掺铒光纤激光放大的研究

本文研究了描述掺铒光纤激光放大的速率方程解,分析了光纤中几种场分布和铒离子横向分布时的解析解,并进行了数值计算.得到了任意信号强度(包括大信号)时的增益以及影响信号增益的主要参数,利用532nm激光泵浦掺铒光纤,得到信号的最大增益为29.5dB.     

A Novel Erbium-Doped Fiber Amplifier Simulator for Gain Excursion Estimation in Multi-Channel Dynamic Optical Network

Abstract

A novel erbium-doped fiber amplifier simulator designed using the SIMULINK toolbox of MATLAB 7.0 (The MathWorks, Natick, MA, USA) is reported in this article. The present simulator has an ability to incorporate multi-channel amplification simultaneously in both the C- and L-bands. It is realized by defining new FUNCTION block sets and replacing the MATLAB FUNCTION block set reported earlier for multi-channel amplification. Spectral variation of gain for an erbium-doped fiber amplifier simulator is first verified in both the C- and L-bands. Next, the simulator is employed to study gain excursion in a multi-channel dynamic optical network, where the change in the gain excursion by varying the pump power has also been estimated. The present approach to estimate the gain excursion will find applications in quantifying inter-channel cross-talk due to cross-gain saturation among co-propagating multi-channels in a dynamic optical network.     

掺铒光纤放大器的频率响应和瞬态增益

根据掺铒光纤放大器（ＥＤＦＡ）的速率方程和传播方程,忽略自发辐射噪声,推导出了小信号调制时频率响应函数的解析表达工以及大信号调制时描述瞬态增益的方程。数值计算表明,当输入信号的调制频率大于５ｋＨｚ时,放大器的瞬态增益变化很小,频率响应很弱。通过计算机仿真,描述了关闭一个信道时的放大器的增益变化过程。     

基于高双折射光纤布拉格光栅的自动增益控制掺铒光纤放大器

掺铒光纤非均匀展宽引起的空间烧孔现象导致单波长激光并不能完全控制放大器增益,提出了一种新颖的自动增益控制掺铒光纤放大器的结构:即采用高双折射光纤布拉格光栅产生抽运光,其写制光栅的波峰对应的波长分别为1549.3 nm和1549.83 nm,波长间隔为0.53 nm。通过调整偏振控制器,就实现了单激光或双激光的增益控制。这种设计增益控制范围为40 nm(1530~1570 nm),当输入功率在-40~-15 dBm的动态范围内,双激光增益控制的掺铒光纤放大器的平均增益和噪声系数分别约为22.22 dB和8.69 dB,而它们的漂移分别被钳制在0.69 dB和1.51 dB。系统性能测试表明:双激光控制掺饵光纤放大器在稳定性方面比单激光有着明显的优势。     

一种增益可调掺铒光纤放大器的研究

在所设计的增益可调掺铒光纤放大器中,采用可编程控制器PC机控制可变直流电压源引发压电陶瓷的电致伸缩效应,导致光纤布拉格光栅的Bragg波长发生漂移,实现被调制参数的变化.分析了双光纤光栅受到压电陶瓷电致伸缩效应时的反射谱变化规律和增益可调掺铒光纤放大器的放大特性.由该放大器的增益与输入信号功率的关系得出小的波长间隔,增益较小,但控制范围较大;大的波长间隔,增益较大,但控制范围较小的结论.在输入宽带光源时,得到两光纤布拉格光栅在不同中心波长之差时的掺铒光纤放大器的增益特性.     

掺铒光纤中的双稳态现象的研究

在以掺铒光纤为增益介质的环形光纤激光器中观察到了光学双稳态现象,定性分析了双稳态形成的机理,即掺铒光纤不同位置分别存在增益饱和和吸收饱和,而且吸收饱和有着更低的饱和阈值。通过理论衍生的公式对增益特性曲线进行了拟合,并结合增益特性曲线对光双稳态的产生给出了定量的解释。     

光纤参变放大器光纤长度的优化设计

随着高输出功率掺铒光纤放大器和高非线性光纤的出现和使用,光纤参变放大器(OPAs)中出现了越来越多的增益饱和现象,这是光放大器中应该尽量避免的。对此,提出了依据光纤参变放大器的光纤非线性系数、抽运光功率、信号输入功率等参量对光纤长度进行优化设计的解决思路。明确提出最佳光纤长度的概念,即在其他参量一定的情况下使信号增益或信号输出功率达到最大所需的最小光纤长度,而且最佳光纤长度有利于提高光纤参变放大的增益带宽和波长转换带宽。通过数值积分求解描述光纤参变放大过程的非线性耦合方程,并运用控制变量法深入研究了最佳光纤长度与光纤非线性系数、抽运光功率、信号输入功率的关系。最后用最小二乘法进行数据拟合确定系数,得到简洁、实用的最佳光纤长度解析表达式。与已有实验结果比较表明,该解析式可很好地用来计算和优化光纤参变放大的光纤长度。     

小信号脉冲抽运时掺铒光纤自发辐射的研究

自发辐射(ASE)是掺铒光纤放大器(EDFA)的重要噪声源,对于由EDFA构成的光纤激光器有重要影响。理论与实践证明,它与抽运方式紧密相关,所以研究脉冲抽运时掺铒光纤(EDF)的自发辐射有重要的学术价值。同时,脉冲抽运对于EDFA锁模激光器的研究也有一定意义。从理论和实验两方面研究了小信号脉冲抽运时,抽运脉冲宽度和幅度对于EDF的自发辐射特性的影响,得到了小信号抽运时输出ASE噪声平均值的近似解析解。研究发现,小信号脉冲抽运时输出信号的幅度与抽运脉冲的宽度成正比。这个新现象可用于脉冲宽度的全光检测。     

自启动被动锁模掺铒光纤激光器的研究

在非线性光纤环形镜非线性开关效应和块状半导体波导饱和吸收效应的共同作用下，实现了掺铒光纤激光器的自启动被动锁模，获得了十分稳定的锁模脉冲序列，观察到高次谐频锁模脉冲输出。分析了非线性光纤环形镜的非线性开关反射特性。     

120 nm Bandwidth Erbium-doped Fiber Amplifier

A new dual band erbium-doped fiber amplifier configuration that provides 120 nm of optical bandwidth is simulated. This configuration employs a split-band architecture in which optical signals are splitted using a 1550/1610 nm port filter into two independent sub-bands which then pass in parallel through separate branches of the optical amplifier. Each branch may be optimized for the sub-band that traverses it. The independent sub-bands are combined and flattened before output, resulting in a 120 nm bandwidth gain-flattened optical amplifier.     

高增益掺铒光纤的设计和制备研究

掺铒光纤放大器在光通信中有着广泛的应用。根据掺铒光纤的性能要求设计了合理的折射率剖面图,制备了高增益的掺铒光纤,在1530nm的吸收达到22dBm,在980nm泵浦光的吸收达到12dBm。其平坦增益带宽范围为1490—1560nm。     

Characteristics of the bandwidth in gain-clamped erbium-doped fiber amplifiers

1.IntYoductionErbium-dopedfiberamplifiers(EDFAs)arepresentlyofgreatinterestinopticalfibercommunicationsystem.Thegainprofiles,thatis,thegainforallwavelengthsofinter-est,areveryimPortantproPertiesofEDFAsinthewavelength-division-multip1exing(WDM)fibersystems['j.Manynumericalandanalyticalmethods(seeforexampleL1jandreferencestherein)canbeusedtoinvestigatethegainprofile8ofEDFAs,buttheyneedcumbersomemeasurementS(forexampIesPectraImeasurementsofEr-dopingabsorWtionandemission,andsoon)andhence…     

掺Yb双包层光纤放大器的瞬态增益和频率响应

在理论上和实验上对掺Yb双包层光纤放大器(YDCFA)的瞬态增益特性进行了研究.建立了简化的瞬态增益基本模型,数值计算了低频光脉冲经过双包层光纤的放大波形,分析了瞬态增益饱和和恢复特性.在实验中对种子源放大的YDCFA的脉冲特性进行了分析,证实了其瞬态增益的低频响应特性.     

抽运方式对混合拉曼光纤放大器性能的影响

通过实验比较了前向抽运拉曼光纤放大器与掺铒光纤放大器组成的混合放大器、后向抽运拉曼光纤放大器与掺铒光纤放大器组成的混合放大器的性能。实验采用75km标准单模光纤作为增益介质。采用20信道(符合ITU-T建议的波分复用信号)，波长为1537．377～1560．605nm，作为混合放大器的测试信号。20信道总功率-2．86dBm，每一信道用2．5Gb／s、码长2^7-1的非归零码通过电吸收调制器(EA)进行外调制。实验结果表明，前向抽运方式混合放大器的性能优于后向抽运方式的混合放大器，其中噪声系数的改善值为2．28～6．55dB。采用前向抽运时，各信道的增益同后向抽运相比，增加值均大于5dB。但不论采取那种抽运方式，采用混合放大的形式，各信道的光信噪比均大于26．9dB。     

Effect of Cascading Amplification Stages on the Performance of Serial Hybrid Fiber Amplifier

Abstract

This study demonstrates simulation and experimental validation of a wideband serial hybrid Raman/erbium-doped fiber amplifier. Two configurations are adopted; in type A, a Raman amplifier is the first stage, and in type B, an erbium-doped fiber amplifier is the first stage. At low input signal power, the average gain level is 20 dB with a flat gain bandwidth of 40 nm for both configurations. The noise figure in type B is dominated by the erbium-doped fiber amplifier and produces lower values and flatter spectra than in type A. The gain of the proposed hybrid amplifiers is affected more by the second amplification stage.     

Gain Flattened Erbium-Doped Fiber Amplifier Using Simple Equalizing Film

A simple scheme using a piece of SiO₂ with an equalizing film platted on one side to get flattened gain spectrum of EDFA is studied in this paper. The film works as an inter-stage wavelength-selective filter, it is optimized to place at the middle of the EDF to suppress the ASE light generated by the first piece of EDF and pre-emphasize the signals before they enter the second EDF at the same time. The simulating results of 8 WDM signals show pretty good performance of gain flatness and noise figure as well. It is a facile equalization scheme for wide-band WDM systems.     

Reduction of Soliton Interaction in Distributed Erbium-Doped Fiber Amplifiers

Methods of reducing the soliton interaction in distributed erbium-doped fiber amplifiers have been studied. The results show: if the optical phase conjugation is applied in proper periodic length, input relative phase between two solitons, and non-equal amplitude input is chosen, the soliton-soliton interaction and soliton self frequency shift can be deleted effectively.     

喇曼光纤放大器结构对性能的影响

详细分析了拉曼光纤放大器的结构对性能的影响.基于受激喇曼散射效应中泵浦光与信号光之间相互作用的常微分方程,进行了数值模拟.模拟结果表明,喇曼光纤放大器结构对性能有着非常大的影响作用.后向泵浦结构,输出信号的光功率相对高于前向泵浦输出信号的光功率.当不考虑泵浦波动时,前向泵浦结构输出信号的信噪比高于后向输出信号的信噪比.在任何一种泵浦结构中都可获得高于41dB信噪比.设计了一种后向泵浦、增益平坦的放大器.该放大器可以实现90km、40×10Gbit/s复用信号的无损传输,增益波动小于1.2dB.     

掺铒光纤放大器的增益特性

采用980nm无铝InGaAs/InGAsP/InGaP高功率量子阱激光器泵浦掺铒光纤放大器。在泵浦功率为20mW时,增益为33dB,最大增益系数6．7dB/mW,饱和输出功率为6dBm,并给出掺铒光纤长度和泵浦功率与增益特性的关系。以及输出功率与增益特性的关系。     

Pulse Signal Distortion Characteristic in Erbium-doped Fiber Power Amplifier

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