1. Gain modulation induced by the injected optical signals in Semiconductor Optical Amplifier (SOA) is the basis of the whole work in this thesis. For a good understanding of the gain dynamics in SOA, we studied the propagation of lightwave and the carrier density dynamics in SOAs. Detailed theory and simulation results about the gain modulation characteristics induced by the injected signals into the SOA are presented. The simulation results have a good guidance for the experiments in this thesis. / 2. The theory of the actively mode-locked ring laser is studied. Following the theoretical discussion about the actively mode-locked ring laser, the experimental study about a novel actively mode-locked ring laser based on cross-gain-modulation in a SOA, which is employed as both the gain medium and mode-locking element, is proposed and demonstrated. Stable uniform pulse trains with pulse-widths about 24ps at 5GHz repetition frequency are obtained. The wavelength of the mode-locked optical pulses can be continuously tuned from 1533nm to 1565nm. In the whole tuning range, the pulse-width and bandwidth of the output pulses are respectively within 22-26ps and 0.7-0.8nm. / 3. Generation and wavelength switching of picosecond pulses by optically modulating a SOA in a ring laser with eight cascaded fiber Bragg gratings playing the role of the wavelength selecting element is proposed and demonstrated. Stable amplitude equalized pulse trains with a pulsewidth about 43ps at 2.5GHz have been obtained by injecting optical control signals into the laser. When we change the modulation frequency of the injected optical signals from 2.5 GHz to 10 GHz, wavelength switchable optical pulses at 10 GHz have also been obtained through optimizing the experimental parameters such as the SOA driving current and the power of the injection optical signals. Wavelength switching among eight wavelengths is achieved by merely tuning an intra-cavity optical delay line. The theoretical analysis of multi-wavelength operation using the proposed ring cavity has also been presented. / 4. In the actively mode-locked ring laser based on 1.55mum SOA, there exist changes of both gain and refractive index since the wavelengths of the control signal and the data signal are in the same gain spectral region. The gain change is sometimes unwanted because it may result in the amplitude fluctuations of the mode locked pulses and pattern effects. We proposed an all-optical FM actively mode-locked ring laser scheme based on a 1.3mum SOA as a gain-transparent phase modulation only element. The principle of the phase modulation in 1.3mum SOA has been discussed. / 5. Optical clock recovery, which extracts a continuous train of pulses or clock from the modulated data, is an essential technology to realize all optical signal processing such as all optical regeneration repeater and all optical de multiplexing. We experimentally studied all optical clock recovery at 10GHz with switchable wavelengths using the proposed mode-locked ring laser. Very stable clock signals corresponding to the bit rate of the injection data have been obtained by injecting 10Gbit/s 231-1 PRBS data signals into the laser cavity. The side-mode-suppression ratio of the recovery clock signals is better than 28dB. The clock recovery scheme can still function well when the wavelength, polarization state and the density of zeros of the injected data signals are changed. / 6. Finally, we discussed the noises in all optical networks and all optical methods of noise reduction. All optical noise reduction methods are reviewed. We also discussed the feasibility of all optical noise reduction method using the proposed ring laser scheme. / With the advances in Dense Wavelength Division Multiplexing (DWDM) and Optical Time Division Multiplexing (OTDM) technologies and their ever-widening applications, optical transport networks will eventually evolve into all optical networks based on DWDM and OTDM or their combination. However, the adoption of optical technologies has a significant impact on network transmission performance because there will be many optical amplifiers, wavelength division multiplexing devices and optical cross connects which may bring optical noises and time jitters to the all optical networks. Hence many key technologies including the generation of ultrashort optical pulses and all optical signal regeneration are needed in order to realize all optical transport networks. This dissertation mainly describes the generation of optical pulses and all optical clock recovery for all optical signal regeneration. Several theoretical and experimental research results have been obtained as follows. / He Jian. / "April 2006." / Adviser: K. T. Chan. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6610. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_343783 |
| Date | January 2006 |
| Contributors | He, Jian, 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 (xii, 165 p. : 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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