在自由空间光通信(FSO)中,通信端机所处的平台在各种随机干扰力下发生振动,使正常的通信光路发生偏移,对误码率(BER)产生影响。为了减小振动引起的误码率,提出通过控制接收端光斑形状和大小来抑制误码率,并给出利用像散来获得指定光斑的设计方法和实例。结果表明,在实际通信环境中,通过选取合适的光斑参量可以使振动引起的误码率达到最小,通过调节发射端光学天线参量可以获得指定的光斑参量。对于振动不对称的情况,接收端光斑应该选择为椭圆形。

For free space optical communication (FSO), various stochastic interfering factors make the communication platform oscillate, as a result the original collimated link is broken, and the bit error rate (BER) increases. For the purpose of reducing BER, the method of controlling the optical spot's shape and size on the receiving end is given, also the principle of obtaining a certain optical spot via astigmatism and the design example are presented in this paper. The result indicates that the BER introduced by vibration could be reduced to the minimum while choosing the optical pot parameters on the receiving end via adjusting the transmitting optical antenna. For the situation of dissymmetry oscillation, the optical spot should be ellipse.