Andrea Peri1, Giulio Gualandi2,3, Tommaso Bertapelle1, Mattia Sabatini1, Giacomo Corrielli3, Yoann Piétri1, Davide Giacomo Marangon1,4, Giuseppe Vallone1,4, Paolo Villoresi1,4, Roberto Osellame3, Marco Avesani1,4
Advanced Photonics 8(1) 016009
DOI: 10.1117/1.AP.8.1.016009
1Università degli Studi di Padova, Dipartimento di Ingegneria dell’Informazione, Padua, Italy
2Politecnico di Milano, Dipartimento di Fisica, Milan, Italy
3Consiglio Nazionale delle Ricerche (CNR), Istituto di Fotonica e Nanotecnologie, Milan, Italy
4Università degli Studi di Padova, Padua Quantum Technologies Research Center, Padua, Italy
Continuous variable quantum key distribution (CV-QKD) and continuous variable quantum random number generation (CV-QRNG) are critical technologies for secure communication and high-speed randomness generation, exploiting shot-noise-limited coherent detection for their operation. Integrated photonic solutions are key to advancing these protocols, as they enable compact, scalable, and efficient system implementations. We introduce femtosecond laser micromachining (FLM) on borosilicate glass as a platform for producing photonic integrated circuits (PICs) realizing coherent detection suitable for quantum information processing. Employing off-chip detectors, we exploit the specific features of FLM to produce a PIC designed for CV-QKD and CV-QRNG applications. The PIC features fully adjustable optical components that achieve precise calibration and reliable operation under protocol-defined conditions. The device exhibits low insertion losses (≤1.28dB), polarization-insensitive operation, and a common-mode rejection ratio exceeding 73 dB. These characteristics allowed the experimental realization of a source-device-independent CV-QRNG with a secure generation rate of 42.74 Gbit/s and a quadrature phase-shift-keying-based CV-QKD system achieving a secret key rate of 3.2Mbit/s. Our results highlight the potential of FLM technology as an integrated photonic platform, paving the way for scalable and high-performing quantum communication systems.
This article was covered in the media, and can be found in the article Laser‑written glass chip pushes quantum communication toward practical deployment.