Super-dense WDM transmission technology in the zero-dispersion region employing distributed Raman amplification

This paper describes a practical system design and the transmission performance of high-capacity super-dense-wavelength-division-multiplexing (SD-WDM) transmission in the zero-dispersion region employing distributed Raman amplification (DRA). By combining several semiconductor laser diodes (LDs) of different wavelengths, gain-flattened DRA can be achieved. We quantitatively clarify the relation between the pump power and the maximum input signal power that can be injected into a transmission fiber by taking into account gain saturation due to pump depletion. Based on these analytical results and computer simulations on transmission performance, an SD-WDM transmission experiment is conducted. By employing four-wavelength, backward-pumped DRA and forward-error correction, we successfully demonstrate 1-Tb/s (100 /spl times/ 10 Gb/s) SD-WDM transmission with 25-GHz channel spacing (0.4-b/s/Hz spectral efficiency) in the C-band (zero-dispersion region) over 4 /spl times/ 80 km of dispersion-shifted fiber. These results show that DRA is a powerful technology in realizing high-capacity SD-WDM transmission, particularly in the zero-dispersion region.     

A product-coded WDM coding system

Forward error correction is a feasible approach for reducing the bit error floor of lightwave systems, arising from the fact that a simple single-error-correcting code can reduce the error floor from O(P _e) to O(P_e²). We propose a novel wavelength demultiplexer (WDM) coding system using a product code to improve the performance of WDM systems with an error floor caused by fiber dispersion or system noise     

60 GHz amplifier employing slow-wave transmission lines in 65-nm CMOS

A three-stage V-band amplifier implemented in 65-nm baseline CMOS technology is presented in this paper. Slow-wave coplanar waveguides are used for matching and interconnects to study the benefits of using this line type in amplifier design. Measured power gain, noise figure and 1 dB output compression point at 60 GHz are 13 dB, 6.3 dB and +4 dBm, respectively. The amplifier has 19.6 GHz of 3 dB bandwidth, thus covering entirely the unlicensed band around 60 GHz. The performance is achieved with a 1.2 V supply and 45 mA DC current consumption.     

Development of miniature optical fiber hybrid WDM coupler employing the FBT technology

An innovative technique for fabricating the optical fiber hybrid wavelength-division multiplexing (WDM) coupler is presented. The device is comprised of two components, a wavelength division multiplexer and an optical fiber coupler, in a miniature stainless steel tube. The outstanding features of the ultra-low polarization dependent loss (PDL) under 0.05 dB and the compact size of ∅3.5 × 65 mm for bare-fiber type of package are accomplished by using the pioneering methodology combining the main techniques of twisted and parallel fusion processes in the fused biconical taper (FBT) technology. Besides, its miniaturization is more competitive in both of the applications of optical communication and sensing systems where a compact-sized package is required for extending the flexibility of installation.     

无源WDM技术在5G前传中的应用

无源WDM技术是现阶段5G前传采用的主要技术,由于5G前传的速度高达25G,色散成为影响5G前传的主要因素。介绍了无源WDM前传方案的技术原理和常用模型的波长分配,通过对光模块的发送和色散代价(TDP)指标的研究,分析了TDP的各影响因素及其对5G前传的影响,最后结合光纤链路传输指标要求,提出了无源WDM技术在5G前传中的部署建议。     

Multistage WDM access architecture employing cascaded AWGs

Here we propose passive/active arrayed waveguide gratings (AWGs) with enhanced performance for system applications mainly in novel access architectures employing cascaded AWG technology. Two technologies were considered to achieve space wavelength switching in these networks. Firstly, a passive AWG with semiconductor optical amplifiers array, and secondly, an active AWG. Active AWG is an AWG with an array of phase modulators on its arrayed-waveguides section, where a programmable linear phase-profile or a phase hologram is applied across the arrayed-waveguide section. This results in a wavelength shift at the output section of the AWG. These architectures can address up to 6912 customers employing only 24 wavelengths, coarsely separated by 1.6 nm. Simulation results obtained here demonstrate that cascaded AWGs access architectures have a great potential in future local area networks. Furthermore, they indicate for the first time that active AWGs architectures are more efficient in routing signals to the destination optical network units than passive AWG architectures.     

基于交叉复用技术的OFDM-WDM 光传输系统的性能分析

基于正交频分复用(OFDM)与波分复用(WDM)的基本原理,构建了一套基于OFDM技术的WDM传输系统的系统模型,并对其相关系统性能进行了理论分析。基于维纳相位噪声模型,文章对OFDM系统中相位噪声引起的公共相位误差和子载波间干扰进行了分析,在此基础上深入分析了基于交叉复用OFDM技术的OFDM子载波间干扰的消除方法,降低相位噪声对系统性能的影响。最后结合理论分析结果对系统模型的相关性能进行模拟计算,分析结果表明:采用交叉复用OFDM技术在降低相位噪声对OFDM系统性能的影响的同时,提高了系统的信号处理能力。     

基于悬置微带线的U波段分谐波混频器设计

采用商用DMK2308Ga As肖特基二极管管对,设计了一种U波段分谐波混频器。利用全波电磁场分析算法提取了二极管管对无源部分的寄生参量,建立了二极管管对的等效电路模型,并用于分谐波混频器的设计。测试结果显示:本振功率为10d Bm时,变频损耗在50~58GHz小于14.5d B,与仿真结果基本吻合,证明了所建模型的有效性。     

An AWG-based WDM-PON architecture employing WDM/TDMA transmission for upstream traffic with dynamic bandwidth allocation

In this article, we examine a candidate architecture for wavelength-division multiplexed passive optical networks (WDM-PONs) employing multiple stages of arrayed-waveguide gratings (AWGs). The network architecture provides efficient bandwidth utilization by using WDM for downstream transmission and by combining WDM with time-division multiple access (TDMA) for upstream transmission. In such WDM-PONs, collisions may occur among upstream data packets transmitted simultaneously from different optical networking units (ONUs) sharing the same wavelength. The proposed MAC protocol avoids such collisions using a request/permit-based multipoint control protocol, and employs a dynamic TDMA-based bandwidth allocation scheme for upstream traffic, called minimum-guaranteed maximum request first (MG-MRF), ensuring a reasonable fairness among the ONUs. The entire MAC protocol is simulated using OPNET and its performance is evaluated in terms of queuing delay and bandwidth utilization under uniform as well as non-uniform traffic distributions. The simulation results demonstrate that the proposed bandwidth allocation scheme (MG-MRF) is able to provide high bandwidth utilization with a moderately low delay in presence of non-uniform traffic demands from ONUs.     

基于空时编码的高效星地数据传输技术

为提升星地数据传输效率,多采用时间域变速率传输模式,但改善程度有限。文中从空间域角度着手,提出基于空时编码的高效星地数据传输技术,通过空时预编码将多个混叠的数据流分离开来,形成多个编码通道同时传输多路并发数据,并且能够在空间域上收集散射、反射路径功率,从而充分利用有限的链路功率。分析与仿真结果显示,采用星上2天线对2个用户的传输模式,相比传统点对点的传输模式其频谱效率可提升0.5～1 b?s~(-1)?Hz~(-1)。     

WDM coding for high-capacity lightwave systems

An interchannel parallel coding scheme in the wavelength domain-the WDM coding system-is proposed. The system differs from the usual serial coding systems and provides many advantages. First, data channels are completely unaltered in the coding process, rendering it very suitable for practical lightwave systems with standard bit rate. Second, parallel encoding/decoding systems are simpler than those of serial coding systems, being easier to be implemented in high-speed optical systems. Third, compared with serial coding, WDM coding is able to reduce heavily the number of encoding/decoding pairs. For example, a (15, 11) Hamming coded WDM system reduces the number from 12×11=132 to 1 at the line rate of STS-12. Fourth, the WDM coding system could offer infinite coding gain in dispersion-limited lightwave systems. Finally, WDM coding systems could correct single-channel burst error. The system performance was evaluated and the system limitation imposed by bit-skew among wavelength channels was analyzed. The results indicated that a 15-channel Hamming coded WDM system can reduce the uncoded BER from 10^-9 to 3×10^-17 and the distance limitation imposed by bit-skew is 250 km if a dispersion-shifted fiber is used and a channel span of 30 nm is assumed     

A 90-nm logic technology featuring strained-silicon

A leading-edge 90-nm technology with 1.2-nm physical gate oxide, 45-nm gate length, strained silicon, NiSi, seven layers of Cu interconnects, and low-/spl kappa/ CDO for high-performance dense logic is presented. Strained silicon is used to increase saturated n-type and p-type metal-oxide-semiconductor field-effect transistors (MOSFETs) drive currents by 10% and 25%, respectively. Using selective epitaxial Si/sub 1-x/Ge/sub x/ in the source and drain regions, longitudinal uniaxial compressive stress is introduced into the p-type MOSEFT to increase hole mobility by >50%. A tensile silicon nitride-capping layer is used to introduce tensile strain into the n-type MOSFET and enhance electron mobility by 20%. Unlike all past strained-Si work, the hole mobility enhancement in this paper is present at large vertical electric fields in nanoscale transistors making this strain technique useful for advanced logic technologies. Furthermore, using piezoresistance coefficients it is shown that significantly less strain (/spl sim/5 /spl times/) is needed for a given PMOS mobility enhancement when applied via longitudinal uniaxial compression versus in-plane biaxial tension using the conventional Si/sub 1-x/Ge/sub x/ substrate approach.     

A secure WDM ring access network employing silicon micro-ring based remote node

A secure and scalable wavelength-division-multiplexing (WDM) ring-based access network is proposed and demonstrated using proof-of-concept experiments. In the remote node (RN), wavelength hopping for specific optical networking unit (ONU) is deployed by using silicon micro-ring resonators (SMR). Using silicon-based devices could be cost-effective for the cost-sensitive access network. Hence the optical physical layer security is introduced. The issues of denial of service (DOS) attacks, eavesdropping and masquerading can be made more difficult in the proposed WDM ring-based access network. Besides, the SMRs with different dropped wavelengths can be cascaded, such that the signals pass through the preceding SMRs can be dropped by a succeeding SMR. This can increase the scalability of the RN for supporting more ONUs for future upgrade. Here, error-free 10 Gb/s downlink and 1.25 Gb/s uplink transmission are demonstrated to show the feasibility of the proposed network.     

基于网络编码的水下传感器可靠传输技术

网络编码技术可以极大的提高网络的吞吐量,同时能提高网络的鲁棒性。为了提高水下传感器网络数据传输的可靠性,利用网络编码对消息的备份性进行能量收集。该方案节省了电池能量,提高水下传感器节点的生存周期。     

Optimizing subcarrier-multiplexed WDM transmission links

We present an analytic approach to optimizing the information capacity of a subcarrier-multiplexed wavelength-division-multiplexed optical communication link. Receiver and relative-intensity noise, clipping distortion, and crosstalk between wavelength channels due to optical nonlinearities in the fiber are the signal impairments considered.     

WDM coding system with single parity-check channel

We propose a modified WDM coding system with a single parity-check channel to achieve an efficient and flexible WDM coding system. The system provides most of the advantages of the original WDM coding system with just one parity-check channel. The bit rate and the data sequences are unaffected by the coding processes, making it very attractive for practical lightwave systems with standard rates. Compared to serial coding systems, it is able to reduce the number of encoding/decoding pairs in an m-channel WDM transmission system operated at STS-N from m×N to one. We have evaluated the system performance and analyzed the performance of frame synchronization needed for the modified WDM coding system. An example shows that the WDM coding can reduce the error floor of a four-channel dispersion-limited WDM system from 10^-10 to 10^-19 with reliable frame synchronization     

2×10 Gbit/s WDM 1310-nm optical transmission over 63.5-kmstandard single-mode fiber using optical preamplifiers

Twenty Gbit/s transmission over 63.5 km SMF at 1310 nm is reported by using two channel 10 Gbit/s wavelength (de)multiplexing (Δλ=1.5 nm). Two 1310 nm SL-MQW semiconductor optical amplifiers are utilized for loss compensation and sensitivity improvement. For the 1310 nm wavelength domain, a record bitrate x distance product of 1.27 Tbit/s.km has been obtained. Crosstalk penalties are identified, and the feasibility of an extension up to at least four, 10 Gbit/s channels is discussed     

Proposal for simplified WDM transmission configuration

A new WDM (wavelength division multiplexing transmission configuration for local communications is proposed. In this configuration, the demultiplexing function is performed using narrow spectral sensitivity optical detectors and a demultiplexer is not required, allowing economical and simple WDM transmission. Dual-wavelength WDM transmission of 0.86 ?m and 0.73 ?m over 2 km on GI fibre is experimentally confirmed, using commercially available LEDs for both optical sources and detectors.     

Network coding based all-optical multicast in WDM networks

Wavelength division multiplexing(WDM) has been becoming a promising solution to meet the rapidly growing demands on bandwidth. Multicast in WDM networks by employing free wavelength is an efficient approach to saving bandwidth and cost. However, the free wavelength may not identical between different hops in a multicast light-path, particularly in heavy load optical WDM networks. In order to implement multicast applications efficiently, a network coding(NC) technique was introduced into all-optical WDM multicast networks to solve wavelength collision problem between the multicast request and the unicast request. Compared with the wavelength conversion based optical multicast, the network coding based optical multicast can achieve better multicast performance with paying lower cost.     

移动IP中基于网络编码的单跳传输技术的研究与实现

在基站与移动节点的单跳传输中,引入了网络编码的传输思想.在此基础上,提出了编码组的概念,并描述了以编码组为控制单元的传输模型.在该模型基础上,引入了网络编码和嵌套网络编码2种编码组传输方式,并通过对2种编码组传输方式的分析,提出了编码组传输控制算法及其改进算法.最后通过仿真实验表明,与传统单播传输相比,编码组传输模型确实可以提高无线网络传输的正确率,降低无线网路的重传率,提高移动IP的整体性能.