共查询到19条相似文献,搜索用时 156 毫秒
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人们将零色散波长移位到1.55Pm和EDFA的问世,打破了常规光纤传输系统在速率上和传输距离上受“电子瓶颈”的限制。但是这种零色散移位光纤对开发密集波分复用技术(HD-WDM)不太适用。因为当色散为零时,四波混频(FWM)现象严重,会明显降低WDM系统的性能。近年来开发出的非零色散移位光纤(Non-ZeroDispersionShiftedFiber)较适用于HD-WDM传输。1996年利用这种非零色散移位光纤在360km的路径上,以200GHz约亚.6urn)相同间隔,进行了8×10Gb/sWDM通道无误码传输试验,而且没有采用色散管理技术。这种NZDSF的群速色… 相似文献
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研究了同向泵浦分布式拉曼放大器(DRA)中泵浦-信号间的四波混频(FWM)效应.基于分段求和法,导出了不同零色散波长光纤组成的前向泵浦DRA中FWM功率的计算公式.考虑受激拉曼放大的情况下,数值模拟了DRA中FWM引起的信道串扰随光纤传输距离的演变,以及FWM与光纤零色散波长之间的关系.理论分析了色散补偿光纤(DCF)对FWM串扰的抑制效应.计算结果表明,在采用非零色散位移光纤(NZDSF)作为传输介质的DRA中,泵浦-信号间存在着较强的FWM效应,严重影响了密集波分复用(DWDM)系统的传输性能.引入适量DCF,不仅能降低DRA中FWM引起的信道串扰,还可有效消除色散导致的波形失真. 相似文献
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光纤色散和非线性是影响密集波分复用(DWDM)系统性能的主要因素。高阶色散管理技术,可以有效地减小四波混频(FWM)和信号波形失真。介绍了该技术的基本原理及不同色散分布方法对系统性能的影响。 相似文献
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掺铒光纤放大器(EDFA)的引入带来了许多非线性效应,其中四波混频(FWM)现象对密集波分复用(DWDM)系统造成了较大的不利影响,必须采取相应的措施予以克服。文中首先分析了FWM产生的机理和影响混频效率的主要因素,然后研究了FWM对DWDM系统性能的影响,最后提出了几种克服FWM对DWDM系统性能影响的方法。 相似文献
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基于光纤四波混频DPSK系统相位噪声提取检测和抑制 总被引:1,自引:1,他引:0
差分相移键控(DPSK)在长距离光纤通信系统中有高接收机灵敏度、高频谱效率以及抗非线性效应方面的优势,最近受到广泛关注。在DPSK通信系统中,线性相位噪声和非线性相位噪声是影响系统性能的主要因素。研究了如何利用光纤四波混频(FWM)效应来监测和抑制相位噪声,降低相位噪声对DPSK通信系统的影响。结果表明利用光纤FWM效应产物可以检测相位噪声值,并且基于光纤饱和FWM效应全光限幅器可以有效地降低非线性相位噪声,提高了DPSK系统性能。该结果对研究高速全光通信有重要意义。 相似文献
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利用数值计算的方法对40G WDM系统进行了仿真.在考虑了光纤群速度色散(GVD)、三阶色散(TOD)、自相位调制(SPM)、交叉相位调制(XPM)、四波混频(FWM)和偏振模色散(PMD)的前提下,通过对比眼图和Q因子,对归零码(RZ)和非归零码(NRZ)调制格式的传输性能进行了研究. 相似文献
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本文对陆上级联接掺铒光纤放大器(EDPA)波分复用光纤通信系统中国波混频所造成的各个光信道光信噪比的恶化提出了一套计算方法,并结合常规单模光纤及一种特殊设计的色散位移光纤进行了分析计算。结果表明:在四波混频所引入的光信噪比恶化中,因新生频率分量导致的噪声增加一般远大于光信号功率的减弱。不等信道间隔划分能有效地避免四波混频的影响,而光滤波器的带宽应在允许范围内尽量压窄。对采用色散补偿技术的级联EDFA波分复用系统,在同一光中继段内,使常规单模光纤置于特殊设计的色散位移光纤之前,能进一步减少四波混频带来的光信噪比的恶化。 相似文献
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Zeiler W. Di Pasquale F. Bayvel P. Midwinter J.E. 《Lightwave Technology, Journal of》1996,14(9):1933-1942
A theoretical model is presented for analyzing the propagation of densely spaced WDM optical signals through a cascade of erbium-doped fiber amplifiers and single-mode optical fibers with nonuniform chromatic dispersion. By combining a numerical solution for the EDFA and an analytical expression for FWM components generated through the cascade, the model allows a realistic system analysis which includes gain peaking effect, amplified spontaneous emission accumulation and the effect of dispersion management on the four-wave mixing efficiency. The FWM power distribution at the end of the multi-amplifier transmission link is computed taking into account the phase relation between FWM light amplitudes generated within different sections of the link. The transmission of many WDM channels, evenly spaced around 1547.5 nm, has been analyzed for various dispersion management techniques and propagation distances. Numerical results point out the importance of such a model for a realistic design of WDM optical communication systems and networks. A proper choice of chromatic dispersion, amplifier characteristics, span length, input signal powers and wavelengths, combined with the use of gain equalizing filters, allows to maximize the transmission distance ensuring acceptable signal-to-noise ratio (SNR) and limited SNR variation among channels 相似文献
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This letter describes the four-wave-mixing (FWM) suppression effect of dispersion varying fiber (DVF) whose chromatic dispersion increases (or decreases) along its length. The FWM suppression performance is investigated for the dispersion variation rate and its cycle number in the DVF. Moreover, it is clarified experimentally that the DVF functions efficiently in wavelength division multiplexing (WDM) systems with an input power of more than 10 dBm/ch 相似文献
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We propose a fiber dispersion management scheme for large-capacity long-haul wavelength division multiplexing (WDM) transmission systems that considers not only second- but also third-order dispersion characteristics using transmission fibers with opposite dispersion signs. It eliminates the waveform distortion of WDM signals that originates from the existence of third-order dispersion, which is a constraint placed on WDM capacity in conventional dispersion management, while reducing the interchannel interaction caused by the interplay of fiber nonlinearity and second-order dispersion. Design concept of the scheme is discussed to show the feasibility of using actual fiber parameters. An experimental investigation on transmission performance regarding the signal pulse format, nonreturn-to-zero (NRZ) and return-to-zero (RZ), and interchannel interaction caused by four-wave mixing (FWM) and cross-phase modulation (XPM) is described for optimizing WDM system performance. It is experimentally shown that RZ pulse transmission is possible without significant spectral broadening over a wide wavelength range in dispersion managed fiber spans. Using these results together with a wideband optical amplifier gain-bandwidth management technique, yields long-distance WDM transmission with the capacity of 25×10 Gb/s over 9288 km 相似文献
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Four-wave mixing (FWM) is the most serious fiber nonlinearity associated with low-input optical power levels in long-haul multichannel optical systems employing dispersion-shifted fiber. To reduce the crosstalk due to FWM, a generalized suboptimum unequally spaced channel allocation (S-USCA) technique is proposed and investigated. Even though the developed technique is useful in combating FWM crosstalk in wavelength division multiplexing (WDM) lightwave systems with up to 12 channels, its main virtue is in designing multichannel WDM lightwave systems with more than 12 channels. Comparisons of power penalty due to FWM between equal channel spacing (ECS) systems and the S-USCA systems are presented. It is shown that for an intensity modulation/direct detection (IM/DD) transmission system operating in an optical bandwidth of 16 nm with 0 dBm (1 mW) peak optical input power per channel, while a conventional ECS WDM system with 0.84-nm channel spacing cannot even achieve a bit-error rate (BER)=10-9, the suboptimum technique developed in this paper, for the same minimum channel spacing, can achieve a BER=10-9 with an FWM crosstalk power of less than 1 dB at the worst channel in a 20-channel WDM system 相似文献
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Nakajima K. Ohashi M. Shiraki K. Horiguchi T. Kurokawa K. Miyajima Y. 《Lightwave Technology, Journal of》1999,17(10):1814-1822
The four-wave mixing (FWM) suppression effect of dispersion distributed fibers (DDF's), which have a nonuniform chromatic dispersion along their length, has been investigated experimentally and theoretically. We fabricated two different kinds of DDF by the vapor-phase axial deposition (VAD) method to clarify the FWM suppression effect. Moreover, we investigated experimentally the effect of our fabricated DDF's on the transmission characteristics of 4×10 Gb/s wavelength division multiplexing (WDM) systems. We confirmed that the proposed DDF's can not only suppress PWM but also improve the input power limitation for WDM systems 相似文献
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Channel crosstalk due to fiber four-wave mixing (FWM) in multichannel systems operated around the zero-dispersion wavelength is experimentally studied. After determining the wavelength at which FWM light is most efficiently generated, the FWM efficiency is measured for possible frequency combinations which generate FWM light at that wavelength. Using these data, FWM crosstalk in multiwavelength systems is evaluated. The results show that actual crosstalk, is less than the value estimated by the theoretical model assuming the uniformly distributed chromatic dispersion for 80-km-long fibers. It is concluded that the theoretical model can be applied to system design dealing with the worst condition 相似文献
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LIZhong-gui QIUKun 《半导体光子学与技术》2003,9(3):137-140
Using mean field method proposed in Ref. [4], the 40 Gb/s multi--channel WDM optical fiber transmission systems with different dispersion maps are simulated. By this method, the computation time can be greatly reduced since following only the full time evolution of a limited number of channels while treating the other ehannels as continuous wave. But since dispersion plays an important role in the process of FWM and XPM,different dispersion maps will affect the application of the method. The dependence of the method on dispersion maps is investigated. The results not only confirm the mean field method,but also give useful approach for system design. 相似文献
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Differential phase shift keying (DPSK) modulation is being considered as a possible candidate for future optical wavelength division multiplexed (WDM) transmission systems. In a single channel link, the balanced interferometric DPSK receiver exhibits increased tolerance against amplified spontaneous emitting (ASE) noise and fiber nonlinear effects. In this paper, a model is presented that can be used to estimate the performance of a multichannel DPSK system taking into account the influence of interchannel phenomena, namely cross-phase modulation (XPM) and four wave mixing (FWM), in the phase noise statistics. The model is based on an approximate solution of the fiber propagation equation and the multicanonical Monte Carlo (MCMC) method. It provides an efficient tool that can be used to investigate the influence of many link design parameters such as channel spacing, launch power, and fiber dispersion. The model is illustrated in the comparison of the performance of multichannel DPSK to on-off keying (OOK) systems. It is verified that, even in the presence of interchannel effects, DPSK modulation greatly enhances the system performance compared to OOK. 相似文献