铷原子法拉第共振滤光特性研究

我们在不同磁场强度、原子气体密度下，实验观测了７８０ｎｍ铷原子气体的法拉第共振滤光效应，并进行了理论分析。结果表明：透射峰中心频率的调谐能力为￣１００ＧＨｚ／Ｔ，透过率大于４０％，通频带宽为０．００１ｎｍ￣０．０１ｎｍ，背景光抑制本领优于１０＾－４。     

Faraday色散光学滤波器的研究进展

本文综述了Faraday反常色散光学滤波器的国内外研究进展,并提出发展前景。     

级联法拉第反常色散滤光器研究

本文提出级联法拉第反色散滤光器的新构思．这种新结构滤光器带宽～１ＧＨｚ，噪声抑制比优于１×１０－５．     

光隔离器用法拉第旋转器的Mueller矩阵形式

本文通过分析在理想情况下不同偏振态的光经过法拉第旋转器前后Ｓｔｏｋｅｓ矢量的变化，从理论上导出理想的光隔离器用法拉第旋转器的Ｍｕｅｌｌｅｒ矩阵形式。     

半导体激光器的原子法拉第反常色散光学滤波器光反馈稳频

为提高半导体激光器的频率稳定性，利用原子法拉第反常色散光学滤波器（FADOF）超窄带的选频透射特性，将其置于半导体激光器的外腔中作选频元件，采用光反馈的方法，使得透射率低的激光频率分量被抑制，透射率高的激光频率分量被加强，有效地实现了光反馈激光稳频。利用Cs原子法拉第反常色散光学滤波器工作于D2线852nm的4峰窄带透射状态。通过调节半导体激光器的温度和电流，调谐半导体激光器的输出波长，将激光器锁定在任何一个透射峰上，用26％的光反馈量，使稳频后的激光频率长期稳定性保持在75MHz／2h以内，而且采用这种稳频方法的输出激光中心波长一直稳定在频率基准上，没有单方向漂移。同时，还实现了Cs原子法拉第反常色散光学滤波器稳频半导体激光器结构的一体化，使其具有实用性。     

光隔离器用法拉第旋光器的研究

分析了法拉第旋光器旋光角的精度对光隔离器参数的影响，以及圆形磁环的磁场在磁旋光晶体上的分布；并对具体实例进行了计算。     

Optical fibre Faraday rotation current sensor with closed-loop operation

A novel closed-loop fibre-optic current sensor based on the Faraday effect is described which maintains a constant sensitivity to AC currents in the presence of large quasi-DC and low-frequency current fluctuations. A Verdet constant of 2.55×10?6 rad/A (at 0.83 ?m) is reported for the fibre used.     

Preamplifier with a second-order high-pass filtering characteristic

A new preamplifier for suppressing low-frequency interference is presented. The proposed preamplifier, with its front end being implemented by an instrumentation amplifier, enjoys the following advantages: differential high-pass filtering, high input impedance, high common--mode rejection ratio and low passive sensitivity. This circuit can be realized with commercial operational amplifiers with enough phase margin, or fabricated in a chip for practical measurement of physiological signals.     

用于冷原子研究的小型集成化法拉第磁光隔离器

研制了一种高均匀性、小型化的法拉第磁光隔离器,用于780nm波长的光路中,并对设计方案进行了数值模拟和验证。采用了新颖的三段式“π”形磁体的组合设计方案,提高了剩磁利用率。隔离器整体体积为52cm3,其中磁体体积为18cm3,是相当小的。它的通光孔径为5mm,隔离比为34.6dB,透过率为90.9%。与之类似的“II”型磁体体积更小,磁场均匀性稍差,也是可行的设计方案。成品隔离器比商用隔离器磁场均匀度更高,体积更小,隔离比更高,可以有效满足研发中的冷原子平台的小型化、高精度需求。     

光隔离器法拉第旋光材料磁偏角的测量

研制光隔离器,关键技术之一在于经抛光后的法拉第旋光片在饱和磁化条件下,其磁偏角必须为45°。否则,隔离度将严重下降。本文给出了测量其磁偏角的测试系统。精度较高,且外加磁场强度连续可调,以满足具有不同饱和磁化条件的各种法拉第旋光材料的测试。     

Faraday Optical Isolator/Gyrator Design in Planar Dielectric Waveguide Form

The possibilities of using the magnetic Faraday effect to provide a planar dielectric waveguide isolator or circulator are studied. At least two active elements which couple the TE and TM waveguide modes are required. One of these is magnetooptic. Preliminary design data for a dielectric waveguide isolator in which the mode-converting media forms the substrate and top layer of a single waveguide structure are reported. This design should prove more practical than the optical tandem structures proposed previously.     

Optical adaptive filtering for Doppler shift simulator

Based on free space laser communication, this article describes the working principle of electro-optical frequency shifting, designs an optical adaptive filtering module, and builds the core module of the dynamic optical Doppler shifting simulator for laser channel. It is expected to be applied to the heaven-ground integrated communication link. In this article, we adopt the electro-optical frequency shifting technique combined with the microwave-light wave. In the 1 550 nm band, the negative feedback algorithm is used to complete the adaptive filtering, which realizes optical Doppler frequency shifting and high-precision locking. The frequency shift range reaches +5.5—+32 GHz, and the analog precision is better than 645 Hz. When the microwave frequency is greater than 13.5 GHz, the signal-to-noise ratio (SNR) of the output optical power reaches 20 dB, which lays the foundation for the next stage space laser communication.     

干涉型光纤陀螺中磁光Faraday效应的研究

基于Jones矩阵法,采用以分段保偏光纤(PMF)级联模拟普通单模光纤(SMF)的模型得出的光纤环传输矩阵,对Faraday效应在干涉型光纤陀螺(IFOG)中的影响做了系统的分析,得出可定量分析IFOG由Faraday效应所引起的相位漂移的一般公式.利用此公式,以采用PMF的IFOG为例进行了仿真分析,结果表明,Faraday效应致相位漂移受光纤偏振主轴偏转影响显著.在一定偏转范围内,相位漂移随偏转呈指数增长关系.由此得出,在采用PMF制作IFOG时光纤环与IFOG芯片的熔接过程中对光纤旋转机构的精度要求.     

单光子探测条件下Rb法拉第反常色散滤波器的研究

报道了单光子探测条件下的法拉第反常色散滤波器(FADOF)滤波特性的实验结果。测量结果表明，工作在D2共振线的Rb原子780nm法拉第反常色散滤波器的翼谱透射率为28％，滤光带宽为0．7GH2，以及最小可探测激光功率为0．16pW／cm^2。由于使用了单光子探测器测量法拉第反常色散滤波器物理参数的方法，极大地提高了实验测量的探测灵敏度。通过实验数据分析，给出了相关的讨论。在日光情况下，如果使用这种780nm Rb法拉第反常色散滤波器代替干涉滤波片，将极大地降低背景光噪声和减少误码率，使得在单光子水平的激光通信更接近于实用。     

Optical regeneration using self-phase modulation and quasi-continuous filtering

We propose a scheme for 2R optical regeneration based on self-phase modulation in fiber and quasi-continuous filtering. Numerical simulations demonstrate the possibility of increasing the transmission reach from 3500 to more than 6000 km at 10 Gb/s using 100-km spans. Spectral broadening is shown to be small using this technique, indicating its suitability for wavelength-division-multiplexing regeneration.     

Multilevel index structure for information filtering based on user characteristic

Aimed at information overload and personalized characteristic of user information requirement, this letter presents a type of multilevel index structure and algorithm which is applied to large scale information filtering system and has better performance and stronger scalability.     

旋转机械振动信号中的小波滤波和特征提取

将小波方法应用于旋转机械状态检测中信号滤波与提取。利用小波Mallat算法对采集信号进行高频滤波，利用小波Packet算法对特征信号进行提取，并通过实验证明上述方法取得很好的效果。     

Optical Switching Based on the Conditional Faraday Effect With Electron Spins in Quantum Dots

We present the theoretical foundation of a novel concept for optical switching based on the conditional Faraday effect with electron spins in quantum dots (QDs). Calculations for light of wavelengths $lambda=1.3 mu{hbox {m}}$ and $lambda=1.55 mu{hbox {m}}$ show devices with active regions of a few hundred microns are possible. Case studies for both spherical and nonspherical QDs are considered, with calculations for the nonspherical case showing a 20% reduction in the required device length due to the lifting of the light and heavy hole band degeneracy.      

目标/星空背景光学特性仿真方法研究

为新一代成像导弹武器系统的研制提供目标光学仿真环境,需要进行光学特性仿真方法研究.从目标仿真系统的组成,即计算机图像生成软件、硬件,视频/光学图像转换器以及光学投影系统几方面,分析了各部分对可见光成像光学特性仿真的影响,并对其光学特性标校方法做了说明.在系统硬件确定后,调节图像生成软件中的三维模型的材质和纹理、场景中光源亮度、环境光亮度等是使仿真目标的光学特性与真实的相一致的有效方法.该方法已在导弹半实物仿真试验中得到应用和验证.     

Optical filtering to reduce chirping influence in LD wavelength conversion

The use of an optical filter to reduce chirping influence in LD wavelength conversion is demonstrated. A part of broadened spectrum of wavelength-converted light is eliminated by a narrow-band optical filter, and sensitivity degradation due to frequency chirping is reduced as a result. In an experiment using a fiber Fabry-Perot filter, the sensitivity was improved by about 1.5 dB in 1.55-/spl mu/m transmissions with normal dispersion fibers when an LD converter was biased at two times the threshold current.