Wideband Hybrid Fiber Amplifier Using Er‐Doped Fiber and Raman Medium

In this paper, we report the experimental results of a hybrid wideband fiber amplifier. The amplifying medium is a concatenated hybrid fiber consisting of Er‐doped fiber (EDF) and dispersion compensating fiber (DCF). The gain mechanisms are based on stimulated emission in the EDF and stimulated Raman scattering (SRS) in the DCF. Since we simultaneously use optical amplification by the two processes, the gain bandwidth is easily expanded over 105 nm by a two‐tone pumping scheme. Using an experimental setup constructed with a hybrid structure of EDF‐DCF‐EDF, we analyzed the spectral behavior of amplified spontaneous emission for pumping powers. We achieved an optical gain of over 20 dB in the wavelength range from 1,500 to 1,600 nm under optimized pumping conditions to make the spectral gain shape flat.     

5G系统中SRS对基于FWM参量放大器的影响

5G网络的运营,对光模块的功能和性能提出了更高的要求。本文基于光纤中的SRS效应和FWM效应,对基于FWM效应的参量放大器的增益性能做出改进,用龙格-库塔法数值模拟了SRS效应对光纤参量放大器增益性能的影响。分析得到:考虑SRS效应时,信号光增益谱更加平坦,最大增益可达44 dB,增益带宽达到了67 nm。     

Corn stover ethanol yield as affected by grain yield,Bt trait,and environment

Literature values for glucose release from corn stover are highly variable which would likely result in tremendous variability in bio-refinery ethanol yield from corn stover feedstock. A relatively recent change in United States corn genetics is the inclusion of the Bacillus thuringiensis (Bt) trait, which now accounts for three-fourths of all US planted corn acreage. The objective of this study was to evaluate the effect of corn grain yield, inclusion of the Bt trait, and location environment on corn stover quality for subsequent ethanol conversion. Two hybrid pairs (each having a Bt and non-Bt near-isoline) were analyzed giving a total of 4 hybrids. In 2010 and 2011, field plots were located in Michigan at four latitudinal differing locations in four replicated plots at each location. Stover composition and enzymatic digestibility was analyzed and estimated ethanol yield (g g⁻¹) was calculated based on hydrolyzable glucan and xylan levels. Analysis showed that there were no significant differences in total glucose or xylose levels nor in enzymatically hydrolyzable glucan and xylan concentrations between Bt corn stover and the non-Bt stover isolines. Regression analyses between corn grain yield (Mg ha⁻¹) and corn stover ethanol yield (g g⁻¹) showed an inverse relationship indicative of a photosynthate source-sink relationship. Nevertheless, the quantity of stover produced was found to be more critical than the quality of stover produced in maximizing potential stover ethanol yield on a land area basis.     

多波长泵浦宽带拉曼放大器功率增益的Lorentz近似研究

本文采用Lorentz线型近似,研究了多波长泵浦宽带Raman放大器的增益特性,并提出了宽带增益平坦的多波长泵浦方案。研究结果表明,增益平坦程度与泵浦波的频率间隔密切相关。对ITU－T的G．652、G．653及G．655光纤和新型的大有效面积非零色散平坦光纤的Raman放大增益特性研究表明,Raman增益与光纤的种类和光纤传输特性有关,特别是随光纤有效纤芯面积的增大而明显减小。     

氯化乙丙橡胶增容PVC/SBS共混体系的研究

以氯化乙丙橡胶(CEPDM)为相容剂,研究了SBS对PVC的共混增韧改性。结果表明CEPDM能明显改善SBS与PVC的相容性,使共混物中SBS颗粒尺寸明显减小,分布更均匀,共混物的t_g内移,常温和低温下缺口冲击强度增大。当PVC/SBS/CEPDM为80/20/6(质量比)时,共混物的常温缺口冲击强度为56.3kJ/m~2,低温(-20℃)缺口冲击强度为32.4kJ/m~2。     

简述安全报告系列第19号(SRS 19)修订版中筛选系数的变化

本文对安全报告系列第19号(SRS 19)及其修订版进行了介绍,阐述了修订的必要性,并归纳总结了SRS 19修订版中地表水排放、大气排放和污水管道系统排放这三种排放途径的筛选系数所发生的变化,为放射性物质排放造成的公众照射和环境影响进行前瞻性评估提供参考。     

窄脉冲泵浦的Raman放大研究

基于振幅耦合方程,引入入射处信号脉冲与泵浦脉冲的时间差,研究了光纤中单个信号脉冲与窄泵浦脉冲的作用。将泵浦脉冲取为双曲正割形式,得到交叠因子、信号光振幅、泵浦光振幅的解析解,及信号功率沿光纤的分布。研究了长光纤中信号脉冲与多个泵浦脉冲的作用,推导出考虑插损时的信号增益。     

多晶硅铸锭新工艺的研究

多晶硅定向凝固铸锭技术是多晶硅太阳能电池生产的关键技术之一。本文提出多晶硅铸锭新技术-（SRS）法,与传统工艺相比,SRS工艺提纯效果更明显,硅锭中间部分杂质含量更低,硅锭的少子寿命和电阻率更高且分布均匀,大大提高了硅料从硅锭到硅片的利用率。     

DWDM系统中受激拉曼效应的数值解

文章提出一种新的数值计算分析法,运用该计算方法得到了密集波分复用(DWDM)系统在衰减、色散走离和受激拉曼散射(SRS)效应耦合条件下的输出信号功率的数值解.并使用 MATLAB 软件进行了数值模拟仿真,通过数值计算绘出了在短距离传输条件下,不同输入光功率以及不同信道数时SRS效应对光通信系统性能的影响图.     

光子晶体光纤中四波混频光谱增益特性的研究

采用脉冲宽度为5 ps、峰值功率为5 W的可调谐钛宝石激光器泵浦长度为4.8 m,零色散点在810 nm的光子晶体光纤(PCF),观察到四波混频(FWM)3 dB的信号光增益,信号光和闲频光的间距为20 nm.通过调谐泵浦光的入射中心波长,研究了不同泵浦波长对FWM信号增益的影响,并与理论结果进行了对比,结果表明了很好的一致性.