掺饵光纤放大器中交叉相位调制效应的研究

本文建立了考虑交叉相位调制效应（XPM）的光放大模型,得到了（XPM）效应对小信号增益系数的影响,分析得到:掺铒光纤放大器（EDFA）中XPM引起的强度起伏和非线性系数、输入的泵浦功率以及放大器长度有关。仿真结果证明:EDFA中XPM效应的影响不能忽略,并且当γ≥0.01/W·m时,级联EDFA中第一个EDFA产生的XPM效应的影响也是不能忽略的。     

基于EDFA和级联RFA的混合光纤放大器的设计

基于EDFA的理论模型和受激拉曼散射效应的分析理论,利用EDFA和RFA的增益谱互补特性,对拉曼光纤放大器(RFA)采用两根光纤级联方式,研究并设计了EDFA与级联光纤的RFA相结合的混合放大器结构.仿真结果表明:在不使用增益均衡器的条件下,所设计的混合光纤放大器在输出端得到了近似相等的输出光功率,得到了增益平坦度为0.62 dB、波长带宽为70 nm(1 550～1 620 nm)的结果,在密集波分复用光通信系统中有重要的应用价值.     

激发态吸收(ESA)对掺铒光纤放大器的影响

本文分析了掺铒光纤放大器(EDFA)的激发态吸收(ESA)现象,得到了存在ESA时的EDFA增益与阈值的表达式。分析结果表明,ESA严重时将使EDFA不能正常工作。     

利用自相位调制效应测量微结构光纤的非线性系数

报道了利用光纤中的自相位调制(SPM)效应对微结构光纤的非线性系数进行测量的实验.实验中采用半导体激光器作为脉冲光源,输出宽度为1.6 ps的双曲正割型脉冲,经掺铒光纤放大器(EDFA)放大后进入80 m的色散平坦微结构光纤,由于自相位调制效应,出射光谱得到展宽.通过测量输入微结构光纤的脉冲峰值功率和输出光谱,可以计算得到微结构光纤的非线性系数.该测量方法简单、准确,实验测量值与光纤的标称值误差小于1%.     

用增益钳制法观察烧孔效应

掺铒光纤放大器(EDFA)的烧孔效应(SHB)是导致放大器增益不平坦主要因素，进而影响长距离波分复用(wDM)光纤传输系统的性能。与此同时，对于EDFA的非均匀加宽作用的物理学研究并不成熟，所提出的几个理论模型也只是从经验和统计方面对SHB在一定程度上进行分析。为此，我们首次提出了利用放大器恒定增益控制来研究SHB的实验方法，分析了室温下1530～1564nm波长范围内SHB的深度、宽度与饱和信号波长的关系，以及SHB的深度与饱和信号功率的关系。     

抑制EDFA瞬态效应方法的研究

分析了掺铒光纤放大器(EDFA)瞬态效应的产生机理，讨论了其对DWDM网的危害，给出了采用抽运源控制法对其进行抑制的实验．从实验结果可以看出此方法对EDFA的瞬态效应确实起到了一定的抑制作用。     

XPM对WDM系统中一阶PMD补偿的影响

介绍了交叉相位调制(XPM)效应的概念,数值分析了其对波分复用(WDM)系统中一阶偏振模色散(PMD)补偿性能的影响.文章基于两信道WDM系统PMD效应模型,数值模拟了XPM对一阶PMD补偿性能的影响,对比分析了考虑XPM前后系统的性能.文中给出了采用补偿后考虑XPM以及不考虑XPM时信道的眼图,可以看出XPM在一定程度上降低了眼图的张开度,削弱了一阶PMD补偿效果.     

利用单模光纤实现增益平坦掺铒光纤放大器

从理论上分析了利用光纤环形镜(FLM)中的偏振耦合效应作为滤波器,对掺铒光纤放大器(EDFA)实现增益平坦化的方法。利用3km普通单模光纤(SMF)得到EDFA自发发射谱(ASE),在34nm带宽内的不平坦度为±0.6dB。     

EDFA中基孤子脉冲的传输及啁啾特性

文章数值分析了负色散掺铒光纤放大器(EDFA)中基孤子脉冲传输及啁啾特性,给出了一种利用EDFA获得线性啁啾的新方法.数值分析结果发现:增益系数μ>1时,基孤子脉冲在EDFA中传输能够获得很好的线性啁啾,并且啁啾的特性受选取的EDFA长度L的影响,L越大时线性啁啾越明显,线性啁啾所占的脉冲区域越窄.最后计算了输出脉冲在啁啾补偿后获得的压缩因子和基座能量比.     

高入纤功率光纤通信系统的可靠性研究

掺铒光纤放大器(EDFA)和拉曼放大器(FRA)的使用,使得光纤通信系统中的入纤功率有了很大的提高.较高的入纤功率不仅会在光纤中引起各种非线性效应,对光脉冲的传输产生影响,也会对光纤本身的可靠性产生影响,为此介绍了高入纤功率对光纤系统的影响,分析了其产生的机理,并提出了应对措施.     

Cross-phase modulation in an L-band EDFA

We measure the cross talk in a wavelength-division-multiplexed (WDM) system arising from cross-phase modulation (XPM) in an L-band erbium-doped fiber amplifier (EDFA). This effect has the potential of becoming the dominant nonlinear crosstalk mechanism in L-band WDM systems using standard fiber. We discuss how appropriate amplifier design can reduce the XPM in the EDFA     

The contribution to cross-phase modulation in L-band WDM systemsfrom erbium-doped fiber amplifiers

It has been suggested that the level of cross-phase modulation (XPM) produced in erbium-doped fiber amplifiers (EDFA's) may be greater than that produced in the transmission fiber. We measure and compare the levels of XPM produced in an EDFA to that produced in both dispersion-shifted fiber (DSF) and conventional transmission fiber for a 10-Gb/s L-band wavelength-division-multiplexed system. Our results show that, for a system with twenty channels, the levels of XPM produced by our amplifier was negligible compared to that from the DSF, and a factor of approximately nine smaller than for the conventional fiber     

New pump wavelength of 1540-nm band for long-wavelength-band erbium-doped fiber amplifier (L-band EDFA)

A long-wavelength-band erbium-doped fiber amplifier (L-band EDFA) using a pump wavelength source of 1540-nm band has been extensively investigated from a small single channel input signal to high-power wavelength division multiplexing (WDM) signals. The small-signal gain coefficient of 1545-nm pumping among the 1540-nm band is 2.25 times higher compared to the conventional 1480-nm pumping. This improvement in gain coefficient is not limited by the pumping direction. The cause for this high coefficient is explained by analyzing forward- and backward-amplified spontaneous emission spectra. The gain spectra as a function of a pump wavelength suggest that a broadband pump source as well as a single wavelength pump can be used as a 1540-nm-band pump. In the experiment for high-power WDM signals, the power conversion efficiency for 256 WDM channel input is 48.5% with 1545-nm pumping. This result shows more than 20% improvement compared with the previous highest value for the L-band EDFA. Finally, the 1545-nm bidirectionally pumped EDFA is applied as a second stage amplifier in an in-line amplifier of an optical communication link with a 1480-nm pumped first stage EDFA, in which the input power of the second-stage EDFA is +2.2 dBm. The power conversion efficiency yields a 38% improvement without noise figure degradation compared with the case of 1480-nm pumping.     

High-gain coefficient long-wavelength-band erbium-doped fiberamplifier using 1530-nm band pump

A 1530-nm band has been studied as a pump wavelength for the long-wavelength-band erbium-doped fiber amplifier (L-band EDFA). The pump source is built using a tunable light source and cascaded conventional-band (C-band) EDFA. The L-band EDFA uses a forward pumping scheme. Within the 1530-nm band, the 1545-nm pump demonstrates 0.45-dB/mW gain coefficient, which is twice better than that of conventional 1480-nm pumped EDFA. The noise figure of the 1530-nm pump is at worst 6.36 dB, which is 0.75 dB higher than that of the 1480-nm pumped EDFA. Such high-gain coefficient indicates that the L-band EDFA consumes low power     

Performance comparison of an 80-km-per-span EDFA system and a 160-km hut-skipped all-Raman system over standard single-mode fiber

In this paper, we present a comprehensive comparison of the performance of an 80-km-per-span erbium-doped fiber amplifier (EDFA) system and a hut-skipped (160-km-per-span) all-Raman system over standard single-mode fiber (SSMF) for the first time, using semianalytic models. The numerical results reveal that a hut-skipped all-Raman system (using one-order Raman pumping) can achieve comparable performance as the conventional 80-km-per-span EDFA system for a common 50-GHz-spaced 80 /spl times/ 10 Gb/s nonreturn-to-zero (NRZ) wavelength division multiplexing (WDM) system at typical fiber loss of 0.22 dB/km. For 100-GHz-spaced 40 /spl times/ 40 Gb/s carrier-suppressed return-to-zero (CS-RZ) WDM transmission, it was found that a hut-skipped all-Raman system can achieve even better performance than the current 80-km-per-span EDFA system. It was also found that the impact of pattern-dependent Raman crosstalk is more severe than interchannel cross-phase modulation (XPM) in a hut-skipped all-Raman system with 80 /spl times/ 10 Gb/s capacity.     

基于非线性放大环镜的全光开关特性研究

采用掺铒光纤放大器(EDFA)和高非线性色散位移光纤(HNL—DSF)组成非线性放大环镜(NALM)，利用掺铒光纤放大器的高增益系数和高非线性色散位移光纤的光学克尔效应构造全光开关，实现脉冲整形和消除干扰噪声。采用分布傅里叶法分析了高非线性色散位移光纤的群速度色散(GVD)对非线性放大环镜开关特性的影响，讨论了掺铒光纤放大器的增益系数、增益饱和特性以及耦合器的耦合比等因素的影响，研究了入射光为高斯脉冲的情况下，非线性放大环镜与入射光信号强度相关的放大滤波特性。通过优化非线性放大环镜的各项参数，可以在实现高开关效率的同时，降低对开关功率的要求，对峰值功率低于1mW的超短脉冲进行Tbit／s量级的开关操作，从而适用于超高速大容量光通信系统中。     

Modeling the saturation induced by broad-band pulses amplified inan erbium-doped fiber amplifier

We theoretically study the saturation of a homogeneously broadened optical amplifier with a slow response time. This model approximates well the behavior of the erbium-doped fiber amplifier (EDFA). When a broad-band pulse propagates inside such amplifier the saturation is determined by the overlap between the amplifier gain profile and the pulse spectrum rather than by the energy of the pulse. This effect may significantly increase the output power of an EDFA that amplifies broad-band pulses     

NOLM中反向交叉相位调制作用分析

提出了反向交叉相位调制(XPM)耦合方程,得出了非线性光学环路镜(NOLM)中正、反向信号脉冲在传输过程中共同作用的非线性相移,研究了高斯脉冲情况下NOLM的开关特性,NOLM作为解复用器时反向XPM的影响,及作为光路由选择单元时无放大联接的级数.最后讨论NRZ码情况下的开关特性.     

适用于WDM的几种增益平坦的掺铒光纤放大器

近年来，掺铒光纤放大器（ＥＤＦＡ）与波分复用（ＷＤＭ）相结合的传输技术已成为高速率，大容量光通信发展的主流方向。本文分析总结了国外研制适用于ＷＤＭ的增益平坦ＥＤＦＡ的几种有效方案，为适用于ＷＤＭ的ＦＤＦＡ实用化研究提供参考。