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A method to calculate an optimum Erbium distribution to enhance the gain efficiency in EDFA is proposed. This method calculates
Erbium distribution based on optical pump envelop, pump power and optical properties of Erbium ion. The intensity-based Erbium
distribution is obtained for single-mode fiber and dispersion-shifted fiber types EDFA for pump power from 10 to 40 mW. All
of the profiles have a Gaussian-like shape. For single-mode fiber type EDFA, high gain enhancement is obtained in a relatively
short optimal length of fiber. Optimal length of EDFA, using intensity-based Erbium distribution, is increased by a factor
of 1.5–3 with respect to the one using stepwise. This optimal length increasing factor is considerably smaller than that of
the EDFA, using the one-fourth confinement Erbium profile. 相似文献
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L-band EDFA性能与增益光纤长度关系的分析 总被引:1,自引:0,他引:1
分析和模拟L_band EDFA的增益特性对其优化设计和实验有着重要的意义。基于Giles模型,数值模拟了L_band EDFA中的信号光、泵浦光和放大自发辐射(ASE)在一定泵浦功率下与铒光纤长度的关系;分析了L_band EDFA本征增益平坦的产生机理;数值模拟了小信号增益平坦特性。结果表明,在一定的泵浦功率下,如果在所选择的L_bandEDFA中铒光纤长度合适,则不需要任何平坦化处理就可以得到比较平坦的增益谱线。 相似文献
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A global design of an erbium-doped fiber and an open-loop erbium-doped fiber amplifier (EDFA) in a steady-state operation is discussed by applying genetic algorithms. Taking a signal gain and a bandwidth as objective functions, 7 parameters of the EDFA (erbium concentration, core radius, erbium-doped radius, refractive index difference, fiber length, pumping wavelength and signal power) are optimized by solving optical propagation equations, assuming a homogenous two-level active medium and a single-mode propagation. There is evidence to show that the 1480 nm pump utilized in usual EDFAs is not an optimal choice, which should be chosen around 1460 nm. The optimal core radius ranges 0.465–0.548 μm on pumping power 50–200 mW. Under different design objects and with different pumping powers, however, there are different optimal Er-doped concentrations, reflective index differences and fiber lengths. As a single fiber EDFA, 35 dB signal gain or 35 nm bandwidth is obtained with the 7 optimal parameters, 100 mW pumping power and 0.001 mW input signal power. 相似文献
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THE NONLINEAR SCHR?DINGER EQUATION AND THE CROSS-PHASE MODULATION IN ERBIUM-DOPED FIBER AMPLIFIERS 下载免费PDF全文
The nonlinear Schr$\ddot{o}$dinger equation(NLSE) in erbium-doped fiber(EDF) was obtained. The cross-phase modulation (XPM) in the erbium-doped fiber amplifiers (EDFA) was studied based on this NLSE and the rate equations. A more generalized form of the propagation equation in EDFA was obtained which included the phase shifts the EDFA induced. An analytical expression was given to the XPM in the EDFA. It was found that the XPM in the EDFA dose not change very much with the wavelength except at the neighboring wavelengths (around 1531 nm) where the absorption and emission cross-sections of the erbium ions reach their maxima, and the XPMs have opposite signs on the two sides around 1531 nm. Furthermore, it was found that the XPM increases with the increase of the length of EDF. 相似文献
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Rajneesh Kaler 《Optik》2011,122(5):440-443
In this paper, we compare the Gain and Noise figure characteristics of physical EDFAs and Compact EDFAs in an optical system consisting of cascade of both the amplifiers. We demonstrate the gain, noise figure variations of a forward pumped EDFA and Compact EDFAs as functions of Er3+ fiber length, injected pump power and up-conversion co-efficient. It is observed that the gain becomes constant when the length of both the amplifiers reaches above 20 m. The comparison shows that the higher gain with flatter output is obtained in case of Compact EDFAs than Physical EDFAs in a system consisting of chain of both the amplifiers. It is further investigated that the agreement between the Compact and Physical EDFA models is good up to 10 m with the no up-conversion co-efficient. Also, the noise figure obtained in case of Physical EDFA is higher than Compact EDFAs when same amplifier length is more than 20 m and then becomes constant for both the amplifiers. 相似文献
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Haleem M. R. Al-Mansoori M. H. Jamaludin M. Z. Abdullah F. Din N. Md 《Laser Physics》2011,21(2):419-422
We demonstrate an efficient double-pass L-band erbium-doped fiber amplifier (EDFA) incorporating chirped fiber Bragg grating
(CFBG). The amplifier structure exploits the characteristics of CFBG to reflect the amplified signal back into the gain medium,
filter out the recycled forward amplified spontaneous emission and block the residual 1480 nm pump power. The amplifier configuration
has high gain and low noise figures as compared to double-pass EDFA using broadband mirror. The demonstrated amplifier has
gain of more than 48 dB and low noise figure of less than 4 dB at low input signal power of −40 dBm. 相似文献
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提出半导体激光器混沌交叉相位调制(XPM)光反馈提高混沌载波发射机带宽方法,建立了有外腔光纤传输反馈XPM控制下的激光动力学物理模型.理论导出XPM作用下激光双反馈频率失谐公式,指出XPM产生的非线性相移影响了激光器增益和线宽增强因子,其光纤二阶非线性效应使激光振幅和相位变化更加丰富,而非线性相移的出现进一步增加了新的频率分量并使频谱展宽.数值结果表明,XPM使激光器混沌带宽增加到4倍以上,使激光混沌张弛振荡频率增加到2.85倍,其光纤长度、入纤光功率、面镜反射系数、光纤二阶非线性系数等都能影响激光混沌带宽. 相似文献
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《Optics Communications》2002,201(1-3):61-69
A reflection L-band erbium-doped fiber amplifier (EDFA), which can effectively suppress and completely exploit the backward C-band amplified spontaneous emission (ASE) with a feedback reflection loop, is presented in this paper. The mechanism of the backward ASE secondary pumping effect is experimentally investigated in detail. Our experimental results have shown that, for a given input pump power, compared to the end-pumped EDFA, the gain and output power of the reflection EDFA can be improved considerably without paying much noise penalty. When the EDFA operates with flattened gain spectra, the gain is improved by about 7 dB with an extra noise penalty of about 1.2 dB, where the saturation output power is increased by 2.5–3.2 dB and which may also be made independent of the input signal power. 相似文献
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A dual-stage erbium doped fiber amplifier (EDFA) having a flat gain wavelength response throughout L-band transmission window is presented. By applying pump power distribution technique, the pump power is distributed to two different stages with different length of EDF depending on the coupling ratio. By controlling these two parameters, gain of 19.1 dB with small gain variation of less than 0.5 dB and a noise figure of less than 10.5 dB are achieved in this architecture using bidirectional pumping. However, when another 3 dB power coupler is added to split the pump power equally at the second stage in bidirectional, a better noise figure of less than 7.5 dB was obtained. Comparison with a conventional single-stage optical amplifier was made in order to validate the performances of this dual-stage EDFA. 相似文献
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光纤参变放大器光纤长度的优化设计 总被引:1,自引:1,他引:0
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。 相似文献
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Mrinmay Pal M.C. Paul A. Dhar A. Pal R. Sen K. Dasgupta S.K. Bhadra 《Optics Communications》2007,273(2):407-412
We present the results of an investigation of optical gain and noise figure for simultaneous multi-channel amplification of an erbium doped fibre amplifier (EDFA) under optimized pump condition. Different pump configurations with varying input signal levels show interesting features on gain flatness. In the experiment, population inversion along the fibre length which determines the gain-spectra and noise characteristics of the amplifier is adjusted through optimized fibre length and injected pump power in order to minimize the gain-tilt at C-band. It is observed that bi-directional pumping manifests the best combination of low noise and high gain of EDFA which are useful as in-line repeaters in WDM network. We obtain 30 ± 1.5 dB intrinsically flat small signal gain from 1538 nm to 1558 nm band of wavelength with noise figure <4 dB for 16-channel simultaneous amplification in a single stage EDFA without gain flattening filter. 相似文献
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The modulation instability of continuous waves for a system of four coupled nonlinear Schrödinger equations, two of which are in the unstable regime, is studied. In earlier studies, plane or continuous waves for a system of two coupled, nonlinear Schrödinger equations is shown to exhibit modulation instability (MI), even if both modes are in the normal dispersion regime, provided that the coefficient of cross phase modulation (XPM) is larger than that of self phase modulation (SPM). Requirements for MI in this system of four coupled, nonlinear Schrödinger equations can be relaxed. MI can occur even if the magnitude of XPM is less than that of SPM, and the magnitude of instability is generally larger than that of each mode alone. The implications for parametric process and wavelength exchange in optical physics with two pump waves are discussed. 相似文献
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以速率方程模型为基础研究了光谱特性对半导体泵浦碱蒸气激光器性能的影响。结果表明:碱蒸气激光器的运行存在最优温度,温度和长度对碱蒸气激光器性能的影响是等价的,可以定义一个与温度和长度无关的效率描述其它参量一定时激光器的最优效率;泵浦谱宽对阈值泵浦强度的影响是线性的,由于碱金属原子在谱线远翼具有较大吸收截面,即使泵浦谱宽几倍或十几倍于原子吸收谱宽时也可能获得较高的效率;原子吸收谱宽对阈值泵浦强度的影响是非线性的,随着原子吸收谱宽的增加激光器光-光效率出现饱和下降;泵浦谱宽和原子吸收谱宽越宽,半导体激光器由于温度或电流导致的中心波长漂移的影响越小,实际中采用外腔压窄的半导体激光器阵列(谱宽小于200 GHz)可以控制其温度或电流漂移,使得碱蒸气激光器的性能基本不受影响。 相似文献