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Design of Volume Holographic Code Division Multiple Access (CDMA) Systems

Parsay, Alireza | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51111 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Salehi, Javad
  7. Abstract:
  8. The amount of assigned computation to data centers, which generally process data streams in a parallel manner has grown in recent years. Switches are one of the most important components in such centers, and their appropriate design can reduce the power loss and increase the processing gain. Among such devices, holographic CDMA switches, which exploit the high storage capability of thin holograms to reduce the size of switches, are suitable alternatives to the traditional electronic switches. In this research, the fairly high power loss of such switches has significantly decreased by modifying the output filter. This modification includes two steps. In the first, the typical matched filter has been replaced by the phase only filter. In the second, we have proposed a method for circular correlation instead of storing all of the input patterns which are the cyclic shift of each other. Also, we have proposed a method in which all the codes are generated by using the multiplication of the space base codes instead of utilizing liquid crystal spatial modulators for increasing the switching rate. Moreover, the idea of storing the pseudo random input ports' patterns in a single volume hologram crystal by code multiplexing has been proposed, which reduces the switch size to a great extent by exploiting the third dimension of space. Finally, the tradeoff between physical size and loss in these structures has been investigated
  9. Keywords:
  10. All Optical Switch ; Electrooptic ; Optical Code Division Multiple Access (OCDMA) ; Volume Hologram ; Photo-Refractive Materials ; Bragg Selectivity

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