铋镓铝共掺的高浓度掺铒光纤及放大器

研制出了铋镓铝共掺的高浓度掺铒光纤,这种掺铒光纤在1 530 nm处的吸收系数达到了28.5 dB/m.利用这种铋镓铝共掺的高浓度掺铒光纤制成了C波段和L波段的掺铒光纤放大器(EDFA),测试这两种放大器的荧光谱和增益谱线.利用2.5 m的高浓度掺铒光纤制作的C波段EDFA就实现了高增益.利用10 m这种掺铒光纤制作的L波段放大器实现了有效的I波段放大.     

57nm的低噪声宽带掺铒光纤放大器

采用双级级联单程放大实现高增益、低噪声的C波段掺铒光纤放大器(EDFA)；采用双级级联双程放大实现高增益、超平坦的L波段EDFA。在此基础上，采用并联结构实现了30dB以上的高增益、3dB带宽为57nm的低噪声宽带EDFA。     

C波段和980 nm抽运的两段级联L波段掺铒光纤放大器

提出了由C波段和传统的 980nmLD两段级联抽运L波段信号的结构 ,C波段的功率和波长由掺铒光纤激光器控制。从实验和理论上分析了注入不同波长和功率的C波段对其增益的影响。设计的掺铒光纤放大器(EDFA)结构 ,在C波段波长为 15 2 5nm ,注入功率为 5mW时 ,功率为 - 2 0dBm ,波长为 15 80nm的信号增益提高了 7 7dB。     

一种新型宽带EDFA及其实验研究

文章提出了一种基于三端口增益平坦滤波器、且在拓扑结构上不同于以往并行或串行结构的掺铒光纤放大器（EDFA）的新结构。理论模拟显示，同常规的并行结构EDFA相比，该新型结构在保证C波段EDFA性能的同时亦可将L波段掺铒光纤（EDF）用量减少48％以上，改善L波段泵浦效率55％以上。实验中，我们在C波段使用两只输出功率分别为106．9和109．6mW的980nm泵浦激光器，两段EDF的长度分别为8．5和9．6m，在L波段我们仅用1只80mW的1480nm泵浦激光器，EDF长度为19．8m。试验结果显示，在C＋L波段内得到的信号增益〉23dB，增益平坦度〈0．6dB，噪声指数在C和L波段内分别〈4．4dB和5.6dB。     

L-波段掺铒光纤放大器增益谱特性研究

对掺铒光纤放大器 (EDFA)在L 波段 (L Band ,15 70～ 16 10nm)的增益谱特性进行了理论和实验研究。理论和实验研究得出在最佳反转粒子数密度 (N=0 39) 条件下 ,掺铒光纤L Band的平坦增益谱宽为 2 2nm(± 0 5dB) ,抽运功率与输入信号功率呈线性关系。实验测得L BandEDFA单信道小信号增益为 33dB。     

掺铒光纤放大器增益和噪声研究

文章首先介绍了掺铒光纤放大器(EDFA)的结构和工作原理,然后运用能级理论和激光原理,深入全面地分析了影响EDFA增益和噪声的主要因素,得出了EDFA增益和噪声与泵浦功率、泵浦方式、输入信号光功率和掺铒光纤长度等关系的一些重要结论,并且通过实验进一步验证了这些结论;提出了提高EDFA增益,减小噪声系数的方法;最后根据文中得出的结论,设计了一种高增益低噪声的C波段EDFA光路,该光路已经应用于工程实践中.     

基于光纤环形镜的增益平坦L波段掺铒光纤放大器优化设计

L波段掺铒光纤放大器（EDFA）的增益介质具有本征增益平坦特性,但平坦增益值低,放大器实用性差,因此对放大器优化设计提高平坦增益有十分重要的意义。使用光纤环形镜（FLM）作为增益平坦滤波器进行L波段掺铒光纤放大器的增益平坦化实验,实现了高增益值的平坦输出。     

高增益低噪声L波段掺铒光纤放大器实验研究

针对L波段掺铒光纤放大器(EDFA)增益低、噪声大的缺点,提出了L 波段双级级联双程放大的放大器结构,并对优化设计结果进行了实验验证。实验中前级和后级所用的铒纤长度分别为6.5m 和32.5m,泵浦功率分别为130mW 和119mW。在小信号功率(-30dBm)输入条件下、1568～1602nm 波长范围内,放大器输出增益都大于38.84dB 同时增益平坦度优于2.04dB。其噪声指数在整个L 波段都小于5.29dB(1590nm 处噪声指数仅为3.95dB)。实验结果表明此放大器不仅完全满足预放级放大器高增益、低噪声的要求,而且具有成本低、泵浦效率高的优点。     

L波段EDFA的仿真和实验

文章介绍了L波段掺铒光纤放大器(EDFA)的理论模型，并根据L波段EDFA的实验结果对理论模型进行了验证，实验结果和理论分析相吻合．     

L-波段掺铒光纤放大器的优化设计

针对传统L-波段掺铒光纤放大器(EDFA)转换效率不高，提出了一种在未泵浦掺铒光纤的输入端插入一根布拉格光栅(FBG)的L-波段EDFA新结构。实验表明这种结构可以提高功率转换效率，小信号增益增加约3dB。基于考虑ASE噪声的Giles模型，建立了这种EDFA的理论模型，并运用数值模拟算法系统地分析了布拉格波长及其反射率等参量对放大性能的影响。     

S-band erbium-doped fiber amplifiers with a multistage configuration /sub e/sign, characterization, and gain tilt compensation

We report an S-band erbium-doped fiber amplifier (EDFA) with a multistage configuration in terms of its design, gain, and noise characteristics for various pump powers and input signal powers, the temperature dependence of the gain spectra, and gain tilt compensation for changes in input signal power and temperature change. We show that there is a tradeoff between low noise and efficiency in the S-band EDFA and describe the development of an S-band EDFA with a flattened gain of more than 21 dB and a noise figure of less than 6.7 dB. We also show that there is a change in the gain spectra with changes in the pump power and input signal power that is different from that observed in C- and L-band EDFAs, and that our EDFA has a temperature-insensitive wavelength. Furthermore, we develop a gain tilt compensated S-band EDFA that can cope with changes in input signal power and temperature.     

Gain control in L-band EDFAs by monitoring backward travelingC-band ASE

A novel and simple technique for gain flatness control is reported for gain shifted, long wavelength band (L-band) erbium-doped fiber amplifiers (EDFAs). Utilization of the backward traveling amplified spontaneous emission (ASE) in the C-band is analyzed with respect to controlling the gain tilt observed in the L-band when the total input power of the EDFA is changed. It is shown that a gain flatness of 0.6 dB/30 nm can be achieved over a dynamic range greater than 10 dB by using the backward traveling ASE power in the C-band as a monitor to adjust the copropagating pump power of the EDFA. The proposed technique eliminates the need to extract the output signals from the monitored ASE signal, demonstrating the suitability and simplicity of the proposed technique for wavelength division multiplexed applications     

Inherent enhancement of gain flatness and achievement of broad gainbandwidth in erbium-doped silica fiber amplifiers

We report new methods to inherently increase the flatness and bandwidth of erbium-doped silica fiber amplifiers from three perspectives: fiber design, pump-signal WDM coupler optimization, and amplifier structure. First, to achieve inherent control of the gain spectrum, a new type of composite fiber structure with an Er-doped core and a Sm-doped cladding ring is proposed and experimentally demonstrated. Interaction of the optical field with the Sm-doped cladding to produce evanescent wave filtering is modeled, which provides an in-line control of gain fluctuation in the erbium-doped flier amplifier (EDFA) C band, 1530-1560 nm. Second, the effect of the spectral characteristics of WDM couplers over the L band of an EDFA is explored. A fused taper fiber coupler for a 1480-nm pump is optimized for signals in the wavelength range of 1570-1610 nm by measuring the small-signal gain, gain tilt, and noise figure in an L-band EDFA. Finally, a new all-fiber structure for a wide-band EDFA, where the L and C bands were coupled serially, is demonstrated with optimized pump-signal couplers. Further optimization of the new composite fiber structure and the transient effects in the serially coupled EDFAs are also discussed     

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     

Improvement of gain and noise figure in double-pass L-band EDFA by incorporating a fiber Bragg grating

An obvious improvement on both the gain and noise figure (NF) is demonstrated in the new double-pass L-band erbium-doped fiber amplifier (EDFA) with incorporating a fiber Bragg grating (FBG). Compared with the conventional L-band EDFAs, the gain is improved by about 6 dB in the new configuration for a 1580-nm signal with an input power of -30 dBm at 60 mW of 980-nm pump power. It is important that the NF is greatly reduced in the new configuration, as the FBG greatly compresses the backward amplified spontaneous emission. For the economical utility of pump power and erbium-doped fiber length, such a configuration may be a very competitive candidate in the practical applications of L-band EDFAs.     

Effective suppression of signal-wavelength dependent transients in a pump-controlled L-band EDFA

Typical pump-controlled L-band erbium-doped fiber amplifiers (EDFAs) in a feed-forward scheme give significant transients due to gain difference on wavelength of input signal when only a few channels are left. The fiber Bragg grating added pump-controlled L-band EDFA eliminates the wavelength dependent gain difference and transients.     

基于单个光纤光栅反射技术的高性能L波段EDFA

基于单个光纤光栅反射技术提出一种高性能L波段EDFA。用一个光纤布拉格光栅(FBG)反射EDFA产生的一部分C波段放大自发辐射(ASE)噪声,该部分ASE噪声被重新注入到掺铒光纤中以提高增益效率。用静态均衡器平坦输出的增益谱,在L波段范围内,增益被箝制在25.5dB,增益不平坦度小于0.5dB,噪声指数小于5.5dB,为DWDM系统提供了一项有效的解决方案。     

L-波段掺铒光纤放大器的优化设计

针对L-band的泵浦效率不高的缺点改进了光链路:在EDFA的前端加入一个光纤环行镜用来反射铒纤产生的后向放大自发发射谱(ASE),通过实验和数值分析发现,在较大的波长范围内光纤环形镜(FLM)可以反射后向ASE的能量,平均增益在12．5 dB以上,提高了泵浦效率,证明这一结构对提高L-band EDEA的转换效率是简单有效的。