All-Optical Modified Discrete Cosine Transform (MDCT) Using MMI Structures
The Modified Discrete Consine Transform (MDCT) have found applications in digital signal, image and video processing and particularly in transform coding systerm for data compression and decompression. Multimode interference (MMI) in optical silicon on insulator (SOI) waveguides is attractive for realizing all-optical MDCT transforms as they have the advantages of low loss, ultra-compact size and excellent fabrication tolerances. In this paper, for the first time, a novel approach to realize all-opptical MDCT based on multimode interference structures on silicon on insulator platform is proposed. Base on the transfer matrix method, the analytical expressions describing the characteristics of the MMI structures are derived. Designs of the proposed devices are then verified and optimized using 2D and 3D BPM (Beam propagation method( simulations.