Optical Networks - _References7_93

# Optical Networks - _References7_93 - 466 WDM Network...

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466 WDM Network Elements (b) Next suppose that 25% of the lightpaths passing through need to be con- verted from one wavelength to another. This is done by sending the lightpath to one of a pool of regenerators/wavelength converters attached to the OXC. Each such regenerator uses two ports in the OXC. Thus a lightpath needing to be converted uses four OXC ports. Now, how many WDM line systems can the OXC support? (c) Now suppose the WDM line systems are designed with eight bands, each with four wavelengths. Assume that all the lightpaths passing through can be passed through at the band level without having to be demultiplexed down to the individual channel. For lightpaths that are dropped and added, the entire band is dropped and demultiplexed after the bands are passed through the OXC. No wavelength conversion is needed. How many WDM line systems can the OXC support? 7.7 Consider the wavelength plane switch architecture of Figure 7.14. Consider the situation where we have a total of four ﬁbers and 40 wavelengths on each ﬁber. We must design the node such that any four signals can be dropped. (Note that this implies we could potentially drop all the wavelengths on a particular ﬁber while passing through all the wavelengths on the other ﬁbers.) The wavelengths are dropped onto transponders, which have tunable lasers. The 40 wavelengths are split into ﬁve bands of 8 wavelengths each, and a tunable laser can tune over a single band. (a) Draw a block diagram of this node and indicate the minimum number of transponders needed. Compare this against an approach using large non- blocking switches. (b) Now suppose we have tunable lasers that can tune over two bands instead

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## This note was uploaded on 01/15/2011 for the course ECE 6543 taught by Professor Boussert during the Spring '09 term at Georgia Tech.

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Optical Networks - _References7_93 - 466 WDM Network...

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