Realization of Discrete Fourier Transform and Inverse Discrete Fourier Transform on One Single Multimode Interference Coupler

In this letter, we propose to realize optical discrete Fourier transform (DFT) and inverse discrete Fourier transform (IDFT) on one single multimode interference (MMI) coupler. In comparison to the previous MMI coupler-based DFT device, this device does not require any couplers or cascaded structures. The simulation results show that it can realize the DFT/IDFT precisely.