Optical time-division-multiplexing is another promising solution for high-speed signal generation. Using the in-fiber PCF-MZI, we have also performed OTDM signal generation at different bit rates. The setup offers comparable performance to commercial multiplexers. We generated 160-Gb/s and 320-Gb/s OTDM signals based on PCF-MZIs. / Orthogonol frequency division multiplexing (OFDM) has attracted quite a lot of interests due to its incomparable advantages in high spectral efficiency optical communication, which significantly enlarges the optical transmission capacity. Optical demultiplexing (DEMUX) of OFDM signals requires FFT processing, which can be efficiently achieved by using cascaded delay interferometers. We theoretically and experimentally studied the transmission properties of cascaded and multi-section Sagnac interferometers and demonstrated their application for the optical OFDM DEMUX. 4-channel OFDM DEMUX is experimentally demonstrated with open eye obtained. / Our study on optical processing of high speed OTDM signals continues with fiber-based techniques using third order nonlinear effects. Based on HNLF, we can construct active fiber interferometer, namely here as nonlinear optical loop mirrors (NOLM). We investigate dispersion asymmetric nonlinear optical loop mirror (DA-NOLM) based on cross phase modulation for simultaneous two-channel demultiplexing (DEMUX) usmg only a single baseband control pulse. Reconfigurable DEMUX has been achieved for 40-Gb/s OTDM signals. The DEMUX are also switchable between two-channel and single-channel operations. Utilizing the tunable delay, DA-NOLM has also been applied to signal processing including pulse format conversions, and repetition rate multiplication. / Photonic crystal fiber based Mach-Zehnder interferometer (PCF-MZI) is constructed by a single line PCF, which is an in-line, all-fiber and coupler free device. As a delay interferometer (DI), PCF-MZI offers enhanced thermal stability in its operation. To date, applications of the in-fiber PCF-MZI are mainly focused on optical sensing instead of communications, which is a major objective in this thesis work. We have fabricated PCF-MZIs with different PCF lengths to introduce desirable delays for optical signal processmg, including differential phase shift keying (DPSK) demodulation, pulse format conversion, repetition rate multiplication and high speed optical time-division-multiplexing (OTDM) signal generation. / The continuously growing Internet traffic has resulted in a huge amount of data flow in the optical networks, particularly along with the recent developments of 3G/4G service, cloud computing, and Internet of things. High-data-rate optical transmission and interconnection are highly desirable in the near future, for next generation communication networks. Accompanied with the traffic growth is the requirement for faster signal processing technology. In this regard, all-optical processing plays a key role in eliminating optical-electrical-optical conversion, thus offering unmatched operation speed with reduced complexity and power consumption. This thesis focuses on high speed all-optical signal processing technologies based on innovative fiber-based interferometers, including Mach-Zehnder and loop mirror interferometers constructed by photonic crystal fiber (PCF), birefringent fiber and highly nonlinear fiber (HNLF). / We also investigated signal processing using nonlinear devices beyond those fiber interferometers. FWM is utilized for chirp magnification which was successfully applied to optical comb generation for obtaining optical OFDM signals. Optical comb generation with extinction ratio enhancement and flatness improvement is demonstrated utilizing a stimulated Brillouin scattering (SBS) based optical loop mirror. Clock recovery of OTDM-OOK signals has been successfully demonstrated over a wide range of bit rates using the SBS loop mirror. / With dispersion management inside the loop mirror interferometer, we have further proposed and demonstrated a modified DA-NOLM. The new device introduces a larger asymmetry in the propagation of the two interfering branches while maintaining a zero total dispersion in each of them. Consequently, pulse broadening is reduced and higher bit rate operation is supported. With the device, we have successfully achieved error-free two-channel DEMUX for 80-Gb/s OTDM signals. / Du, Jiangbing. / Adviser: Chester Shu. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344968 |
| Date | January 2011 |
| Contributors | Du, Jiangbing., Chinese University of Hong Kong Graduate School. Division of Electronic Engineering. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xviii, 175 leaves : ill.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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