抽运光与信号光的光强重叠因子和掺铒玻璃波导放大器的增益特性

在掺铒玻璃波导放大器（EDWA）的三能级速率-传输方程中,考虑两次离子交换工艺中波导掩模窗口宽度w不同所导致的抽运光、信号光模场与光强分布的不同,讨论不同w对EDWA增益特性的影响,得到光强分布的数值解.引入描述波导中抽运光和信号光的归一化光强重叠因子,对EDWA的传统近似解提出修正,得到了修正解,使其更加接近光强分布的数值解.模拟结果表明,在条波导长度为4 cm、抽运光波长为980 nm、功率为80 mW、信号光波长为1534 nm、功率为-10 dBm条件下,不同w所导致EDWA的增益差别可达297 dB.修正解的结果比传统近似解更加接近光强分布的数值解.修正解对于EDWA的理论研究、器件设计具有指导作用. 关键词： 集成光学 掺铒玻璃波导放大器 重叠积分因子 增益     

掺铒光波导放大器的速率方程分析

用重合积分的方法 ,分析了描述掺铒光波导放大器 (EDWA)的速率方程 ,得到了 980nm波段抽运的掺铒光波导放大器增益的隐式解析解 ,在此基础上得到了抽运阈值功率的解析表达式。计算了掺铒平面光波导放大器中的光场与铒掺杂浓度分布的重叠因子。讨论了铒掺杂浓度对抽运阈值功率的影响及抽运功率对增益的影响。     

掺铒光波导入大器的速率方程分析

用重合积分的方法，分析了描述掺铒光波导放大器（EDWA）的速率方程，得到了980nm波段抽运的掺铒光波导放大器增益的隐式解析解，在此基础上得到了抽运阈值功率的解析表达式。计算了掺铒平面光波导放大器中的光场与铒掺杂浓度分布的重叠因子。讨论了铒掺杂浓度对抽运阈值功率的影响及轴运功率对增益的影响。     

掺铒磷酸盐玻璃波导放大器的特性研究

研究了掺铒磷酸盐玻璃波导放大器的特性。利用重叠因子将980nm光抽运的掺铒玻璃波导放大器四能级模型的速率-传输方程进行化简,在考虑上转换效应和放大自发发射的情况下．利用数值模拟的方法,得到了掺铒玻璃波导放大器的增益与Er^3 离子浓度、抽运功率、波导长度等参量之间的关系曲线;同时模拟出放大自发发射曲线并与实验测量结果进行比较。结果表明在考虑上转换效应和放大自发发射的情况下,理论结果和实验测量结果是一致的。同时看到,选择合适的铒离子浓度是制作掺铒玻璃波导放大器的关键;并且为了全面发挥掺铒玻璃波导放大器的性能,需要抽运功率、波导长度等各个参量配合起来。     

脊形掺铒Al2O3光波导放大器级联特性的模拟计算

利用有限元法分析了脊形掺铒Al₂O₃光波导放大器内信号光和抽运光的场模式分布、速率方程求解铒离子五能级系统的粒子数分布.数值模拟了光波导净增益与信号光功率的关系和多个放大器级联的净增益特性.结果表明：级联系统存在着净增益亏损.低掺铒浓度的光波导作前级放大器的组合方式,级联系统总净增益最大.     

掺Er及Yb-Er共掺Al2O3光波导放大器的理论与实验研究

抽运波长为0.98μm时,考虑合作上转换、交叉弛豫、激发态吸收等上转换机理给出了掺Er及Yb-Er共掺系统的速率方程,并利用二维波导的有限元理论及包含正反向放大的自发辐射的场传输方程,建立了一套分析光波导放大器增益特性的综合理论模型。得到掺Er及Yb-Er共掺Al2O3光波导放大器增益与波导长度、抽运功率、掺杂浓度等多个参量的关系,绘制出具有实用性的优化设计曲线。将该理论模型应用于实际制作的Yb-Er共掺Al2O3光波导放大器,结果与实验数据相符。     

掺铒聚合物光波导放大器的数值分析

针对掺铒聚合物光波导放大器(EDWA),提出了一种基于Douglas离散格式改进的有限差光束传播法(FD-BPM)的数值计算方法。对每一传输步长结合多能级速率方程计算出EDWA中光场传输强度分布,及掺铒光波导放大器的增益传输特性。设计并研究了掺铒聚合物通道波导和Y形分束器的放大增益特性。在掺铒聚合物直波导中,Er3 浓度为9.0×1025ions·m-3,输入信号和泵浦光功率分别为1μW和2mW,其增益为1.6dB/cm;在掺铒聚合物Y形分束器中,输出信号光分束比相等,并能实现无损耗分束。     

纵向非均匀掺铒的光波导放大器特性数值模拟研究

提出一种通过非均匀掺铒方法提高光波导放大器增益和抽运效率的优化设计方案，并在有限 元法基础上构建了光波导放大器模型.计算中考虑到合作上转换、交叉弛豫和激发态吸收等 效应. 利用自适应法求解了两种铒离子浓度分布方案，分别使脊形光波导放大器增益在固定 长度和增益最大值有1027%和565%的提高. 计算结果与级联掺铒玻璃样品的实验结果相 符合. 关键词： 掺铒光波导放大器 非均匀掺杂 增益特性 自适应算法     

阶跃掺杂Er∶Al2O3光波导放大器增益特性数值模拟

构建了纵向阶跃非均匀掺杂的掺铒Al2O3光波导放大器理论模型,利用有限元法、速率方程和传输方程,数值模拟了放大器的净增益特性.计算结果表明:阶跃掺杂掺铒Al2O3光波导放大器提高了抽运效率,净增益和信号光输出功率比优化后的均匀掺杂光波导放大器分别提高了9.2%和90.5%,长度却缩短了16.9%.     

阶跃掺杂Er∶Al_2O_3光波导放大器增益特性数值模拟

构建了纵向阶跃非均匀掺杂的掺铒Al2O3光波导放大器理论模型,利用有限元法、速率方程和传输方程,数值模拟了放大器的净增益特性·计算结果表明阶跃掺杂掺铒Al2O3光波导放大器提高了抽运效率,净增益和信号光输出功率比优化后的均匀掺杂光波导放大器分别提高了9.2%和90.5%,长度却缩短了16.9%.     

Modeling of graded index waveguide fabricated by ion exchange on Er3+ doped glass

A general numerical tool,based on thermal diffusion equation and full-vectorial eigen-mode equation,has been presented for the systematic analysis of graded index channel waveguide fabricated by ion exchange on Er3+ doped glass.Finite difference method with full-vectorial formulation(FV-FDM) is applied to solving the full-vectorial modes of graded index channel waveguide for the first time.The coupled difference equations based on magnetic fields in FV-FDM are derived from the Taylor series expansion and accurate formulation of boundary conditions.Hybrid nature of vectorial guided modes for both pump(980 nm) and signal light(1550 nm) are demonstrated by the simulation.Results show that the fabrication parameters of ion exchange,such as channel opening width and time ratio of second step to first step in ion exchange,have large influence on the properties of waveguide.By optimizing the fabrication parameters,maintenance of monomode for signal light and improvement of the gain dynamics can be achieved in Er3+ doped waveguide amplifier(EDWA) fabricated by ion exchange technique.This theoretical model is significant for the design and fabrication of EDWA with ion exchange technique.Furthermore,a single polarization EDWA,which operates at wavelength from 1528 nm to 1541 nm for HE polarization,is numerically designed.     

Numerical analysis of amplification characteristic of erbium-doped waveguide amplifiers by FD-BPM

An efficient analysis method for erbium-doped optical waveguide amplifiers (EDWA) is presented. By solving the rate equation, the propagation in EDWA is stimulated using the finite difference beam propagation method (FD-BPM). The dependence of the gain of EDWA is investigated on the waveguide length, erbium concentration, and signal and pump power. The analysis shows that considerable gain levels, 3.35 dB/cm can be achieved in 10 cm-long EDWA with an erbium concentration of 2.0 × 10²⁶ ions/m³, signal power 1 W and pump power 100 mW at 980 nm.     

Influence of multimode-pump propagation on the gain characteristics of erbium–ytterbium doped waveguide amplifier

Channel waveguides with channel opening widths (COWs) from 4.5 to 7.5 μm with increment of 0.5 μm have been fabricated by two-step ion exchange on the same erbium-ytterbium uniformly doped phosphate glass substrate of 4.3-cm length. Experimental results indicate that the gain for 1534-nm small signal light pumped at saturation is maximized and shows a 3.6-dB enhancement for these erbium-ytterbium doped waveguide amplifiers (EYDWAs). The intensity profile overlap between signal and multimode-pump light in waveguide leads to the improvement in the gain of EYDWA. This can be used to explain the experimental results and shows the general dependence of the gain characteristics on the modal behavior of EYDWA. The presence of higher order modes of pump light and the optimization of this intensity profile overlap are significant to improve the gain properties of EYDWA.     

Correct determination of net gain in Er-doped optical waveguide amplifier from pump-on/off measurement

Starting with evolution equation of signal optical power in an Er-doped channel waveguide, rigorous theoretical expressions used for correct determination of net gain from signal enhancement measured by using pump-on/off method are derived. These expressions allow to clarify the argument on relationships between net gain, internal gain and signal enhancement in some earlier literatures. Physical implications of net gain, internal gain and signal enhancement expressions are analyzed. Standardized definitions for the three physical quantities are proposed. The definition for net gain is proposed on the basis of practical application of an EDWA in optical fiber communication and the definitions for the latter two are suggested based on the physical implication analysis of their expressions.     

Simulation of IR Waveguide Amplifiers Using FDTD-Based Overlapping Integral-RK Method

A novel algorithm, calling FDTD-based overlapping integral-RK method, is proposed to analyze Er-Yb co-doped phosphate glass IR waveguide amplifiers. This new method is derived from the combination of Finite-Difference Time-Domain(FDTD), overlapping integral and RK method. First the normalized eigen-fields of signal and pump lights in Er-Yb co-doped phosphate glass waveguide are calculated by FDTD algorithm, and then the overlapping integrals between light fields and the distribution of Er³⁺(Yb³⁺) concentrations are obtained, finally the distributions of powers of signal and pump along waveguide are calculated by RK method. Gain performance of IR waveguide amplifiers is obtained from calculated signal power. Comparison of the simulation result with an experiment is given, it demonstrates that this new algorithm is valid and shows good agreement with experimental results.     

掺铒磷酸盐玻璃离子交换波导表面保护的研究

对离子交换波导制备过程中掺铒磷酸盐玻璃表面的侵蚀问题进行了研究,分析了产生侵蚀的原因,提出镀K9玻璃薄膜的方法,对掺铒磷酸盐玻璃表面进行保护.采用光学显微镜和原子力显微镜对波导表面特性进行了表征,同时对平板波导的光学特性进行了测试.研究表明K9玻璃薄膜不仅能够对掺铒磷酸盐玻璃起到保护作用,同时允许交换离子透过进入磷酸盐玻璃形成波导层.