system, in C-band
G.652, G.653, G.655 optical fibre-supported
Attenuation (dB/km)
•
Optical
channels
....
0.6
0.5
O
E
S
C
L
U
0.4
0.3
0.2
0.1
1200
1300
1400
1500
1600
1700
Wavelength (nm)
SDH
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Multichannel (DWDM) interfaces (G.959.1)
Multivendor interoperability:
Vendor A Mux/Demux can be connected to
Vendor B Mux/Demux.
Vendor A
Gigabit Ethernet
G.959.1
OEO
DWDM
Mux/Demux
SDH
Vendor B
Gigabit Ethernet
OEO
DWDM
Mux/Demux
Fibre Channel
Vendor A
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Single channel (coloured) interfaces (G.698.1,
G.698.2)
Multivendor interoperability:
Vendor A transceiver can be connected through
Vendor B Mux/Demux to Vendor C transceiver
G.698.1
G.698.2
G.698.1
G.698.2
Vendor B
Vendor C
DWDM Transceiver
DWDM Transceiver
DWDM Transceiver
DWDM Transceiver
Optical
Mux
DWDM Transceiver
www.itu.int/ITU-T
Fibre Channel
Optical
Demux
DWDM Transceiver