铒纤长度对EDFA增益斜率影响的实验研究和数值模拟

基于掺铒光纤放大器(EDFA)的增益斜率随着铒纤(EDF)长度变化的实验现象,对EDFA的增益斜率进行了分析,研究了不同EDF长度对EDFA的增益斜率的影响,从理论上对实验现象进行了解释。然后用OptiSystem模拟不同EDF长度下的EDFA增益谱,与实验室增益斜率数据相一致,得出了用EDF的长度来控制EDFA增益斜率的方法。     

基于长周期光纤光栅滤波器的掺铒光纤放大器理论和实验研究

从理论和实验上研究了带有高频二氧化碳激光写入的低成本长周期光纤光栅（LPFG）掺铒光纤放大器（EDFA）.结果表明,单波长和多波长EDFA的性能都可以通过在掺铒光纤（EDF）中插入长周期光纤光栅用作自发辐射噪声（ASE）滤波器或增益平坦器来提高性能.优化设计了带LPFG噪声滤波器的线放EDFA,与没有LPFG噪声滤波器相比,线放的噪声和小信号增益分别被减小和提高了约0.5 dB和7 dB。通过在多波长EDFA的EDF中插入一个LPFG增益平坦滤波器的方法,获得了1.5 dB的增益平坦度,与没有LPFG平坦器相比,EDFA的噪声被减小了0.1 dB,增益被提高了1 dB.     

纤维光学 光纤器件

TN253 2005053635 增益可控的小型化掺铒光纤放大器的研制=Development of gain controllable miniature Er-doped fiber amplifier[刊, 中]／魏敦楷(复旦大学通信工程系．上海(200433)),沈俊 …∥半导体光电．-2005,26(1)．-22-25,29 介绍了一种利用980 nm泵浦源、两段式光路结构设 计和实现的增益可控的小型化掺铒光纤放大器(EDFA)的 方法。首先应用谱求解的方法对EDFA的理论模型进行 了研究,基于该模型对两段式EDFA进行优化,优化设计 后的EDFA的增益比单段式结构提高了1．9 dB,反向自发 辐射噪声也得到了抑制。给出了小型化EDFA系统设计 框图和主要温控电路结构,对EDFA系统的泵浦源工作状 态、增益及光信噪比等参数进行了测量,得到了与理论建 模相符合的结果。图9参7(严寒)     

由Giles模型对L-band EDFA的理论分析

本文通过运用Giles模型对L-band EDFA在不同泵浦波长下的增益、不同泵浦功率与光纤长度的关系以及各种增益特性等进行了数值模拟,并同时辅以C-band EDFA进行比较计算,从理论上对L-band EDFA的特性进行了较为详细的分析说明,并得出了新颖的结论.     

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.     

WDM用增益平坦的高增益低噪声双段级联掺铒光纤放大器

给出了设计波分复用(WDM)用高增益、低噪声和宽带宽增益平坦的双段级联掺铒光纤放大器(EDFA)的一般步骤和方法.通过优化设计各种参量,研制出了一台高增益、低噪声和宽带宽增益平坦的双段级联EDFA样机,实现了从1524.8～1561.4 nm共36.6 nm带宽内±0.325 dB的平坦增益,0 dBm输入时,饱和输出功率大于15 dBm的高功率输出;噪声指数低于5 dB.     

掺铒光纤放大器的理论模拟与全局分析

基于Giles模型并考虑了ASE噪音,对各种泵浦方式下的掺铒光纤放大器(EDFA)进行了数值模拟.提出了一种新的分析方法(增益噪音指数全局分析法),直观有效地分析了EDFA的增益和噪音指数与掺铒光纤长度和泵浦功率的依赖关系,并对各种EDFA的性能作了全面的比较.     

L-band EDFA性能与增益光纤长度关系的分析

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。     

宽带喇曼/EDFA混合放大器的优化设计

采用改进的模拟退火算法对Raman/EDFA混合放大器的增益谱进行了优化，根据EDFA及Raman的功率传播方程获得了简洁的目标函数.通过对模拟退火算法几个优化环节的改进，使其能够更快速地应用于Raman/EDFA的多峰值问题的优化设计，可以在短时间内获得最优的放大器参量.计算结果表明选择合适的喇曼抽运波长和抽运功率，仅用4个反向抽运的分布式喇曼放大器加C波段的EDFA就可以获得C+L波段约70 nm的带宽、开关增益达到15 dB、最大增益波动小于1.2 dB的平坦增益谱，而且无需额外的平坦滤波器.     

L-Band掺铒光纤放大器的优化设计

提出了泵浦分配两段级联,并利用前向ASE推动下一级EDF工作的L-Band放大器的新结构.基于Giles模型并考虑了ASE噪声的影响,运用数值模拟算法系统分析了泵浦光功率分配和铒光纤分配比例对这种EDFA性能的影响.最后优化得到高增益且增益谱平坦的L-Band EDFA,其在输入信号光功率为-20 dBm时,在1571～1608 nm范围内,增益值高达35 dB,增益偏差小于1 dB.     

线性啁啾长周期光纤光栅用作EDFA增益平坦滤波器的理论研究

提出用具有特定折射率调制包络的线性啁啾长周期光纤光栅作为掺铒光纤放大器(EDFA)的增益平坦滤波器.采用龙格库塔迭代法数值求解该类型光栅耦合模方程,就特定的掺铒光纤放大器增益谱,用Nelder-Mead优化算法对光栅结构参量(光栅长度、周期、线性啁啾系数、折射率调制包络的形状等)进行优化,设计出能在C波段35 nm带宽范围内对掺铒光纤放大器进行平坦化(增益起伏在±0.5 dB之内)的平坦滤波器.     

Enhancement of Gain in L-Band Bismuth-Based Erbium-Doped Fibre Amplifier Using an Un-pumped EDF and Midway Isolator

A hybrid L-band erbium-doped fibre amplifier (EDFA) with enhanced gain characteristic is demonstrated without a significant noise figure penalty. It uses a backward C-band amplified stimulated emission from both the ends of a bismuth-based EDFA system to pump an unpumped erbium-doped fibre (EDF) for gain enhancing. The maximum gain enhancement of 4.0dB is obtained at wavelength 1604nm with EDF length of 20m. The gain spectrum is reasonably fiat in this amplifier compared with the amplifier without an EDF. The gain varies from 27.4 dB to 30.2 dB at wavelength region 1564-1608 nm with incorporation of 20 m EDF. Noise figure also varies from 6.0 to 7.TdB at this wavelength region.     

Thermally tunable EDFA gain equalizer using point symmetric cascaded Mach-Zehnder coupler

In this paper, a thermally tunable EDFA gain equalizer filter based on point symmetric cascaded Mach-Zehnder (CMZ) filter based two mode interference (TMI) coupler is presented with its mathematical model. Transmission characteristics of these CMZ couplers are analyzed and compared with Y symmetric CMZ couplers by using this model. For EDFA gain equalizer, point symmetric CMZ circuit is chosen due to its higher wavelength flattening width than Y symmetric CMZ circuit. The ripples of equalized EDFA gain spectrum are formulated and estimated from the equalized gain spectrum of point symmetric CMZ filters. It is found that 2 stage point symmetric CMZ coupler with binomial coupler distribution (2PB CMZ) using Δn = 5% provides gain equalized width of 35 nm with ripple of 0.4-0.6 dB and bending loss of 0.24 dB and device length is ∼15 times lower than that of the existing EDFA gain equalizer based CMZ filter. It is also seen that if during the fabrication process, waveguide core width w is increased or decreased by 0.1 μm (in percentage ∼±6.6%), the power imbalance of TMI based 2PB CMZ filter is slightly increased by ∼8% in comparison to that based on directional coupler (DC) by 40%. Low power thermooptic structure of varying gap between two waveguide cores with silicon trench just below the heater is used and it requires ∼1.5 times less heating power than the conventional structure for thermal tuning of EDFA gain equalization.     

平均孤子在能量补偿偏离时的自稳定传输

分析了平均孤子传输系统中用于能量补偿的掺铒光纤放大器增益超过或低于理想值时平均孤子传输特性的劣化,提出并证明了利用工作在饱和区的掺铒光纤放大器可实现平均孤子在能量补偿偏离时自稳定传输,讨论了这一措施的可行性及适用范围。     

Active measuring method for investigating the irradiation effect on the gain characteristics of an erbium-doped fiber amplifier in inter-satellite optical communication

An active measuring method is proposed for the first time to study the irradiation effect on the gain characteristics of an erbium-doped fiber amplifier (EDFA) for inter-satellite optical communication, which is feasible from the engineering viewpoint. The measuring method based on the irradiation model can predict the irradiation effect on the gain characteristics just by measuring the variation of the EDFA signal output power at one irradiation dose rate in the irradiation experiment. Therefore, one can avoid removing the erbium-doped fiber (EDF) from the EDFA, which is needed in the previously tested passive measuring method. These experimental measurements meet completely the requirements of the technical specifications for inter-satellite optical communication. Finally, an irradiation experiment has also been carried out to evaluate the new method by a simple test procedure.     

双向掺铒光纤放大器的特性分析

讨论了双向掺铒光纤放大器的结构方案,利用考虑放大的自发辐和北员耗影响的双向掺铒光纤放大器稳态放大速率方程模型分析的增益与掺铒光纤长度、输入信号光功率、帛运光功率及抽运方式等参数之间的关系,研究了单向和双向等功率抽运下正反向噪声系数随正反向信号光输入功率的变化行为。     

Gain-clamping in two-stage L-band EDFA using an unwanted backward ase from second stage

A gain clamping technique for the long wavelength band erbium-doped fiber amplifier (L-band EDFA) is presented. It uses two circulators and a broad band fiber Bragg grating to route wasted backward C-band ASE from the second stage and launch it back into the input end of the first stage of a two-stage amplifier. The two-stage L-band EDFA has shown a small signal gain improvement of 5.7 dB compared to a single-stage amplifier with a slight noise figure degradation. By utilizing the wasted backward ASE, a L-band gain-clamped EDFA with high gain can be realized. Compared to the unclamped case, this gain-clamping technique is effective in reducing the total gain variation as small as 0.3 dB.     

Amplification enhancement of L-band erbium-doped fiber amplifiers by reflection scheme

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.     

PDL-Compensated Mechanically Induced Long-Period Grating for EDFA Gain Flattening

We present and demonstrate a polarization-insensitive mechanically induced long-period fiber grating (MLPG) for EDFA gain flattening. By forming a 90° fiber rotator in the middle of the MLPG the PDL of the MLPG was substantially reduced. The PDL-compensated MLPG was able to flatten the ASE spectrum of an EDFA successfully without deterioration of the polarization characteristics.