Multimode continuous-variable quantum key distribution with CMOS-compatible photonic-electronic integration

Yiming Bian; Sarah Bastiaens; Saeed Hakimi; Huy Quang Nguyen; Aboobackkar Sidhique; Cédric Bruynsteen; Govind J. Wanjalkar; Ali Al Hadi Amhaz; Jasper Jans; Axl Bomhals; Ulrik L. Andersen; Tobias Gehring; Xin Yin; Adnan A. E. Hajomer

arXiv · 2610.35410

Multimode continuous-variable quantum key distribution with CMOS-compatible photonic-electronic integration

Yiming Bian·Sarah Bastiaens·Saeed Hakimi·Huy Quang Nguyen·Aboobackkar Sidhique·Cédric Bruynsteen·Govind J. Wanjalkar·Ali Al Hadi Amhaz·Jasper Jans·Axl Bomhals·Ulrik L. Andersen·Tobias Gehring·Xin Yin·Adnan A. E. Hajomer

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Abstract

Multiplexing and photonic-electronic integration offer a route to scalable and high-throughput quantum key distribution (QKD) networks through parallel transmission and compact hardware suited to volume manufacturing. Realizing this route requires multichannel transmitters and receivers, and a security analysis accounting for mode coupling. Here we present a CMOS-compatible photonic-electronic multimode continuous-variable QKD architecture, using polarization multiplexing as a two-mode example. Silicon-photonic transmitter and receiver chips prepare and detect two polarization modes in parallel. The receiver is co-integrated with a dual-channel 28-nm CMOS transimpedance amplifier, providing shot-noise clearances exceeding 20 dB in both channels. Pilot-assisted unitary digital recovery removes the need for active optical polarization control, while a multimode security analysis accounts for the mode crosstalk. At 2 percent residual crosstalk, the multimode analysis extends the simulated secure distance from 39 to 84 km, near the crosstalk-free limit of 89 km. Over 10 km of deployed fibre, the mean total finite-size secret-key rate estimate is 6.69 Mbit/s, 12 percent above the single-mode analysis from the same digitally recovered data. These results establish a route to scalable multimode quantum-secured networks built on technology suited to mass production.

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Yiming Bian, Sarah Bastiaens, Saeed Hakimi, Huy Quang Nguyen, Aboobackkar Sidhique, Cédric Bruynsteen, Govind J. Wanjalkar, Ali Al Hadi Amhaz, Jasper Jans, Axl Bomhals, Ulrik L. Andersen, Tobias Gehring, Xin Yin, Adnan A. E. Hajomer. 2026-10-26. Multimode continuous-variable quantum key distribution with CMOS-compatible photonic-electronic integration. https://arxiv.org/abs/2610.35410

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