Two-Dimensional Discrete Sine Transform and Discrete Cosine Transform Based on Two-Dimensional Multimode Interference Couplers

In this letter, all-optical two-dimensional discrete sine transform and discrete cosine transform (2DDST/DCT) are proposed to be realized on two-dimensional multimode interference (2DMMI) couplers. Similar to the one-dimensional case, the 2DDST/DCT requires only one 2DMMI coupler and a few phase shifters.