双包层Er3+/Yb3+共掺光纤放大器粒子数特性分析

基于速率方程和光传输方程,对双包层Er3+/Yb3+共掺光纤放大器的计算模型进行了讨论,并利用数值模拟结果对980nm激光抽运双包层Er3+/Yb3+共掺光纤放大器Er3+上能级粒子数的分布特性进行了分析。分别给出了正向抽运和反向抽运条件下,Er3+归一化上能级粒子数分布曲线。利用上能级粒子数沿光纤的分布曲线解释了信号光沿光纤的分布规律。     

双包层Er2Yb 共掺光纤放大器理论模型研究

针对以往双包层Er2Yb 共掺光纤放大器理论模型存在的问题,在考虑了纤芯横截面内 不同能级的粒子数分布与信号光强大小关系的基础之上,重新建立了双包层Er2Yb 共掺光纤放大器的理论模型。并利用该模型分析了双包层Er2Yb 共掺光纤放大器Er3 + 、Yb3 + 上能级的粒子数分布,以说明该理论模型的合理性。     

双包层Er-Yb共掺光纤放大器理论模型研究

针对以往双包层Er-Yb共掺光纤放大器理论模型存在的问题,在考虑了纤芯横截面内不同能级的粒子数分布与信号光强大小关系的基础之上,重新建立了双包层Er-Yb共掺光纤放大器的理论模型.并利用该模型分析了双包层Er-Yb共掺光纤放大器Er3+、Yb3+上能级的粒子数分布,以说明该理论模型的合理性.     

超宽带Er,Tm共掺石英光纤放大器稳态研究

分析了波长为980nm激光抽运下的Er3+,Tm3+共掺石英光纤放大器的工作原理,并根据此工作原理,建立了Er3+与Tm3+之间能量转移过程的数学模型。基于速率方程和功率传输方程,数值模拟了此种光纤放大器稳态工作特性,给出了不同光纤长度、不同输入抽运功率以及不同掺Tm3+浓度下多路光信号放大时输出信号功率谱的变化规律。仿真结果表明,当输入抽运功率为400mW时,Er,Tm共掺石英光纤放大器的3dB带宽可达90nm(比传统掺Er3+光纤放大器的增益带宽大两倍以上),平均增益可达10dB,可用于未来密集复用系统(DWDM)中的宽带放大器件。     

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.     

超宽带Er3+-Tm3+共掺石英光纤放大器串联特性分析

在不影响Er3 -Tm3 共掺石英光纤超宽带放大特性的前提下,提出了利用串联的方式提高系统功率增益的方法,并模拟仿真了两级串联此种石英光纤的工作特性.仿真结果表明:两级串联的Er3 -Tm3 共掺石英光纤的功率增益可达20 dB,基本上解决了其宽带放大但只具有低功率增益的特性.通过与现阶段其它宽带光放大器比较,可以看出采用此种方式的Er3 -Tm3 共掺石英光纤放大器无论在系统复杂度还是在成本方面都具有明显优势.     

被动锁模掺Er3+氟化物光纤激光器理论研究

根据非线性薛定谔方程建立了基于可饱和吸收体被动锁模掺Er3+氟化物光纤激光器的理论模型,研究了中红外超短脉冲在掺Er3+氟化物光纤激光器中形成的物理机制,数值模拟了被动锁模掺Er3+氟化物光纤激光器中中红外超短脉冲的演化过程,重点分析了掺Er3+增益光纤长度,可饱和吸收体不饱和损耗对被动锁模掺Er3+氟化物光纤激光器产生中红外超短脉冲的影响,并给出了参数设置范围。研究发现:当小信号增益系数、可饱和吸收体不饱和损耗、腔内净色散量为一定值,掺Er3+氟化物光纤长度在一定范围时,才会出现稳定的锁模脉冲,且随着掺Er3+氟化物光纤长度增加脉冲宽度变窄、光谱变宽、峰值功率增高;当掺Er3+氟化物光纤长度、腔内净色散量、小信号增益系数为一定值时,可饱和吸收体不饱和损耗在一定的范围时可以得到稳定的锁模脉冲,且随着可饱和吸收体不饱和损耗的增加脉冲宽度变窄,光谱先变宽后变窄变化范围不大,峰值功率增加。     

Er3+/Yb3+共掺双包层光纤与掺Yb3+光纤中上转换效应实验研究

报道了Er3+/Yb3+共掺双包层光纤中由于上转换效应产生的荧光现象,并将此荧光与掺Yb3+光纤中产生的绿色荧光进行了详细测量和对比分析,结果表明,Er3+/Yb3+共掺双包层光纤中的绿色荧光仍然是Er3+离子激发态吸收所产生,而Yb3+只起到能量搬运的作用,两种光纤受激产生的荧光光谱、功率,及其随泵浦功率的变化关系,都遵循不同规律。     

Er3+/Yb3+共掺磷酸盐玻璃光纤放大器的增益综述

主要从磷酸盐玻璃光纤的离子掺杂浓度、量子转换效率、信号波长与功率、抽运波长与功率以及光纤长度等方面概述了Er3+/Yb3+共掺磷酸盐玻璃光纤放大器的增益.并简要介绍了国外在该方面的研究进展.     

高功率窄线宽光纤放大器及放大线宽特性

研制了高功率窄线宽光纤放大器.该放大器采用双级放大结构,其中第一级预放为掺Er3+光纤放大器,第二级功率放大采用10 m长的Er3+/Yb3+共掺双包层光纤作为增益介质,抽运源采用两支波长为980 nm的大功率激光二极管.当抽运功率为10.7 W时,得到放大激光输出功率为1.94 W,光一光转换效率为17%,斜率效率20%.采用延迟自外差方法对种子激光器及各级放大器输出的激光线宽进行了测量,测量结果表明窄线宽激光谱线经过掺Er3+光纤与双包层光纤放大后均有不同程度的明显展宽.分析认为激光线宽展宽的主要原因是由于种子激光器中弛豫振荡或自脉冲的强度波动引起的自相位调制.     

A simple set searching optimization method for Er3+-Yb3+ co-doped fiber lasers

A simple set searching optimization algorithm is proposed for Er³⁺-Yb³⁺ co-doped fiber lasers in this paper. This method enables fiber lasers to acquire the optimum fiber length and Yb³⁺-Er³⁺ concentration ratio for a given accuracy. The numerical results illustrate that the optimum Yb³⁺-Er³⁺ concentration ratio changes very little, the optimum fiber length shortens and the corresponding output power is increased with erbium ions concentration increasing. The total Yb³⁺ and Er³⁺ contents are nearly constant under certain pump power, while the optimum total erbium ions and ytterbium ions are decreased with pump power decreasing.     

Effect of Yb^3＋ concentration on Er^3＋ luminescence properties of sol-gelderived silica-alumina xerogels

Er~(3 )-activated silicate glasses are recognized of tech-nological interest in several areas and,in particular ,it iswell known for their successful application in opticalamplification at the C band (1530 -1565 nm) of tele-communications[1].Inside this l…     

High power cladding-pumped Er3+/Yb3+ fiber amplifiers: technologies, performances and impact of nonlinear effects

Yb³⁺-sensitized Er³⁺-doped fibers are attracting increasing interest because of the high achievable performances, such as high gain and pump efficiency. High output power can be obtained from a double clad (dc) Er³⁺/Yb³⁺ co-doped fiber pumped with broad area high power pump laser diodes. The principle of amplification in this kind of co-doped fibers is presented in this paper. Different solutions for the injection of pump power in the 1^st-cladding have been described. The energy transfer mechanism in a Er³⁺/Yb³⁺ co-doped system including cooperative-upconversion process is explained. Gain and absorption properties ofdc fibers have been determined experimentally and inserted in a theoretical amplifier model. Good agreement between measurements and modelling has been obtained. Hybrid Er³⁺-Er³⁺/Yb³⁺ amplifier architectures are suitable to obtain + 30 dBm output power. The gain bandwidth is in the 1535–1565 nm range for single wavelength operation. A spectral gain flatness is observed in a reduced C-bandWDM operation (i.e. 1545–1565 nm) without gain-flattening filter. Nonlinear effects such as the optical Kerr effect or the stimulated Brillouin scattering can be observed in high power amplifiers due to the high output peak power confined in the fiber core. These two nonlinear phenomena have been investigated for different high power amplifier configurations. Numerical modelling have also confirmed the observed signal distortions.     

Spectral properties and energy transfer in Er3+/Yb3+ co-doped LiYF4 crystal

Laser crystals of LiYF4 (LYF) singly doped with Er3+ in 2.0% and co-doped with Er3+/Yb3+ in about 2.0%/1.0% molar fraction in the raw composition are grown by a vertical Bridgman method. X-ray diffraction (XRD), absorption spectra, fluorescence spectra and decay curves are measured to investigate the structural and luminescent properties of the crystals. Compared with the Er3+ singly doped sample, obviously enhanced emission at 1.5 μm wavelength and green and red up-conversion emissions from Er3+/Yb3+ co-doped crystal are observed under the excitation of 980 nm laser diode. Meanwhile, the emission at 2.7 μm wavelength from Er3+ singly doped crystal is reduced. The fluorescence decay time ranging from 18.60 ms for Er3+ singly doped crystal to 23.01 ms for Er3+/Yb3+ co-doped crystal depends on the ionic concentration. The luminescent mechanisms for the Er3+/Yb3+ co-doped crystals are analyzed, and the possible energy transfer processes from Yb3+ to Er3+ are proposed.     

Ag纳米颗粒对Er3+/Tm3+/Yb3+共掺铋锗酸盐玻璃上转换发光特性的影响

采用传统熔融淬冷法制备了系列Er³⁺/Tm 3+/Yb³⁺共掺复合Ag纳米颗粒的铋锗酸盐玻璃样品。从吸收光谱中 确定了Ag纳米颗粒表面等离子体共振(SPR)峰位于545nm附近;透射 电镜(TEM)图像中观察到均匀分布的Ag纳米颗粒,尺寸 约为6～18nm。研究了纳米Ag含量对Er3＋/Tm3＋ 共掺复合Ag纳米颗粒铋锗酸盐玻璃上转换发光特性的影响,结果表 明,Tm³⁺离子472nm处的上转换蓝光、Er³⁺离子525nm处的上转换绿光、543nm处的上转换 绿光和661nm处的上转换红光发光强度在AgCl含量的质量百分数为 1%时达到最大值,与未掺杂AgCl的基质玻璃相比,分别提高了约3.2、3.8、5.4倍。     

Er3+–Tm3+ co-doped tellurite fibers for broadband optical fiber amplifier around 1550 nm band

Tellurite fibers with 7500 ppm Er³⁺ concentration and diverse 2500–15,000 ppm Tm³⁺ concentrations were manufactured, and their amplified spontaneous emission (ASE) intensities 1550 nm band around were obtained for 980 and 790 nm pump laser. Maxima 187 nm bandwidth at −3 dB points using Er³⁺–Tm³⁺ co-doped tellurite optical fibers pumping at 790 nm was obtained, and energy transfer (ET) process between ⁴I_13/2 Er³⁺ and ³F₄ Tm³⁺ levels related with the amplifier quantum efficiency was studied from experimental and calculated lifetime.     

Electrospinning Preparation and Drug‐Delivery Properties of an Up‐conversion Luminescent Porous NaYF4:Yb3+, Er3+@Silica Fiber Nanocomposite

Up‐conversion (UC) luminescent porous silica fibers decorated with NaYF₄:Yb³⁺, Er³⁺ nanocrystals (NCs) (denoted as NaYF₄:Yb³⁺, Er³⁺@silica fiber) are prepared by the electrospinning process using cationic surfactant P123 as a template. Monodisperse and hydrophobic oleic acid capped β‐NaYF₄: Yb³⁺, Er³⁺ NCs are prepared by thermal decomposition methodology. Then, these NCs are transferred into aqueous solution by employing cetyltrimethylammonium bromide (CTAB) as secondary surfactant. The water‐dispersible β‐NaYF₄:Yb³⁺, Er³⁺ NCs are dispersed into precursor electrospinning solution containing P123 and tetraethyl orthosilicate (TEOS), followed by preparation of precursor fibers via electrospinning. Finally, porous α‐NaYF₄:Yb³⁺, Er³⁺@silica fiber nanocomposites are obtained after annealing the precursor fibers containing β‐NaYF₄:Yb³⁺, Er³⁺ at 550 °C. The as‐prepared α‐NaYF₄:Yb³⁺, Er³⁺@silica fiber possesses porous structure and UC luminescence properties simultaneously. Furthermore, the obtained nanocomposites can be used as a drug delivery host carrier and drug storage/release properties are investigated, using ibuprofen (IBU) as a model drug. The results indicate that the IBU–loaded α‐NaYF₄:Yb³⁺, Er³⁺@silica fiber nanocomposites show UC emission of Er³⁺ under 980 nm NIR laser excitation and a controlled release property for IBU. Meanwhile, the UC emission intensity of IBU–α‐NaYF₄:Yb³⁺, Er³⁺@silica fiber system varies with the released amount of IBU.     

Effect of B2O3 on the spectroscopic properties in Er3+/Ce3+ co-doped tellurite-niobium glass

The high phonon energy oxide of B2O3 is introduced into the Er3+/Ce3+co-doped tellurite-niobium glasses with composition of TeO2-Nb2O5-ZnO-Na2O.The absorption spectra,1.53 μm band fluorescence spectra,fluorescence lifetime and Raman spectra of Er3+in glass samples are measured together with the calculations of Judd-Ofelt spectroscopic parameter,stimulated emission and absorption cross-sections,which evaluate the effect of B2O3 on the 1.53 μm band spectroscopic properties of Er3+.It is shown that the introduction of an appropriate amount of B2O3 can further improve the 1.53 μm band fluorescence intensity through an enhanced phonon-assisted energy transfer(ET) between Er3+/Ce3+ions.The results indicate that the prepared Er3+/Ce3+co-doped tellurite-niobium glass with an appropriate amount of B2O3 is a potential gain medium for the 1.53 μm bandbroad erbium-doped fiber amplifier(EDFA).     

Influence of the melting atmosphere on Yb3+/Al3+ co-doped silica glass with powder melting technology

We demonstrated the formation of Yb²⁺ ions in Yb³⁺/Al³⁺ co-doped silica glass using the powder melting technology based on the high-frequency plasma furnace. The Yb³⁺ ions can be deoxidated into Yb²⁺ ions under the atmosphere of N₂ or Ar. The appearance and optical properties of the Yb³⁺/Al³⁺ co-doped silica glass are also changed.     

Down/Up Conversion in Ln3+‐Doped YF3 Nanocrystals

Nanocrystalline Ln³⁺‐doped YF₃ phosphors have been synthesized via a facile sonochemistry‐assisted hydrothermal route. YF₃ nanoparticles are demonstrated to be a good host material for different lanthanides. Varying the dopants leads to different optical properties. In particular, the feasibility of inducing red, green, and especially blue emission in the Yb³⁺/Er³⁺ co‐doped YF₃ sample by up‐conversion excitation in the near‐infrared region is demonstrated. Such unusually strong 411 nm blue up‐conversion emission has seldom been reported in other Yb³⁺/Er³⁺‐doped systems. The up‐conversion mechanisms have been analyzed.