Multimode all-optical switch based on an inorganic–polypyrrole–organic hybrid waveguide structure

The mode optical switch is a critical component in mode-division multiplexing systems, enabling control of signal transmission states across optical channels. To achieve high performance while maintaining compactness, simplified architecture, and fabrication feasibility, this work introduces a novel, to our knowledge, switch that operates through mechanisms different from those of previously reported Michelson interferometer-, micro-ring resonator-, or phase-change material-based designs. This multimode all-optical switch employs a straight waveguide structure comprising SiO 2 (inorganic), polypyrrole (PPy), and polymer (organic) layers. In the on state, the device supports the transmission of signal modes E 01 , E 11 , and E 03 . When pump light is applied, heating in the PPy film induces a thermal phase modulation, leveraging opposing thermo-optic coefficients, which converts the signal mode energy into lower-order modes. These are then absorbed by the PPy, turning it to the off state. Simulations confirm the device’s multimode switching capability, rapid response, structural simplicity, and integration potential for practical optical switching applications.