像差对星间相干光通信接收系统误码性能的影响

以空间链路方程为基础,详细推导了具有不同像差时的星间相干光通信接收系统信噪比表达式。以通信距离为60000km、速率为2Gb/s的2PSK零差同步轨道接收系统为例,通过数值仿真,全面比较了接收天线的倾斜、离焦、彗差和像散等像差对接收系统误码率(εBER)的影响。结果表明,不同像差单独作用时,倾斜像差的影响最大,象散的影响最小;不同像差相互作用时,它们中的某些能部分实现相互校正,从而降低误码率。以εBER≤10-6为比较标准,当彗差W31/λ≤1.00时,调整倾斜像差能实现它们之间的部分校正;当像散W22/λ≤0.53时,调整离焦能对像散进行部分校正。因此,在设计接收系统时,接收天线的像差所产生的影响不容忽视。这将为设计星间相干通信接收系统提供必要的理论依据。

Effect of Aberration on Performance of the Bit Error Rate in an Inter-Satellite Coherent Optical Communication Receiving System

Based on the space optical communication link equation, it is given in detail that the signal-to-noise ratio (SNR) equations for the inter-satellite coherent optical communication receiving system (ISCOCRS) with different aberrations. With communication distance for 60000 km, transmission rate of 2 Gb/s binary phase shift keying (2PSK) homodyne geosynchronous orbit receiving system as an example, through numerical simulation, the effect of the tilt, defocusing, coma and astigmatism aberrations on the bit error ratio(BER) of the ISCOCRS is compared systematically. The simulation results show that effect of the tilt aberration is the BER is more seriously than the astigmatism when the different aberrations influence the ISCOCRS individually, at the same time, the different aberrations can be partly corrected by another when they effect mutually, Which leads to the lower BER. With the BER more than 10-6 as standard, through adjusting the tilt, the coma can be partly corrected when the normalized coma is more than 1.00, and adjusting the defocusing can partly correct the astigmatism when the normalized astigmatism is more than 0.53. Therefore, the aberrations′ influence should be overlooked in the process of designing the ISCOCRS. These results provide some theoretic basis for the ISCOCRS.