Two-Frequency Brillouin Fiber Laser Based on Bragg Grating Fabry-Perot Cavity

A novel and simple two-frequency Brillouin fiber laser is presented. It is based on a fiber Fabry-Perot cavity with fiber Bragg gratings as reflectors. The model of stimulated Brillouin scattering in fiber grating-based Fabry-Perot resonator is investigated. The laser allows conversion efficiency of close to 100% and suppresses the higher-order Stokes waves. The theoretical prediction is presented and the experimental demonstration is realized.     

分析布拉格光栅破坏的两纤芯不同的光纤耦合器

进一步推广了描述纤芯不同光纤耦合器的耦合模理论，用于解释被布拉格光栅破坏的两纤芯不同光纤耦合器的耦合现象，理论分析的结果与已报道的实验结果相符，与单独的布拉格光栅所起的反射作用不同,这里布拉格光栅所起的作用主要是引入了强烈的色散，在光栅的频谱范围内使耦合器不再同步，在被布拉格光栅破坏的光纤耦合器的选择性频谱中，其边缘部分出现非常弱的波动，而在其阻带内出现非常强的凹陷。     

一种实现光源与光纤耦合的方法

本文介绍了一种用显微镜筒与透镜构成的光学系统来实现光源与光纤耦合的方法。该方法具有光路系统小巧方便、耐用、耦合效率高等优点。     

降脂经验方降脂作用的临床观察

采用自拟的降脂方治疗血胆增高患者６３人，并与用月见草油胶丸治疗患者６１人比较，前者疗效优于后者，两组有显著性差异。     

偏振模色散补偿控制中偏振度技术的性能

基于主偏振态理论，导出了光信号偏振度的解析表达式.并对40 Gb/s光传输系统中的信号偏振度受各种因素的影响进行了数值模拟，包括啁啾、脉冲形状、脉冲宽度、自发辐射噪声以及消光比等.结果表明，偏振度技术能有效地监测和控制40 Gb/s系统中小于37.5 ps的偏振模色散.而且发现就最大化偏振度技术对差分群延时的容许范围而言，脉冲的1/e强度半宽取0.45个位宽（11.25 ps）是最优的.     

Comparison of polarization-mode dispersion tolerances in polarization-multiplexing systems with different modulation formats

The polarization-mode dispersion (PMD) tolerance of 10 Gb/s polarization-multiplexing (PM) system is investigated. Using the importance sampling (IS) method, the outage probabilities of the PM systems with three modulation formats, including on-off keying (OOK), differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK), are quantified. When the amplified spontaneous emission (ASE) noise is assumed to be dominant, we evaluate the optical power penalties caused by the PMD effect at bit error rate (BER) of 10⁻¹². The performance of compensated PM systems with variable optical delay line is also described. The simulation results indicate that the OOK signal with higher duty cycle (DC) performs better in the PM systems with PMD compensation. It is found that the higher-order PMD impairs seriously the performance of the PM system, and phase-keying formats are more sensitive to the PMD than the OOK.     

Banach空间中无限维线性系统的能控性

研究在非自反状态空间和自反控制空间中无限维线性系统x(t)=Ax(t) Bu(t)的精确能控性和精确零能控性.当A生成C-半群时,得到这个系统关于L~p([O,T],U),1相似文献   

The nonlinear study of microstrip lines containing ferrite dielectric layers

In this paper, the transient responses of microstrip containing ferrite dielectric layers are studied by using extended FD-TD method. When the microwave signal propagating along the microstrip is comparable with the applied DC magnetic field on the ferrite, the nonlinearity of ferrite medium is represented. The propagating procedure of Gaussian pulse in the microstrip are simulated. It is shown that the effects of the pulse amplitude on the transmission distortion of Gaussian pulse is pronounced.     

空间几何构造分析的有限单元法

提出空间杆系几何构造分析的有限单元法，构造了两种单元(链杆单元和准梁单元)的几何约束矩阵，集成为整体矩阵并引入承条件后，通过对其阶数与秩的比较分析确定体系的几何可变性及静定性．本法原理简单，便于计算机实施，结果完备：对于几何不变体系，可指出多余约束的数目；对于几何可变体系，可给出体系的自由度数及相应的运动模态，并确定自由度的常变瞬变性质．     

Exponential stability for the wave equations with local Kelvin–Voigt damping

We consider the wave equations with local viscoelastic damping distributed around the boundary of a bounded open set We show that the energy of the wave equations goes uniformly and exponentially to zero for all initial data of finite energy. This author supported partially the National Natural Sciences Foundation grant 10271111. Received: February 8, 2005; revised: July 3, 2005