Edwin Jan Klein - Universiteit Twente

Chapter 7
Figure 7.12. Measured eye patterns of the
input signal (top) and the signal at IDrop1
(bottom). The resonator is tuned “on
resonance”.
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Figure 7.13. The Measured eye patterns of
the signal at IDrop1 when the resonator is tuned
“off resonance”.
The multicasting feature of the OADM as it was shown in Figure 7.4 (for customers 1
and 5) was tested by tuning the first two resonators in the OADM such that each drops
an equal part of the input signal as is illustrated in Figure 7.14 (the figure is idealized,
typically MR1 is tuned so that it drops 50 % while MR2 is tuned to be on-resonance
to drop the rest of the signal). Figure 7.15 shows the two eye patters that were
measured at IDrop1 and IDrop2 and for this configuration. Although the amplitude of the
measured signals was lower compared to a single dropped signal, as can be expected,
the eye-patterns are still open. This shows that, at a bitrate of 40 Gbit/s, this OADM is
indeed capable of multicasting.
Dropped power (dB)
0
-3
-6
-9
-12
-15
MR1
MR 2
-18
1548 1549 1550
Wavelength (nm)
1551 1552
Figure 7.14. Multicasting principle: Each
resonator is tuned such that only part of the
signal (at λ=1550 nm) is dropped.
Figure 7.15. Multicasting principle: Each
resonator is tuned such that only part of the
signal (at λ=1550 nm) is dropped.