Loading...

Small Signal Analysis of Fiber Bragg Grating (FBG) Arrays and Experimental Verification

Rajabvand, Mohammad | 2010

1461 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 41148 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Behnia, Fereidoon
  7. Abstract:
  8. In-fiber and all-optical wavelength-selective signal processing are key aspects of fiber Bragg grating (FBG)-based devices in optical communication systems. FBGs with sharp filtering properties have already been used in fiber optic communication networks as dispersion compensators, optical add–drop multiplexers, fiber lasers, and optical label switching modules. We have developed an in-fiber wavelength-selective optical intensity modulator to superimpose low rate overhead data on the transit high-speed payload signals. The tunable fiber Bragg grating (FBG), as the heart of a wavelength-selective modulator (WSM), is designed and properly biased to implement the desired modulation specification. Experiments with strong and relatively weak gratings confirm the wavelength-selectivity and stability of modulation. The fiber-based modulator is employed for optically tagging or labeling individual wavelength channels using baseband and amplitude-shift keying (ASK) modulated signals. Potential performance limitations of WSM are investigated and described in terms of eye opening penalty and crosstalk between WDM channels. A simple overhead (OH)/label erasing technique is also provided and used for modifying the labels through cascaded WSMs. The performance of such cascaded systems is calculated both with and without considering the optical loss compensation. The results confirm the ability of WSMs for low speed applications such as quality of service (QoS) management and service level agreement (SLA) for differentiated services. Uniform fiber grating can have a large group delay in the edge of transition band (TB). In fact, large time delay near a photonic band edge is a general property of finite periodic structures. We describe delay response of FBG in detail to design the appropriate parameters and selecting different FBG samples with optimum bandwidth and delay characteristics. We present theoretical analysis for the phase and amplitude of a microwave modulating signal when the optical carrier is passed through the band edge of a uniform grating. Amplitude and phase response of device have been computed in order to compare their operation at different RF throughout the microwave bands (2–16 GHz)
  9. Keywords:
  10. Fiber Bragg Grating (FBG) ; Transtion Band ; Wave Length-Selective Modulation ; All-Optical Label Swapping ; Band Edge Delay Line

 Digital Object List

  • محتواي پايان نامه
  •   view