多阵元光纤相干列阵的理论与实验研究

Theoretical and experimental study of multi-element coherent fiber array

基于Fraunhofer衍射理论,建立了六角形相干列阵远场分布的理论模型,采用Strehl比和能量集中度作为评价参数,分析了列阵排列方式、振幅、填充因子对远场分布的影响.并由爬山法相位控制技术和六棱台合束器,构建了七阵元光纤相干列阵实验系统.在0.66填充因子情况下,获得了Strehl比为0.70、能量集中度为0.40七阵元合成光束,以及获得了能量集中度分别为0.45和0.18的二阵元线阵和四阵元矩形阵合成光束.

The theoretical model of the hexagonal fiber array is established based on Fraunhofer diffraction theory.The far field distribution of the hexagonal fiber array is presented.Energy contained in the central lobe and Strehl ratio are taken as the two evaluation parameters of coherent combined system.The effects of arrangement,amplitude,filling factor and phase errors on far field distribution are analyzed and simulated.A seven-element hexagonal fiber array with a hexagonal prism is experimentally constructed.The hill climbing method is employed to detect and lock the element phase.The filling factor of the coherent array achieves 0.66.The combined beam of Strehl ratio of 0.70 and energy contained in the central lobe of 0.40 is experimentally obtained.And the energy contained in the central lobe of two-element linear array and four-element square array are 0.45 and 0.18,respectively.