高功率

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。

Strongpoints of microwave radiation for synthesis of veratraldehyde were short timeconsuming, high yied and complete reacting.The optimal condition was power 260W,time 5min.

微波辐射法制备藜芦醛反应时间短、收率高、反应完全；微波辐射的最佳条件为功率260 W，时间5 min。

Simulation experiments' data show that by using this methods it can precisely generate non Gaussian correlate random sequence with specified probability density and power spectrum,and reproduce verisimilarly the scatter coherent video signal of radar sea clutter containing both amplitude and phase.

其中迭代算法用来计算非线性变换过程中高斯序列相关性的变化，而随机向量法用来完成线性变换，仿真实验数据证明利用这种方法可精确地产生具有指定概率密度和功率谱的非高斯随机序列，逼真地复现既包含振幅又包含相位的雷达海杂波相干视频散射信号。

We gained 3.3W green laser when we pumped the system at 25W power while the temperature of Nd: YVO4 was controlled at 22℃, LBO was at 18℃, the efficiency of light-light reached 14.3%, and the conclusion nearly come to the same thing with the theory, this result is better than the need to gain 3W green laser of industrialization, and surpasses it 10 percentage.

使Nd∶YVO_4晶体的温度控制在22℃、LBO的温度控制在18℃，整个系统在泵浦光功率为25W的情况下，获得了3.3W的绿光输出，光-光转换效率为14.3％，实验结果与理论预期基本相符，比产业化项目的目标要求—绿光输出3W高出10个百分点。

The track places low demands on brakes and engines (only 61 percent of the lap is at full throttle), but a premium on aerodynamic efficiency and good handling balance.

他们中的一些已经完成了6000公里的练习，赛地对刹车和引擎的要求不高（一圈之中只有61%需要以全速行驶），但却对空气动力学的功率和控制平衡有额外的要求。

It has been received and upheld by the people. It involves a great deal content that is extensive and intricate. It bestrides subject of three aspects.

现代高频开关稳压电源作为电源的一个分支，由于它具有功率小，效率高，体积小，重量轻，稳压范围宽，可靠安全等一系列特点，现在正越来越受到青睐和推崇。

In the original system, there are many problems such as the communication distance between the tire module and the central monitoring module is too close, the eradiating power of the UHF transceiver is not enough, the error rate is too high and the data information is lost in high frequency and so on.

针对原有系统存在的轮胎检测模块和中央监视器模块之间的通信距离过短，信号的发射功率不足，误码率过高，数据信息频繁丢失等诸多问题，设计可行的解决方案。

Based on the expression of diffractive field distribution of the Gaussian beams restricted by a rectangular aperture and focalized by a lens,the relationship between the width of the rectangular aperture and the spot size of the restricted beam,as well as the relationship between the aperture width and the power in the bucket,was numerically calculated with MATLAB.

为了研究矩形光阑边长与透镜像方焦面处光束光斑尺寸以及光斑内所包含功率的关系，根据高斯光束经矩形光阑和透镜变换后在透镜像方焦面的衍射场分布表达式，采用MATLAB进行数值计算的方法，进行了理论分析。

For the heftier E 500, there's the CM50K full exhaust kit which includes racing headers, high-performance catalysts and stainless steel mufflers providing a 55 hp increase in power output.

对于更高é 500 ，还有CM50K充分排气套件，其中包括赛车头，高性能的催化剂和不锈钢消声器提供一个55马力的输出功率增加。

In the paper,Power Spectrum Density of Orthogonal Unified Binary Shift Keying is figured out.

推导了统一的正交二元偏移键控信号的功率谱密度表达式，去除了高次谐波，获得了基本波形的优化结果，提高了频谱效率。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。