Some novel basic optical units to produce fractional Fourier transforms were suggested, which were constructed by one Fresnel transform and one lens. It augments an alternation for the available models in optical designing. In comparison with the Lohmann's setup, these novel basic optical units have asymmetric structure. For a given single lens, these units can perform some fractional Fourier transforms that can not be implemented by Lohmann's setup composed of one lens, such as the fractional Fourier transforms for standard focus and enlargement or reduction.
