Highly efficient measurement of optical quadrature squeezing using a spatial light modulator controlled by machine learning

Abstract

Pulsed squeezed light is a key resource for many quantum information processing tasks. Among the various methods for generating squeezed light, single-pass parametric amplification has various advantages such as broad bandwidth, compactness, and stability. The challenge in achieving high-level pulsed squeezing has been to improve detection efficiency. We used a spatial light modulator controlled by machine learning to improve the spatial mode matching between the local oscillator and squeezed light. We achieved pulsed squeezing of 5.88 dB generated by optical parametric amplification in a waveguide. To the best of our knowledge, this is the highest obtained pulsed squeezing, and we believe this achievement will lead to more compact and efficient quantum information technology.