光载无线系统中传输方案与光域微波信号处理技术的研究

发布时间：2017-12-27 00:07

本文关键词：光载无线系统中传输方案与光域微波信号处理技术的研究　出处：《北京交通大学》2017年博士论文　论文类型：学位论文

【摘要】：随着智能手机设备数量和互联网业务的持续增长,促使基于流媒体技术的交互式网络电视(IPTV)、高清电视(HDTV)、视频会议等一系列高速率、高质量、高带宽业务的不断发展,在无线接入网中,用户对系统容量和速率的需求也不断提高。受益于光纤传输的低损耗大容量特性,光载无线(RoF)技术被认为是下一代光接入网的关键技术之一。本论文主要围绕在RoF系统中信号传输方案和微波光子处理技术两方面内容进行了研究。在RoF系统的信号传输方案的研究方面,论文主要研究了三类新型的接入技术;在微波光子技术方面,本文主要探讨了微波光子信号的混频技术和利用光子滤波器实现频率相位可调谐的电振荡器(OEO)。论文取得的主要研究成果与创新点如下:1.提出了一种基于相位相关偏振正交光产生(POLG)技术实现多服务共存的上行无色化的RoF系统,并对该方案进行了理论推导和实验验证。POLG是由偏振旋转器(PR)与马赫增德尔调制器(MZM)的偏振敏感特性实现的,通过射频信号驱动调制器之后,光载波与边带相互正交且相位相关。在这个方案中,通过调节远端接入单元的偏振控制器,可以针对不同的服务信号实现不同的调制方式,例如:低频信号对应双边带调制;毫米波信号对应载波抑制调制。与此同时,光载波在不使用额外的滤波器和偏振控制器(PC)的情况下,可以被上行信号重新利用实现上行传输。因此,该方案成功实现了低频信号、毫米波信号的下行传输和无色化的上行传输。2.提出了远端接入单元(RAU)偏振不敏感的全双工毫米波RoF系统架构。在这个方案中,通过在RAU端重新利用偏振正交光来实现上行传输,使得上行信号的误码率(BER)值与入射光信号的偏振状态无关。因此不需要使用偏振追踪系统来将入射光对准调制器主轴,实现了 RAU端的偏振不敏感特性。论文对该结构进行了理论分析和实验验证。实验中实现了 1.2Gb/s的下行正交相移键控-正交频分复用(QPSK-OFDM)信号和5Gb/s的上行开关键控(OOK)信号的传输,在背靠背传输和经过15公里传输之后上行信号的误码率(BER)值均可以粗略达到10-9,因此使用该方案不需要使用前向纠错。通过对上行信号的传输,相比于传统方案,本论文提出的方案中的信号BER曲线更加平稳,BER值均保持在一个较好的水平内。3.提出了两种补偿色散引起的功率衰退的传输方案。第一种方法是使用光单边带(OSSB)调制。在这种方案中,利用Sagnac环和调制器可以实现光载波边带比(OCSR)可调的OSSB调制。本论文对这个方案进行了实验验证。在实验中,通过调节偏振控制器,可以生成从-1OdB到27dB的可调OCSR的OSSB调制。该方案具有波长不依赖特性,可以支持低频微波带宽和灵活的波长选择。第二种方法是基于POLG技术来实现。在中心站中,使用PR和MZM来实现POLG。在远端接入单元中,通过调节PC,可以控制光载波和边带之间的相位差,进而可以改变不同的射频服务的频率响应。在实验中实现了在25公里和30公里光纤传输之后,将不同射频服务的频率响应值从最低点平移到最高点。4.基于Sagnac环和MZM的偏振相关调制原理,提出并实验验证了实现微波光子混频器的新方案。该方案在Sagnac环中使用了一个双平行MZM(DPMZM),利用其行波特性,使得环中正向经过的光被光单边带(OSSB)调制,而相反方向没有被调制。两个方向的光经过偏振合成器(PBC)结合之后,生成了部分正交的OSSB信号。生成的信号入射到偏振相关的MZM中,再经过起偏器和光探测器之后实现了相位稳定的微波信号。通过调节MZM的偏置电压,实验生成了加载到8GHz微波上的1Gb/s的OOK、幅移键控(ASK)信号和二进制相移键控(BPSK)信号的清晰的眼图和波形图,实现了微波信号的光域混频。5.提出并理论分析和实验验证了基于受激布里渊散射(SBS)和DPMZM实现OEO的频率和相位可调谐特性的方案。在该方案中,DPMZM用来实现载波相移的双边带调制,SBS效应用来选取OEO环中的振荡频率。通过调节DPMZM的偏置电压,可以改变光载波和边带的相位差,从而实现OEO的相位可调;受益于布里渊频移的波长依赖特性,通过调节输入载波的波长实现OEO的频率可调特性。本论文实验生成了频率为8.950GHz到9.351GHz,相位为0°到360°可调的微波信号。
[Abstract]:With the continued growth of the intelligent mobile phone equipment and the number of the Internet business, the interactive network TV based on Streaming Media Technology (IPTV), high definition television (HDTV), the development of video conference and a series of high speed, high quality, high bandwidth services, in the wireless access network, the user needs to system capacity and rate of continuous improvement. The optical wireless (RoF) technology is considered to be one of the key technologies of the next generation optical access network, which has benefited from the low loss and large capacity characteristics of optical fiber transmission. This thesis focuses on two aspects of the signal transmission scheme and the microwave photon processing technology in the RoF system. In the study of signal transmission scheme of RoF system, this paper mainly studies three kinds of new access technologies; in microwave photonic technology, this paper mainly discusses the electric oscillator mixing technique for microwave photonic signals and frequency tunable phase using photonic filter (OEO). The main research achievements and innovations of the paper are as follows: 1., a RoF system based on phase correlation polarization quadrature light generation (POLG) technology is proposed to achieve multi service coexistence and uplink colorless. The theoretical derivation and experimental verification of the scheme are carried out. POLG is realized by polarization sensitive property of polarization rotator (PR) and Machka Del modulator (MZM). After driving the modulator through RF signal, the optical carrier and sideband are orthogonal and correlated. In this scheme, by adjusting the polarization controller of the remote access unit, different modulation modes can be achieved for different service signals, for example, the low-frequency signal corresponds to the bilateral band modulation, and the millimeter wave signal corresponds to the carrier suppressed modulation. At the same time, the optical carrier can be reused by the uplink signal to achieve uplink transmission without the use of additional filters and polarization controllers (PC). Therefore, the scheme has successfully realized the downlink transmission of low frequency signal, millimeter wave signal and the uplink of colorless transmission. 2. a full duplex millimeter wave RoF system architecture for remote access unit (RAU) polarization insensitivity is proposed. In this scheme, the upstream transmission is realized by using the polarization quadrature light at the RAU terminal, which makes the bit error rate (BER) of the upstream signal independent of the polarization state of the incident light signal. Therefore, the polarization tracking system is not needed to align the incident light with the spindle of the modulator, and the polarization insensitivity of the RAU end is realized. This paper has carried on the theoretical analysis and experimental verification to the structure. Experiment to achieve downlink orthogonal 1.2Gb/s phase shift keying orthogonal frequency division multiplexing (QPSK-OFDM) uplink key switch signal and 5Gb/s control (OOK) signal transmission, in back-to-back transmission and after 15 km transmission of uplink signal bit error rate (BER) value can be roughly 10-9, so the use of the scheme need to use fec. Compared with the traditional scheme, the BER curve of the proposed scheme is more stable and the BER values are kept at a good level through the uplink signal transmission. 3. the transmission scheme of two kinds of compensation dispersion caused by power decline is proposed. The first method is to use the optical single side band (OSSB) modulation. In this scheme, the OSSB modulation of the optical carrier band ratio (OCSR) can be realized by using the Sagnac ring and modulator. In this paper, the experimental verification of this scheme is carried out. In the experiment, the OSSB modulation of an adjustable OCSR from -1OdB to 27dB can be generated by adjusting the polarization controller. The scheme has no dependence on wavelength, and it can support low frequency microwave bandwidth and flexible wavelength selection. The second method is based on POLG technology. In the central station, use PR and MZM to implement POLG. In the remote access unit, the phase difference between the optical carrier and the side band can be controlled by adjusting the PC, and the frequency response of different radio frequency services can be changed. In the experiment, the frequency response values of different RF services were moved from the lowest point to the highest point after the optical fiber transmission of 25 km and 30 km. 4. based on the principle of polarization dependent modulation of Sagnac ring and MZM, a new scheme for realizing microwave photonic mixer is presented and verified experimentally. The scheme uses a double parallel MZM (DPMZM) in the Sagnac ring, and uses the traveling wave property to make the light passing through the loop modulated by the optical single sideband (OSSB), while the opposite direction is not modulated. After the light of two directions is combined with a polarization synthesizer (PBC), a partially orthogonal OSSB signal is generated. The generated signal is incident into the polarization dependent MZM, and then the phase stable microwave signal is realized after the polarizer and the photodetector. Through adjusting the bias voltage of MZM, the generation is loaded into 8GHz microwave 1Gb/s on OOK, amplitude shift keying (ASK) signal and binary phase shift keying (BPSK) signal of the clear eye diagram and waveform diagram, realize the mixing of microwave signals in optical domain. 5. a scheme based on stimulated Brillouin scattering (SBS) and DPMZM to realize the frequency and phase tunable characteristics of OEO is presented and proved by theory and experiment. In this scheme, DPMZM is used to realize the bilateral band modulation of carrier phase shift, and the SBS effect is used to select the oscillating frequency in the OEO ring. By adjusting the bias voltage of DPMZM, the phase difference between optical carrier and sideband can be changed, so that the phase of OEO can be adjusted. It benefits from the wavelength dependent characteristics of Brillouin frequency shift and adjusts the frequency tunable characteristic of OEO through adjusting the wavelength of input carrier. In this paper, a microwave signal with a frequency of 8.950GHz to 9.351GHz and a phase adjustable from 0 to 360 degrees is generated.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN915.63

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