All-optical signal processing circuits using silicon waveguides

There has been much recent research interest in photonic circuits that can achieve all-optical signal processing. In this paper, the use of multimode interference (MMI) devices for building basic elements to realize all-optical signal processing circuits is investigated. The proposed structures are optimized using analytical and numerical simulations. In addition, an approach for realizing all-optical discrete Fourier transforms using the proposed structures is presented. The approach can be extended to design other larger scale all-optical signal processing circuits. The designs of these MMI based devices use silicon waveguides, which are compatible with existing CMOS technology.