Arora, Poonam (2008)
Design, Realization and Applications of Dynamically Controllable Bragg Gratings.
Technische Universität Darmstadt
Ph.D. Thesis, Primary publication
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Item Type: | Ph.D. Thesis | ||||||
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Type of entry: | Primary publication | ||||||
Title: | Design, Realization and Applications of Dynamically Controllable Bragg Gratings | ||||||
Language: | English | ||||||
Referees: | Tschudi, Prof. Dr. Theo ; Birkl, Prof. Dr. Gerhard | ||||||
Advisors: | Tschudi, Prof. Dr. Theo | ||||||
Date: | 1 February 2008 | ||||||
Place of Publication: | Darmstadt | ||||||
Date of oral examination: | 19 December 2007 | ||||||
Abstract: | This dissertation emphasizes on the realization, investigation and manipulation of Bragg gratings with external electrical control especially for spectral filtering applications. Volume photorefractive Bragg gratings realized in bulk lithium niobate crystals are manipulated with external electric field in order to demonstrate fast electrically switchable holographic lenses and mirrors. Furthermore, photorefractive Bragg gratings are inscribed in lithium niobate waveguides and a fast electrically tunable integrated optical spectral filter is demonstrated. In addition, a detailed investigation of higher harmonic components of nonlinear photorefractive waveguide gratings in reflection geometry has been reported. The most important and interesting part of the entire work is the introduced concept of phase-shift keying of corrugated waveguide Bragg gratings which was used to dynamically reconfigure the Filter transfer function. This novel concept comprises, for the first time to the best of my knowledge, the use of external electric field to dynamically inscribe phase-shifts to more than two sections of the already fabricated integrated corrugated Bragg grating. Employing this technique, a fast (< one microsecond) reconfiguration or synthesis of the transfer function into several desirable profiles is demonstrated. Some of the realized reconfigurations e.g. continuous tuning of a single selected channel, reconfiguration from pass-band to stop-band, reconfiguration from one to two, three and five pass-bands, reconfiguration to a flat-top profile, dynamic correction of the transfer function profile, dynamic control of the bandwidth and the shape of the transfer function are presented and discussed. One of the most promising results was the estimation of switching time. The demonstrated switching with time less than 1 microsecond (few GHz). With such fast switching, the proposed integrated optical filters with reconfigurable transfer functions are very promising not only for the existing DWDM networks but also for the next generation high-speed reconfigurable telecommunication networks like OCDMA (optical code division multiple access). |
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Uncontrolled Keywords: | Bragg gittern, Photorefraktive optik, Optische filtern | ||||||
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URN: | urn:nbn:de:tuda-tuprints-9371 | ||||||
Divisions: | 05 Department of Physics | ||||||
Date Deposited: | 17 Oct 2008 09:22 | ||||||
Last Modified: | 08 Jul 2020 23:01 | ||||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/937 | ||||||
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