载有轨道角动量(OAM)的光可用于提高光通信网络的带宽，而对不同轨道角动量态的区分是有效利用轨道角动量光的核心。利用空间光调制器设置合适的传递函数以实现傅里叶平面间的光学坐标变换。变换后，轨道角动量光随方位角的相位变化变成横向相位变化。相位修正后将不同轨道角动量的光聚焦到不同的横向位置，实现了对轨道角动量光的有效区分。

While light carrying orbital angular momentum (OAM) has much potential in increasing the bandwidth of communication networks, sorting of different OAM states is one of the key techniques to utilize it effectively. A method is proposed to realize optical coordinate transformation between two Fourier planes with the aid of spatial light modulator. After the transformations, the phase of light depending on azimuthal angle is changed to depend on transverse position. Each OAM state is focused to a lateral position after a phasecorrecting element. This method realizes sorting of light with OAM efficiently.