【作者】 霍际伟；

【导师】 余重秀；

【作者基本信息】 北京邮电大学 ， 光学， 2011， 硕士

【摘要】 无线通信的飞速发展为人们提供了无处不在的灵活接入方式,但同时也面临着带宽资源紧张的难题。面对人们对通信容量和接入灵活性的急切需求,具有低损耗高带宽特性的光纤技术和无线接入技术的融合成为必然趋势。在这种情况,光载射频(ROF)技术应运而生,它结合了光纤低损耗高带宽和射频无线接入的优点,该技术将基站的复杂设备移至中心控制局,使得基站成本大为降低,有利于部署覆盖范围小的微微蜂窝基站。ROF技术在为光与无线融合提供有效解决方案的同时,也面临许多技术难点,如模拟光链路无杂散动态范围的提高,毫米波频率的上下变换,以及毫米波的非视距传输方案等。本论文着重对毫米波ROF系统中频率变换技术进行研究,其主要研究工作包括以下几方面：(1)深入研究了铌酸锂调制器的电光效应(亦称Pockels效应),对调制器在不同偏置情况的调制特性进行分析,完善了调制器抑制载波的理论模型；仿真了基于马赫-曾得尔调制器的DSB调制和DSB与OCS调制级联的上变频方案；提出并仿真了一种基于OCS的高倍频上变频方案。(2)搭建ROF仿真系统,仿真了基于MZM的DSB调制和OCS调制的下变频方案,仿真结果说明设计的变频方案是可行的；比较了几种变频方案的特点。(3)研究了PCF材料的非线性特性,并且在此基础上设计并仿真了一种基于PCF中四波混频效应的频率上变换方案,分析了影响频率变换性能的因素。更多还原

【Abstract】 The rapid development of wireless communications has provided the flexible and ubiquitous access for subscribers, but also brought about the challenges due to limited bandwidth resources. In order to meet the insistent demand for high capacity and more flexibility, the integration of optical fiber and wireless access is an inevitable trend of development. In this case, radio-over-fiber (ROF) has emerged as the technology to make full use of the advantages of fiber and wireless communications. It makes the complex equipment shifted to the central station, and thus greatly reduces the cost of base station, making it easier for the implement of small honeycombs. However, many issues and difficulties remain for ROF technology, such as improvement of spur-free dynamic range (SFDR) for analog-optical links, millimeter-wave frequency up and down-conversion, and the non-line of sigh (NOLS) of millimeter-wave transmission, etc.This thesis focuses on the research of millimeter-wave frequency up and down-conversion, and the main work includes several parts:(1) Carrying out an in-depth research of the lightning effect of lithium niobate modulator, a.k.a. Pockles and improving the theoretical model for modulator inhibit carrier based on an analysis of modulators in different situations; simulating the up-conversion of DBS modulation, OCS modulation as well as the cascade modulation of both on the basis of Mach-Zehnder’s modulator; coming up with a high-frequency up-conversion program.(2) Simulating the down-conversion program based on MZM’s DSB and OCS modulation; establishing ROF system to prove the feasibility of the frequency conversion plan; comparing the respective characteristics of several such plans. (3) Conducting a research on the non-linear characteristic of PCF material, then designing and simulating an up-conversion program on the basis of PCF four-wave mixing effect, with an analysis of variables that may influence the frequency conversion performance.更多还原