Multiple-frequency basestation RoF system based on polarization multiplexed FWM in SOA

An approach of multiple-frequency millimeter-wave(mm-wave)signal generation is proposed for radio-over-fiber(RoF)system with multiple-frequency basestations(MFBSs).Two groups of orthogonally polarized signals are injected into a semiconductor optical amplifier(SOA),and subsequently ten new different wavelengths are generated via four-wave mix-ing(FWM)effect.At each MFBS,different wavelengths are filtered out using demultiplexer and then input to a photodiode(PD)to generate the mm-wave signals with the frequencies from 52 GHz to 68 GHz at the interval of 2 GHz.Simulation results verify that the proposed multiple-frequency generation for MFBS RoF system can work properly.     

Ultra-Broadband Wireless Home Network Based on 60-GHz WPAN Cells Interconnected via RoF

In this paper, we first identify the key requirements for the deployment of a 1-Gb/s ultra-broadband home area network (UBB-HAN). Second, we propose an architecture based on a transparent optical backbone feeding local access points. Third, we underline the role of the IEEE802.15.3c pre-standard to provide a suitable radio interface for the UBB-HAN and demonstrate the technical feasibility of the concept using radio over fiber (RoF). More than 1-Gb/s transmission is demonstrated for 50-m optical antenna remoting using radio-over-fiber plus 15-m radio transmission.      

基于双平行PM调制的60GHz光毫米波RoF系统研究

提出了一种采用相位调制器产生六倍频光载毫米波的RoF系统。该系统使用一个双平行相位调制器实现六倍频的调制,通过调节相位调制器的相位偏移量,产生出抑制一阶边带的光谱,耦合相减后得到三阶边带信号,在光电检测器中拍频,产生六倍于射频信号的光载毫米波。仿真结果表明,10GHz射频信号可以产生60GHz光载毫米波信号,5Gb/s的数据信号可在单模光纤中传输10km以上。     

一种利用四波混频效应实现光的码相关接收的新方案

本文提出了一种利用四波混频效应实现双极性的光处理相关运算的新方案。普通单极性光相关运算由于缺少负极性成分而性能不令人满意。利用四波混频效应将同一频率上幅度或功率之间的单极性运算转变成频率之间的运算，从而实现了光处理中的双极性，突破了电子相关器件速度的限制，对于发展ＤＳ／ＣＤＭＡ技术在高速局域网中的应用有很大意义     

An Impulse System for 60-GHz Wireless Networks Based on Polymer Optical Fiber

A specific impulse optical fiber system has been achieved to enhance the connectivity of 60-GHz wireless networks. Using an impulse technology, this original configuration is an efficient alternative to the conventional 60-GHz radio-over-fiber systems. Baseband subnanosecond pulses first modulate the amplitude of a 60-GHz radio-frequency carrier and second the intensity of a distributed feedback laser operating at 1300 nm. Properties of the multimode plastic optical fiber based on a perfluorinated material are exploited to transmit such signals. The overall system performance has been tested experimentally in a multihop configuration; bit-error-rate measurements are better than for transmission data rates up to 200 Mb/s.     

All-Optical Flip-Flop Based on an SOA/DFB-Laser Diode Optical Feedback Scheme

We report on the dynamic all-optical flip-flop (AOFF) operation of an optical feedback scheme consisting of a semiconductor optical amplifier (SOA) and a distributed feedback laser diode (DFB-LD), bidirectionally coupled to each other. The operation of the AOFF relies on the interplay between the optical powers in both the DFB-LD and the SOA. Switching times as low as 150ps for switch pulse energies of around 6 pJ and a repetition rate of 500MHz have been measured. The contrast ratio was measured to be above 12 dB     

一种改进的光载波抑制产生光毫米波的方法

为了延长光毫米波的传输距离,提出了一种改进的光载波抑制产生光毫米波的方法。在中心站采用马赫-曾德尔调制器将射频信号调制到光载波上产生光载波抑制调制光信号,再将产生光信号的2个边带分离,将2.5Gbit/s数据信号调制到其中1个边带上,再与未调信号耦合后产生光毫米波并通过光纤传送至基站。在基站中通过光电转换器产生电毫米波。从理论上分析了这种光毫米波的传输特性并通过实验验证了光毫米波在光纤中可以传输40km。仿真和实验结果表明,这种方式产生的光毫米波具有很好的抗色散能力,延长了传输距离。     

Polarization-Insensitive All-Optical Upconversion for Seamless Integration Optical Core/Metro/Access Networks With ROF Systems Based on a Dual-Pump FWM Scheme

We have proposed and experimentally demonstrated a novel scheme to realize polarization-insensitive all-optical upconversion for single-channel or wavelength-division multiplexing signals. This scheme is based on the copolarized-pump four-wave mixing effect in nonlinear media. The copolarized pump is generated by using optical carrier suppression in an external intensity modulator; therefore, the two pumps are always parallel and phase locked. This scheme has some unique advantages for the integration between optical transport networks and radio-over-fiber systems, such as a polarization-insensitive, low-frequency bandwidth requirement for optical and electrical components, and high wavelength stability.      

Full-Duplex 1.0 Gbit/s Data Transmission Over 60 GHz Radio-on-Fiber Access System Based on the Loop-Back Optical Heterodyne Technique

Full-duplex transmission over a 60 GHz radio-on-fiber access system based on the optical heterodyne technique is verified in this paper. With this technique, an optical carrier generator on the transmitting side consolidates the functions of wavelength and polarization control for optical heterodyne detection in uplinks and optical millimeter-wave generation in downlinks, on behalf of each optical transmitter/receiver. Therefore, the whole system configuration can be significantly simplified. A full-duplex 1.0 Gbit/s transmission experiment over 10 km of single-mode fiber, which represents an access network transmission, is demonstrated using the simultaneous modulation/photodetection operation of an electroabsorption modulator (EAM). Bit error rates of less than 10$^{-9}$ were obtained in both the uplink and downlink without noticeable mutual interference, even though the laser source and the EAM is shared by both links, and no significant dispersion-induced degradation was observed. Moreover, the experimental results showed that an optical link budget of 9.2 dB can be achieved with the experimental configuration.      

基于光载波抑制产生6倍频毫米波的RoF系统

搭建了一种基于光载波抑制产生6倍频毫米波的 RoF系统。系统采用马赫-曾德尔强度调制器（MZM）和滤波器抑制了偶次和一阶光边带,2个三阶光边带在基站端的光电检测器中进行拍频,得到了6倍频毫米波信号。仿真结果表明,采用10 GHz的微波信号,可以产生60 GHz的毫米波,2.5 GB/s的信号可以在单模光纤中传输15 km以上。     

基于富勒烯聚合物的光限幅效应研究

介绍了富勒烯材料在光限幅领域的研究进展,利用杂化合成方法制备了聚苯乙烯-富勒烯聚合物,并对合成的样品进行了性能表征,合成的聚合物材料具有均匀的分布特性,通过Z扫描实验对材料的非线性特性进行了测试分析。结果表明,该材料在较高线性透过率条件下具有良好的非线性限幅效应,对研制高性能的激光防护器具有重要意义。     

基于Linux上NBD的NC本地运行模式的另一解决方案

网络计算机的核心技术是其底层实现机制。网络块设备是Linux下通过模拟一个本地块设备来控制远端网络资源。进而向本地提供文件系统支持的技术。本文提出了一种基于Linux上网络块设备的NC本地运行模式的一种解决方案。     

基于SOA中四波混频效应的全光波长变换

基于半导体光放大器的四波混频效应进行了 2 .5 Gbit/s的光脉冲的波长变换。向上波长变换间距为 1 0 nm,向下变换间距大于 1 0 nm。对基于半导体光放大器四波混频效应的波长变换技术进行了较为详尽的试验报道     

基于GPRS技术的配电自动化系统通信解决方案

由于配电网点多面广,线路接线复杂且变化频繁,给通信系统的建设带来很大困难. GPRS网络的开通为地理位置分散的电能计量点的监测提供了经济可靠的通信手段.文中对配变监测系统提出了两种不同的网络接入方案.方案一:VPN方式;方案二:APN专网方式.从安全性方面考虑确定APN专网方式接入到GPRS网络作为网络接入方案.     

基于频域均衡的Tb/s级相干光单载波系统

对相干光单载波频域均衡系统(CO-SCFDE)、相干光单载波频分复用系统(CO-SCFDM)以及相干光正交频分复用系统(CO-OFDM)的理论和实验进行了对比研究,结果表明基于频域均衡的相干光单载波系统既保留了正交频分复用方式计算复杂度较低、频谱效率高和抗色散性能好的优点,又有效地减小了光纤非线性带来的传输损伤,是高速长距离光纤传输的一种有潜力的技术方案。     

Impact of Optical Transmission on Multiband OFDM Ultra-Wideband Wireless System With Fiber Distribution

Multiband (MB) orthogonal frequency-division multiplexing (OFDM) ultra-wideband (UWB) wireless, which provides high data rate access, is required to be distributed by using optical fiber. The performance of MB-OFDM UWB over fiber transmission system is investigated considering optical modulation and demodulation impact. Theoretical analysis of the effect of fiber dispersion, optical transmitter, and optical receiver response on system performance is carried out considering amplitude and phase distortion. Experiments are conducted and verified by our theoretical analysis and good agreement is obtained. It is found that RF modulation index of $sim {hbox {4}}%$ is optimum for optical transmitter with Mach–Zehnder modulator, and optical receiver with Chebyshev-II response is the best for MB-OFDM UWB over fiber. Compared to back-to-back UWB over fiber, optical transmission is mainly limited by laser phase noise converted relative intensity noise and phase distortion induced by fiber dispersion when optimum modulation index is used. Higher modulation index is limited by amplitude and phase distortion to OFDM signal induced by optical transmitter and receiver response nonlinearities and fiber dispersion and the spectral mask. It is also found that highly received optical power is required for transmission of MB-OFDM UWB signal over fiber.      

基于超结构光纤光栅的新型OCDMA编解码方案

提出了一种基于超结构取样光纤光栅的光码多分址(OCDMA)编解码器.以修正Walsh码为例,研究了利用间隔光0.8 nm的超结构取样光纤光栅编解码器的实现方法,通过控制温度实现了基于超结构取样光纤光栅的OCDMA编解码器的变址.研究表明:采用该编解码器实现谱域编码,可以避免光纤光栅串联方案中多个光纤光栅接点引起的损耗,易通过应力或温度变化调节中心波长、尺寸小及调谐方便,有利于实用化.     

基于压电效应的振荡水柱发电系统CFD分析

"透明海洋"开发需要为远洋检测传感器提供可持续电源,基于压电效应的振荡水柱发电原理是采集波能驱动压电功能材料形变实现能量转换,系统结构简单,稳定性好。基于线性波浪理论,建立振荡水柱(OWC)二维数值波浪水槽。流体动力学(CFD)分析结果表明,造波稳定,波浪在气室内形成的空气压强在时域上呈现一定周期性,经数据处理拟合为正弦曲线。应用ANSYS软件系统的参数化设计语言(APDL)功能开发空气驱动压电材料形变输出能量的仿真模型,分析产生电压变化特性。     

Crosstalk Analysis of a Fiber Laser Sensor Array System Based on Digital Phase-Generated Carrier Scheme

A detailed study on analyzing the crosstalk in a wavelength division multiplexed fiber laser sensor array system based on a digital phase generated carrier interferometric interrogation scheme is reported. The crosstalk effects induced by the limited optical channel isolation of a dense wavelength division demultiplexer (DWDM) are presented, and the necessary channel isolation to keep the crosstalk negligible to the output signal was calculated via Bessel function expansion and demonstrated by a two serial fiber laser sensors system. Finally, a three-element fiber laser sensor array system with a 50-dB channel-isolation DWDM was built up. Experimental results demonstrated that there was no measurable crosstalk between the output channels.     

基于Asmuth-Bloom门限方案的会议密钥分配

当多个用户举行保密的电子会议时,会议机密信息的安全性在很大程度上取决于会议的密钥。本文基于Asmuth-Bloom 门限方案提出了一种会议密钥分配方案,并分析了该方案的正确性和安全性。