Chromatic dispersion compensation by sub-band
AssigneeCisco Technology, Inc.
InventorsMarco Mazzini, Federico Carniel
Life of this patent
Estimating the term…
Abstract
End of line dispersion compensation is applied on a sub-band by sub-band basis. Adequate end-of-line dispersion compensation may be provided for high data rate WDM systems even for optical link lengths of 1000 km or more. Dispersion compensating gratings (DCGs) may be used as the dispersion compensating components. There is a great savings in cost and package volume compared to per-channel compensation schemes.
Claims18
In a WDM communication system, apparatus for terminating a WDM link comprising:
- a splitter splitting a WDM signal on said WDM link into a first portion and a second portion;
- a circulator receiving the first portion;
- a first dispersion compensating element that compensates dispersion of a first subband of the first portion, said first subband comprising a first group of adjacent channels of said WDM signal, said first dispersion compensating element comprising a dispersion fiber grating coupled to said circulator;
- a first demultiplexer that demultiplexes said first group of channels onto separate fibers for each channel following dispersion compensation by said first dispersion compensating element;
- a second demultiplexer that demultiplexes a second subband of said first portion onto separate fibers for each channel, said second subband comprising a second group of adjacent channels and not overlapping said first subband, said second demultiplexer serially coupled to said circulator after said first dispersion compensating element.
In a WDM communication system, a method for terminating a WDM link comprising:
- splitting n WDM signal on said WDM link into a first portion and a second portion;
- circulating said first portion through a circulator;
- compensating for dispersion of a first subband of said first portion by employing a first dispersion fiber grating, said first subband comprising a first group of adjacent channels of said WDM signal, wherein said first dispersion fiber grating transmits without reflection a second subband of said first portion;
- demultiplexing said first group of channels onto separate fibers after compensating for dispersion of said first subband;
- and
- demultiplexing said second subband of said first portion onto separate fibers, said second subband comprising a second group of adjacent channels and not overlapping said first subband.
In a WDM communication system, apparatus for terminating a WDM link comprising:
- means for splitting a WDM signal on said WDM link into a first portion and second portion;
- means for circulating said first portion:
- a first dispersion compensating means for compensating for dispersion of a first subband of said first portion, said first subband comprising a first group of adjacent channels of said WDM signal;
- means for demultiplexing said first group of channels onto separate fibers after dispersion compensation by said first dispersoncompensating means;
- and
- means for demultiplexing a second subband of said first portion onto separate fibers, said second subband comprising a second group of adjacent channels and not overlapping said first subband, said means for demultiplexing said second subband serially coupled to said means for circulating after said first dispersion compensating means.
Dependencies are inferred from the claim text.