多模光纤斑纹场及其应用

本文重点研究了多模光纤束斑纹场的特性和应用,将它与单根多模光纤及散射屏产生的斑纹进行比较,通过实验证明由He-Ne激光激励的多模光纤束辐射场是准均匀、稳定的单色斑纹场,如能恰当地选用光纤束,     

半导体激光多模光纤束斑纹场的特性

本文研究 650rm波长的半导体激光照明多模光纤束产生的斑纹场的特性 ,讨论了决定这种斑纹场特性的各种因素。用自己设计的Y型多模光纤束 ,拍得了质量较好的半导体激光光纤束斑纹全息图。用两次曝光法再现了清晰的杨氏干涉条纹。     

多模光纤束激光斑纹场的一些特性

实验研究了不同结构的多模光纤束斑纹场的单缝、双缝、三缝衍射花样及锲形空气薄膜干涉条纹.用Y型多模光纤束拍摄了斑纹场全息光栅,研究了它的衍射花样.成功地用多模光纤束传光,测量散射物体的面内位移.     

多模光纤束斑纹场的某些特性

本文研究多模光纤束斑纹场经透镜后的光场特性以及两种有应用价值的斑纹场实验。     

对光纤斑纹场的研究及用于传感的探索

本文研究了光纤所产生的斑纹场的光强分布，并成功地利用此斑纹场的强度作传感参数，测量了微位移。     

使用多模光纤实现光纤放大器和激光器单模工作的新方法

本文介绍了一种使用多模光纤实现放大器和激光器单模工作的新方法,这种光纤放大器和激光器的增益光纤是绕成圈的多模光纤。这种技术可大幅度提高光纤放大器和激光器的光输出功率并保持优异的束质量。     

多模光纤反馈半导体激光器产生无时延特征混沌

提出了一种基于多模光纤模间色散的无时延特征混沌产生方案。在多模光纤长度为4.4 km、芯径为62.5μm、反馈强度为0.1的条件下,实验获得了无时延特征的混沌信号。进一步理论分析了多模光纤的纤芯直径、相对偏移、长度对混沌光模场的影响,结果显示：随着纤芯直径和相对偏移的增大,模式数量逐渐增多,模场分布变复杂;随着光纤长度的增加,模式分离程度（即模间色散）增大。最终探明了多模光纤相对偏移、反馈强度、长度对时延特征的抑制规律。结果表明,在与实验相同的纤芯直径和反馈强度下,消除时延特征的多模光纤的临界长度为1 km。     

多模光纤在网络中的应用潜力

本文阐述了多模光纤技术的发展及其在网络中的应用历程，以此为背景介绍了新一代多模光纤的特点及应用前景，同时粗略估计了新一代多模光纤标准的推出对我国今后科研生产可能产生的影响。     

新型大模场光子晶体光纤传输系统及其传输特性分析

通过在多模光子晶体光纤的两端分别连接一根单模光子晶体光纤,对其选择合适的参数,形成一种可以实现低弯曲损耗、大模场单模传输的光纤传输系统。运用数值仿真,分析了该传输系统在模场面积、弯曲损耗、连接损耗等方面的特性。研究结果表明,多模光子晶体光纤与单模光子晶体光纤所组成的系统可实现有效的单模传输;工作波长为1064nm时,多模光子晶体光纤在直波导状态时的基模模场面积可达1593μm2;在弯曲半径低至10cm时,多模光子晶体光纤仍然可以保持低损耗传输。经过对多模光子晶体光纤结构参数的优化,其与单模光子晶体光纤的连接损耗降低至0.085dB。     

刚体沿其表面法线方向的平移所引起的激光斑纹运动的观察

一束激光照亮物体的漫射表面,在物面前的空间形成散射斑纹场.物体沿其表面法线方向的刚性平移(也叫离面平移或纵向平移),将引起空间斑纹场的变化.对这种斑纹运动,曾利用不同方式作过观察.     

Measurement and simulation of the turn-on delay time jitter ingain-switched semiconductor lasers

The turn-on delay time jitter of four different unbiased gain-switched laser types was determined by measuring the temporal probability distribution of the leading edge of the emitted optical pulse. One single-mode 1.5-μm distributed feedback laser and three multimode Fabry-Perot lasers emitting at 750 nm and 1.3 μm were investigated. The jitter was found to decrease for all lasers with increasing injection current. For multimode lasers it decreases from 8 ps excited slightly above threshold down to below 2 ps at three times the threshold current. The jitter of the distributed feedback (DFB) laser is a factor of 3-5 larger than the jitter of the three multimode lasers. A model for predicting the turn-on delay time jitter is presented and explains the experiments quantitatively     

Subkilohertz fluctuations and mode hopping in high-powergrating-stabilized 980-nm pumps

The behavior of fiber Bragg grating (FBG)-stabilized 980-nm pump lasers is experimentally and theoretically investigated. The subkilohertz noise in the emitted power is related to the coexistence and oscillation between coherence collapsed state and narrow linewidth single-mode (SM) operation. These findings are theoretically discussed by using a multimode time-domain model that accounts for spatial harmonics and includes nonlinear gain. One additional result is an indication that kinks in the L-I curve can be explained by nonlinear mode competition     

Radiation power loss in the output unit of the multiwave Cherenkov generator

The power loss of the multiwave Cherenkov generator is estimated for the output unit when gigawatt pulses are emitted to atmosphere. A simplified model of the output unit that represents a series of multimode circular waveguides, couplers, and a horn with a relatively large opening angle and a thick dielectric window is used in the analysis. The transforming properties of couplers and the passage of radiation through the window are studied. The results of numerical calculations are presented for the output unit that was used in experiments.     

High-power and tunable operation of erbium-ytterbium Co-doped cladding-pumped fiber lasers

We describe erbium-ytterbium co-doped fiber lasers in different free-running and tunable configurations. The lasers were cladding-pumped by high-power multimode diode sources. We compare pumping at 915 and 980 nm. With a free-running laser, we obtained slope efficiencies of up to 50% with 915-nm pumping and 38% with 980-nm pumping, with respect to absorbed pump power. We reached a double-ended output power of 16.8 W from the free-running laser. Thanks to a high rare-earth concentration and a small inner cladding area (possible with the high-brightness pump sources we used), the operating pump absorption of the fiber reached 8 dB/m. With such high absorption, short fibers with high nonlinear thresholds are possible even with cladding pumping. The tunable fiber laser had a tuning range from 1533 to 1600 nm and emitted 6.7 W of output power at 1550nm in a high-brightness, single-polarization, narrow linewidth beam.     

玻璃基多模波导光功分器的研制

利用Ag+-Na+电场辅助玻璃基离子交换技术制作了低损耗的掩埋多模波导,并在此基础上研制了多模波导光功分器.测试分析了多模波导和光功分器的损耗和偏心率特性.所研制的多模直波导传输损耗小于0.1dB/cm,所制作的1×2的多模波导光功分器附加损耗小于1.3 dB.     

三态叠加MSCS光场中广义磁场的不等幂高次和压缩

利用多模压缩态理论,研究了由多模复共轭虚相干态、多模复共轭虚相干态的相反态和多模复共轭相干态的线性叠加所组成的一种新型的三态叠加多模薛定谔猫态光场|Ψ~((3))>_q中广义磁场分量的不等幂次高次和压缩特性。结果发现:态|Ψ~((3))>_q是一种典型的三态叠加多模非经典光场;在一定条件下,态|Ψ~((3))>_q的广义磁场分量可呈现出周期性变化的广义非线性不等幂次高次和压缩效应。     

掺镱多模双包层光纤激光器弯曲选模研究

为了使大芯径多模双包层光纤激光器实现基模输出以抑制高功率双层光纤激光器中的非线性效应,采用将大芯径的多模双包层光纤适当弯曲进行选模使双包层光纤激光器获得单模激光输出的方法,进行了理论分析和实验验证,取得了大芯径多模双包层光纤内包层折射率、纤芯半径、光纤内传输信号光波长、光纤弯曲半径等因素对弯曲损耗及激光器输出光场模式影响的数据,并采用国产掺镱多模双包层光纤进行了弯曲选模实验,实现了多模光纤激光器的单模输出.结果表明,激光器最大输出功率达9W,斜率效率达17.3%,输出为基模.这一结果对大芯径多模双包层光纤激光器的选模是有帮助的.