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构建了基于微波光子倍频的光载无线传输系统。基于偏振调制器实现了六倍频光毫米波产生,利用马赫增德尔调制器实现了QAM信号调制并进行光载无线传输,测试了41.5GHz QAM信号调制和10km光载无线传输光纤传输之后的QAM信号星座图。该系统实现了远距离音视频或高清数字信号传输。 相似文献
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首先对不同类型光调制器性能做了简单比较,并结合近几年的研究进展情况,对各种电光调制器优缺点进行介绍,尤其对其中具有广泛应用前景的硅基电光调制器作了详尽的介绍,最后讨论了传输线电极设计对各类电光调制器性能的影响,并介绍了近几年在改善电光调制器的调制带宽方面的研究进展。 相似文献
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近年来,基于微波光子技术应用的光载无线系统(ROF)作为一种实现低成本超宽带无线接入的光纤通信技术被广泛关注.同时无线个域网技术由于其可以满足未来室内高速多媒体业务的需求而进入标准化阶段.作为ROF系统关键技术的微波光子信号处理技术在处理高速信号时表现出众多优势和潜力.本研究组提出了多种基于电光调制器的微波光子技术用以实现微波信号处理功能[1,2],本文重点介绍全光UWB冲击脉冲产生与毫米波段全光矢最调制技术. 相似文献
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LiNbO3电光调制器制作技术 总被引:1,自引:0,他引:1
张瑞君 《光纤光缆传输技术》2003,(4):31-34
光调制器是光通信的关键器件之一。国内外已对LiNbO3电光调制器开展了基础理论、结构设计、工艺制作和性能测试等方面的研究。介绍了LiNbO3电光调制器的关键制作技术与工艺。 相似文献
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高功率激光器的高速率外调制技术是空间光通信发射系统中的关键技术。系统采用光纤耦合的激光器, 有效减少了传输媒质对激光功率的损耗。为了获得大功率、高速率的激光调制信号, 采用1 mm光输入口径的铌酸钽晶体电光调制器进行光强度调制, 电光调制器的调制带宽为1 GHz, 调制方式选用外调制方式。为了保证了调制器工作在线性区域, 同时降低对电光调制器的驱动电压的要求, 系统采用了自动偏置控制技术。通过加正弦波和方波信号进行调制实验, 系统实现了激光器调制速率300 Mb/s, 输出功率100 mW的指标要求。 相似文献
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提出了一种新型的聚合物波导电光调制器,同时利用了聚合物材料的Pockels效应和Kerr效应,在不增加调制电压的情况下,通过引入直流偏压增加了调制器的调制度,调制深度随着直流偏压的增加而增加。采用峰-峰值9.9V的调制电压、100V的直流偏压,利用pockels电光系数γ33仅为4.052×10-14 m/V和二次电光系数S33为6.889×10-21 m2/V2的聚合物材料制备了波导电光调制器,实现了7.54%的调制度。如果采用具有更高的分子极化率及电光系数的非线性共轭聚合物材料,可期待在更低的直流偏压和工作电压情况下,得到更高的调制深度。调制器的工作面积大,可以实现大面积光斑的调制。本文的聚合物波导电光调制器适用于激光脉冲喷丸强化与成形技术,通过调整调制器的直流工作偏压,能够实现激光光斑能量的精细调节。 相似文献
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Yichuan Yu S. Karlsson C.P. Liu R. Schatz U. Westergren O. Kjebon C.H. Chuang Sailing He L. Thylen A.B. Krysa J.S. Roberts A.J. Seeds 《Photonics Technology Letters, IEEE》2006,18(6):770-772
An InGaAsP multiple-quantum-well asymmetric Fabry-Pe/spl acute/rot modulator/detector has been developed for radio-over-fiber systems. The measured bandwidth is more than 6 GHz and the total insertion loss is 7.1 dB. The property of nonlinearity and spurious-free dynamic range (SFDR) has been studied theoretically. By optimizing the operation optical wavelength and bias voltage based on the numerical simulation, fifth-order nonlinearity dominates the intermodulation distortion and an SFDR of 101 dB/spl middot/Hz/sup 4/5/ has been achieved experimentally. 相似文献
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In this paper, a novel radio-over-fiber (ROF) scheme to simultaneously generate and transmit wideband code division multiple access (WCDMA) and millimeter-wave (MMW) signals by using a single dual-electrode Mach-Zehnder modulator (MZM) is proposed. There is no apparent nonlinearity induced by the ROF system. By employing this ana- log ROF signal transmission technique, the highly transparent fiber-wireless networks, which are ideal for multi-standard wireless system operation, can be realized. 相似文献
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Jianjun Yu Ming-Fang Huang Zhensheng Jia Ting Wang Gee-Kung Chang 《Photonics Technology Letters, IEEE》2008,20(7):478-480
We have proposed and experimentally demonstrated a novel scheme to generate optical millimeter-wave (mm-wave) signals by using single-sideband modulation with low-frequency local oscillator (LO) signals. In this architecture, by incorporating the proper dc bias of the modulator in central office, the optical mm-wave carriers are generated with two times frequency of the LO signal while largely reducing the bandwidth requirement of the modulator. We quantify the optical carrier-to-sideband ratio (CSR) of downstream transmission in this radio-over-fiber (ROF) link and establish that the performance of the ROF system can be significantly improved when the optical signals are transmitted at CSR equal to 0 dB. 相似文献
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A novel radio-over-fiber (ROF) scheme to simultaneously generate and transmit the 3rd generation telecommunication (3G) and millimeter-wave (MMW) signals by using a single dual-electrode Mach-Zehnder modulator (MZM) is proposed. There is no apparent nonlinearity induced by the ROF system. By employing this analog ROF signal transmission technique, highly transparent fiber-wireless convergence networks can be realized, which are ideal for multi-standard wireless system operation. 相似文献
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Lin Chen Wen S.C. Ying Li Jing He Hong Wen Yufeng Shao Ze Dong Yazhi Pi 《Lightwave Technology, Journal of》2007,25(11):3381-3387
We have proposed and experimentally demonstrated three different optical front-ends to implement in wavelength-division-multiplexing (WDM) radio-over-fiber (ROF) networks to minimize the cost of the ROF system. When the number of WDM channels is small, such as smaller than four channels, the simplest front-end to generate WDM optical millimeter (mm)-wave signals is to use only broadband direct-modulation laser (DML) for each WDM channel. In this case, the expensive external modulator can be removed. However, when the number of WDM channels is large, such as larger than four, the frond-end to generate WDM optical mm-wave signals can be realized by using an external modulator to upconvert simultaneously all channels after the WDM channel signals are multiplexed. In this way, the cost of the expensive external modulator will be shared by all channels. For seamless integration of WDM signals that come from the existing backbone with ROF system, a broadband external modulator can be used to upconvert WDM signals. 相似文献
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一种基于OPM和FBG滤波器的新型双工ROF系统 总被引:1,自引:1,他引:0
提出了一种采用光相位调制器(OPM)和光纤布 拉格光栅(FBG)滤波器实现的双向光纤无线通信(ROF)系统。在中心站,系统采用OPM和FBG滤波器产生抑制一阶边带的多边带光信号 ,而2.5Gbit/s 的下行链路信号只调制在中心光载波上同时经过光纤进行传输。在基站,未被调制的边带信 号用来重新调 制上行链路信号。建立了产生光载毫米波的理论模型,分析了光纤色散导致的相位影响,并 通过仿真实验 验证了系统的可行性。结果显示,经过60km光纤传输后,上、下行 链路信号的眼图都清晰可见,上行链 路功率代价小于0.2dB,下行链路功率代价小于1.8dB,系统具有较好的抗色散能力。 相似文献
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Fong T.K. Sabido D.J.M. IX Kalman R.F. Tabara M. Kazovsky L.G. 《Lightwave Technology, Journal of》1994,12(3):526-534
The use of coherent detection in analog optical links offers several advantages over direct detection: improved receiver sensitivity, inherent frequency translation, and the ability to utilize angle modulation and separate wavelength division multiplexed (WDM) signals. In this paper, we investigate an externally modulated coherent AM optical link. We study the dynamic range of the coherent AM link, considering receiver noise, laser phase noise, laser relative intensity noise (RIN), and system nonlinearities. With proper selection of the receiver's IF bandwidth, the coherent AM link can be made insensitive to the laser linewidth. For optical powers less than 5 mW, RIN of less than -160 dB/Hz reduces the spurious-free dynamic range (SFDR) by less than 3 db with the use of a balanced receiver. The external modulator nonlinearity is the dominant nonideal effect; it reduces the SFDR by 5-19 dB from the theoretical limit for 100% modulation index. We compare the performance of the coherent AM link with that of a conventional direct detection link for two applications: point-to-point links and distribution networks. When the received optical power is less than 1 mW, the coherent link can provide higher SFDR than the direct detection link. Thus, coherent links are well-suited for long distance point-to-point links and FM video distribution systems 相似文献
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实验研究了一种采用单个光载波和一个单臂LiNdO3调制器同时产生多个不同频率光毫米波的光无线通信(ROF)系统。在中心站,多路不同频率的射频(RF)信号与相应的基带数据信号进行混频,再用功率耦合器将它们耦合成一路信号,输出信号用于驱动单臂LiNdO3调制器进行载波抑制调制去产生多频率的光毫米波信号。经过光纤传输后,在基站,利用光滤波器将载有不同频率光毫米波的光频成分进行分离,之后再分别进入光电检测器(O/E)进行检测。实验结果显示,采用频率为10 GHz与20 GHz的RF信号源可以产生频率为20GHz与40 GHz的光毫米波,20 GHz的毫米波携带2.5 Gb/s的下行基带数据信号在单模光纤中可以传输40km以上,因此这种方案是有效和可行的。 相似文献
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In optical fiber-based wireless access schemes, the radio signal is transmitted through fiber without frequency conversion radio-over-fiber (ROF). Although the fiber has adequate bandwidth, nonlinear distortion due to electrical to optical (E/O) conversion is a concern. In the uplink, the dynamic multipath wireless channel is followed by this static memoryless ROF link; this forms a Wiener system. In this paper, we propose a Hammerstein type decision feedback equalizer (HDFE) for the fiber-wireless uplink to combat the nonlinear distortion and the wireless channel dispersion. The proposed equalizer is less complex because it handles static and dynamic distortions separately. The nonlinear distortion is compensated first, reducing the power of cross modulation products significantly. Analytical results show that the lower bound of the mean squared error depends on the optical and wireless channel noise. The bit error rate (BER) performance of the HDFE for the nonlinear channel approaches the performance of a decision feedback equalizer (DFE) in a linear channel when the nonlinearity is adequately compensated. 相似文献
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在雷达指标体系中,探测距离和目标分辨能力是其中的重要参数。而噪声系数(NF)和接收链路的压缩动态范围(CDR)则影响着这两个指标。随着射频光传输(ROF)在雷达接收链路中应用的推进,除了对光链路本身的探讨外,还需扩展到接收链路中微波和光波的协同分析。因此,将其中的微波前级放大、射频光传输(ROF)、微波后级放大进行耦合,普适性地探讨接收链路CDR和NF。例如,当光链路噪声功率谱密度为?164 dBm/Hz,光链路增益?20 dB时,可设计前级放大41 dB。在这种情况下,接收链路CDR1dB达143 dB·Hz,噪声系数为4.15 dB,能够同时满足探测距离和目标分辨的要求。对外调制光链路而言,调制器的半波电压可选择在2.0~5.8 V之间,实现性能和成本的平衡。分析从系统角度出发,探讨了基于ROF的接收链路,能够满足雷达功能要求,同时,也为接收链路中电器件和光器件的设计提供了依据。 相似文献