基于InP/空气隙分布布拉格反射镜的微机械可调谐光滤波器

采用表面微机械技术制作了一种1 310 nm基于InP/空气隙分布布拉格反射镜的微机械可调谐Fabry-Perot光滤波器.该滤波器的通光孔直径约为70 μm,在1.4 V的调谐电压下,调谐范围达到15 nm.并采用光学传输矩阵方法,分析了斜入射对这种可调谐光滤波器透射谱的峰值半高宽的影响.     

地市级农信业务网络系统安全解决方案

信息加密的目的是保护网内的数据、文件、口令和控制信息不被窃取,保护网上传输的数据不被窃取和修改。网络加密常用的方法有链路加密和端到端加密。链路加密的目的是保护网络节点之间的链路信息安全;端     

Experimental optimization of an erbium-doped super-fluorescent fiber source for fiber optic gyroscopes

Double-pass forward and double-pass backward erbium-doped super-fluorescent fiber sources(EDSFSs) were combined in one configuration.A 980 nm laser diode pumped the same erbium-doped fiber from both directions using a coupler as a power splitter.The double-pass configuration was achieved by coating the fiber end face.Firstly,an optimal fiber length was found to obtain a high stability of output light wavelength with pump power, and then 1530/1550 nm wavelength division multiplexing was used for spectrum planarization,which expanded the bandwidth to more than 22 nm.The final step was a test of temperature stability.The results show that the rate of the central wavelength change kept to below 3.5 ppm/℃in the range of -40 to 60℃and 1-2 ppm/℃in the range of 20-30℃.Considering all the three factors of the fiber optic gyro applications,we selected 80 mA as the pump current,in which case the central wavelength temperature instability was calculated as 2.70 ppm/℃, 3 dB bandwidth 22.85 nm,spectral flatness 0.2 dB,output power 5.17 mW and power efficiency up to 9.92%.This experimental result has a significant reference value to the selection of devices and proper design of ED-SFSs for the application of high-precision fiber optic gyroscopes.     

FSO中多路语音数据复接的设计及实现

为了研究数据复接和分接,设计采用基于自由空间光通信系统的多路语音数据复接实现方案.该方案充分发挥了自由空间光通信技术的优势,利用现场可编程技术,结合了电话线传输系统,其中现场可编程门阵列控制模块由Verilog语言完成,且利用QUARTUSⅡ软件进行了仿真,达到提高信道利用率、扩大传输容量的结果.结果表明,该系统可传输...     

A nonlinear optical loop mirror-based linear cavity swit- chable multi-wavelength erbium-doped fiber laser

A nonlinear optical loop mirror (NOLM)-based linear cavity switchable multi-wavelength erbium-doped fiber (EDF) laser is proposed and experimentally demonstrated. Due to the characteristics of the intensity-dependent transmissivity, the NOLM can effectively mitigate the mode competition of the homogenous broadening gain medium, so that the multi-wavelength lasing can be achieved at room temperature. By adjusting the states of the polarization controllers (PCs), the number of the lasing wavelengths in the proposed laser can be adjusted flexibly from 11 to 13 with a wavelength spacing of 0.4 nm around the wavelength of 1 530 nm.     

两种介质柱构成复式正方晶格的完全光子带隙

由一个正方介质柱和两个圆介质柱构造一个二维正方复式晶格的光子晶体.应用平面波展开的方法研究了光波在其中的传播规律.通过调节介质柱几何尺寸和介电常数,该结构产生了完全光子带隙.     

Si掺杂的AlGaInP/GaInP多量子阱光学特性

低压MOCVD方法生长了掺Si与不掺Si的AlGaInP/GaInP多量子阱结构,运用X射线双晶衍射与光荧光技术研究了掺Si对量子阱性能的影响.测试结果表明掺Si使量子阱的生长速度增加,掺Si量子阱的光荧光强度比未掺Si量子阱的光荧光强度改善了一个数量级.     

探测波导全息光栅傅里叶变换光谱的新方法

提出一种利用波导全息光栅分光元件 ,通过测量波导光栅附近区干涉条纹 ,经快速傅里叶变换达到测量光谱的新方法。讨论了波长测量范围和光谱分辨率。给出了在设计波导光栅、确定探测器时应该考虑的几个问题。对系统测量误差进行了分析。该光谱探测方法具有光谱分辨率高、波长范围宽和结构简单等优点。     

数值分析渐变DBR对垂直腔面发射激光器谐振腔模的影响

通过数值分析研究了含线性渐变层的Al0.9Ga0.1As/AlyGa1-yAs/GaAs/AlxGa1-xAS DBR的光学特性及其对VCSEL谐振腔光学特性的影响,建立了渐变型DBR渐变层厚度与折射率的关系,通过特征矩阵法计算了突变GaAs/Al0.9Ga0.1AS DBR和渐变型DBR的反射谱和反射相移,分析了渐变层对DBR反射率和反射相移的影响.对渐变型DBR,要使VCSEL谐振腔满足中心波长相位匹配条件,还需要在DBR靠近谐振腔一侧的最前面增加一定厚度的渐变层,称为相位匹配层.通过计算,我们得到了使VCSEL谐振腔满足相位匹配条件时均匀层和相位匹配层的厚度.     

MIMO雷达协方差矩阵重构波束形成算法

协方差矩阵类算法在MIMO雷达大失配误差情形下依然具有很强的鲁棒性,但往往存在计算复杂度较高的问题。针对高性能与低计算复杂度间的矛盾,提出对失配误差模型进行修正,从两方面改进算法:一方面基于双边约束的方式,在发射端和接收端分别建立单边导向矢量误差集,然后获取离散的联合导向矢量失配误差集;另一方面基于小不确定集模型结构特点,提出用K-means聚类算法获取少量加权特征采样点来代替原先大量的离散采样点,减少协方差矩阵重构所需采样点数,从而降低计算复杂度。仿真实验表明,所提算法在失配误差较大情形下具有很强的鲁棒性,且输出SINR性能达到最优。