新型低损耗1×3光分路器的优化设计

针对传统Y分支光分路器损耗较大的缺陷,采用直锥形波导代替传统的直波导来减小器件的尺寸,并且采用激模波导结构设计1×3分支波导.设计中,利用辐射模和本征基模的叠加来修正光波场,通过改善模匹配来降低分支耦合损耗,并通过对对称输出弯曲分支波导的优化来降低弯曲损耗,最后在1×3光分路器中的两弯曲波导的输入端加入过渡锥形波导来降低损耗和优化分路器的输出均匀性,并用有限差分光束传播法对该1×3分支波导进行数值模拟.模拟结果表明,该结构具有均匀性好、器件尺寸小、损耗小和结构简单等优点,有利于器件的进一步集成.     

基于3×3耦合器的光纤陀螺信号解调算法

采用3×3耦合器构成非互易结构的开环光纤陀螺，具有灵敏度高、测量范围大等优点。信号检测在光纤陀螺系统中占有非常重要的地位，其解调精度的大小直接影响光纤陀螺的分辨率。根据使用3×3耦合器的开环光纤陀螺输出信号模型的特点，采用一种新的信号解调算法，可以准确解调任意动态范围的输入，克服在工作点附近灵敏度低的缺点，改善被测信号的精度。实验结果表明，算法能快速、准确解调被测物理量。     

光纤干涉信号的3×3耦合器解调及偏振衰落分析

建立了基于3×3耦合器的光纤Mach-Zehnder（MZ）干涉型传感系统。在对3×3耦合器信号解调方案进行了推导和分析后,对干涉信号中偏振衰落现象进行了理论分析和实验研究,并指出了它对3×3耦合器信号解调方案的影响。针对偏振衰落现象的特点,提出了消除这一问题的方案,实现了干涉仪信号的无偏振衰落输出。     

TMS320C3×DSP的软件开发调测及程序优化

文章描述了ＴＭＳ３２０Ｃ３×系列ＤＳＰ的软件开发与调试环境及开发过程,分析了用Ｃ语言和汇编语言编程的优缺点及应用场合,介绍了一些编程技巧,以实现ＴＭＳ３２０Ｃ３×高效编程。     

TMS320C3×浮点DSP的高效编程

文章分析了TMS320C3×采用C语言编程的优缺点及基适用场合，介绍了它的分支、寄存器和存储器三种流水线冲突类型及其避免的方法以及代码和数据的存储器存放原则。提供了一些经并行阵列运行证明其极为有效有高效编码技巧。     

LiNbO3 1×2非对称电极Y分叉数字光开关的研究

文章提出一种关于非对称电极低串扰数字光开关的新型设计方案，在Y分叉后端引入S弯曲波导，通过在Y分叉处的非对称电极和弯曲波导的弯曲电极处施加一定的同步电压，实现了比没有S弯曲的开关更低的串扰。此种设计采用有限差分光束传播方法（FDBPM）来分析，模拟结果显示，在光波长为1．55μm时，开关电压8V．串扰〈-25dB。     

基于光子晶体1×3谐振腔滤波器的研究

考虑到滤波器输入波导中入射电磁波和反射电磁波的相位差,通过CMT理论分析了不同设计情况下的工作性能,然后优化设计了光子晶体1×3谐振腔滤波器结构.用FDTD方法研究了滤波器工作特性,改变1×3谐振腔下侧调谐柱位置得到滤波器结构的96个不同通带峰值波长平均正规化传输率为89.6%,相邻峰值波长平均间隔为1.25nm、平均传输带宽为1.19nm、谐振腔平均品质因数为1350.2、提取的峰值波长调谐范围在1534.04～1653.16nm.结果表明:该滤波器具有正规化传输率高、带宽窄、波长信号提取强度平稳等特性.其结构在密集型波分解复用(DWDDM)系统设计、光信号传感器件设计、密集型光路集成化设计等领域具有潜在的应用价值.     

Dissymmetrical 3×3 Coupled Optical Accelerometer

Without adding feedback to modulate light path system, the dissymmetrical 3 × 3 coupled optical accelerometer reduces the complexity of the design of light path system. Experiments prove that it can attain good demodulation effects. As carrier is not needed in this system, the frequency range of input signal is diminished so as to decrease the sampling frequency of accelerometer. This makes for the system on programmable chip（SOPC） design of digital demodulating system. The upper limit of accelerometer working frequency can reach 3 500 Hz. But affected by the inherent frequency of sensitive components, its working frequency is 10 Hz-1 000 Hz, and the sensitivity is 8. 718 0 V/（m @ s^-2）. This accelerometer can detect the dynamic range of acceleration signal real-timely, steadily and accurately, solving the dissymmetrical problem of light path caused by circumstances and the complexity of process.     

声光可调谐滤波器中波导与模分离器的设计

声光可调谐滤波器（AOTF）是一种基于集成光学技术的光学器件,它的性能主要取决于它的各个关键模块,特别是光波导和模分离器的设计．首先采用有效折射率法设计了工作于1．55um处的Ti：LiNbO3单模波导,之后对所设计波导的模场进行了模拟,并对模拟结果进行了分析．在单模光波导设计的基础上,采用光束传播方法（BPM）设计了TE／TM模分离器,并分析了它的消光比．最终得出波导和模分离器的优化设计结果．     

自由空间与偏振无关的1×N和N×1光开关设计

基于光开关在全光通信和光互连网络中的重要作用，设计了由偏振光分束器（PBS）、相位型空间光调制器（PSLM）和反射镜构成的1×N和N×1光开关模块，其中N＝2m，m＝1，2，3…。该设计利用PSLM对信号光偏振态的控制，在自由空间实现信号的路由和切换，信号光的P光分量和S光分量同时参与工作，并在输出端口重新会合，因此光开关表现出与信号光偏振态无关的特点。同时，该光开关所用器件少，具有结构简单紧凑、控制方便灵活和操作迅速快捷等特点，而且具有很强的重构与升级能力，对于构建大规模的交换矩阵具有一定的作用。     

基于双面反射镜的N×N光开关的特性分析和实验研究

报道了基于双面反射镜的N×N光开关器件。介绍了使用双面反射镜的2×2，4×4光开关的集成光路设计和工作原理；采用Benes网络，以2×2和4×4光开关为基本单元的N×N光开关器件的整体结构，并根据“一笔画”原理，分析了4×4，8×8和16×16光开关矩阵的可重排无阻塞特性和光开关矩阵的光路选择算法。最后，基于2×2，4×4光开关技术制备了16×16光开关矩阵。测试表明，该器件具有良好的插入损耗、回波损耗、串扰和开关时间等性能，从而验证了设计思想和工艺的可行性。在基于双面反射镜的光开关矩阵中，双面反射镜的使用大大减少了光开关矩阵中运动镜片的数量，简化了控制程序，并有利于提升光开关器件的可靠性能，有望在中小型光交换机、网络管理和光路测量中获得应用。     

基于33耦合器相位解调的光纤声音传感器设计

为了在某些应急情况下无源传输声音信号,采用基于光纤迈克尔逊干涉仪原理光纤声音传感的方法结合了收音弹性盘片和光纤粘接的工艺设计,使用33耦合器相位解调方法对传感信号进行相位解调,实现了一种新型光纤声音传感器系统。给出了干涉仪3路输出信号相位差的表达式,利用最小二乘法拟合求出干涉仪3路输出信号的平均相位差,取得了仿真与实际测试数据。经过测试,该系统可以准确有效地还原出设计带宽内的声音信号。结果表明,该光纤声音传感器系统适用于电磁恶劣等应急环境中,验证了该设计方案的可行性。     

1-3型压电复合材料设计分析

1-3复合材料作为敏感元件已经被广为研究,但作为一种激励元件的研究极为有限。利用有限元原理研究一种1-3型压电复合材料。这种材料中,PZT-5H压电陶瓷作为单元支梁,聚合物作为这种压电陶瓷周围的填充基体。通过改变PZT-5H在这种材料中的体积比率,再经过谐响应分析,可以得到一种具有最高的机电耦合特性的结构。为了简化有限元建模的复杂程度和缩短计算时间,将这种1-3型复合材料等价为单一相的材料,并加以验证。这种新型的1-3型压电复合材料作为前沿技术可以用在半导体封装领域键合机的换能器上。     

Optical properties of CdS<Subscript>0.2</Subscript>Se<Subscript>0.8</Subscript>:V

We report here a comparison between two methods for calculating the index of refraction of the CdS_xSe_1−x alloy system and a calculation of the phase-matching angles for second harmonic generation for this system. Analytical expressions for the index and the birefringence of all x values are presented. The low-temperature photoluminescence spectrum has been measured and reveals a native defect at 1.45 eV and a peak at 1.8 eV caused by the vanadium dopant, as well as an exciton peak at 2.24 eV. The transmission spectrum displays three peaks due to the vanadium dopant at 0.979 eV, 1.087 eV, and 1.181 eV. The birefringence has been measured for x = 0.2 from 1 μm to 14 μm and varies from 0.0185 to 0.0125.     

Optical properties of CdSe<Subscript>x</Subscript>Te<Subscript>1−x</Subscript> epitaxial films studied by spectroscopic ellipsometry

We have determined the dielectric constants for a series of CdSe_xTe_1−x thin films grown on Si substrates using a rotating-analyzer spectroscopic ellipsometer. Initially, the alloy concentration and the sample quality were determined using x-ray diffraction. A standard inversion technique was then used to obtain the dielectric constants from the measured ellipsometric spectra. Using these calculated absorption spectra, we were able to estimate the fundamental bandgap for these CdSe_xTe_1−x alloys. In addition, we also determined the dispersion of the indices of refraction as well as the critical points related to the higher-order electronic transitions for this alloy.     

A Novel Room‐Temperature Multiferroic System of Hexagonal Lu1−xInxFeO3

In the present work, h‐RFeO₃ multiferroic ceramics are designed and created by introducing chemical pressure (In‐substitution for Lu) in LuFeO₃. Lu_1?xIn_xFeO₃ (x = 0‐0.75) ceramics are prepared by the standard solid‐state reaction process. The crystal structure of the present ceramics is tuned from centrosymmetric Pbnm (x = 0) to non‐centrosymmetric P6₃cm (x = 0.4–0.6), and subsequently to centrosymmetric P6₃/mmc (x = 0.75), while the Pbnm and P6₃cm biphase structure is detected for x = 0.25. The Curie temperature for the polar P6₃cm (x = 0.4–0.6) phase decreases from >1000 to ≈550 K with increasing x. Cloverleaf ferroelectric domain structures are determined in polar Lu_0.5In_0.5FeO₃ samples, and the ferroelectric domain walls at atomic scale are evaluated by the aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy (HAADF STEM), where the spontaneous polarization of 1.73 µC cm^?2 is determined for x = 0.5. The spontaneous polarization is also confirmed by calculating the site displacement from the centrosymmetric phase based on the X‐ray diffraction (XRD) data. Meanwhile, two magnetic transitions are determined for all compositions, that is, paramagnetic to antiferromagnetic transition at Néel temperature T_N (≈350 K for x = 0.4–0.6), and antiferromagnetic to weak‐ferromagnetic transition at spin‐reorientation temperature T_SR. The co‐presence of ferroelectric and antiferromagnetic orders confirms the present ceramics as promising room‐temperature multiferroic materials.