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WDM optical network and switching node with pilot tone communications

  • US 6,556,321 B1
  • Filed: 08/12/1999
  • Issued: 04/29/2003
  • Est. Priority Date: 08/27/1997
  • Status: Expired due to Term
First Claim
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1. A fiber optic wavelength division multiplexed ring, comprising:

  • a plurality of switching nodes, means for generating a plurality of wavelengths organized into bands on said ring, and transmitting a like plurality of traffic channels associated with said wavelengths; and

    means for transmitting maintenance channel data on at least one of said wavelengths as a pilot tone;

    wherein said maintenance channel has a modulation depth such that it matches the bit error rate (BER) or waterfall curve performance of the data channel so that the system can determine the performance of the data channel by monitoring the maintenance channel data and without looking at the maintenance channel payload.

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