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Research Of All-optical Ultra-wideband Signal Generation And Modulation

Posted on:2013-02-23Degree:MasterType:Thesis
Country:ChinaCandidate:S J HuangFull Text:PDF
GTID:2218330371957589Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
Ultra-wideband (UWB) technology has various advantages such as large system capacity,high transfer rate, and strong ability of anti-multipath interference and so on. Therefore, it hasdifferent applications in high-speed wireless communications, internet of things and other fields.However, the transmission distance is limited to a few meters to within ten meters according to thequite low transmit power of UWB. To further expand the coverage of the UWB signals, the UWBover fiber technology is proposed. The optical generation and modulation technology of UWBsignal are key technologies to achieve UWB-over-Fiber, and attractive much reasearchers attentionin recent years. In this thesis, the optical generation and modulation technology of the UWBsignals are studied and several new schemes are presented. The main achievements andconclusions are listed as follows:(1)The research background and significance of the optical generation and modulationtechnology of the UWB signals are introduced. The international research development of them issummarized.(2)A new optical generation scheme for achieving doublet signal source based on gainsaturation in semiconductor optical amplifier (SOA) is proposed, which has various advantagessuch as simple structure, easily operated and so on. By using the software of Optisystem 7.0, theimpact of source power, pulse width, injection current and source wavelength on doublet signal arestudied.(3)An improved UWB pulse amplitude modulation (PAM) scheme based on cross-gainmodulation (XGM) in SOA is presented, which has various advantages such as simple structure,easily operated and so on. By using the software of Optisystem 7.0, both the impact of source power,modulation rate and source wavelength on the PAM signal and the transmission characteristics ofPAM signal are investigated.(4)A new UWB pulse shape modulation (PSM) based on XGM in SOA and cross-absorptionmodulation (XAM) in electro-absorption modulator (EAM) is presented. By using the software ofOptisystem 7.0, both the impact of source power, modulation rate and source wavelength on thePSM signal and the transmission characteristics of PSM signal are investigated.(5)An improved UWB multifunctional modulator scheme based on cascade of phase modulation (PM) and filters is presented, which could switch a variety of UWB modulation formatflexibility by simple preconding. By using the software of Optisystem 7.0, by simulation throughoptisystem software, both the impact of source power, modulation rate and source wavelength onmodulated signal and the transmission characteristics of modulated signal are investigated.
Keywords/Search Tags:Ultra wideband signal modulation, Semiconductor optical amplifier, Gain saturation, Cross-gain modulation, Electro absorption modulator, Phase modulator
PDF Full Text Request
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