大气光通信中大气闪烁时间平滑效应研究

利用大气闪烁的时间平滑效应,增加光电探测器曝光时间是克服大气闪烁对大气光通信的瞄准、捕获、跟踪链路影响的有效途径之一.基于科尔莫戈罗夫谱,导出了弱湍流起伏区无限平面波和球面波的大气闪烁时间平滑因子的一般表达式,并且用几何光学近似得到了在大孔径和小孔径接收情况下的时间平滑因子近似表达式.在孔径远大于菲涅耳区尺度时,平面波和球面波的时间平滑因子的近似表达式与精确表达式的误差分别小于6%和3%.分析结果表明,孔径越小,时间平滑效应越显著,并且菲涅耳区尺度对时间平滑效应影响的程度也随着孔径的增加而减弱.

Time-averaging Effects for Atmospheric Scintillation in Atmospheric Optical Communication

Based on time-averaging effects for atmospheric scintillation,extending photoelectric(detector's) exposure time is one of the effective ways to mitigate the effect of atmospheric scintillation on the link of atmospheric optical communication.Based on the Kolmogorov spectrum,the expressions are derived for time-averaging factors associated with atmospheric scintillations of unbounded plane wave and spherical wave,in the weak turbulence regime.Approximate expressions of the time-averaging factors for small-and large-aperture receivers are provided by use of geometrical optics approximation,respectively.When the aperture is much larger than Fresnel scale,approximate expressions differ from exact numerical results by less than 6% in the case of plane wave and 3% for spherical wave.Results show that the strength of timeaveraging effects goes up along with the aperture decrease,and the effect of Fresnel scale on time-averaging effects weakens along with the increase of the aperture.