以...为目标

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。

The classification, mixing mode and the structure of core-sheath filament/staple composite yarns were illuminated. An analysis of the migration mechanism of fibers and the unreeled conditions of rigid, flexible and elastic filaments was made, and the spinning parameters were analyzed and optimized. Then, the process technology of spinning core-sheath filament/staple composite yarns on the ring spinning frame using rigid, flexible and elastic filaments was put forward.

先回顾短纤／长丝复合纱的分类、组合方式及其结构，进而分析刚性长丝、柔性长丝、弹性长丝的退绕条件、纤维转移机制，优化了复合成纱的工艺参数，提出以制备芯鞘型刚性长丝包芯纱、柔性长丝包芯纱、弹性长丝包芯纱为目标的复合纺纱工艺技术和纺纱工艺参数。

Members boot any doubts as to not miss the target and immediately issued instructions to open packages.

开机员以不放过任何疑点为目标，立即下达开包指令。

All efforts should aim at preserving the utmost goal of freeing humanity from the scourge of hunger, he stressed.

所有的努力都应以将人类从饥饿的苦难中解救出来为目标，他强调说。

In this paper, based on the research about main technological parameters in abrading, the optimization in theory and the optimization in orthogonal experiments are done in order to achieve maximum productivity, and results with a certain reference value are obtained.

本文在对研磨加工主要工艺参数研究的基础上，以最大生产率为目标，对工艺参数进行了理论优化和正交实验优化，获得了具有一定参考价值的结果。

In this paper , based on the research about main tecimological parameters in abrading , the optimization in theory and the optimization in orthogonal experiments are done in order to achieve maximum productivity, and results with a certain reference value are obtained.

本文在对研磨加工主要工艺参数研究的基础上，以最大生产率为目标，对工艺参数进行了理论优化和正交实验优化，获得了具有一定参考价值的结果。

Our company has always adhered to the market demand as the goal.

我们公司始终坚持以市场需求为目标。

Between the edge of CYCAN itself and the geographical advantage of pilot universities, we will start a series of coordinated initiatives on climate change in order to strengthen the youth momentum in dealing with the issue and promote the influence of CYCAN, thus attainting the goal of raising public awareness of energy-saving, emission reduction and climate change.

结合CYCAN自身和试点高校的地理优势，开展一系列有关气候变化倡导型联动项目，以提升公众节能减排和气候变化意识为目标，不断提升青年应对气候变化的行动力和CYCAN的影响力。

The objective of processing technology for cambered cam isothermal extrusion forming is net-shape and near-net shape. Using MSC.

弧面凸轮等温挤压成形是以净成形和近净成形为目标的加工技术。

On one hand, it was a new drama about spoiled teens cavorting around New York, potentially just another slapped-together program aimed at American youth.

一方面，它是一部关于活跃在纽约的被宠坏青少年的新剧情剧，也许只是另外一部草草拍摄的以美国青少年为目标的节目。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。