基于多载波发生器的ROF系统关键技术研究

发布时间：2018-06-08 15:07

本文选题：ROF系统 + 多载波发生器　；参考：《北京交通大学》2016年博士论文

【摘要】：微波光子学是将微波学和光子学相结合的一门新兴学科。其研究范围主要包括高频微波发生器、光子信号处理技术、ROF接入系统等。其中,ROF技术结合了传统的光纤通信和无线通信两大技术,可以实现高达Gbps量级的无线宽带接入,为未来大容量网络通信提供了契机。本文结合国家自然科学基金面上项目,针对多载波发生器、高频毫米波光子发生器、多路信号全光频率上变换、最佳单边带调制技术及全双工WDM-ROF传输技术,展开了一系列较为深入的理论、仿真及实验研究。具体研究成果和内容有以下几方面:1.实验研究了 ROF系统应用中的多载波发生器。采用FP激光器可以实现多条光载波信号的输出,虽然有低成本优势,但是其频谱范围和多载波平坦度不足,在此基础上提出了光学调制器级联产生的超平坦多载波发生器结构,可进一步提高了多载波的频谱范围和平坦度,实验验证了该方案的可实施性。2.提出并研究了基于多载波发生器的高频毫米波光子产生方案。利用多载波发生器的谱特性,通过选择频率间隔不同的两条光载波信号进行拍频得到不同频率的高频毫米波信号,进一步提高可产生高频毫米波的频率范围和传输链路的性能。分别实现了 440GHz和480GHz高频毫米波信号的产生。3.提出并研究了 ROF系统中基于多载波发生器的多路信号同时全光上变频方案。对现有转换效率低下的全光上变换技术进行改进,通过对多载波发生器的输出光谱进行再调制实现了 7路信号同时上变频到60GHz的毫米波信号,为进一步提高全光上变频转换效率,又利用超平坦多载波发生器实现了 15路信号的同时全光上变频。4.提出了基于多载波发生器的ROF双向传输方案。首先提出了一种基于波长重用技术的ROF双向传输系统。将中心站的光载波在基站加以重新利用,为上行传输链路提供光源,下行链路60GHz毫米波产生的同时实现了上行数据的加载和传输。为进一步提高频谱利用率和系统性能,又提出了一种基于多载波发生器的全双工WDM-ROF系统。利用其超平坦谱特性提供WDM系统的多信道光源,实现了具有高频谱利用率和低功率代价的1:7全双工WDM-ROF系统的高效传输。5.提出并实验研究了基于光纤光栅的单边带调制优化方案。分别利用相移光栅和实验室自制的FBG-FP的大范围透射斜边特性,将其应用于ROF模拟光链路中,实现单边带滤波及OCSR调节。通过对双边带信号中的一个边带和中心光载波进行不同程度的衰减,实现了 DSB信号到SSB信号转换的同时优化OCSR至OdB,提高了 ROF模拟光链路的接收灵敏度。此外,论文还对光纤长度及OCSR对链路性能的影响进行了分析和研究。
[Abstract]:Microwave photonics is a new subject which combines microwave and photonics. The research scope mainly includes high frequency microwave generator, photonic signal processing technology and ROF access system. With the combination of traditional optical fiber communication and wireless communication, ROF technology can realize wireless broadband access of up to Gbps, which provides an opportunity for future large capacity network communication. This paper aims at multi-carrier generator, high-frequency millimeter-wave photonic generator, all-optical frequency up-conversion of multi-channel signal, best single sideband modulation technology and full-duplex WDM-ROF transmission technology. A series of theoretical, simulation and experimental studies are carried out. The concrete research results and contents are as follows: 1. The multicarrier generator used in ROF system is studied experimentally. The output of multi-optical carrier signals can be realized by using FP laser. Although it has the advantage of low cost, its spectrum range and multi-carrier flatness are insufficient. On the basis of this, an ultra-flat multicarrier generator is proposed, which is generated by cascaded optical modulator. The spectrum range and flatness of the multi-carrier can be further improved, and the feasibility of the scheme is verified by experiments. A high frequency millimeter wave photonic generation scheme based on multi-carrier generator is proposed and studied. By using the spectral characteristics of the multi-carrier generator, two optical carrier signals with different frequency intervals are selected to beat to obtain the high-frequency millimeter-wave signals with different frequencies, which can further improve the frequency range of the high-frequency millimeter-wave generation and the performance of the transmission link. The generation of high frequency millimeter-wave signals at 440 GHz and 480 GHz is realized respectively. In this paper, a multi-channel signal and all optical up-conversion scheme based on multi-carrier generator in ROF system is proposed and studied. The existing all optical upconversion technology with low conversion efficiency is improved. By remodulation of the output spectrum of the multicarrier generator, 7 signals are simultaneously up-converted to 60 GHz millimeter wave signals. In order to further improve the efficiency of all-optical up-conversion, 15 channels of signals are realized by using ultra-flat multicarrier generator, and all optical up-conversion. 4. 4 is realized at the same time. A two-way ROF transmission scheme based on multi-carrier generator is proposed. Firstly, a new ROF bidirectional transmission system based on wavelength reuse technology is proposed. The optical carrier of the central station is reused in the base station to provide the light source for the uplink transmission. The downlink 60GHz millimeter wave is generated and the uplink data is loaded and transmitted at the same time. In order to further improve spectrum efficiency and system performance, a full duplex WDM-ROF system based on multicarrier generator is proposed. The multichannel light source of WDM system is provided by using its ultra-flat spectrum characteristic, and the 1:7 full-duplex WDM-ROF system with high spectral efficiency and low power cost is realized. An optimized scheme of single sideband modulation based on fiber grating is proposed and experimentally studied. The phase-shifted grating and FBG-FP are applied to ROF analog optical link to realize single sideband filter and OCSR adjustment. By attenuation of a sideband and a central optical carrier in a bilateral band signal, the OCSR to OdB can be optimized while the DSB signal is converted to SSB signal, and the reception sensitivity of the ROF analog optical link is improved. In addition, the influence of fiber length and OCSR on link performance is analyzed and studied.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN929.1

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