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Cyan Z-Series Engineering and Planning Guide
Release 5.0
700-0023-05-00 Rev. 1
© 2013 Cyan, Inc. – All Rights Reserved.
P a g e
151
Configuring the LAD-40E Gain Parameters
Note: The default values should only be adjusted after consulting a Cyan system engineer to
determine the proper settings.
LAD-40E TX Pre-Amp attenuation should be set to 10 dB, and the TX Post-Amp attenuation should be set
to 3 dB. These values should not be changed. This guarantees a launch power of -1 dBm per channel.
LAD-40E RX Pre-Amp attenuation and RX Amplifier gain is set according to the span loss, as shown in the
table below.
Span Loss
RX Pre-Amp
Attenuator
RX Amp Gain
Less Than 13 dB
13 – Span Loss
15
Greater Than or Equal to 13 dB
0
Span Loss + 2
Note: The LAD-40E supports manual gain tilt control. Gain tilt can occur when channel gain is not flat
upon reaching the optical amplifier. In this situation, higher signals receive more power, while lower
signals receive less power.
3.3 Dispersion Compensation Modules
Cyan offers Dispersion Compensation Modules (DCMs) for various amounts of dispersion. Typically,
optical fiber spans with LAD-2P/LAD-4/LAD-8/LAD-8i/LAD-40 or LAD-4A/LAD-8A modules have
distances shorter than 95 km before regeneration and carry 10G waves and do not need dispersion
compensation. Longer links provided by the LAD-8E module, LAD-40E module, or optical-optical-optical
(OOO) links that are amplified optically, require dispersion compensation.
The following table shows a list of DCM units offered:
Fiber Type
Distance
(km)
Dispersion
(ps/nm)
Max Loss
(dB)
Max PMD
(ps)
Size
(1
RU)
SMF-28
10
-164
2.1
0.30
0.5
SMF-28
20
-328
2.7
0.40
0.5
SMF-28
40
-656
4.1
0.50
0.5
SMF-28
60
-985
5.5
0.60
0.5
SMF-28
80
-1313
6.9
0.70
0.5
SMF-28
100
-1641
8.3
0.80
1.0
TW-RS
20
-90
2.9
0.21
0.5
TW-RS
40
-180
3.4
0.30
0.5
TW-RS
60
-270
3.9
0.37
0.5
TW-RS
80
-360
4.4
0.43
0.5
TW-RS
100
-450
4.9
0.48
0.5
LEAF
20
-76
3.9
0.30
0.5
LEAF
40
-153
4.8
0.50
0.5