Efimov Anatoly
Opt Express. 2019 Sep 16;27(19):26874-26881. doi: 10.1364/OE.27.026874.
Recent results show that partially coherent beams (PCB) can be conveniently generated in a multimode fiber and modulated with data at gigabit per second rates, which makes them attractive for free-space optical communication through turbulent atmosphere. An important feature of these realistic beams in contrast to model ones is the presence of residual coherence between pairs of points spatially separated by more than a few coherence radii on the beam aperture. In the present work we experimentally study the influence of this residual coherence on the scintillation of a partially coherent beam in a laboratory turbulence. It is shown that the total scintillation can be considered as a combination of scintillations of the coherent and incoherent parts of the full beam. When residual coherence is large the scintillation is mostly due to speckle motion on the detector. In the opposite case, the scintillation index settles at a low value pertaining to "ideal" homogeneous PCB.
最近的研究结果表明，部分相干光束（PCB）可以在多模光纤中方便地产生，并以每秒千兆比特的速率进行数据调制，这使得它们在通过湍流大气的自由空间光通信中具有吸引力。与模型光束相比，这些实际光束的一个重要特征是在光束孔径上空间分离超过几个相干半径的点对之间存在残余相干。在本工作中，我们通过实验研究了这种残余相干对实验室湍流中部分相干光束闪烁的影响。结果表明，总闪烁可被视为整个光束相干部分和非相干部分闪烁的组合。当残余相干较大时，闪烁主要是由于探测器上的散斑运动。在相反的情况下，闪烁指数稳定在与“理想”均匀PCB相关的低值。
