A Phase — Noise Insensitive Modulation Scheme for CDMA Optical Local Area Networks

  • Ennio Gambi
  • Franco Chiaraluce

Abstract

Optical Local Area Networks have been widely investigated and are now diffusely used in those applications which require very high bit-rate values. With the aim to exploit completely the large bandwidth offered by single-mode fibers, so increasing the number of connectable users, various multiple access schemes have been proposed, based on time, frequency or code division. Among them, our present interest is focused on the last technique, whose employment in the framework of optical systems still presents some open problems. In particular, it is known that the CDMA scheme is based on the auto- and mutual-correlation properties of the code sequences utilized. The best results are obtained with bipolar codes, such as the Gold code, but this implies the adoption of coherent modulation formats, whose performance may be corrupted by the presence of phase noise due to the transmitter and the local lasers. To overcome this drawback, in this paper we propose a hybrid technique, obtained as a combination of phase and polarization modulations, which reveals to be insensitive to the phase noise. After a brief description of the proposed technique, the system performance, in terms of probability error as a function of the code length and the number of users, is derived and compared with a traditional 2-PSK modulation.

Keywords

Phase Noise Modulation Scheme Hybrid Scheme Code Length Local Laser 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Technical Staff of CSELT, “Fiber Optic Communications Handbook”, Federico Tosto Ed., TAB Books, Blue Ridge Summit, PA (1990)Google Scholar
  2. 2.
    F. Khaleghi, M. Kavehrad, “A subcarrier multiplexed CDM optical local area network, theory and experiment”, IEEE Trans, on Commun., Vol. 43, No. 1, pp. 75–87 (1995)CrossRefGoogle Scholar
  3. 3.
    L. A. Rusch, H. V. Poor, “Effects of laser phase drift on coherent optical CDMA”, IEEE J. Selec. Areas Commun., Vol. 13, No 3, pp. 577–591 (1995)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • Ennio Gambi
    • 1
  • Franco Chiaraluce
    • 1
  1. 1.Dipartimento di Elettronica ed AutomaticaUniversità di AnconaAncona

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