掺饵光纤放大器在多路模拟光纤传输系统中的应用

对应用掺饵光纤放大器的副载波频分复用模拟电视光纤传输系统的噪声和失真进行了实验研究，利用掺铒光纤放大器作为系统的功率提升和中继放大器，分别成功地进行了１８５ｋｍ和２１５ｋｍ的系统传输试验。     

掺铒光纤放大器及其在光纤孤子通信系统中的应用

讨论掺铒光纤的制造技术和掺铒光纤放大器的放大原理。结果表明,掺铒光纤放大器非常适用亍光纤孤子通信系统对光孤子进行放大。     

室温掺铒光纤放大器中实现参量控制无损耗光速减慢传输

本文对掺铒光纤放大器中的光速减慢传输系统进行深入研究,提出一种直接利用掺铒光纤放大器中抽运光 强度和掺铒光纤长度,通过优化控制参量来降低信号光强度损耗系数,从而可以实现无强度损耗光速减慢传输, 研究结果表明:当抽运光功率为3.5 mW时,信号光强度损耗系数近似为零;当抽运光关闭时,掺铒光纤长度为 0.1 m时,信号光强度损耗系数近似为零.     

小芯径掺铒光纤与单模光纤低损耗接续的研究

报道了掺铒光纤放大器中降低掺铒光纤与单模光纤接续损耗的一种新方法，采用在芯区直径较小的掺铒光纤端部拉锥的方法，使得掺铒光纤中的传输模场在锥形区域内扩散，从而与单模光纤中直径较大的本征模场良好匹配，实现低损耗接续，初步实验结果表明，该方法可获得小于１ｄＢ的接续损耗。     

基于环形芯光纤的超低差分模式增益涡旋光纤放大器

提出了一种基于环形芯铒离子部分掺杂光纤的涡旋光纤放大器。针对该掺铒光纤的放大特性,研究了光纤长度、掺铒浓度与抽运功率对信号模式增益特性的影响。研究结果表明,该光纤放大器能够支持22个轨道角动量模式稳定传输,且C波段(1530~1565 nm)所有信号模式增益大于23 dB,信噪比高于27 dB,差分模式增益小于0.015 dB。所提出的基于环形芯光纤的涡旋光纤放大器具有支持轨道角动量模式数量多、差分模式增益低、信噪比高的优势,对于OAM复用长距离传输系统中的在线放大具有重要参考价值。     

17dBm功率,46dB增益和3.3dB噪声系数的掺铒光纤放大器

１７ｄＢｍ功率、４６ｄＢ增益和３．３ｄＢ噪声系数的掺铒光纤放大器唐平生刘小明刘丹彭江得范崇澄周炳琨（清华大学电子工程系，北京１０００８４）运转于１．５５μｍ波段的掺铒光纤放大器（ＥＤＦＡ）是光纤通信系统中理想的光放大器，在光纤传输与网络系统中的应用为...     

高浓度镱铒共掺磷酸盐光纤放大器增益特性

在忽略高能级的自发辐射和光纤损耗的情况下，利用速率方程和传输方程理论研究了高浓度Er³⁺/Yb³⁺共掺磷酸盐玻璃光纤放大器的增益特性，讨论了Er³⁺浓度、Yb³⁺浓度、抽运光功率、信号光功率、光纤长度对放大器增益的影响，并与单掺铒光纤放大器进行了比较.由于Yb³⁺的敏化作用降低了铒离子的团簇效应，减少了离子间相互作用，共掺光纤的增益和效率明显高于单掺光纤.数值计算表明，3.2cm长Er³⁺/Yb³⁺共掺光纤在980nm的20dBm(100mW)抽运功率下，1532nm处的增益可达10dB. 关键词： 镱铒共掺光纤放大器 速率方程 传输方程 高浓度     

环形腔声光可调谐掺铒光纤激光器调谐范围的研究

介绍了一种基于声光可调谐滤波器(AOTF)的可调谐掺铒光纤激光器。从掺铒光纤放大器的速率方程和传输方程出发,推导出声光可调谐掺铒光纤激光器的输出公式,理论上解释了该环形腔声光可调谐掺铒光纤激光器调谐范围仅决定于掺铒光纤的增益带宽;并在实验中测得该激光器调谐范围为1 526.05 nm到1 560.63 nm,这个区间对应着实验所得掺铒光纤自发辐射谱的增益区间,从而验证了理论推导所得结论。     

915nm泵浦混合掺铒/铒镱共掺双包层光纤放大器

研究了一种混合掺铒/铒镱共掺光纤放大器,用掺铒光纤放大器作为输入信号的预放大器,用铒镱共掺双包层光纤放大器作为主放大器。掺铒光纤放大器采用20m长掺铒光纤作为增益介质,采用最大输出功率318mW的单模半导体激光器二极管作为泵浦源,预放大器获得的最大输出功率是113mW。铒镱共掺光纤放大器采用14m长铒镱共掺双包层光纤作为增益介质,采用2个915nm多模半导体激光二极管作为泵浦源,在输入信号功率为10mW、信号波长1555nm时,混合光纤放大器获得了最大输出功率为32.04dBm,即1.6W,与此相应的混合光纤放大器的光-光转换效率为18.5%。     

基于掺铒光纤/喇曼混合放大的光纤激光器布喇格光栅传感系统

提出了一种提高长距离光纤布喇格光栅信噪比以进行准分布测量的新方法.该方法基于掺铒光纤/喇曼混合放大的光纤激光器结构,掺铒光纤和滤波器构成的环形结构产生激光作为光源,喇曼光纤放大器对布喇格光栅信号进行低噪音的双向放大,置于远处的掺铒光纤利用剩余的泵浦功率产生自发辐射光和放大传感信号,为远处掺铒光纤之后的布喇格光栅传感器提供信号光以及补偿由于长距离传输造成的光纤损耗.实验显示,与使用宽带光源的传感方式相比,系统的性能得到显著提高,仅使用小功率泵浦,分布在50 km光纤上的FBG均获得了超过58 dB的优良信噪比.     

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。     

The L-band EDFA of high clamped gain and low noise figure implemented using fiber Bragg grating and double-pass method

The L-band erbium-doped fiber amplifier (EDFA) of low noise figure and high clamped-gain using gain-clamped and double-pass configuration is presented in this paper. A total of five different configurations of EDFAs by reflection scheme with single forward pumping schemes are examined and compared here. Among these configurations, we first find the configuration of 1480-nm pumped L-band EDFA with optimum gain and noise figure value. To further minimize the gain variation, a fiber Bragg grating (FBG) with 1615-nm center wavelength and 1-nm bandwidth is determined and added in double-pass L-band EDFA. The gain variation and maximum noise figure of EDFA while channel dropping is investigated. As the number of channel dropping from 32 to 4, the L-band type-A EDFA keep the variation of gain within 2.9 dB and the maximum noise figure below 5 dB with each channel’s input power of −23 dBm.     

High gain double-pass L-band EDFA with dispersion compensation as feedback loop

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.     

Characteristics of low noise hybrid fiber amplifier

The characteristics of hybrid fiber amplifier (HFA) are investigated. HFA is composed of three stages: short-length EDFA pre-stage, DCF Raman amplifier, and power boosting EDFA. HFA has low noise figure, high output power, and also wide input power dynamic range. Gain control method of HFA is presented experimentally, and the transient gain excursion is suppressed to less than 0.5 dB at 3 dB channel add-drop. HFA can be used as line amplifier in optical transmission link even combined with distributed Raman amplifier due to wide input power dynamic range. The transmission performance of HFA is better than EDFA by more than 1.0 dB of Q-factor in 720 km SMF transmission.     

Impact analysis on performance optimization of the hybrid amplifier (RA + EDFA)

The configuration of the hybrid amplifier (Raman Amplifier: RA + Erbium-Doped Fiber Amplifiers: EDFA) has been introduced and the restriction conditions of its optimum design have also been analyzed and discussed, and then the ASE noise and Rayleigh noise in Raman Amplifier (RA) as well as their influences on the Signal Noise Ratio (SNR) of the receiver have been analyzed in depth. Furthermore, the influences, which result from these noises, on the performances of the optimum design for the hybrid amplifier (RA + EDFA) have thoroughly been researched. Finally, some significant conclusions to play an important role in guiding the optimum design of the hybrid amplifier have been obtained by the above analyses and researches.     

低噪声、高增益的L -band EDFA的实验研究

针对传统的L-band EDFA的工作效率低,提出了一种基于单根光纤光栅、泵浦分配、两段级联的EDFA的新结构,其中的光纤光栅用来反射无用的后向C-band ASE.系统地研究了泵浦比例和光纤光栅波长对增益噪声指数的影响关系.最后经实验验证,得到了低噪声、高增益的L-band的EDFA.其在输入信号光（1570 nm）功率为-30 dBm及泵浦功率为70 mW时,增益为22.26 dB,增益噪声指数为4.96 dB.     

Pre-amp EDFA ASE noise minimization for optical receiver transmission performance optimization

Amplified spontaneous emission (ASE) noise mitigation from the pre-amp erbium-doped fiber amplifier (EDFA) to the photon detector (PD) in optical receivers can be reduced by optimizing the EDFA at the optical receiver level to achieve optimal optical receiver transmission performance.     

Proposed Power-Equalized EDFA Modules Using Fiber Bragg Gratings with Various Reflectivities

We proposed and experimentally demonstrated two power-equalized erbium-doped fiber amplifier (EDFA) modules using fiber Bragg gratings (FBGs) with various reflectivities for individual channels. The transmission type power-equalized EDFA module is low-cost for its simple design, while the reflection type power-equalized EDFA module can suppress most of the amplified spontaneous emission noise. Both consist of a bidirectional EDFA, a set of FBG chains with suitable reflectivities, and an optical isolator/optical circulator. They can find potential applications in wavelength division multiplexing lightwave transmission systems.     

Limitation in the intrinsic method of EDFA gain optimization for 32 × 40 Gbit/s WDM systems

The gain flattening of the erbium doped fiber amplifier (EDFA) is one of the most important aspects in the EDFA which the gain is wavelength dependent. For the first time the limitation of EDFA gain optimizing for a 32-channel wavelength division multiplexing (WDM) systems is investigated and reported in this paper. In a 32-channel WDM system the most favorable flatness gain achieved was 23.16 ± 1.51 dB with an average noise figure of 5.70 dB. This outcome proposes that the method does not achieve a uniform spectral gain in a 32-channel WDM system that incorporates a bandwidth of around 25 nm. Based on the simulation results the intrinsic optimization of EDFA causes the poor SNR and peak signal power with great variation over a transmission distance of 480 km single mode fiber.     

The influence of nonfundamental pump modes in erbium-doped fiber amplifiers

This work analyzes how the characteristics of an erbium-doped fiber amplifier (EDFA) depends on the mode distribution of 800-nm pump light. The analysis is performed by using a large-signal model of an optimally pumped erbium-doped fiber amplifier. Special attention is given to the gain degradation, and noise figures of the amplifier for co- and counterpropagating pump light.