High-extinction-ratio, visible-light thermo-optic switch based on two-stage mode management

Visible-light interference imaging uses distributed sub-apertures to surpass the diffraction limit, offering a promising approach for large-aperture imaging. Traditional systems are limited by bulky free-space optical paths, while on-chip integration suffers from the lack of high extinction ratio optical switches in the visible spectrum. We propose a two-stage mode management strategy to enhance the extinction ratio. We also optimize the thermal transfer model of the interferometric arm to reduce drive power and response time. The device achieves a 39.9 dB extinction ratio at 532 nm and maintains high phase modulation linearity across the 0 to π (RMSE < 0.0004 rad) and the π to 2π (RMSE < 0.0021 rad) phase shift range. Moreover, relative to a conventional design, the drive power is reduced by 28% and the rise time is reduced by 21%. This device offers a solution for multi-channel parallel interference imaging systems or portable high-resolution imaging devices.