查询词典 reflection grating

This paper analyzes the optical characteristics of fiber grating according to the theory of mode-coupling in nonsymmetrical optical wave-guide, which affords the gist for the testing of optical characteristics and tuning characteristics of fiber grating. Moreover, we deduce the linear relationship between reflected wavelength shift of fiber grating and vertical displacement of cantilever beam which the fiber grating is sticked on.

论文根据非均匀光波导中的模式耦合理论，分析讨论了光纤光栅的光学特征，为光纤光栅的光学特性和调谐特性的测试提供理论依据；并根据材料力学原理推导了光纤光栅波长漂移量与侧向位移的线性调谐关系。

The wavelength resolution of the sensing measurement is 0.05nm. A novel FBG Bourdon tube sensor has been constructed, utilizing the pressure mechanic amplify function of Bourdon tube. The measured pressure sensitivity is two orders of magnitude higher than a simple monomode fiber with an in-fiber grating. Especially the pressure sensitivity of the sensor can be determined by changing the parameters of the cantilever beam. Adopting polymer package technique, we coat fiber Bragg grating by using polymer with different mechanic properties. Due to the driving effect of the polymer substrate, the enhanced pressure sensitivity is more than 20 times and 31. 7 times than that of a bare fiber grating. The packaged grating exhibits no significant chirp due to the adoption of special packaging technique.

全部采用国产元器件，成功地研制了掺铒光纤超荧光宽带光源，并将其组装成仪器；设计了利用可调谐FBG滤波器对光纤光栅传感信号进行检测的实验方案，对这一传感检测方案进行了理论分析和实验研究，由于采用了高性能的光电测量系统，传感测量的波长分辨率可达2pm，对应的应变分辨率为1.7με，在此基础上对FBG的波分复用传感特性进行了研究；对比调谐滤波检测技术，对光纤光栅可调谐光源波长检测技术进行了理论分析；采用长周期光纤光栅作为边带滤波器，对光纤布拉格光栅的传感信息进行解调，设计了一种全光纤传感测试系统，其波长分辨率可达0.05nm。

By adjusting the positions and angles of the two DVD optical pick-up heads, the relative distance of the two laser spots can be equivalent to one quarter of the grating pitch. When the grating moves, the surface profile of the grating can be measure directly, in order to obtain the two quadrature sinusoidal signals. Then by counting the zero crossing of these two quadrature sinusoidal signals and calculating the interpolation value of these two quadrature sinusoidal signals, the moving direction and moving displacement value of the grating can be obtained.

采用两个光学读取头，且两个光学读取头共用同一分光镜与同一聚焦物镜，於搭配光路的设计，可使两个光学读取头之光束打入同一聚焦物镜，藉由调整两个DVD光学读取头的位置与角度，使聚焦物镜聚焦的两相近聚焦光点的距离相等於四分之ㄧ光栅尺间距，当光栅尺移动时，可直接量测光栅尺的表面轮廓变化，以获得一组正交的弦波讯号，继而利用讯号四分割与细分割处理，计算出光栅尺之移动方向与移动量。

The variations of the performance of the fiber Bragg grating Fabry-Perot etalon with the length of the cavity and the reflection coefficient of fiber Bragg grating have been discussed, according to the theory of fiber Bragg grating Fabry-Perot etalon.

并利用光纤光栅法布里-珀罗标准具理论，分析了光纤光栅标准具随腔长变化的性质、光纤光栅标准具随光栅反射率变化的性质。

Finally, We analyze and experimentally demonstrate that both the bandwidth of the fiber Bragg grating's short wavelength loss and the bandwidth of fiber Bragg grating's reflection increase with the increase of strain gradient along the length of grating.

最后，我们对光纤光栅的反射和短波损耗的应变特性作了理论分析和实验测试，发现在光纤光栅的反射带宽随光栅轴向应变梯度的增加而增加的同时，光栅短波损耗带宽也随光栅轴向应变梯度的增加而增加。

Fiber Bragg grating is a fiber2op tic wavelength modulation device. Using fiber Bragg grating reflection of a certain wavelength which was affected by the parameters of the outside world because of the sensitive effect, a fiber grating sensorwas developed.

光纤Bragg光栅是一种波长调制型光纤器件，利用光纤Bragg光栅反射波长对某外界参量的敏感效应，可以研制出光纤光栅传感器。

The mode field of photonic crystal fiber structured with hexagon symmetry hole cladding was analyzed by coupled-mode, and the effective indexes of base mode of different wave length were got. The characteristics of this photonic crystal fiber grating were computed and simulated by coupled-mode method and transmission matrix method. Moreover, the differences were compared between conventional fiber grating and photonic crystal fiber grating on their reflection spectrum and delay.

利用多极法对包层空气孔为正六边形对称结构光子晶体光纤的模式场进行了分析，计算出不同波长下基模的有效折射率，结合使用模式耦合理论和传输矩阵法对基于光子晶体光纤的布拉格光栅特性进行了计算和仿真，对比了常规单模光纤所成光栅与相同光栅周期的光子晶体光纤布拉格光栅反射谱及时延特性之间的差异。

The strain gradient, the fiber Bragg grating's reflection and the short wavelength loss decide the two stopbands. Because of having no extra loss result from coupler and no high cost result from circuitor, the band pass filter formed by single chirped fiber grating have many good characters such as little insert loss its insert loss is the fiber splice loss, small volume, low cost and excellent property, moreover there is no report about fabricating filter by using this method, thus we will apply national invent paten about the method of fabrication fiber band pass filter using single chirped fiber grating. According to the parameters linearly chirped fiber gratings of Canada BRAGG Photonics Inc.

由于没有耦合器带来的3dB的额外损耗，也没有环行器带来的高的制作成本，用单支chirped光纤光栅形成可调光纤带通滤波器具有插入损耗极小（插入损耗为光纤与光纤之间的融接损耗）、体积小、制作成本低廉并且性能优良等特点，而且国内外还未见类似制作方法的报道，我们对用单支chirped光纤光栅形成可调光纤带通滤波器这一制作方法正在申请国家发明专利。

First, the effects of magnetic RAM relaxation time and the rise-time of incident pulse signal on reflection signal are discussed, the relationship between the rise-time of incident pulse and relaxation time based on the energy of reflection signal is revealed. Then, the effects of magnetic hysteric, susceptibilities and saturation upon reflection signal are analyzed, the results reveal the reflection of RAM target and UWB signal design. In the meantime, dielectric relaxation time effect about dielectric RAM target is analyzed simply, and the effects of relaxation time and the width of incident pulse upon reflection signal are probed. Finally, a few RAM targets are measured in the chamber using the impulse radar experiment system which is developed by the team of anti-stealth impulse radar on Department of Electrical Engineering, National University of Defense Technology. The experimental results show the similarity of the rule of echos with the theory. From the compared results of different tagets, we concluded, compared with 15% wideband sinusoidal signal, the impulse signal has increased 10～12dB energy from the same loaded RAM target; this, in turn, shows the nonlinear effects of RAM to the echoes, and the potentiality of the impulse signal to RAM targets.

首先分析了磁性RAM的弛豫时间及入射脉冲信号的上升时间对反射信号的影响，从反射信号能量角度出发，给出了入射脉冲上升时间与弛豫时间的关系；接着分析了磁性RAM的磁滞特性、磁化率及磁化强度对反射信号的影响，给出了RAM目标辐射和有关UWB信号设计的一般性结论；其次，对介电RAM的弛豫时间效应作了简单的分析，探讨了介电弛豫时间及入射脉冲宽度对反射信号的影响；最后利用国防科技大学电子技术系&反隐身冲激雷达技术研究组&研制的冲激雷达实验系统，在微波暗室中对几种不同的RAM目标进行了测量，结果表明：其反射波形的基本规律与上述理论分析相一致；从各种不同目标回波的能量对比结果得出，涂覆RAM目标对冲激信号的吸收比15％带宽的正弦信号要小10～12dB，证实了RAM的非线性效应对回波的影响，也证实了冲激信号反隐身的潜力。

A reflection type diffraction grating according to the present invention has a structure in which a metal film as a first layer with reflectance not lower than 30 % with respect to the wavelength of incident light and a transparent dielectric film as a second layer are laminated successively on the surface of the reflection type diffraction grating.

本发明的反射型衍射光栅的结构以金属膜为第一层，相对于入射光波长，具有不低于30％的反射率，以透明绝缘膜为第二层，所述第一和第二层依次被层叠在所述反射型衍射光栅的基底表面上。

A backer of an Afghan law that critics say legalizes marital rape has rejected the international outcry as foreign meddling.

饱受批评的一项法律的拥护者说合法化的婚内暴力不会受国际舆论的干涉。

Years ago, a ancient Egyptian fleet went to the Land of punt for seeking a kind of flavor named "myrrh", and aromatic plants which has dense exotic style for the queen Hatshepsut.

3500年前的一个古埃及的舰队到&彭特之地&寻找一种叫没药的香料。