Effect of misalignment on optical fractional Fourier transforming systems

The effect of misalignment on optical fractional Fourier transforming systems is analysed in this paper. Meanwhile, a concept of perturbed fractional Fourier transform is put forward. By using the generalized misaligned diffraction integral formulae for misaligned optical systems, it is shown that the diffraction characteristics for misaligned Lohmann's fractional Fourier transforming systems and quasi-asymmetric inhomogeneous media are able to perform the perturbed fractional Fourier transform and are essentially equivalent. And also, a relative discussion is given.