4 Serial and parallel filtering designs for DWDM transport stages
Staged Parallel Filtering
Staged Serial Filtering
Full-Band Filtering
Band filter
C/L-band
splitter
Band
preamp
Trunk
Channel filters
C-band
interleave filter
(optional)
Loss fixed per
stage count
Narrow band
???amplets??? (optional)
Band preamp
C/L-band
splitter
Trunk
Loss increases with
channel count
Trunk
Full-band AWG filters
(16, 20, 32, 40 channels)
C/L-band
splitter
Band
preamp
Increased up-front
channel costs
Figure 8.5 Fiber and WDM layer survivability schemes
1x2
switch
Working
Protection
Fiber Span Protection (1+1) Dedicated Protection Ring
Unidirectional Path-Switched Ring (UPSR)
Shared Protection Ring
Bidirectional Line Switched Ring (BLSR) Mesh Recovery
Two-fiber dedicated
channel protection
Working
(inner fiber)
Protection
(outer fiber)
Source bridging
Receiver
switching
2:1
splitter
1x2
switch
Working
Protection
Fiber Span Protection (1:1)
2x1
switch
OTM
OTM
OADM
Span
signaling
Working
lightpath
Protection
lightpath
Preemptable,
shared lightpath
Two-fiber dedicated
channel protection
Bidirectional
connection
Preemptable
bidirectional connection
Receiver
switching
ROADM
OXC
Fiber and WDM 205
two copies of each signal.
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