掺铒磷酸盐玻璃波导放大器的两种模型的比较研究

光波导放大器是继光纤放大器之后的又一新型光放大器.为了在厘米量级的长度上获得一定高的增益,铒掺杂浓度比光纤放大器大两个数量级,高浓度掺杂会引起铒离子的聚集,降低了抽运效率和放大器增益.为了减轻铒离子聚集对放大器的影响,可与铝元素进行联合掺杂.描述掺铒磷酸盐玻璃光波导放大器的两种模型是考虑聚集的影响与不考虑聚集的影响.本文对这两种模型进行了比较研究.详细讨论了铒掺杂浓度对放大器增益特性的影响.得到了两种模型之间转换的铒掺杂浓度.(OD1)     

铒镱共掺波导放大器的增益特性

在忽略放大自发辐射(ASE)及均匀掺杂和稳态的情况下,在初始能量转移效率的基础上从速率方程和传输方程出发,推导出了用于分析铒镱共掺波导放大器(EYCDWA)的新公式.利用这些公式分析了泵浦光功率、信号光功率、掺杂浓度、波导长度对放大器增益特性的影响,并与单掺铒波导放大器(EDWA)进行了比较,得到了一些具有实用价值的模拟结果.     

铒镱共掺波导放大器的增益特性

在忽略放大自发辐射(ASE)及均匀掺杂和稳态的情况下,在初始能量转移效率的基础上从速率方程和传输方程出发,推导出了用于分析铒镱共掺波导放大器(EYCDWA)的新公式.利用这些公式分析了泵浦光功率、信号光功率、掺杂浓度、波导长度对放大器增益特性的影响,并与单掺铒波导放大器(EDWA)进行了比较,得到了一些具有实用价值的模拟结果.     

OD光通信有源及无源器件

掺铒磷酸盐玻璃波导放大器的两种模型的比较研究陈海燕　刘永智　官周国(电子科技大学光电子技术系 ,成都 610 0 5 4)光波导放大器是继光纤放大器之后的又一新型光放大器。为了在厘米量级的长度上获得一定高的增益 ,铒掺杂浓度比光纤放大器大两个数量级 ,高浓度掺杂会引起铒离子的聚集 ,降低了抽运效率和放大器增益。为了减轻铒离子聚集对放大器的影响 ,可与铝元素进行联合掺杂。描述掺铒磷酸盐玻璃光波导放大器的两种模型是考虑聚集的影响与不考虑聚集的影响。本文对这两种模型进行了比较研究。详细讨论了铒掺杂浓度对放大器增益特性的影响…     

光纤长度优化的高功率铒镱共掺光纤放大器

为了研究不同增益光纤长度下1555nm高功率光纤放大器的输出功率,采用两级混合结构的方法,用掺铒光纤放大器和双包层铒镱共掺光纤放大器分别作为1级预放大器和2级主放大器。掺铒光纤放大器对信号光进行预放大,并提高放大器的信噪比;双包层铒镱共掺光纤放大器为主放大器,其双包层结构可以把更多的多模抽运光耦合进系统。对铒镱共掺光纤的最佳长度做了理论分析和实验验证,在信号光功率为10mW、掺铒光纤放大器的抽运功率为318.58mW、双包层铒镱共掺光纤放大器的抽运功率为11.71W、增益光纤长度为14m时,输出功率取得了2.11W的实验数据。在分析输出信号光谱时发现,L波段附近有放大自发辐射谱出现,这是选择的增益光纤过长导致的。结果表明,在光功率和信号光功率一定时,光纤放大器有一个最佳的光纤长度。这一结果对研究光纤放大器的高功率输出是有帮助的。     

掺铒平面光波放大器材料

掺铒平面光波导放大器对工作波长1.5 μm的集成光有广泛的应用.这些器件具有增益高、抽运阈值低、器件尺寸小等优点.目前用于光波导放大器的掺铒材料有四类:氧化物薄膜(Al2O3)、有机物、硅和玻璃等. 最小的放大器(1 mm2)用Al2O3的沟道波导,抽运功率10 mW,输出增益为2.3 dB.在此类材料中,增益受激活离子Er之间的上转换限制.使用不同的方法,相同的铒离子浓度,Y2O3中的上转换效应完全不同.Eu共掺降低了上转换的影响,使增益增加.在SiO2中用Yb或Si量子点增加了抽运效率.制作4.1 dB/cm的增益光放大器成为最佳光纤通讯网络组件.铒离子掺入有机化合物中形成波导,在1.5 μm的发射带宽为70 nm,荧光寿命长,有的达17 ms敏化.可增加激发效率.纳米结构材料可克服浓度淬灭. 硅是1.5 μm非常好的波导材料,很有希望制作电抽运光放大器.掺铒硅单晶中观察到1.5 μm荧光,但在室温下,后向传输产生强烈的浓度淬灭.使用纳米技术制作的Si,可制作小尺寸光子晶体波导. 磷酸盐玻璃是制作高增益光波导放大器的理想材料,荧光寿命较长,受激发射截面大.采用离子交换法制作的波导净增益高,损耗低,制作成本低.(PD2)     

1.55 μm波段聚合物光波导放大器的研究

合成了铒镱共掺的三元配合物［Er1/2Yb1/2(HFA)3(TPPO)2］,并将其掺杂在聚甲基丙烯酸甲酯(PMMA)中,制备了铒镱共掺的聚合物光波导有源材料,对材料的吸收、发射特性进行了表征。在980 nm抽运光激发下,该配合物在1535 nm波长处的荧光半峰全宽为80 nm。针对该材料,建立了980 nm抽运光激发下的原子速率方程和光功率传输方程,理论计算了铒离子掺杂浓度、重叠积分因子、信号光发射截面等参数对铒镱共掺聚合物光波导放大器性能的影响。计算表明,当材料中铒离子的掺杂浓度为0.3×1020 cm-3时,在2 cm长的波导中可获得1.87 dB的光增益。     

高浓度掺铒/镱铒共掺硅酸盐玻璃丝的净增益测量

室温下测量了两种高浓度掺杂硅酸盐玻璃丝的净增益随抽运功率、玻璃丝长度的特性曲线,在100mW功率抽运下,掺铒质量浓度为0.19g/cm3的硅酸盐玻璃丝的单位长度净增益为1.96dB/cm,阈值功率为36mW,最佳长度为4.5cm;掺镱质量浓度为1.1g/cm3、掺铒质量浓度为0.12g/cm3的镱铒共掺硅酸盐玻璃丝,单位长度净增益为3.07dB/cm,阈值功率为28mW,最佳长度为2.5cm。结果表明,在厘米长度量级上可获得近10dB的净增益。镱铒共掺硅酸盐玻璃丝的净增益随抽运功率增长未出现饱和趋势,说明镱作为敏化剂可以改善掺铒光纤放大器的增益特性。     

铒镱共掺磷酸盐玻璃波导放大器及上转换性质

研究了采用离子交换和电场辅助退火法制作的铒镱共掺磷酸盐波导放大器的增益特性,测量了Er2O3,Yb2O3掺杂浓度分别为2.2wt%和4.7wt%,长度为1.2cm的器件增益,在130mW,976nm泵浦光泵浦下,输入信号光功率小于1mW时,在1535nm处得到8.5dB的小信号相对增益;当泵浦功率为30mW时,可观测到绿色的上转换辐射光,发光强度随泵浦功率增加而增大;通过单色仪和光电倍增管接收此光,确定是铒粒子由2H11/2和4S3/2能级分别跃迁至基态的上转换辐射光.     

铒镱共掺磷酸盐玻璃波导放大器及上转换性质

研究了采用离子交换和电场辅助退火法制作的铒镱共掺磷酸盐波导放大器的增益特性,测量了Er2O3,Yb2O3掺杂浓度分别为2.2wt%和4.7wt%,长度为1.2cm的器件增益,在130mW,976nm泵浦光泵浦下,输入信号光功率小于1mW时,在1535nm处得到8.5dB的小信号相对增益;当泵浦功率为30mW时,可观测到绿色的上转换辐射光,发光强度随泵浦功率增加而增大;通过单色仪和光电倍增管接收此光,确定是铒粒子由2H11/2和4S3/2能级分别跃迁至基态的上转换辐射光.     

Theoretical and experimental research on Er-doped and Yb-Er co-doped Al2O3 waveguide amplifiers

The rate equations of Er-doped and Yb-Er codoped systems pumped at 0.98 μm are presented, with consideration for the upconversion mechanisms such as cooperative upconversion, cross relaxation, and excited state absorption. A multi-theoretical model is founded to analyze the gain characteristics of Er-doped and Yb-Er co-doped Al2O3 waveguide amplifiers by using rate equations, a two-dimension waveguide finite element model and propagation equations with forward and backward amplified spontaneous emission. The dependence of the gain on amplifier length, pump power and doping concentration is obtained. The optimum design curve is given for designing waveguide amplifiers. The new theory is used to analyze the gain performance of a practical Yb-Er co-doped Al2O3 waveguide amplifier, and the analyzed results are in accordance with the experimental data.     

Optimization of an Er-doped silica glass optical waveguideamplifier

The optical gain performance of a highly Er-doped waveguide amplifier is affected by concentration quenching and cooperative upconversion effects. Based on materials parameters, which were previously determined for Er-doped sodalime-silicate glass, we calculate how the gain performance can be improved by reducing these limiting processes. For amplifiers with an Er concentration exceeding 0.1 at.%, the Er dc-excitation rate is dominated by cooperative upconversion rather than radiative decay or nonradiative decay due to coupling to defects. The effect of lowering the waveguide loss and reducing the optical mode diameter is also demonstrated     

Yb3+对掺铒碲酸盐玻璃红外和上转换发光的影响

研制了Er3+/Yb3+共掺TeO2-ZnO-La2O3玻璃,测试了Er3+离子的吸收谱、荧光谱和上转换发光谱,系统研究了975 nm抽运下Yb3+离子对于Er3+离子1.5 μm波段荧光性能及其上转换发光性能的影响.结果表明,随着碲酸盐玻璃中Yb2Os含量的增加,Yb3+离子对Er3+离子的能量传递增强,Er3+离子1.5 μm波段的荧光强度和上转换发光强度相应增大,但后者相对于前者增加更为迅速.通过对粒子数速率方程的理论模拟,计算结果与实验测量结果较为一致,表明Er3+/Yb3+共掺碲酸盐玻璃是一种优良的潜在上转换激光器增益介质.对上转换发光分析表明,强烈的绿光和红光激发是基于双光子的吸收过程.     

Numerical analysis of optical amplification in Er/sup 3+/-Yb/sup 3+/ codoped Ti:LiNbO/sub 3/ strip waveguides

Optical amplification at 1530 nm in 980-nm pumped Er/sup 3+/-Yb/sup 3+/-diffused Ti:LiNbO/sub 3/ strip waveguides was numerically analyzed on the basis of rate equation model of Er/sup 3+/-Yb/sup 3+/ system and pump/signal power propagation equations. The model includes total eight energy levels of the Er/sup 3+/-Yb/sup 3+/ system and simultaneously takes into account the excited state absorption (ESA) and upconversion processes within the Er/sup 3+/ ions as well as possible energy transfer processes between Yb/sup 3+/ and Er/sup 3+/ ions. A comparison of numerical results from the eight-level model and highly simplified five-level model has indicated that the /sup 4/S/sub 3/2/ manifold of Er /sup 3+/ ion must be included in the rate equation model. Dependences of threshold pump power and amplification gain on pump power (for gain only), Yb/sup 3+/ surface concentration and waveguide length were calculated and discussed. The characteristics of pump power evolution along the waveguide axis and population density distribution, as well as the influences of energy transfer coefficient from Yb/sup 3+/ to Er/sup 3+/, 550-nm (Er/sup 3+/), and 1060-nm (Yb/sup 3+/) fluorescence lifetime and above-mentioned detrimental processes including ESA, upconversion, and cross-relaxation processes on numerical result were studied. The role of Yb/sup 3+/ is demonstrated. A novel design idea that Yb/sup 3+/ is only incorporated at the end of the waveguide is proposed.     

On the Temperature-Dependent Gain and Noise Figure Analysis of C-Band High-Concentration EDFAs With the Effect of Cooperative Upconversion

We present an efficient temperature-dependent analysis to study the effect of cooperative upconversion on the temperature-dependent gain (TDG) performance of the C-band erbium-doped fiber amplifier (EDFA) at high-concentration. The influence of cooperative upconversion on the TDG is examined by using a set of temperature-dependent rate and light propagation equations. In the analysis given, the amplified spontaneous emission (ASE), as well as the excited state absorption (ESA) are also considered. In the forward pumping configuration at a signal wavelength of 1547 nm and in the temperature range of - 40degC to + 80degC, the variations of the TDG and the noise figure (NF) are about 1.7 and 0.9 dB, respectively. Numerical analysis results show that, with 260-mW/1480-nm pump power, an erbium-doped fiber amplifier having a doping concentration of 4.4 times 10²⁶ ion/m³ and optimum length of 9.2 cm may reach a signal gain of 44.6 dB and a noise figure of 3.9 dB at room temperature.     

Er3+/Yb3+共掺Bi2O3-GeO2-Na2O玻璃的上转换发光

研究了不同Er3 /Yb3 掺杂比46Bi2O3-44GeO2-10Na2O(B46G44N10)(摩尔分数)玻璃的吸收光谱、红外吸收谱和上转换光谱性质,分析了玻璃中Yb3 敏化Er3 的上转换发光机制。测试了Er3 离子在不同Yb3 浓度下玻璃中的上转换荧光强度,得到最佳的掺杂质量比Er3 ∶Yb3 =1∶6。计算了在980 nm激发下Er2O3质量分数为0.5%和Yb2O3质量分数为3.0%的Er3 /Yb3 共掺B46G44N10玻璃的绿光上转换效率为2.27×10-4。比较了不同基质材料玻璃的上转换效率,结果表明B46G44N10玻璃是一种良好的上转换基质材料。     

Polarization-dependent enhancement of population inversion and of green upconversion in Er:LiNbO/sub 3/ by Yb codoping

We have investigated the polarization dependence of both the population inversion of the /sup 4/I/sub 13/2/ state and the green upconversion to the /sup 4/S/sub 3/2/ state in Er:LiNbO/sub 3/ optical fiber amplifier when codoped with Yb and pumped around 980 nm. The presence of Yb/sup 3+/ enhances the population of the /sup 4/I/sub 13/2/ state of the Er/sup 3+/ ions when pumped at /spl sigma/-polarization (>2.5 times) and at /spl pi/-polarization (>5.5 times), and introduces a broad useful pump band around 940-960 nm at /spl sigma/-polarization, relaxing fabrication tolerances on semiconductor pump sources. An enhancement of green upconversion is also observed by the Yb codoping. Lifetime measurements indicate that, as in glass substrates, nonradiative energy transfer is responsible for these enhancements.     

碲基掺铒光纤放大器增益特性的理论研究

在综合考虑Er^3 离子的能量上转换、交叉驰豫、激发态吸收效应以及光纤背景损耗后，依据所建立的均匀加宽四级结构速率方程组和光功率传输方程组，对碲基掺铒光纤放大器的增益特性进行了数值模拟，模拟结果与报道的实验测量结果达到了很好的一致。同时，对碲基掺铒光纤放大器的增益特性与输入信号功率、泵浦功率和光纤长度的关系进行了简要分析。     

Solid-state laser pumping of 1.5-μm optical amplifiers andsources for lightwave video transmission

An optical power amplifier and a laser source are demonstrated at 1.5 μm. A diode-pumped Nd:YAG laser is used as the pumping source for an Er/Yb co-doped gain medium. The power scaling advantages of this approach are demonstrated. Up to +21 dBm of output power is obtained from the Er/Yb amplifier and up to +19 dBm is obtained from the laser source. The Er/Yb power amplifier was deployed in a 42-channel AM link with 40 km of fiber, and an optical loss budget of 18 dBm was demonstrated     

Upconversion fluorescence modulation of CaTiO3:Yb3+/ Er3+ nanocubes via Zn2+ introduction

rials, CaTiO3:Yb3+/Er3+/Zn2+ nanocubes with uniform size were prepared by solvothermal method in this paper. They were respectively characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), photoluminescence (PL) spectroscopy and their fluorescence lifetimes. The results show that the average size of the nanocubes is about 550 nm×650 nm×850 nm with good upconversion luminescence (UCL) properties. Under 980 nm laser excitation, the effects of the ratio between activator Er3+ and sensitizer Yb3+ and Zn2+ doping on the upconversion fluorescence properties were investigated, and the optimal ion ratio was obtained. The results of steady-state spectra show that the strongest fluorescence intensity of CaTiO3:Yb3+/Er3+ was obtained with the addition of 10 mol% Zn2+ at a Yb3+/Er3+ molar doping ratio of 3:0.3, which was attributed to the crystal field asymmetry generated by the introduction of Zn2+ ions. The energy transfer and upconversion mechanism between Yb3+ and Er3+ ions in CaTiO3 nanocubes were investigated by analyzing the upconversion fluorescence kinetics.