A novel chromatic dispersion monitoring method for 1 024 QAM fiber-optic system based on asynchronous amplitude sampling

A new chromatic dispersion (CD) monitoring method is proposed, and the CD monitoring is achieved on the whole range of 0—600 ps/nm. A dual-polarization (DP)-1 024 quadrature amplitude modulation (QAM) 400 Gbit/s CD monitoring system is built using OptiSystem14.0 software. With different optical signal to noise ratio (OSNR) values, different filter bandwidths or different duty cycles, the simulations are carried out. The simulation results show that this new CD monitoring method can be less affected by noise and has a high tolerance for different filter bandwidths. At the same time, this method can do effective CD monitoring on the signal with duty cycle greater than 80%. A high sensitivity in 0—200 ps/nm can be achieved using this CD monitoring method. The technique supports a wide range of data traffic and enhances operation flexibility of optical networks. This work has been supported by the National Natural Science Foundation of China (Nos.61274121 and 61574080). E-mail:zhub@njupt.edu.cn      

A novel chromatic dispersion monitoring technique for 16/64-QAM system based on asynchronous amplitude histogram

A novel chromatic dispersion (CD) monitoring technique based on asynchronous amplitude histogram (AAH) for higher order modulation formats is proposed in this paper. Without demodulating the signal, in the monitoring scheme, the received signal is sampled asynchronously, and thus clock information and high-speed sampling units are unnecessary, resulting in low cost and high reliability. Simulations of CD monitoring technique for non-return-to-zero/return-to-zero (NRZ/RZ) 16- and 64-quadrature amplitude modulation (QAM) systems with different optical signal-to-noise ratios (OSNRs) and duty cycles are investigated, and the tolerance of the scheme is also discussed. Simulation results show that the presented CD monitoring technique with high sensitivity can be applied to monitor the residual CD of a transmission link in the next-generation optical networks.     

256 QAM Modem for Multicarrier 400 Mbit/s Digital Radio

This paper describes the performance of a 256 QAM modem with 400 Mbit / s transmission capacity. A variety of novel techniques are introduced as ways to achieve good performance. Key techniques include 1) an accurate 256 QAM modulator employing a new monolithic multiplier IC, 2) a carrier recovery circuit which satisfies such requirements: good phase jitter performance and no false lock phenomenon, 3) a highly stable high-level decision circuit, and 4) a forward error correcting code. As an overall modem performance, BER characteristics and signatures are presented. The equivalent CNR degradations of 1 dB(at BER of 10^-4) and 2 dB (at BER of 10^-9)are obtained using a single Lee-error correcting code and a seven-tap baseband transversal equalizer. The residual bit errors are decreased below the order of 10^-10. The performance of a 256 QAM multicarrier modem has given prospect for the development of 400 Mbit/s digital microwave radio system.     

40 Gbit/s CSRZ-DPSK transmission system with signed online chromatic dispersion detection

A chromatic dispersion measurement scheme based on arrival time detection, an active interferometer phase stabilisation, and a standard clock-and-data recovery circuit are used in this 40 Gbit/s carrier-suppressed return-to-zero differential phase shift keying system. Chromatic dispersion measurement noise is 100 fs/nm.     

Electronic compensation of PMD and chromatic dispersion with an ICin 10 Gbit/s transmission system

A system experiment is reported in which polarisation mode dispersion (PMD) and chromatic dispersion (CD) compensation was achieved using an SiGe IC linear equaliser, with a transmission rate of 100 bit/s over 95 km of standard single-mode fibre (DL=1600 ps/nm). Full equalisation was obtained, with a differential group delay (DGD) of <65 ps and a penalty reduction to 3.4 dB for DGD=100 ps     

An chromatic dispersion monitoring method based on spectral-shift of SOA

A remnant dispersion monitoring method based on spectral-shift of SOA in high speed optical communication system with CSRZ format and single channel speed of 40 Gbit/s is proposed. The system performance can be optimized by careful choosing bandwidth and center wavelength of the optical fiber grating filter. The dynamical monitoring range is ±60 ps/nm and the monitoring precision is about 5 ps/nm. This method can be suitable for the application in dynamical dispersion compensation of high speed optical communication systems.     

Bit rate flexible quality monitoring of 10 to 160 Gbit/s opticalsignals based on optical sampling technique

Bit rate flexible quality monitoring of 10 to 160 Gbit/s RZ optical signals up to the bit error rate of 1×10^-13 based on an ultrafast optical sampling technique is demonstrated. In addition, a compact optical signal monitoring unit that uses a readily available gain-switched laser diode as the optical sampling pulse source is reported     

Performance of non-fibre based dispersion compensation for long-haul 10.7 Gbit/s DWDM transmission

Non-fibre based in-line dispersion compensation is employed to achieve long-haul transmission of 80 channels at 10.7 Gbit/s bit rate over 1200 km of LEAF fibre. Average system margins of more than 4 dB and small transmission are demonstrated. The additional penalty incurred by the periodic nature of the dispersion compensator is assessed.     

外调制器啁啾对10 Gbit/s色散补偿系统的影响

讨论了10 Gbit/s光通信系统中光发射模埠的外调制器产生啁啾的原因和特性。通过数值计算，分析了外调制器啁啾对色散补偿系统的影响，结果表明积极利用小量的负啁啾可以降低接收器输出端电眼图代价（EOP）0.5dB，从而改善系统性能。     

A 10 Gbit/s OCDMA system based on electric encoding and optical transmission

An electric encoded/optical transmission system of code division multiple access （CDMA） is proposed. It encodes the user signal in electric domain, and transfers the different code slice signals via the different wavelengths of light. This electric domain encoder/decoder is compared with current traditional encoder/decoder. Four-user modula- tion/demodulation optical CDMA （OCDMA） system with rate of 2.5 Gbit/s is simulated, which is based on the optical orthogonal code （OCC） designed in our laboratory. The results show that the structure of electric encoding/optical transmission can encode/decode signal correctly, and can achieve the chip rate equal to the user data rate. It can over- come the rate limitation of electronic bottleneck, and bring some potential applications in the electro-optical OCDMA system.     

400Gbit/s光通信用超低损耗超大有效面积光纤的研究

从电磁场基 本理论出发,采用标量波动方程进行分析与计算,设计出一种超低损耗超大有效面积单模光 纤(SMF)的折 射率剖面结构,纤芯折射率为1.461,纤芯直 径为13.99μm,内包层引入低折射率下凹 环,其折射率为1.455,宽为 6.95μm;采用连续化学气相 沉积(CCVD)工艺,制造出包层直径为125μm的SMF。测试表明,研 发的光纤具备超低损耗 与超大有效面积特性,其在1550nm波长的衰减 为 0.165dB/km,在1625nm波长的衰减为0.179dB/km;在 1550nm波长的模场直径为13.96μm,有效面 积为153μm²;光纤具备优良的抗弯曲性能,在弯曲半径为30mm 的芯轴上弯曲100圈的条件下, 其在1550nm的弯曲附加损耗为0.032dB,在1625nm波长的弯曲附加损耗为0.093dB。实验结果表明, 本文研发的SMF能够满 足400Gbit/s高速光通信的应用需求,可为下一代高速光纤通信提供 关键基础材料支撑。     

基于DSP实现的100 Gbit/s DP-QPSK系统相干接收技术

对100 Gbit/s 偏振复用-正交相移键控（DP-QPSK）系统中使用数字信号处理（DSP）技术同时实现对光信号色散补偿、偏振解复用和相位估计的方案进行了讨论,并采用OptiSystem 9.0软件对该方案的效果进行了验证,仿真结果表明该技术方案实现简单且可靠性高,对优化相干光检测硬件有参考意义。     

A novel symmetric 10 Gbit/s architecture with a single feeder fiber for WDM-PON based on chirp-managed laser

We propose the single feeder fiber architecture for wavelength division multiplexing passive optical network(WDM-PON)based on directly modulated chirp managed laser(CML).The downlink(DL)signal output from the laser is converted to return-to-zero(RZ)differential phase shift signal using a pulse carver.The downstream signal is reused as a carrier for the upstream using intensity modulation technique.Simulation results show the error-free performance at symmetric data rate of 10 Gbit/s per channel with negligible power penalty and improved receiver sensitivity for the uplink(UL),over 25 km standard single-mode fiber(SSMF).A low-cost and reduced circuitry network design is implemented on a single feeder fiber with the elimination of differential encoder and one external modulator.     

A novel partial-to-partial registration method based on sampling network

Point cloud registration is mainly to estimate a rigid transformation between point clouds. The traditional optimization-based registration method requires a good initial position, and it is easy to fall into a local optimal solution. Some learning-based methods are introduced to reduce the dependence on the initial transformation, but they cannot handle partial-to-partial registration tasks. This paper proposes a learning-based registration method for partial-to-partial scenario. The local geometry is encoded into the feature representation of each point. A transformer network is used to enhance attention features. A designed sampling network down-sample key matching points and their corresponding features. The rigid transformation is calculated according to virtual correspondence by a singular value decomposition layer. The ModelNet40 dataset and Stanford 3D Scanning models are used to test the registration performance. Experimental results show that the proposed method achieves better registration accuracy than traditional methods, and it is robust to any initial transformation and noise.     

40Gb/s单信道RZ调制格式光传输色散补偿的比较

对基于RZ调制格式的单通道40Gb/s系统的色度色散补偿进行了仿真,比较了前置、后置、对称、预失真补偿的传输性能,最终得出长距离传输时,预失真补偿和对称补偿的性能最优.     

基于10Gbit/s传输的光纤旁路系统平台研究与设计

本文基于MPC8308ERDB设计了一款基于10Gbit/s传输的光纤旁路保护器,用于保护接入骨干网的节点设备,重点分析了针对MPC8308ERDB开发板的u-boot移植过程中的关键问题。凭借U-boot对PowerPC系列处理器最为丰富的支持,结合飞思卡尔提供的BSP源代码包,详细地分析了u-boot源代码的编译及配置过程,重点分析了u-boot的移植过程。     

1.25 Gbit/s millimetre-wave band wired/wireless radio-over-fibre system based on RSOA using injection-locking effect

A new architecture for a millimetre-wave band radio-over-fibre system is proposed. Both optical carrier suppression and injection locking effect are used to simultaneously generate a 1.25 Gbit/s wired signal and a 63 GHz wireless one. Error-free transmissions (bit error rate of 10^-11) of downlink and uplink data are achieved to verify the proposed scheme. No impact of a downlink data transmission on an uplink one owing to the wavelength reuse is observed. It is checked that there is only the 2 dB power penalty of the uplink owing to the Rayleigh backscattering noise.     

基于DML的18.6Gb/s无色散补偿DDO-OFDM系统

为了降低直接检测光正交频分复用(DD0-OFDM)系统的成本并提高传输速率,采用载波选择性填充和预加重技术,利用带宽为10GHz的DML激光器实现了信号速率达18.6Gb/s的20km标准单模光纤(SSMF)无色散补偿的传输.实验结果表明利用本方案采用的技术,可以实现结构简单、频谱利用率高、成本低的直接检测OFDM传输系统.     

Low-jitter design method based on Wn-domain jitter analysis for 10 Gbit/s clock and data recovery ICs

A low-jitter design method based on vn-domain jitter analysis for the clock and data recovery (CDR) ICs using the linear phase-locked loop (PLL) is proposed. Using this method, the loop parameters of the PLL can be optimised, which makes it possible to design the CDR IC for various targets.     

一种基于TCP／IP远程通信协议的新型远程智能电源监控切换系统

为了更好地保障铁路运输的安全和效率,确保采用双路供电的铁路系统的不间断工作,提出了一种基于TCP／IP远程通信协议的智能电源切换系统。系统由电源屏双路输入远程切换单元、控制中心的TCP／IP通信链路、用户软件控制系统组成。电源屏双路输入远程切换单元由电源信号监控、切换单元组成。TCP／IP通信链路采用嵌入式操作平台,功能包括TCP／IP链路控制;用户软件控制系统采用C＋＋编写完成,包括界面操作,授权控制等功能,能满足站点现场电源切换要求的功能。