ELECTRO-OPTIC MODULATED RANDOM PHASE HOLOGRAPHIC MULTIPLEXING TECHNIQUE

Open Access
Author:
Liu, Hongbo
Graduate Program:
Electrical Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
July 18, 2007
Committee Members:
  • Ruyan Guo, Committee Chair
  • Amar S Bhalla, Committee Member
  • Iam Choon Khoo, Committee Member
  • Sridhar Komarneni, Committee Member
Keywords:
  • fiber optic
  • holographic multiplexing
  • Volume holographic
  • random phase modulation
Abstract:
Volume holograms are formed by means of interference. When a volume hologram is recorded in thick photorefractive materials, a photo-induced periodic index variation ∆n is produced. Due to the nature of volume holograms, it is possible to record multiple images in a common area. Such technique, so called volume holograms multiplexing, can be realized by changing different optical parameters, such as incident angular, wavelength and phase. Currently, several multiplexing techniques, such as angular multiplexing, wavelength multiplexing, phase-coded multiplexing, or the combination of them have been developed. In this thesis work, a detailed study of a new volume hologram multiplexing technique using ferroelectric crystal fiber speckle patterns as reference beam is presented. By adopting ferroelectric solid crystal as modulation material, this technique makes a GHz data retrieving process achievable. Meanwhile, the waveguide form of modulation unit allows a more compact architecture and provides a basis for the future system integration. This thesis is planed as follows. In chapter 1, a brief introduction of some background related to photorefractive effect, volume hologram and multiplexing techniques will be given. Chapter 2 will give a statement of the thesis objective. A theoretical analysis about our modulation mechanism will be introduced in chapter 3. The simulation results and experimental results are presented in chapter 4. In chapter 5, a theoretical analysis of crosstalk noise is developed and the crosstalk noise-to-signal ratio of the system with multiple images recorded is estimated based on this analysis. Chapter 6 is devoted to some key optimization elements due to the waveguide-based modulation mechanism. A polarization multiplexing technique which allows a 30% system capacity enhancement under current experiment configuration is also proposed in this chapter. In chapter 7, a future work plane based on our preliminary work is proposed. Some relevant research works previously accomplished in our lab are also presented in this chapter.