【摘 要】
：
In this Letter, we investigate the packet error rate (PER) performance of digital pulse interval modulation (DPIM) for free-space optical (FSO) links under the combined effect of turbulence and pointing errors. The theoretical model is developed by consid
【出 处】
：
ChineseOpticsLetters
论文部分内容阅读
In this Letter, we investigate the packet error rate (PER) performance of digital pulse interval modulation (DPIM) for free-space optical (FSO) links under the combined effect of turbulence and pointing errors. The theoretical model is developed by considering the effect of some important parameters, including turbulence condition, beamwidth, receiver aperture size, jitter variance, data rate, transmitted optical power, etc. A closed-form average PER expression for DPIM is derived for this fading channel. The results of numerical simulation are further provided to verify the validation of our model. This work can be helpful for selecting DPIM in the FSO system design.
其他文献
以纯镍丝为填充材料，采用精密脉冲激光实现了厚度为0.2 mm的TiNi形状记忆合金/不锈钢异种材料的焊接，研究了熔化区（焊缝和熔合区）的组织形貌和微观结构。结果表明，焊缝中心晶粒呈外延连续生长的特征。连续生长的枝晶可以跨越3~5个脉冲激光形成的鱼鳞纹，长度可以达到约200 μm。焊缝与两侧母材的熔合区呈现完全不同的形貌，在不锈钢母材与焊缝的接合界面，枝晶沿着不锈钢母材的熔合线生长，在枝晶间有二次晶轴；在TiNi合金与焊缝的熔合区，有一层宽度约为5 μm的过渡层将焊缝与母材隔开。
The dispersion of Yb-doped fiber is measured by a spectral interferometric technique. The experimental verification is achieved by comparing the measured data with published data of the Nufern 1060xp fiber and the measurement relative error is 1.36%. The
现有的高光谱图像分类方法多注意到空间信息的利用,并未考虑地物在空间分布上具有连续性的特点。基于此,提出了一种空谱加权近邻(SSWNN)高光谱图像分类算法。通过构造测试样本点的近邻空间,过滤近邻空间中与测试样本标签不一致的空间近邻点,有效解决了近邻空间内异类点对中心像元分类的干扰,改善了图像的椒盐效应。根据空间近邻点和测试像元之间的光谱相似性为空间近邻点赋予不同的权重,增大了同类像元间的相似性和异类
A novel polarization splitter based on octagonal dual-core photonic crystal fiber (O-D-PCF) is proposed. The impacts of several fiber parameters on the coupling characteristics of the polarization splitter are investigated by full-vectorial finite element
碱卤晶体中色心的激光振荡开拓了在近红外光谱区获得有效的可调谐光源，并在可见和紫外光谱区建立这种光源的可能性。所有现存的色心激光器都是使用光泵激发的，一般使用气体离子激光器的辐射激发。如果能够用电泵浦直接激发，色心激光器的紧凑性将得到相当大的改善。
通过建模仿真，从改善陀螺输出带宽以及提高互易性噪声抑制能力出发，对单路闭环谐振式微光学陀螺（R-MOG）和双路闭环R-MOG进行了分析研究。相比于单路闭环R-MOG，双路闭环R-MOG在抑制互易性噪声的同时，能较好地改善输出带宽，并进一步提高陀螺系统的线性度。在此基础上，搭建了双路闭环R-MOG的实验系统，并进行了陀螺零偏稳定性以及输出响应特性测试。实验结果表明，陀螺1 h的零偏稳定性为0.53 °/s，在±1000 °/s转速范围内，陀螺系统的线性度为99.995%。
A novel structure of fiber optic biosensor and its principle are introduced. The sample is detected in microchannels of several microns diameter in fiber optic biosensors. The relation between the optic fiber tapered angle and the fluorescence incident an
提出了一种可有效滤除输出信号中干扰信号的新的光纤陀螺信号降噪方法。中高精度光纤陀螺的随机噪声中包含了白噪声和具有长程相关性、自相似性及l/ fY类型谱密度特点的一种非平稳随机噪声l/fY类型分形噪声。利用传统的滤波方法无法有效去除该类分形噪声,而新方法以经验模态分解(EMD) 和间值降噪方法为核心,结合提升小波理论对光纤陀螺的输出信号进行软间值滤波,进而提高光纤陀螺的精度。利用这种新方法对多组实测数据进行滤波仿真实验,结果中仅偏置稳定性一项性能指标就已表明,使用新滤波方法滤波后数据精度可提高一个数量级,而