经卡式光学天线发射的高斯光束衍射特性的研究

The Study of Diffraction Characteristics of Gaussian Beam Transmitted by Cassegrain Optical Antenna in Laser Communication

激光通信发射系统一般都是采用卡塞格林式望远镜作为发射天线,由于激光通信采用的光源波形为高斯光束,卡式光学系统的主次镜光学结构为环形结构,以往对均匀波经圆孔光阑后的衍射特性并不适用于激光通信。对基尔霍夫衍射公式进行了简化,利用数值计算的方法,利用仿真软件得到了高斯光束通过卡式光学天线之后的远场衍射分布特性,并与近场菲涅尔衍射分布特性进行分析比对,给出了卡式光学结构的最佳遮拦比为0.2,理论上可以达到1.5倍的近衍射极限发射束散角,在工程计算中有一定的应用价值。

For laser communication transmitter systems,a Cassegrain telescope is generally used as a transmitting anten-na. As the light wave using in laser communication is a Gaussian light beam, and the optical structure of primary and secondary mirrors of Cassette optical system are ring structures,in the past,the diffractions characteristics that Uniform wave pass through circular aperture are not fit to apply in laser communications. The complicated Kirchhoff diffraction formula is simplified in this paper. The distributed characteristics of far-field diffraction that Gaussian beam pass through Cassette optical antenna are got by using simulation software and compared with the distribution characteristics of near-field Fresnel diffraction. The optimum obscuration ratio of Cassegrain optical structure can be 0.2.Theoretically, a 1.5 times transimitted angle of near diffraction limit can be got. There are some certain values in engineering calculations.