Wafer-Scale Squeezed-Light Chips

Abstract

Squeezed-light generation in photonic integrated circuits (PICs) is essential for scalable continuous-variable (CV) quantum information processing. While chip-level sources have been demonstrated, wafer-level reproducibility has been hindered by the extreme susceptibility of squeezed light to device imperfections.

Here, we report the wafer-scale fabrication and characterization of two-mode squeezed-vacuum states on a fully complementary metal-oxide-semiconductor (CMOS)-compatible silicon nitride ($Si_{3}N_{4}$) PIC platform. Across a 4-inch wafer, 8 dies yield 2.9-3.1 dB directly measured quadrature squeezing with < 0.2 dB variation. This performance is enabled by co-integrating ultralow-loss high-$Q$ microresonators, cascaded pump-rejection filters, and low-loss inverse-tapered edge couplers. Our measurements agree with a first-principles theoretical model parameterized by independently extracted device parameters. These results establish a reproducible, wafer-scale route to nonclassical-light generation and lay the groundwork for scalable CV processors and quantum-enhanced sensing.

Recommended citation: Shuai Liu, Kailu Zhou, Yuheng Zhang, Abdulkarim Hariri, Nicholas Reynolds, Bo-Han Wu, Zheshen Zhang. (2025). arXiv preprint arXiv:2509.10445.
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