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With the support of a major research grant of Zhejiang Province (No. 001101027) and the Plan of Promoting Education of Excellence of Zhejiang University in the 21st Century, this dissertation is devoted to address the above problems and fabricate an L-band EDFA with low cost, high performance and technological innovation.First the mechanism of an erbium doped fiber amplifier is introduced. Various theoretical models based on classical rate propagation equations are summarized and compared for their applications. We use a modified numerical model based on the Giles model, which agrees with the experimental results well. This serves as the theoretical base for the whole thesis and will be used to optimize the characteristics of EDFAs. A novel method based on a map of noise figure and gain is proposed to analyze efficiently the dependence of the noise figure and gain for EDFAs on the EDF length and the pump power. The characteristics of various EDFAs are studied and compared.Secondly, some important parameters are introduced to describe the characteristics of EDFAs. The methods and the experimental setups for measuring the gain and noise figure of an EDFA are emphasized. We introduce how to measure the characteristics of each component of an EDFA, especially the gain and absorption coefficient of an erbium doped fiber.Thirdly, four types of simple and novel L-band EDFA structures with low noise, high gain and low gain ripple are proposed to satisfy the requirement of a DWDM system. They can be classified into two categories. In the first category, a single ASE pumping is served asa secondary pump. This category includes the following three types. Type: a new construction using a fiber Bragg grating in an unpumped EDF section at the input side. Type: a new structure of L-Band EDFA with two-stage pumps, which utilizes the forward ASE as a second pump.

本论文本着科技创新、服务于生产实践的精神，以设计价格低廉，性能优越、结构合理简单的L-band EDFA为目标，依托浙江省科技厅重大科学基金资助项目(001101027)和浙江大学振兴教育计划资助的全光网络的搭建—《光通信技术》课程实验建设项目，展开了如下工作：首先，介绍了掺铒光纤放大器的工作原理，归纳总结了基于速率方程基础的EDFA的各种理论模型，分析比较了各个模型的特点和适用场合，最终选择完善的Giles理论模型作为本论文分析设计EDFA的理论基础；针对实际实验条件提出了修正的EDFA模型的数值计算方法；创新地提出了增益—噪声系数全局分析法，直观有效地分析了EDFA的增益和噪声系数与掺铒光纤长度和泵浦功率的依赖关系，并对各种EDFA的性能作了全面的比较；第二，介绍了掺铒光纤放大器特性参数的定义与测量方法，重点介绍了噪声系数和增益系数的测量方法及实验装置；介绍了组成掺铒光纤放大器各组件的特性测量方法，重点介绍了测量掺铒光纤参数的方法和实验装置；第三，针对WDM系统对L-band EDFA谱平坦、低噪声、高增益的要求，我们创新地提出了四种不同的L-band EDFA结构，按设计思路可以分为两大类：一类是基于单抽运二级泵浦法，这一类包括在未泵浦掺铒光纤的输入端插入一根布拉格光纤光栅的两段L-band的EDFA的新结构；基于前向ASE光作为二级泵浦源推动下一级EDF工作的泵浦分配、两段级联L-band的EDFA的新结构；基于单根光纤光栅、泵浦分配、两段级联的EDFA；另一类则是基于同时应用前后向C-band ASE作二级泵浦源的双抽运法，如基于前后向ASE光作为二级泵浦源的三段级联L-band的EDFA的新结构。

Results 37 nurses(31.88%of the total)wone in the state of higher tensity;100 nurses are in the upper limit of normal state,and only one is in the normal state.Conclusions On the base of these,the author pointed out that intervention to psychological behavior should be done to the nurses in the emergency department.

对急诊科护士急需进行心理行为干预：在分析结果基础上，作者提出以下对策：(1)重视自我护理意识，正确对待工作压力，掌握适合自己的放松技巧；(2)创造良好的内外环境，帮助护士建立工作的最佳心身状态；(3)帮助护士掌握护患心理沟通技巧；(4)重视人才选择，加强业务培训。

The wife will get more probabilies to quit her job if both sides of husband and wife have long worktime.

当夫妻双方的工作时间都很长的情况下，女方辞去工作的可能性更大。

Right to engage in foreign trade...外派 send somebody to units or organizations in other areas or to a...foreign country

指由原先任职的组织单位或国家地区，外派至另一个组单位或国家地区从事特定工作的人员，在完成某一段期间的工作任务后，。。。

Export sales staff...外派 send somebody to units or organizations in other areas or to a foreign country ...外企 foreign company

指由原先任职的组织单位或国家地区，外派至另一个组单位或国家地区从事特定工作的人员，在完成某一段期间的工作任务后，。。。

The alchemists who worked in these apothecaries suffered a considerable risk to their health, working so invariably close to poisonous substances.

在药店里工作的炼金术士还要面对极大的健康风险，因为他们的工作地点总是有有毒物质。

Workers will not assist in codifying their tacit knowledge about doing their job if they feel it will jeopardize their employment.

如果工人感到文档化有关如何完成他们的工作的背景知识将危害他们的工作位置，那么，他们不会帮助这样做。

A thick crust, coarse-grained as limestone rough-cast, hardened gradually on top of the four crocks that stood, large pottery bombs, in the small pantry.

我是一个刚开始工作的年轻人，《你在为谁而工作》这本书给了我很多的启示，从中我学到了许多对我一生都有益的东西。

Computerizing the management of package freights and selecting freights for the loading of hazardous goods can take full advantage of static load and load capacity of freight cars and raise efficiency on the basis of safe transportation.

用计算机实现对普通零担货物配装工作的管理，可在保证货物安全运输的基础上，充分利用车辆的容积和载重，提高工作效率。

I spent as much time in goading myself on to duties that I should have liked to shirk or in getting ready to work as I did in actual labor.

对于我想逃避或者应该准备的工作，我会磨蹭半天，磨蹭的时间和工作的时间一样多。

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候，里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色，卵在发育96h后卵基本全部孵化。