All-optical switches based on 3 × 3 generalized multimode interference structure

• Present a new method for realizing new all-optical switches using 3 × 3 multimode interference structures.
• Nonlinear phase shifters based on the Kerr effect are used to achieve switching states.
• Transfer matrix method and BPM simulation are used to confirm and optimize the device structure.
• The directional couplers, phase shifters, MMI couplers are optimized using the BPM simulations.
• The proposed 3 × 3 all-optical switch can be useful for all-optical networks in the future.

Multimode interference in optical waveguide is attractive for optical signal processing in recent years. In this paper, we propose and design a 3 × 3 all-optical switch using 3 × 3 General Interference Multimode Interference (GI-MMI) structures. Nonlinear directional couplers based on the Kerr effect in two arms of the structure are used as phase shifters. We use chalcogenide glass on silica platform for designing the device structure. The switching states of the device can be controlled by adjusting the optical control signals at the phase shifters in the two arms. The transfer matrix method (TMM) and beam propagation method (BPM) are used for designing and optimizing the device structure.