光束准直性对星间相干光通信外差效率的影响

以本振光为高斯光,信号光为艾里斑分布为前提,建立了空间相干光通信系统外差效率的理论模型.分别在信号光垂直入射和存在角失配入射的情况下,对外差效率进行了仿真分析.结果表明,当光敏感面半径与高斯光束腰半径之比为1.53,且高斯光束腰半径与系统F数之比为0.8时,能得到最佳的外差效率为83.3%;信号光与本振光在光敏感面混频时的非准直对外差效率的影响较大,随着失配角的增大外差效率逐渐降低,几毫弧度的失配将使外差效率减小到50%以下.

Effect of Light Collimation on Heterodyne Efficiency for Space Coherent Optical Communication

A theoretical model of the heterodyne efficiency for space coherent optical communication was established based on the precondition of assuming the local oscillator beam as Gauss beam while signal beam as Airy distribution, and the model was simulated under the situations of the signal beam propagating normally and slantingly respectively. The simulation results show that the system can get the optimal heterodyne efficiency of 83.3 % when the ratio of optoelectronic sensor surface radius to the Gauss beam radius is 1.53 and that of Gauss beam radius to the system number F is 0.8. The non-alignment of the beams can impact the heterodyne efficiency seriously when the signal beam is mixed with the local-oscillator beam on the optoelectronic sensor surface. The heterodyne efficiency decreases with the increase of mismatching angle, and a few milliradians mismatch can make the heterodyne efficiency reduce to 50% below.