硫系玻璃基掺铒微结构光纤4.5μm波段中红外信号放大特性

为进一步揭示硫系玻璃基掺Er3+微结构光纤作为中红外光纤放大器增益介质的可行性,数值求解了800 nm泵浦波长下Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤中Er3+离子数速率方程和光功率传输方程组,理论研究了4.5μm波段中红外信号的放大特性。结果显示,Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤具有较高的信号增益和很宽的增益谱。在50 cm光纤长度上,最大信号增益超过了40 dB,高于30 dB信号增益的放大带宽达到了280 nm(4 420~4 700 nm)。同时,进一步研究分析了4 500 nm波长信号增益与光纤长度、信号输入功率和泵浦功率的关系。研究表明,Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤是一种理想的可应用于4.5μm波段中红外宽带放大器的增益介质。     

Er3+/Ce3+共掺铋锗酸盐玻璃及其光纤的制备和光谱性质

用高温熔融法制备了Er3+/Ce3+共掺铋锗酸盐(Bi2O3-GeO2-Ga2O3-Na2O)玻璃,研究分析了该玻璃中Er3+离子1.5μm波段荧光和上转换发光,Ce3+离子共掺引入的Er3+:4I11/2→Ce3+:2F5/2间能量传递能有效地抑制上转换发光并增强1.5μm波段荧光发射.同时,利用该组分玻璃拉制了包层直径为125 μm的铋锗酸盐玻璃掺Er3+光纤,1310 nm波长处光纤传输损耗为3.4 dB/m.通过对975 nm波长激励下光纤的放大自发辐射(ASE)测试表明,铋锗酸盐玻璃掺Er3+光纤可在1450～1650 nm波长范围获得宽带ASE光谱,因此是一种适用于宽带光纤放大器的增益介质.     

宽带Er2Tm共掺石英光纤放大自发辐射特性分析

探索了新型Er2Tm共掺石英基质超荧光光纤光源的特性,在粒子数方程和功率传输方程的基础上对其放大自发辐射(ASE)特性进行了理论分析。在单向泵浦中,分析了泵浦功率和信号功率随光纤长度的变化特性,描述了在不同光纤长度、离子浓度及泵浦功率下信号谱的变化趋势;在双向泵浦中,讨论了泵浦功率和信号功率随光纤长度的变化特性以及信号谱相对于光纤长度和泵浦功率的稳定性。结果显示,利用Er2Tm共掺石英基质光纤可以获得稳定的100nm放大自发辐射带宽,大约是传统掺铒光纤超荧光光源带宽的两倍,但输出功率比后者低3个量级以上。     

掺铒硫系玻璃光纤的中红外增益特性模拟研究

实验制备了Er3+掺杂质量分数为1%的Ga5Ge20Sb10S65硫系玻璃,测试了其折射率、吸收光谱和荧光光谱,利用Judd-Ofelt和Futchbauer-Ladenburg理论计算了Er3+离子的自发辐射几率、吸收截面和受激发射截面等光谱参数。在综合考虑Er3+离子的交叉弛豫、能量上转换和激发态吸收效应的基础上,应用四能级粒子数速率-光功率传输方程模型,模拟计算了Er3+掺杂Ga5Ge20Sb10S65硫系玻璃光纤的中红外2.74μm波段的增益特性。结果显示,Er3+掺杂硫系玻璃光纤在2.74μm中红外波段具有较高的信号增益和较宽的增益谱,最大增益值和20dB增益带宽分别超过了40dB和200nm,表明其是可用于中红外2.74μm波段宽带放大的理想增益介质。     

掺铒碲酸盐玻璃基上转换光纤激光器的理论研究

建立了以掺铒碲酸盐玻璃光纤作为增益介质的上转换光纤激光器数值模型,理论研究了碲酸盐玻璃基上转换光纤激光器的激光输出特性,得到了980 nm抽运源激励下546 nm绿色激光信号输出功率与入射抽运功率、谐振腔光纤长度的变化关系.研究表明,碲酸盐玻璃基上转换光纤激光器可以在厘米长度的增益介质上实现毫瓦功率的绿色激光输出,斜率效率达到了7%左右.相比于报道的氟化物玻璃基上转换光纤激光器,碲酸盐玻璃基上转换光纤激光器显示出一种潜在的小型化固体激光器特征.     

稀土掺杂碲酸盐玻璃放大光纤研究综述

文章介绍了光纤放大的研究历史,分析了掺铒光纤放大器(EDFA)和光纤拉曼放大器的优势和劣势,指明了稀土掺杂碲酸盐放大光纤的应用领域.文章介绍了掺铒和掺铥放大光纤的光放大机理,综述了掺铒碲酸盐和掺铥碲酸盐玻璃放大光纤的研究近况,得出了稀土掺杂碲酸盐玻璃放大光纤越来越接近实用化的结论.     

两段级联宽带碲基掺铒光纤放大器特性研究

利用四能级结构速率方程组和光功率传输方程组,研究了在碲基掺铒光纤(EDTF)中内插一个光隔离器、形成两段级联的碲基掺铒光纤放大器(EDTFA)后对EDTFA性能的改善.结果表明,在给定泵浦方式、泵浦功率、纤芯掺杂浓度和输入信号功率条件下,两段级联EDTFA可以有效的抑制光纤中反向传输放大自发辐射(ASE)噪声,降低反转粒子数的消耗,从而提高信号增益、输出功率,并且降低了噪声系数.对不同光纤长度和光隔离器内插在光纤中不同位置的研究表明,当光纤为最佳长度和光隔离器在最佳位置处时,可使短波长信号增益增加10 dB,噪声系数减小1 dB,并进一步增加了放大带宽以及功率转换效率.     

高掺铒光纤光谱及增益特性研究

对高掺铒浓度光纤的增益及光谱特性进行了实验研究.仅用增益长度2.75米的高掺铒光纤,对于1530nm～1560nm波段0dBm的输入信号,其放大后的输出功率可达+14dBm,且其噪声指数低于4.5dB.所用980nm泵浦源的泵浦功率为80mW.得出掺铒光纤的平坦增益谱宽为30nm(±1dB),其输出功率与输入信号功率呈线性关系.实验测得其1550nm光信号增益为43dB.     

一种小型铒/镱双掺光纤放大器增益特性研究

研究了一种小型铒/镱双掺光纤放大器的增益特性。仅用长度为4.2m的Er/Yb双掺光纤作为增益介质,以1064nm Nd∶YAG固体激光器作泵浦源,获得了1530~1560nm区间的30nm(±1dB)平坦增益谱宽。对于1550nm的信号光,泵浦功率为100mW时,小信号增益为27.95dB,饱和输出功率为8.36dBm。     

宽带碲基掺铒光纤放大器掺杂特性的理论研究

对WDM系统中宽带碲基掺铒光纤放大器(EDTFA)多信道增益谱特性的研究表明,在给定泵浦方式、泵浦功率和光纤长度的工作条件下,碲基掺铒光纤中铒掺杂浓度对EDTFA各信道信号增益的影响并不相同,相比于长波长信道,短波长信道的信号增益随着光纤中铒掺杂浓度的提高更易趋于饱和及快速衰减状态,同时信号增益谱向长波长方向萎缩.     

Enhancement of fluorescence emission and signal gain at 1.53 µm in Er3+/Ce3+ co-doped tellurite glass fiber

Er3+/Ce3+ co-doped tellurite glasses with composition of TeO2-GeO2-Li2O-Nb2O5 were prepared using conventional melt-quenching technique for potential applications in Er3+-doped fiber amplifier (EDFA). The absorption spectra, up-conversion spectra and 1.53 µm band fluorescence spectra of glass samples were measured. It is shown that the 1.53 µm band fluorescence emission intensity of Er3+-doped tellurite glass fiber is improved obviously with the introduction of an appropriate amount of Ce3+, which is attributed to the energy transfer (ET) from Er3+ to Ce3+. Meanwhile, the 1.53 µm band optical signal amplification is simulated based on the rate and power propagation equations, and an increment in signal gain of about 2.4 dB at 1 532 nm in the Er3+/Ce3+ co-doped tellurite glass fiber is found. The maximum signal gain reaches 29.3 dB on a 50 cm-long fiber pumped at 980 nm with power of 100 mW. The results indicate that the prepared Er3+/Ce3+ co-doped tellurite glass is a good gain medium applied for 1.53 µm broadband and high-gain EDFA.     

1.58-/spl mu/m broad-band erbium-doped tellurite fiber amplifier

This paper describes the development of a 1.58-/spl mu/m broad-band and gain-flattened erbium-doped tellurite fiber amplifier (EDTFA). First, we compare the spectroscopic properties of various glasses including the stimulated emission cross sections of the Er/sup 3+4/ I/sub 13/2/ /sup 4/I/sub 15/2/ transition and the signal excited-state absorption (ESA) cross sections of the Er/sup 3+4/ I/sub 13/2/ - /sup 4/I/sub 9/2/ transition. We detail the amplification characteristics of a 1.58-/spl mu/m-band EDTFA designed for wavelength-division-multiplexing applications by comparing it with a 1.58-/spl mu/m-band erbium-doped silica fiber amplifier. Furthermore, we describe the 1.58-/spl mu/m-band gain-flattened EDTFA we developed using a fiber-Bragg-grating-type gain equalizer. We achieved a gain of 25.3 dB and a noise figure of less than 6 dB with a slight gain excursion of 0.6 dB over a wide wavelength range of 1561-1611 nm. The total output power of the EDTFA module was 20.4 dBm and its power conversion efficiency reached 32.8%.     

铒铥共掺碲基质宽带光纤放大器研究

文章作者分析了铒铥共掺碲基质光纤放大器在980 nm泵浦下Er~(3+)-Tm~(3+)离子之间的能量转移过程,建立了速率方程和功率传输方程,并通过仿真得出了其放大增益随光纤长度和泵浦功率的变化规律.仿真结果表明:通过优化光纤长度和泵浦功率,该放大器可以在1 440～1 540 nm波段得到高达50 dB的平坦增益.     

Tm3+/Ho3+共掺碲酸盐玻璃的中红外发光及能量传递机理

用高温熔融法制备了Tm3+/Ho3+共掺碲酸盐玻璃(TeO2-ZnO-Na2O),根据测量得到的吸收光谱,应用Judd-Ofelt理论计算分析了玻璃样品中Ho3+离子的强度参数Ωt(t=2,4,6)、自发辐射跃迁几率A、荧光分支比β和荧光辐射寿命τrad等各项光谱参数。同时,测量得到了不同Ho3+离子掺杂浓度下玻璃样品的荧光发射谱。结果显示,在808nm抽运光激励下Tm3+/Ho3+共掺碲酸盐玻璃样品发射出较强的2.0μm中红外荧光。分析表明,较强的Ho3+离子中红外荧光来自于Tm3+/Tm3+离子间共振的能量传递过程,以及Tm3+/Ho3+离子间基于零声子和单声子辅助非共振的两部分能量传递过程。由此进一步计算得到了Tm3+/Tm3+、Tm3+/Ho3+离子间的能量传递微观速率、临界半径和声子的贡献。最后,计算分析了Ho3+…5I7→5I8能级间跃迁的2.0μm波段吸收截面、受激发射截面和增益系数。研究表明,Tm3+/Ho3+共掺TeO2-ZnO-Na2O玻璃可以作为2.0μm波段中红外固体激光器的潜在增益基质。     

Theoretical analysis of gain characteristics of Er/sup 3+/-Tm/sup 3+/-codoped tellurite fiber amplifier

The rate and power propagation equations of Er/sup 3+/ and Tm/sup 3+/-codoped tellurite fiber amplifier pumped by 800-nm laser are presented and solved to analyze the dependences of gain at both 1470 and 1530 nm on the codoping concentration of Er/sup 3+/ and Tm/sup 3+/, fiber length, and input signal power. The numerical results show that with pump power of 200 mW and fiber length of 1.5 m, the gain at both 1470 and 1530 nm may reach 12.0 dB when the codoping concentration of Er/sup 3+/ and Tm/sup 3+/ reach 4.0/spl times/10/sup 25/ ions/m/sup 3/, 3.2/spl times/10/sup 25/ ions/m/sup 3/, respectively. The fiber length and codopant concentrations are proposed to make the two channels equivalently amplified.     

Effect of Ce2O3 on the 1.53 μm spectroscopic properties in Er3+-doped tellurite glasses

The crown-like zinc oxide(Zn O)samples,which are composed of a hexagonal cap and a tower-like shaft,are prepared by vapor transport method.The hexagonal cap,working as a whispering gallery mode(WGM)resonant cavity,demonstrates density-dependent ultraviolet(UV)lasing emission with a broadened and squared photoluminescence(PL)profile under UV excitation at 355 nm.Theoretical analyses based on Fermi golden rule show that the broadened spectrum profile results from the special optical mode density characteristics in a WGM micro-cavity,which is in agreement with the observed results.     

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.     

Calculation of the noise figure of erbium-doped fiber amplifiersusing small signal attenuations and saturation powers

A theory allowing the noise figure of an erbium-doped fiber amplifier to be computed with a reduced set of fiber parameters is evaluated. The approach is accurate when the amplified spontaneous emission has no significant influence on the gain. Then four parameters, saturation power and absorption coefficient for pump and signal wavelength, are sufficient for 980-nm pumped fiber amplifier. This theory is used to investigate the noise characteristics of a 980-nm pumped booster amplifier within the whole gain spectrum     

Enhancement of 2.0 µm fluorescence emission in new Ho3+/Tm3+/Yb3+ tri-doped tellurite glasses

For enhancing the 2.0 µm band fluorescence of Ho3+, a certain amount of WO3 oxide was introduced into Ho3+/Tm3+/Yb3+ tri-doped tellurite glass prepared using melt-quenching technique. The prepared tri-doped tellurite glass was characterized by the absorption spectra, fluorescence emission and Raman scattering spectra, together with the stimulated absorption, emission cross-sections and gain coefficient. The research results show that the introduction of WO3 oxide can further improve the 2.0 µm band fluorescence emission through the enhanced phonon-assisted energy transfers between Ho3+/Tm3+/Yb3+ ions under the excitation of 980 nm laser diode (LD). Meanwhile, the maximum gain coefficient of Ho3+ at 2.0 µm band reaches about 2.36 cm-1. An intense 2.0 µm fluorescence emission can be realized .