Quasi-continuous PMD setting:
1.
Click the Advanced PMDE button on the left function panel to bring up the
advanced-function PMDE interface.
2.
Click the “Continuous PMD + Polarization Control” tab.
3.
Set the DGD and SOPMD values by dragging the sliders, by entering the desired
values in the value selection boxes under the plot axes and then clicking the
mouse outside the text boxes, or by dragging the red cursor within the plot area.
Click the “Set” button on the right of the screen to set the DGD/SOPMD values.
The DGD and SOPMD indicator boxes on the right of the screen will display the
closest available values to those selected.
4.
Select the continuous SOP scrambling frequency by either selecting a value from
the pull-down menu or typing a value in the box under the pull-down menu and
clicking elsewhere on the screen. Then, click “Enable Scrambling”.
5.2. PMD Mitigation in 40Gb/s systems
As the bit rate of fiber optic communication systems increases from 10 Gbps to 40Gbps,
100 Gbps, and beyond, polarization mode dispersion (PMD) has more and more impact
on system performance. PMD generally causes the two principal polarization components
of a light signal to travel at different speeds and hence spreads the bit-width of the signal,
as shown in Figure 29A. Consequently, it causes an increase in bit-error rate (BER) and
service outage probability. Unlike other system impairments, such as chromatic
dispersion (CD), the PMD effect on the system is random in nature and changes rapidly
with time, making it difficult to mitigate.
Document #: GP-UM-PMD-1000-21
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