DocumentCode :
1294195
Title :
Impact of Phase Noise and Compensation Techniques in Coherent Optical Systems
Author :
Colavolpe, Giulio ; Foggi, Tommaso ; Forestieri, Enrico ; Secondini, Marco
Author_Institution :
Dipt. di Ing. dell´´In formazione, Univ. of Parma, Parma, Italy
Volume :
29
Issue :
18
fYear :
2011
Firstpage :
2790
Lastpage :
2800
Abstract :
One of the most severe impairments that affect coherent optical systems employing high-order modulation formats is phase noise due to transmit and receive lasers. This is especially detrimental in uncompensated links, where an ideal compensator for channel distortions and laser phase noise should first eliminate receive phase noise, then equalize channel distortions, and only later compensate for transmit phase noise. Unfortunately, the simultaneous presence of transmit and receive phase noise makes very difficult to discriminate between them, even in the presence of a pilot tone. Moreover, the picture is different for optical systems using single-carrier or orthogonal frequency division multiplexing, where transmit and receive phase noise components may have a different impact. All these aspects are analyzed and discussed in this paper. A novel digital coherence enhancement (DCE) technique, able to significantly reduce the phase noise of transmit or receive lasers by using an interferometric device plus a very simple electronic processing, is also described. The performance of this technique and the statistical properties of the residual phase noise are analytically derived and verified by simulations, showing a high increase of the maximum bit-rate-distance product. The practical implementation of DCE is finally discussed and some alternative implementation schemes are presented.
Keywords :
OFDM modulation; compensation; laser noise; light coherence; phase noise; bit-rate-distance product; channel distortions; coherent optical systems; compensation techniques; digital coherence enhancement; electronic processing; high-order modulation; interferometric device; laser phase noise; orthogonal frequency division multiplexing; receive lasers; receive phase noise; statistical properties; transmit lasers; transmit phase noise; Dispersion; Equalizers; Laser noise; OFDM; Optical noise; Optical receivers; Phase noise; Coherent detection; group velocity dispersion (GVD); optical communication; orthogonal frequency division multiplexing (OFDM); phase noise;
fLanguage :
English
Journal_Title :
Lightwave Technology, Journal of
Publisher :
ieee
ISSN :
0733-8724
Type :
jour
DOI :
10.1109/JLT.2011.2164237
Filename :
5979171
Link To Document :
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