基于光纤自相位调制多波长全光再生的色散管理优化

针对基于光纤自相位调制效应的多波长全光再生系统,分析了光纤平均色散对再生器品质因子改进量的影响,提出一种色散管理优化方法.由于波长间色散差异会导致再生系统性能的稳定性下降,通过选择色散补偿光纤和单模光纤的长度,使其合成的色散曲线与各波长分别达到最优再生性能时对应的色散曲线近似拟合,同时保证该色散曲线落在性能满意度高的色散区域,然后调整信号输入功率和滤波器的偏移量,可有效改善多波长再生性能的稳定性,实现再生器的色散管理优化.     

GALICS: A direct link between theory and observations

This contribution advocates a new method for comparing theoretical predictions to observations. Properties of virtual galaxies are computed using the hybrid model for hierarchical galaxy formation GALICS (for Galaxies In Cosmological Simulations), which takes advantage of large cosmological N-body simulations to plug in simple semi-analytic recipes describing the fate of the baryons. From such a fake galaxy catalog, one can build light cones, and project them onto virtual CCD devices, taking into account the technical characteristics of the detector/telescope. As a result, realistic mock images can be produced, which can then be directly compared to real observations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Spectro-morphology of galaxies

We present a quantitative method of classification of the multi-wavelength morphology of galaxies, elaborated from the nearby galaxies and usable to high redshift objects. We use the morphological parameters of concentration of light at the galaxy center and 180^°-rotationnal asymmetry, computed in several wavelengths, from ultraviolet (UV) to R band. The variation of these indices with λ reflects the proportion of young and old stellar populations in galaxies, that is characteristic of every morphological type: elliptical/lenticular, spiral and irregular. We need to elaborate some templates of these variation spectra from the study of nearby objects, for an application to distant galaxies. This revised version was published online in August 2006 with corrections to the Cover Date.     

多波长雷达识别冰雹的数值研究

利用中国科学院大气物理研究所三维冰雹云模式,详细地讨论了云雨衰减作用和云中各粒子共存于同一空间给多波长雷达识别冰雹带来的影响.在实际工作中,分析多波长雷达的回波时,这些讨论结果对分析和理解云降水过程有帮助.另外,本工作能为改装多波长雷达提供有益的理论参考.     

基于光纤光参量放大的异步双波长全光再生技术研究

本文提出了一种新型的多波长全光再生方案,利用相位时钟光纤光参量放大,并采用相邻信道偏振正交的方法,实现对由异步信源产生的双波长信号全光再生.理论分析了参量放大中的增益饱和现象用于幅度噪声抑制,以及利用相位时钟及后续色散实现对信号定时的机理.在这个基础上,对两个独立信源产生的异步双波长10 Gbit/s信号进行再生实验,实验表明该方案有效的抑制了基于多波长3R再生系统中信道间的四波混频与交叉相位调制等非线性干扰.系统在单波长和双波长情况下分别将两路信号信噪比改善了至少6.5 dB与4.5 dB.误码率测试结     

GALICS: capturing the panchromaticity of galaxies

This contribution describes results obtained with the GALICS model (for Galaxies In Cosmological Simulations), which is a hybrid model for hierarchical galaxy formation studies, combining the outputs of large cosmological N-body simulations with simple, semi-analytic recipes to describe the fate of the baryons within dark matter halos. Designed to predict the overall statistical properties of galaxies, with special emphasis on the panchromatic spectral energy distribution emitted by galaxies in the UV/optical and IR/submm wavelength ranges, such an approach can be used to predict the galaxy luminosity function evolution from the ultraviolet to far infrared, along with individual galaxies star formation histories. This revised version was published online in September 2006 with corrections to the Cover Date.