MSONoC: a non-blocking optical interconnection network for inter cluster communication

Electric router is widely used for multi-core system to interconnect each other. However, with the increasing number of processor cores, the probability of communication conflict between processor cores increases, and the data delay increases dramatically. With the advent of optical router, the traditional electrical interconnection mode has changed to optical interconnection mode. In the packet switched optical interconnection network, the data communication mechanism consists of 3 processes: link establishment, data transmission and link termination, but the circuit-switched data transmission method greatly limits the utilization of resources. The number of micro-ring resonators in the on-chip large-scale optical interconnect network is an important parameter affecting the insertion loss. The proposed λ-route, GWOR, Crossbar structure has a large overall network insertion loss due to the use of many micro-ring resonators. How to use the least micro-ring resonator to realize non-blocking communication between multiple cores has been a research hotspot. In order to improve bandwidth and reduce access latency, an optical interconnection structure called multilevel switching optical network on chip(MSONoC) is proposed in this paper. The broadband micro-ring resonators(BMRs) are employed to reduce the number of micro-ring resonators(MRs) in the network, and the structure can provide the service of non-blocking point to point communication with the wavelength division multiplexing(WDM) technology. The results show that compared to λ-route, GWOR, Crossbar and the new topology structure, the number of micro-ring resonators of MSONoC are reduced by 95.5%, 95.5%, 87.5%, and 60% respectively. The insertion loss of the minimum link of new topology, mesh and MSONoC structure is 0.73 dB, 0.725 dB and 0.38 dB.

Exploiting the Faster-Than-Nyquist Concept in Wavelength-Division Multiplexing Systems Using Duobinary Shaping

This paper begins with Nyquist wavelengthdivision multiplexing （WDM） and then introduces fasterthanNyquist. In fasterthanNyquist a certain amount of intersymbol interference （ISI） is accepted, which violates the fundamental principle of Nyquist WDM. This results in muchrelaxed transceiver bandwidth and simpler spectral design. However, in fasterthanNyquist, implementation complexity is shifted from the transmitter side to the receiver side. Therefore, successful application of fasterthanNyquist depends on innovation in the receiver structure. In this paper, we discuss the guidelines for implementing suboptimum, lowcomplexity receivers based on fasterthanNyquist. We suggest that duobinary shaping is a good technique for trading off achievable spectral efficiency, detection performance, and implementation complexity and might be preferable to Nyquist WDM. Experiments are conducted to verify robustness of the proposed technique.

Multi-functional optical fiber sensor system based on a dense wavelength division multiplexer

We propose a novel and efficient multi-functional optical fiber sensor system based on a dense wavelength division multiplexer(DWDM).This system consists of an optical fiber temperature sensor, an optical fiber strain sensor, and a 48-channel DWDM.This system can monitor temperature and strain changes at the same time.The ranges of these two sensors are from-20℃ to 100℃ and from-1000 με to 2000 με, respectively.The sensitivities of the temperature sensor and strain sensor are 0.03572 nm/℃ and 0.03808 nm/N, respectively.With the aid of a broadband source and spectrometer,different kinds and ranges of parameters in the environment can be monitored by using suitable sensors.

Hybrid WDM/TDM PON system employing an all-optical wavelength converter

A new hybrid WDM/TDM passive optical network （PON） implemented by using all-optical wavelength converters （AOWCs） is proposed. The AOWCs are based on the cross-gain modulation （XGM） effect of the semiconductor optical amplifier （SOA）. Moreover, the feasibility of this sys- tem is experimentally demonstrated by evaluating the impacts of the optical wavelength conversion, time domain waveforms, eye diagrams and bit-error-rate （BER） in AOWC. The results show that the proposal will be a promising solution for the next generation access networks.

Novel architecture of WDM/OCDMA-PON based on SSFBG and wavelength re-modulation technology

A novel architecture of wavelength-division multiplexing/optical code division multiplexing access-passive optical network （WDM/OCDMA-PON） based on superstructure fiber Bragg grating （SSFBG） and wavelength re-modulation technology is proposed. In this scheme, WDM is overlaid on OCDMA channel in a single network by virtue of a kind of SSFBC, and the total capacity of hybrid PON can be extended by regulating the transmission power reasonably. Re, modulation technology is also a good method to save wavelength-specific components at the optical network unit （ONU） and cost of wavelength management on the customer side. In simulation system, 1.25 Gb/s up/downstream data are transported with good performance. In addition the crosstalk penalties from adjacent wavelength channels （with the same OC） are found to be negligible in upstream and downstream transmissions.

Performance analysis of a hybrid optical CDMA/DWDM system against inter-symbol interference and four wave mixing

This paper reports the implementation and theoretical model for analyzing an optical CDMA/DWDM hybrid system to reduce two major problems,the Inter-Symbol Interference(ISI)and the Four-Wave Mixing(FWM)effects and improve the performance of optical subscriber access networks by using Zero Cross-Correlation(ZCC)optical codes,which helps to reduce the effect of the Multiple Access Interference(MAI).A squeezing method is used in the proposed hybrid system to completely suppress the ISI.In this method,the sequence interval of the signature code is squeezed into a duration of less than one-bit.The hybrid system is capable of accommodating 120 optical CDMA users carried by only 10 DWDM wavelengths spaced by 0.2 nm with 60 Gb/s/wavelength transmitted over 105.075 km of optical fiber.The result shows that the optimum interval of the code sequence is a quarter(i.e.,25%)of the bit duration.Moreover,the results reveal that the CDMA technology based on the spread spectrum is capable of increasing the nonlinear tolerance of the proposed hybrid system as the energy of bits is distributed over the chip sequence code.Also,the number of ones/weight and the positions between them have a significant effect on the performance of the proposed hybrid system.

Impact of Channel Dynamics, Combined Nonlinearities and ASE Noise on Transmission Performance of all Optical Star WDM Networks

For all optical Wavelength Division Multiplexing (WDM) network based on G.653 fibers, we investigate the quality factor deterioration due to combined nonlinear effects and Amplified spontaneous emission (ASE) noise for system parameters based on ITU-T Recommendation G.692. The investigation: (a) emphasizes on stimulated Raman scattering (SRS) and four wave mixing (FWM) effects which are the dominant nonlinearities known to limit WDM system performance and (b) accounts for beating between nonlinearities and beating between ASE noise and nonlinearities. Using the proposed model, performance of the worst affected channels due to SRS and FWM is compared and the results indicate that the worst affected channel due to SRS performs better and hence must be preferred for reliable and efficient transmission over the worst affected channel due to FWM. Further, the results suggest that to achieve a desired error rate (quality factor);there exists an optimal value of channel spacing for a given number of channels. The proposed theoretical model is also validated through extensive simulations over Rsoft OptSimTM simulator and the two sets of results are found to match, indicating that the proposed model accurately calculates the quality factor of the all optical WDM network.

Traffic Scheduling in WDM Passive Optical Network with Delay Guarantee

WDM passive optical network becomes more favorable as the required bandwidth increases, but currently few media access control algorithms adapted to WDM acc ess network. This paper presented a new scheduling algorithm for bandwidth shari ng in WDM passive optical networks, which provides per-flow delay guarantee and supports variable-length packets scheduling. Through theoretical analysis and simulation, the end-to-end delay bound and throughput fairness of the algori thm was demonstrated.

基于光开关阵列的灵活TWDM-PON系统研究

为了满足接入网日益增长的业务流量需求,解决当前因架构固定、资源维度有限而导致的不同无源光网络之间波长无法灵活分配的的问题,提出了一种将发射固定波长的激光器与光开关阵列组合的时分波分混合复用无源光网络结构。在这种新的系统结构中,下行波长资源被集中化处理,采用在局端配置光开关阵列的方法实现波长在不同网络之间的灵活调度,降低系统总体成本的同时能够用来解决负载平衡、流量“潮汐效应”、网络资源利用率低下等问题。通过理论分析和仿真实验验证了系统的可行性,得出该结构与传统无源光网络的兼容性、波长资源的共享性、系统低成本以及节能的特点。结果表明,在没有色散补偿的情况下,信号可以覆盖30 km的传输距离,同时服务512个用户。该研究可以为典型应用场景下的无源光网络部署提供参考。

A SYNTHETIC ALGORITHM FOR WAVELENGTH ROUTING IN OPTICAL NETWORK

After analyzing the merits and shortcomings of Fixed-Alternated Routing algorithm (FAR) and Least Loaded Routing algorithm (LLR),we propose one novel dynamic optical routing algorithm. Having considered the influences of path’s length and path’s congestion just like in FAR and LLR,we take into account the network resource status-amount of free wavelengths in the network. Proposed algorithm sets up connections on three possible paths according to amount of available free wave-lengths in the network,which effectively decreases the blocking probability. The National Science Foundation (NSF) network and mesh-torus network simulation results show that the performance of this algorithm is better than that of FAR and LLR.

4芯光纤WDM器件技术研究

空分复用技术是提高光通信系统传输容量的有效方法之一,主要技术包括多芯光纤(MCF)、少模复用和轨道角动量复用等,其中MCF技术是空分复用技术中较成熟的一种。【目的】为解决光通信传输系统中容量受限的问题,文章设计和研制了一种新型的4芯光纤波分复用(WDM)器件。【方法】文章首先对WDM、空分复用、MCF和MCF耦合技术等进行分析,选取了以毛细管、透镜和腐蚀光纤方案制作的4芯扇入扇出器件为媒介,然后利用MCF和WDM技术相结合的方法,从4芯光纤的选取、4芯WDM调试原理和调试方法出发,最后利用4芯扇入扇出器件设计和研制了一种新型的4芯WDM原样,并利用4芯扇入扇出器件使用差值法对文章研制器件进行了指标测试。【结果】根据实验样品测试的结果显示,该4芯WDM原样1的各反射端和透射端的插入损耗能够控制在0.8 dB以内,反射端的各路隔离度>15 dB,透射端的各路隔离度≥40 dB。【结论】根据测试结果可得到以下结论:与传统单芯WDM方案相比,在同样器件体积下,新型4芯WDM原样可以实现4路通信,极大地提高了光通信容量,同时,填补了国内外对基于MCF技术的空分复用光器件研究的空缺,并且拓展了空分复用的应用范围,让MCF具有长距离传输的潜能。基于空分复用系统制作的WDM器件,在光纤通信系统中具有广泛的应用前景。

Investigation of Differently Modulated Optical Signals Transmission in HDWDM Systems

The authors＇ developed combined system model can be considered under the concept of next generation optical network （NGON） as a model for the future design of backbone networks. Such solution can be topical in the result of different telecom operators＇ optical networks convergence. In this case a necessity to transmit differently modulated signals over a single optical fiber even with different bit rates may occur. This research is performed with OptSim 5.2 simulation software that numerically solves nonlinear SchrOdinger equation. The authors have revealed the optimal parameter configuration for developed combined transmission systems and obtained in system＇s channels detected signals bit-error-rate （BER） correlation diagrams. They represent BER as a function from different system＇s parameters such as channel output power level, optical amplifier fixed output power level and system＇s channels allotment in C-band of ITU-T （Telecommunication Standardization Sector of the International Telecommunications Union） recommended spectral grid. As well as these obtained BER values were compared with the results for similar system, where instead of standard single mode fiber （according ITU-T Rec. G.652 D） optical signals are transmitted over non-zero dispersion shifted fiber （ITU-T Rec. G. 655）.

Analysis of Center Wavelength Shift of VCSEL Light in AWG for WDM-PON Applications

Center wavelength shift of vertical cavity surface emitting laser light in arrayed waveguide gratings is verified with mathematical and experimental analysis.It is induced by the linearly increasing trend of optical power of vertical cavity surface emitting laser by bias current increase.It is retrieved effectively to the original center wavelength by simple correction method of compensation.This was done for application of vertical cavity surface emitting laser as a light source in optical line terminal of wavelength division multiplexing-passive optical network.

Optimization of Disjoints Using WDM-PON in an Optical Network

An optical network is a type of data communication network built with optical fibre technology. It utilizes optical fibre cables as the primary communication medium for converting data and passing data as light pulses between sender and receiver nodes. The major issue in optical networking is disjoints that occur in the network. A polynomial time algorithm Wavelength Division Multiplexing-Passive Optical Networking (WDM-PON) computes disjoints of an optical network and reduces the count of disjoints that occur in the network by separating Optical Network Units (ONU) into several virtual point-to-point connections. The Arrayed Waveguide Grating (AWG) filter is included in WDM-PON to avoid the traffic in the network thereby increasing the bandwidth capacity. In case of a failure or disjoint Ant Colony Optimization (ACO) algorithm is used to find the optimized shortest path for re-routing. For enhanced security, modified Rivert Shamir Adleman (RSA) algorithm encrypts the message during communication between the nodes. The efficiency is found to be improved in terms of delay in packet delivery, longer optical reach, optimized shortest path, packet error rate.

WDM技术在医院院间互联的应用

近年来,随着各大医院新院区的建设,医院对院间网络互联的带宽、运营成本、灵活可扩展性和自主可控性等提出了较高要求。然而,传统的运营商专线或祼纤无法满足带宽需求和成本控制等多方面要求。结合重庆医科大学附属儿童医院(以下简称“重医儿童医院”)两江院区和渝中院区的院间互联传输建设实践,深入探讨使用波分复用(Wavelength Division Multiplexing,WDM)技术在院间传输网络的建设思路和重点环节,以期为医院同行提供借鉴与参考。

新型混合TDM/WDM无源光网络

讨论了4种不同类型的混合型时分/波分无源光网络,并从网络架构、拓扑形态、网络灵活性和应用模式等方面进行了综合分析和比较.分析结果表明,混合型时分/波分无源光网络兼具TDM-PON无源光分支和WDM-PON波长路由的优点,在带宽容量和用户成本方面进行折中考虑,使整个网络在用户扩展和带宽升级方面具有较好的灵活性,同时又保证了较高的用户带宽和较低的用户使用成本.4种混合型网络架构都具有相当大的灵活性和自由度,可以有效应用于从TDM-PON网络到WDM-PON网络的过渡升级.

WDM全光网中功率均衡及功率管理的新方案研究

在对波分复用全光通信网中功率不均衡的来源、限制分析的基础上，本文提出了一种基于“节点隔离原理”的功率均衡新方案．与传统方案的比较分析表明：新方案将ＯＸＣ节点内的功率均衡及放大功能合二为一，更加简捷、有效；在保持了与传统方案几乎一致的信噪比等指标的前提下，允许级联的节点数目增多．从而为ＷＤＭ全光通信网中的功率均衡与管理提供了一种新的途径．

WDM网络中P圈保护算法

为了充分利用WDM光网络中空闲波长资源,并提高整个网络性能,对P圈保护算法进行了深入的研究,提出了不同的P圈评价标准,并以此为基础,进一步从基础圈的选择、P圈扩张策略以及P圈扩张周期3个角度出发,提出了一系列新型的P圈生成算法.仿真结果表明,这些新型的P圈生成算法可以应用于不同的网络环境中,与传统的保护算法相比,提高了网络资源的使用效率.

用于10Gb/sWDM系统色散补偿的波长取样啁啾光纤光栅

研制出一种新型色散补偿光纤光栅——波长取样啁啾光纤光栅 ,它具有 1 0个周期性为 0 .8nm的波长结构 ,每个周期的反射特性和色散特性都基本相同 ,其带宽为 0 .6nm、峰值反射率为 90 %、色散量为 1 30 0 ps/nm、时延抖动小于 5 0 ps,光栅长度为 1 0 cm。利用此波长取样啁啾光纤光栅 ,在 8× 1 0 Gb/s波分复用 ( WDM)系统中 ,进行了 NRZ码 1 40 km标准单模光纤的色散补偿实验 ,补偿效果良好。

WDM光网络中一种优先共享通路保护算法

为了提高波分复用光网络的可靠性,常采用分段共享通路保护算法,该方法通常要求保护通路要均匀分段并且应满足共享风险链路组约束,网络业务的阻塞率也就比较高,因此提出了用优先共享通路保护算法来降低业务阻塞率。通过计算机仿真进行了理论分析和实验验证,取得了两种保护算法下的业务阻塞率和资源预留比的数据。结果表明,优先共享保护通路算法能够有效地融合分段共享通路保护算法的优点,同时在业务的阻塞率和资源预留比方面优于分段共享保护通路算法。