We demonstrate the generation of 12.1±0.2 dB squeezed light from a periodically poled lithium niobate (PPLN) waveguide optical parametric amplifier (OPA). While single-pass OPAs offer squeezed light with THz-order bandwidths, loss from spatial mode mismatch between the squeezed light and the local oscillator (LO) previously capped the squeezing level at ∼10 dB [K. Hirota et al., Opt. Express 34, 7958 (2026)]. In this work, we minimize this loss by introducing a machine-learning-optimized spatial light modulator (SLM) in the path of the LO. Specifically, we employed a double-reflection configuration to increase the spatial degrees of freedom, and directly used the measured squeezing level as the optimization's objective function.
@article{arxiv.2603.02744,
title = {Generation of 12 dB squeezed light from a waveguide optical parametric amplifier using a machine-learning-controlled spatial light modulator},
author = {Gyeongmin Ha and Kazuki Hirota and Takahiro Kashiwazaki and Takumi Suzuki and Akito Kawasaki and Warit Asavanant and Mamoru Endo and Akira Furusawa},
journal= {arXiv preprint arXiv:2603.02744},
year = {2026}
}