采用电光调制器产生光毫米波的全双工通信光纤无线通信系统

实验研究了一种采用单个电光调制器产生光毫米波的方法和相应的全双工无线通信系统。在中心站采用电混频器产生电毫米波,然后再利用电光制器产生双边带信号。利用光交错复用器将中心载波和双频一阶边带信号分离。双频一阶边带用于产生2倍射频信号的光毫米波,而中心光载波用来作为上行链路的光载波。实验显示采用频率为20GHz射频信号产生光毫米波的频率为40GHz,而且将下行链路和上行链路中2.5Gbit/s的数据在单模光纤中传输距离达20km,而功率代价均小于0.5dB。     

DWDM optical millimeter-wave generation for radio-over-fiber using an optical phase modulator and an optical interleaver

We have proposed and experimentally demonstrated a novel scheme to generate a dense wavelength-division multiplexing (DWDM) optical millimeter-wave source by using an optical phase modulator and an optical interleaver. The stability of the DWDM optical millimeter wave generation is largely improved because we use an optical phase modulator without a dc-bias controller and an optical interleaver is subsequently employed to suppress the optical carrier of the DWDM source, which is not as temperature sensitive as a fiber Bragg grating. Moreover, the limitation of chromatic dispersion is greatly reduced due to avoiding the generation of higher order sidebands via driving the phase modulator with optimized RF signal.     

OPM产生四倍频光载毫米波的双向ROF系统

提出一种采用单个光相位调制器(OPM)和光纤布拉格光栅(FBG)滤波器产生四倍频光载毫米波的双向光纤无线通信(ROF)系统。在中心站(CS),系统采用基带信号与射频(RF)信号混频后去驱动OPM,以产生抑制一阶边带的多边带光信号。在基站(BS),利用FBG滤波器将信号的重复频率增至4倍。实验结果显示,经过40km光纤传输后,下行链路信号的眼图清晰可见,功率代价小于1.6dB。本文方案中,由于没有额外增加激光源使得基站结构进一步简化,同时四倍频技术降低了RF信号的频率,系统成本大大降低。     

A millimeter-wave radio-over-fiber system for overcoming fiber dispersion-induced signal cancellation effect

Millimeter-wave(mm-wave) radio over fiber(ROF) using dispersive single-mode fiber is susceptible to signal cancellation effect at the output of the uni-travelling carrier photodiode at the base station(BS).The fiber dispersion effect produces different phase shifts of the sidebands of the intensity-modulated lightwave which can produce a cancellation of the output signal when mixed with the optical carrier.In this paper,we propose and analyze a novel scheme of mm-wave ROF which uses microwave modulation at the central station(CS) and frequency upconversion before the BSs.This scheme can overcome fiber dispersion-induced signal cancellation effect.     

采用PM调制实现光生毫米波的RoF系统

提出有效产生四倍频光载毫米波的RoF系统.系统在中心站配置一个PM调制器和光滤波器,产生抑制一阶边带和中心载波的信号,发送至基站.基站侧两个二阶边带在光电检测器中拍频,产生四倍于射频信号的光载毫米波.仿真结果显示,12GHz射频频率可产生48GHz光载毫米波,2.5Gb/s的数据可在下行链路的光纤中传输35km以上,功...     

一种产生OCS-DPSK光载毫米波的光纤无线系统

提出了一种产生载波抑制-差分相移键控(OCS-DPSK)光载毫米波的光纤无线系统.建立了OCS-DPSK光载毫米波的产生和传输链路模型,分析了光纤色散的影响,并通过仿真实验验证了系统的可行性.实验结果表明,重复频率为30GHz的OCS-DPSK光载毫米波调制2.5Gb/s基带信号经80km光纤传输后,眼图清晰可见,功率代价为3.7dB.     

基于微波光子学的倍频三角波生成方法

为了克服传统任意波形生成方法中电子瓶颈问题，分析了基于微波光子学的射频任意波形的技术类型、特点和应用背景，采用一种基于并联马赫-曾德尔调制器的倍频三角波生成方法，引入均方根误差对输出信号和理想波形来评价，并进行了理论分析和仿真验证。结果表明，通过10GHz驱动信号生成了20GHz的三角波信号，均方根误差为0.038，即输出信号与理想信号吻合度较高; 与其它方法相比，该方法可生成倍频三角波，信号波形与理论波形吻合度良好。该研究对未来基于微波光子学的射频任意波生成有指导意义。     

A novel radio-over-fiber system with optical carrier suppressed-differential phase shift keying (OCS-DPSK) mm-wave generation

提出了一种产生载波抑制-差分相移键控(OCS-DPSK)光载毫米波的光纤无线系统.建立了OCS-DPSK光载毫米波的产生和传输链路模型,分析了光纤色散的影响,并通过仿真实验验证了系统的可行性.实验结果表明,重复频率为30GHz的OCS-DPSK光载毫米波调制2.5Gb/s基带信号经80km光纤传输后,眼图清晰可见,功率代价为3.7dB.     

基于相位调制器倍频技术产生56 GHz毫米波的光载无线通信系统

提出并实验研究了一种基于光相位调制器(PM)倍频技术产生56GHz毫米波的光载无线通信(RoF)系统。在中心站,通过28GHz射频(RF)信号驱动PM产生了56GHz光毫米波,并将下行的2.8Gb/s开关键控(OOK)信号调制到该光载波上,然后经过20km标准单模光纤(SSMF)传输至基站,最后由天线进行发射。用户终端接收后,采用相干解调恢复出基带信号。实验结果表明,56GHz光载毫米波信号经SSMF传输20km后其功率代价小于1dB,通过无线方式传输1.1m后其功率代价小于2.5dB。     

System capacity for millimeter-wave radio-over-fiber distributionemploying an optically supported PLL

We consider the performance of a hybrid radio-over-fiber distribution system with a remote phase-locked loop (PLL) providing the local oscillator for upconversion to millimeter (mm)-wave frequencies. The reference signal for the PLL is transmitted together with digitally modulated subcarriers over a fiber link, allowing centralization of radio processing. Through analysis and simulation, we identify the relationship between the phase noise requirement for the PLL and the data capacity of the fiber link. For a practical link, we provide an upper limit on system capacity for transmission of 16 quadrature amplitude modulation (QAM) subcarriers     

一种改进的载波抑制调制光毫米波信号的产生方案

为了克服光纤无线(ROF)系统中色散对光载波抑制(OCS)调制光毫米波信号传输的影响,提出一种改进的OCS调制方案。使用双驱动马赫-曾德尔调制器(MZM),通过调整两路输入射频信号相位、基带信号增益和直流偏置电压将2.5Gbit/s数据信号仅调制到(OCS)信号的一个边带上传输。理论分析表明,与传统OCS调制光毫米波信号产生方案相比,本文方案解决了色度色散引起的码元走离问题,大大增加了传输距离。仿真实验结果表明,经过110km光纤传输后信号的眼图仍然十分清晰,在BER=10-10条件下,信号经过20、40和60km光纤传输后的功率代价分别为0.78、1.7和1.9dB。     

基于光相位锁定的载波可变光的毫米波产生技术

提出和实现了一种新型适用于光/无线混合接入的光子载微波产生方案.该方案利用直接调制分布反馈式半导体激光器可以产生宽谱信号的特点,将较低频率正弦信号直接调制半导体激光器,在半导体激光器中进行频谱展宽,然后把宽谱信号注入到多个半导体激光器中进行相位锁定从而作为相干锁定光源.用上述光源在不同波长加载不同信号进行传输,在接收端使用不同通带特性的光学滤波器对信号进行处理,可以选择接收基带信号、光子微波时钟信号、上行光源或不同载波频率的光子微波调制信号.作为验证,分别完成了2.5 Gbps基带信号、20 GHz和40 GHz光副载波调制信号的产生与接收.因为受限于试验条件,只进行了原理验证,但该系统理论上可集成波导设计,无需高频调制器件,并可生成更高载频光子微波信号,有利于未来的光/无线混合接入和超密集波分复用系统.     

A simplified optical millimeter-wave generation scheme based on frequency-quadrupling

This paper analyzes and demonstrates a simplified frequency quadrupling configuration for optical millimeter-wave(mm-wave)generation,in which the electrical phase shifter and optical filter are omitted.Theoretical analysis is given to reach the optimum operating conditions including direct current(DC)bias voltage,optical transmission point of the dual-parallel Mach-Zehnder modulator(MZM)bias voltage,optical transmission point of the dual-parallel Mach-Zehnder modulator(DP-MZM),amplitude of the radio frequency(RF)driving signal and the impact of the extinction ratio(EF)on the optical sideband suppression ratio(OSSR)and radio frequency spurious suppression ratio(RFSSR).Experiments prove an OSSR of 15 dB and an RFSSR of 26 dB for the new frequency quadrupling scheme at 6 GHz,8 GHz and 10 GHz of RF driving signal without any electrical phase shifter or optical filter.This system exhibits the advantage of low wavelength dependence and large frequency tunable range.     

一种基于相位调制器的40 GHz OFDM-ROF系统实验研究

实验研究了一种基于相位调制器(PM)并级联强度调制器(IM)实现40 GHz毫米波传输正交频分复用(OFDM)信号的光纤无线通信(ROF)系统。在中心站,采用20 GHz的射频(RF)信号驱动PM,调节驱动信号的强度,使输出的信号经光纤布拉格光栅(FBG)滤除中心载波后再送入IM。2.5 Gbit/s的OFDM信号直接调制在光毫米波上,经过50 km标准的单模光纤(SSMF)传输到基站。在基站,光调制信号经光电转换器(PD)转换成电调制信号,再与RF信号混频,恢复出基带OFDM信号。实验结果表明,在无色散补偿、误码率(BER)为10-3的条件下,下行链路中2.5 Gbit/s的OFDM信号经光纤传输50 km后,其功率代价小于1 dB,而且信号的星座图依然较好。     

A novel scheme to implement duplex 60-GHz radio-over-fiber link with 20-GHz double-sideband optical millimeter-wave transmitted along the fiber

A duplex radio-over-fiber (RoF) link with a novel scheme to generate 60-GHz millimeter (mm)-wave using 20 GHz double sideband (DSB) optical mm-wave with signal carried only by its optical carrier is investigated. In the RoF downlink, the modulation frequency to generate the DSB optical mm-wave is reduced greatly. The theoretical analysis and numerical simulation show that this scheme cannot only eliminate the code form distortion caused by the time shifting of the sidebands, but also reduce the influence of the fading effect as the DSB optical mm-wave signal is transmitted along the fiber. Based on the scheme, the duplex RoF link with the frequency up- (down-) conversion of the down- (up-) link mm-wave signal is built and the uplink transmission performance is analyzed theoretically.     

Resonant-tunneling devices for millimeter-wave generation

Oscillations from resonant-tunneling diodes have been observed up to 200 GHz, and theoretical estimates predict that device performance should extend into the THz range. This paper addresses the issue of the ultimate frequency response and power generation capability of these devices. Techniques recently developed to solve the time-dependent Schrödinger equation are used to predict the rf power vs. frequency obtainable from resonant-tunneling diode oscillators, based on the calculated small-signal response. Factors limiting the rf power output from these devices are presented. Also, recently obtained dc experimental results for the In_.53Ga_.47As-In_xAl_1-xAs heterostructure material system grown on InP are presented. Using a quasi-static approximation, the rf power available from these devices under large-signal conditions is estimated.     

Stable photonic millimeter-wave generation using an integrated reciprocating optical modulator

We investigated stability and phase noise of V-band millimeter-wave generated by using a hybrid integrated reciprocating optical modulator consisting of a pair of fiber Bragg gratings and a LiNbO/sub 3/ optical phase modulator. The amplitude fluctuation of generated millimeter-wave was less than 1% without using feedback stabilization technique. Phase noise of the millimeter-wave was -74.3 dBc/Hz at 10-kHz offset.     

Reciprocating optical modulation for millimeter-wave generation by using a dual-section fiber Bragg grating

We investigated reciprocating optical modulation (ROM) for millimeter-wave generation. The system was composed of an optical phase modulator and a pair of optical filters. A lightwave modulated by V-band millimeter waves was obtained from a 5-GHz electric signal. The spectrum linewidths of the generated 60-GHz millimeter wave was smaller than 300 Hz. By using mode-coupling equations, the spectra of the output lightwave were theoretically calculated. It was shown that the spectra depend on the optical path length between the two optical filters, so that harmonic generation and mixing with baseband signals can be obtained simultaneously. Intensity modulation of the generated millimeter wave was demonstrated by applying a baseband signal to the modulator without using another electric or optical modulator.