Finite element method ( fem ) is a method that is efficient in electromagnetics . for the first time the thesis applied vectorial fem to single mode performance and half - wave voltage analysis and design 有限元法被广泛应用于电磁场的研究中。本论文首次采用了矢量有限元方法来研究质子交换铌酸锂光波导的单模特性和半波电压。
For coupling loss , the method to reduce this loss is pointed out without changing other structural parameters decided by the above requirements . y - branch loss is analyzed by bpm ( beam propagation method ) 对于耦合损耗，指出了在不改变前面结构参数(因为它们的设计是根据半波电压和单模要求设定的)情况下，实现小耦合损耗的方法。
In order to realize low half - wave voltage , high polarzation extinction ratio , low pigtailing polarization crosstalk , low insert loss , precise tapped power ( ratio ) and good splitting beam ratio , the optimum design was performed 为了实现低的半波电压、高的偏振消光比、低尾纤串音、低插入损耗、精确的抽头功率比和良好的分束比,我们对器件结构进行了优化设计。
Meanwhile , we discuss the static electric field distribution in anisotropic materials caused by the applied voltage on the electrodes , which will help to decrease the driving voltage . finally , the device was fabricated during the course of this research 文章同时还利用fd - bpm法初步分析了各项异性材料中的电场的静态分布，为提高电场与光场的耦合因子，减小半波电压奠定基础。
Because of the limitation of the measuring condition , in the thesis we had only measured some characteristics of the phase modulator : channel waveguides " loss coefficient is 0 . 22db / cm , the split - ratio is 52 / 48 and half - wave voltage is < 5v 由于条件所限，论文中仅测量了直波导损耗系数、相位调制器的半波电压和输出分束比。经测量，半波电压小于5v ，直波导损耗系数为0 . 22db cm ，输出分支比为52 48 。
Except the simple and usual filter and algorithm , some advanced filter ways such as frequency sampling filter , karlman filter and several new algorithms such as cosine algorithm , semiwave fourier algorithm and wavelet transform algorithm are also studied 除简单、常见的滤波和算法外，本章还探讨了一些性能先进的滤波方法如频率抽样滤波、卡尔漫滤波和几种微机保护新算法如余弦算法、半波傅氏算法以及小波变换算法等。
This thesis performs the research how to analyze and design lithium niobate optical modulator in i - fog . the analysis concentrates on those performance parameters of a modulator : half - wave voltage , single mode performance , quasi te / tm polarization , loss , bandwidth and split - ratio 这些都是围绕调制器的性能参数来研究的，它们包括：半波电压，单模特性，偏振特性( te和tm模之间的输出功率比值) ，损耗，带宽及分支比等。
After analyse several protection algorithms , this paper adopt a new fast algorithms which is developed from half wave fourieri algorithms and mann - morrison algorithms , and which ensure the reliability and real time of the comprehensive motor protection system 在对多种采样算法进行了深入研究的基础上,采用了半波傅氏算法与mann - morrison算法相结合的一种新型快速算法,这就保证了整个电机综合保护系统在运行中的实时性和可靠性。
All the films were found exhibiting strong ( 001 ) and ( 002 ) plane reflection of xrd analysis , and the film with the k + / nb5 + molar ration of 2 / 3 ( k2 / 3sbn60 afterwards ) showed the strongest intensity of ( 001 ) plane reflection . the film surface was uniform and smooth 同时，测量mgo衬底上的sbn薄膜和掺k的sbn薄膜的几l系数分别为37 . 6pm / f和58 . 5pm / v ，掺k的sbn60薄膜制成的波导，其半波调制电压明显要比不掺k的波导半波调制电压低。
The relationships between extinction - ration , half - wave voltage and electrode structure have been analyzed with transfer matrix theory and effective index method . the following conclusions have been made : 1 ) . the electrode width can be optimized to get the lowest half - wave voltage of boa - type optical switch 我们设计的集总电极型boa光开关理论3db调制带宽大于2 . 5ghz ，半波电压为5v ，消光比大于40db ，对tm模的理论衰减大于45db ，而对te模的损耗小于0 . 15db 。
