共查询到19条相似文献,搜索用时 125 毫秒
1.
4×155Mb/s频分复用(FDM)光纤通信系统的研究 总被引:1,自引:0,他引:1
报道了一个无故障工作时间大于24小时的四路155Mb/s频分复用(FDM)光纤通信系统,实测系统误码率优于0×10(-14)。系统接收机包括解复用光滤波器,接收机灵敏度优于-30dBm(BER=1×10(-9),频道间距为0.1nm,四路FDM信号-20dB的总谱宽为0.7nm。系统采用国产DFB激光器为光源,实际光纤传输距离18km。系统全部实现了脱离光学平台的模块化结构,在长期的系统实验中显示了优良的稳定性。这一成果为FDM在光纤传输接入网中的进一步实用化开发铺平了道路。 相似文献
2.
109公里2.5Gb/s无中继IM/DD光纤传输实验系统 总被引:2,自引:1,他引:1
对国内首次2.488Gb/s光纤传输系统实现结果进行了报道。系统工作波长1550nm,利用常规单模光纤实现了109公里无中继传,要用IM/DD方式,接收机灵敏度为-30.5dBm. 相似文献
3.
1.48μm泵浦EDFA的研制及其在模拟光纤传输系统中的应用 总被引:1,自引:0,他引:1
利用国产1.48μm泵浦LD和优质掺饵光纤研制了一种实用化的掺饵光纤放大器,小信号净增益28dB,噪声系数5.1dB,增益谱宽大于20nm,最大输出功率达4.8dBm和11dBm。实验研究了EDFA在FM/FDM模拟电视光纤系统的应用,利用EDFA作为系统的功率提升和中继放大器,分别成功地进行了185km和224km的系统传输试验。 相似文献
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带宽〉40nm的980nmLD泵浦掺Er^3+光纤放大器模块 总被引:1,自引:0,他引:1
在国内首次用980nm激光二极管和参量优化Er3+/Al3+共掺杂光纤研制成光学带宽>40nm的光电一体化光纤放大器实用型模块样机。模块净增益25dB,饱和输出功率0dBm,最大输出功率8dBm,噪声系数<5dB,可供波分复用光纤通信系统和光孤子传输实验试用。 相似文献
6.
利用自行研制的模块化高稳定度光发射机、光接收机、掺饵光纤功率放大器和掺饵光纤前置放大器,实现了4×622Mb/s×200km、2.5Gb/s×200km和4.354Gb/s(1×2.488Gb/s+3×622Mb/s)×160km的常规单模光纤无中继传输实验。带有掺饵光纤前置放大器的四路光接收机灵敏度达到-46.8dBm(622Mb/s,NRZ223-1 PRBS)和-39.5dBm(4×2.5Gb/s,NRZ27—1PRBS)。系统各信道误码率优于4×10-12~4×10-15。 相似文献
7.
报导了采用全MOCVD生长的1.55μm的单片集成DFB=LD/EA组件的 在DWDM系统上的传输测试结果,出纤功率Pf≥2.5mW@If=75mA,边模抑制比SMSR〉35dB,调制器反向偏压为2.5V时的消光比为14dB,该发射模块在2.5Gb/sDWDM系统上进行了传输试验,传输240Km后无误码,其通道代价≤1dB@BER=10^-12。 相似文献
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在国内首次研制了使用1个光纤放大器的10频道102km无再生中继“WDM+EDFA”全光光纤传输实验系统。每频道传输码率为140Mb/s或280Mb/sNRZ。所用光纤放大器为增益平坦型,小信号增益为35dB。系统全部采用国产DFB激光器,各频道波长分别为1531、1535、1537、1545、1547、1549、1551、1559、1561nm,在波长为1551nm的频道内布置了2路频分复用(FDM)系统。波长分布遍及整个光纤放大器的通带。经无再生中继传输102km后,在误码率为1×10 ̄(-9)条件下,实测了尚有数dB以上(最大为12d8)的功率裕量。系统使用光栅合、分波器作为波分复用和解复用器,频道间隔为2nm及其整数倍,系统具有18个频道的能力。 相似文献
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报导了国内首例宽带,低压铌酸锂电光调制器的研究结果。用傅利叶级数方法设计了长电极,厚金电极和厚SiO2缓冲层的M-Z光波导强度调制器,制成的调制器为实用化带尾光纤包装式器件,在1.55μm工作波光下,其性能指标为3dB光调制带宽15GHz,半波电压5.6V,消光比21dB。 相似文献
10.
报道了运用DFB-LD与M-Z调制器单片集成组件为光源实现10Gb/s100km常规单模光张的传输实验。实验表明,采用光源预啁啾技术可延长系统的传输距离。在误码率BER=10^-10时,传输后的功率代价为1.1dB,接收灵敏度为-16.5dBm。这一结果达到了国外同类实验的水平。 相似文献
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A joint transform correlator has been constructed by a spatial light modulator that uses the electroabsorption effect of GaAs crystal and operates at a high frame rate a TV camera with logarithmic response and a personal computer. In the system, logarithmic values of joint power spectra generated in an optical system were electrically digitized and inverse-Fourier transformed. The system has accomplished the operation of correlation with a throughput time smaller than 10 ms per an input image. 相似文献
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A binary differential impulse radio-ultra wide band (IR-UWB) communication scheme over a singlemode optical fibre is examined. For a receiver structure, the conventional electrical receiver as well as an optical receiver structure, which is similar to the optical receiver used for digital, optically phase-modulated differential phase shift keying, are considered. The optical receiver can alleviate the IR-UWB receiver implementation challenges and it is studied for the first time in the context of IR-UWB. Considering various important noises, for example, phase noise, laser intensity noise, thermal noise and shot noise, analytical expressions for the error probability of the aforementioned receivers are derived. The mathematical models for optical components including laser diode and single-mode fibre, along with the analytical expressions for the receiver?s error probability, are used to evaluate the overall performance of an UWB communication system over a fibre transmission medium. Furthermore, the electrical receiver is compared with the optical receiver and it is shown that the performance of the optical receiver can be as good as that of the electrical receiver and even better. The impact of wireless channel fading, bias current of laser diode and the coherence time of laser diode on the UWB over fibre system performance is also examined. 相似文献
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40Gbps甚短距离并行光传输系统接收电路的设计与实现 总被引:1,自引:0,他引:1
给出了符合OIF-VSR5规范的40Gbps甚短距离光传输系统接收电路的设计与实现。该接收电路实现简单,由一片转换芯片及光接收模块构成。其特点是充分利用现场可编程门阵列(FPGA)内嵌的高速收发器成功实现了16×2.488Gbps和12×3.318Gbps信号的发送和接收,并且在一片FPGA上实现了诸如时钟数据恢复、串/并转换、帧同步、通道对齐、12-16路映射等全部功能。基于二分查找法的帧同步电路则大大提高了转换芯片的工作速度。Signaltap Ⅱ逻辑分析仪的测试结果表明接收电路工作正常,性能良好。在此基础上,给出了VSR5实验系统的点到点测试方法,通过12通道垂直腔面发射激光器并行接收模块和7m 12芯多模带状光纤,将发送电路与接收电路相连,实现了OC768/STM-256 40Gbps的点到点测试,测试结果表明系统误码率小于10~(-12)。 相似文献
14.
《NDT International》1988,21(6):422-426
When performing deformation measurements by interferometric techniques, one component of displacement is measured without direction. In this paper we present a simple method for obtaining both the direction and magnitude of displacement by phase-stepping the reference beam in an electronic speckle pattern interferometry (ESPI) camera. The interferograms are digitized in real time and analysis is performed by a personal computer (PC). The algorithm for obtaining the displacement data only requires four primary interferograms: two for the reference state of the object and two for the deformed state. By suitable averaging over neighbouring pixels, displacement slopes of up to 15λ across the TV target can be measured with an accuracy of ∼λ/15, where λ is the wavelength of the laser. 相似文献
15.
随着计算机技术、多媒体技术、数字压缩技术、网络通信技术等引入视频制作系统后,使数字化电视制作显示出前所未有的巨大威力。本文介绍了用数字化电视制作技术作为基本手段,将摄像机捕捉的图象信号通过技术处理,实现对物体的大小、距离、形状、高度、温度、冲击与振动参数进行定性或定量测量、分析的方法。 相似文献
16.
《Journal of Modern Optics》2013,60(4):349-365
Electronic transmission storage and retrieval of medical X-ray pictures is a feasible concept using today's technology. The large amounts of data can be compressed by digital picture coding techniques. The maximum information within a basic picture element of a film/foil combination has been estimated on the basis of statistical source and receiver properties. Intrinsic dependencies between adjacent picture elements offer the chance of applying efficient redundancy-reducing codes. Several coding schemes have been published for TV and facsimile transmission. These methods, which are mainly predictive and transform coding procedures, have been applied and modified so as to best suit radiographs. Novel schemes, especially adapted for X-ray picture statistics and to suppress error propagation, have been developed. 相似文献
17.
This work experimentally demonstrates the potential of multi-level pulse amplitude modulation with direct detection to maximize carrier spectral efficiency and double the Gigabit passive optical networks (G-PON) network data rate. Three scenarios have experimentally been exploited. First, a 1310?nm vertical surface-emitting laser (VCSEL) has directly been modulated with a 10?Gbps OOK data. A receiver sensitivity of ?19.11?dBm is attained, and a successful error free transmission over 22?km SMF fibre achieved, with a transmission penalty of 0.46?dB. To maximize carrier spectral efficiency, 2/4 PAM modulation formats are adopted respectively. A receiver sensitivity of ?14.64 and ?11.63?dBm is attained for 2-PAM and 4-PAM formats respectively. However, a 3.21?km fibre transmission introduces a penalty of 0.64 and 3.30?dB for 2-PAM and 4-PAM formarts respectively. 2/4-PAM modulation formats significantly increase the aggregated data rate at different ONUs within the G-PON without expensive optics investment, though at the cost of reduced transmission reach due to the high bitrate attained. We further demonstrate the design of a software defined digital signal processing assisted receiver to recover the 2/4 PAM transmitted signal without employing costly receiver hardware. 相似文献
18.
We have fabricated high-speed Si metal-semiconductor-metal photodetectors using(19) F(+) ion implantation in low-doped Si. Bandwidths in excess of 6 GHz have been obtained that represent more than an order-of-magnitude improvement over unimplanted counterparts. Measurements with short optical pulses show that the increase in bandwidth is due primarily to a shorter carrier lifetime in implanted devices. In the absence of implantation, the response under short optical pulse excitation has a long decay with a time constant of ~0.35 ns. We carried out an optical fiber transmission experiment using a GaAs (lambda ~ 0.85 mum) laser source and the implanted Si photodetector. Error-free transmission (bit error rate < 10(-11)) with good receiver sensitivity was obtained at 2 Gbits/s. These results demonstrate that implanted Si can be used as a detector for short-wavelength fiber-optic communication systems for speeds to a few gigabits per second. Monolithic integration of this detector technology with conventional Si processing offers the potential for low-cost receiver designs. 相似文献
19.
介绍一种实际使用的小型跟踪测量电视系统 ,它通过提高光学系统透过率和增强图象对比度 ,以及采用数字背景拟合自适应电平检测的方法 ,达到远距离探测目标的任务。 相似文献