共查询到20条相似文献,搜索用时 78 毫秒
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介绍了波分复用无源光网络(WDM-PON)系统的结构原理及其技术优势.分析了WDM-PON系统中的关键器件,即多波长光源的解决方案.讨论了WDM-PON在宽带接入网中的应用前景. 相似文献
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研究了低密度奇偶校验(LDPC)编码和正交频分复用(OFDM)调制技术在波分复用无源光网络(WDM-PON)中的应用,提出了基于LDPC-OFDM编码调制的无源接入网系统。实验结果表明,该系统可以在20km单模光纤上实现8路10Gb/s LDPC-OFDM编码调制信号的下行传输,较未采用编码调制技术的WDM-PON性能提升了3.2dB。 相似文献
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We propose a novel scheme for synchronous optical sampling based on multicast parametric process. The linearly chirped and time-broadened pulses are utilized to replace the traditional mode-locked sampling pulses. An optical sampling rate of 80 Gbit/s is realized by using only one sampling source with repetition rate of 10 GHz. 相似文献
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D.X. Zhu S. Dubovitsky W.H. Steier K. Uppal D. Tishinin J. Burger P.D. Dapkus 《Photonics Technology Letters, IEEE》1997,9(8):1110-1112
A new class of an all-optical switch-the wavelength recognizing switch is proposed and experimentally demonstrated. The device uses a control signal to sense the wavelength of the input packet and taps a portion of the data packet to the appropriate output port. The device is based on noncollinear four-wave mixing in a broad-area traveling-wave semiconductor optical amplifier. Measured switching efficiency is +8.2 dB with -28.8 dB of crosstalk. The recognition bandwidth is as narrow as 0.03 /spl Aring/ and the 3-dB switching bandwidth is 42 nm. 相似文献
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WDM-PON是未来宽带光接入网的发展趋势,基于动态波长分配的WDM-PON在系统安全和网络带宽升级等方面具有独特优势.文章介绍了WDM-PON的基本结构及运行原理,着重对基于动态波长分配的WDM-PON作了研究,并对其中涉及到的一些关键技术(如多波长光源、ONU光源和MAC协议等)作了深入分析和探讨,总结了WDM-PON的发展现状,提出了应用前景. 相似文献
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The wavelength assignment with multiple multicast requests in fixed routing WDM network is studied. A new multicast dynamic wavelength assignment algorithm is presented based on matching degree. First, the wavelength matching degree between available wavelengths and multicast routing trees is introduced into the algorithm. Then, the wave.length assignment is translated into the maximum weight matching in bipartite graph, and this matching problem is solved by using an extended Kuhn-Munkres algorithm. The simulation results prove that the overall optimal wavelength assignment scheme is obtained in polynomial time. At the same time, the proposed algorithm can reduce the connecting blocking probability and" improve the system resource utilization. 相似文献
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Earnshaw M.P. Cappuzzo M. Chen E. Gomez L. Griffin A. Laskowski E. Wong-Foy A. 《Electronics letters》2003,39(19):1397-1398
The first demonstration of large-scale integration of AWG filters and thermo-optic switches and attenuators in 2% delta silica-on-silicon waveguides is reported. A compact high performance wavelength selective switch is demonstrated. 相似文献
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波长分配是多波长网络中的关键技术,为此研究了在多波长无源光接入网(WDM-PON)中的波长分配问题。分析了波长分配研究的指导原则,以及和带宽分配的关系;并在此基础上提出了一种适合WDM-PON环境的波长分配算法。最后通过仿真验证了这种算法的性能,结果表明这是一种延迟小,带宽利用率高,负载均匀的较好算法。 相似文献
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基于数字证书的树型结构安全多播方案 总被引:1,自引:0,他引:1
该文提出一种基于数字证书的安全多播方案,采用树型的多播拓扑结构。多播树中的每个节点都有一个标识其身份的数字证书,除了成员身份认证外,还可以安全地分发会话密钥和实现会话数据的认证,因而减少了多播群密钥管理的复杂度;由于采用分层的树型多播结构,成员加入和退出有了更大的可扩展性。 相似文献
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Chin‐Chen Chang Yi‐Fang Cheng Iuon‐Chang Lin 《International Journal of Communication Systems》2009,22(1):53-66
Secure multicasting allows the sender to deliver an identical secret to an arbitrary set of recipients through an insecure broadcasting channel, whereas the unintended recipients cannot obtain the secret. A practical approach for securing multicast communications is to apply a session key to encrypt the transmitted data. However, the challenges of secure multicast are to manage the session keys possessed by a dynamic group of recipients and to reduce the overhead of computation and transmission when the membership is changed. In this paper, we propose a new key management scheme for dynamic multicast communication, which is based on privacy homomorphism and Chinese remainder theorem. Our scheme can efficiently and securely deliver an identical message to multiple recipients. In particular, the complexity of the key update process in our scheme is O(1). Copyright © 2008 John Wiley & Sons, Ltd. 相似文献