A low-loss, 24-mode laser-written universal photonic processor in a glass-based platform
Abstract
We report the fabrication of the first 24-mode universal photonic processor (UPP) realized through femtosecond laser writing (FLW), marking the most complex UPP demonstrated to date. Optimized for quantum dot emission at 925 nm, the device exhibits total insertion losses averaging only 4.35 dB, enabling its direct application in advanced multi-photon quantum experiments. Leveraging the versatility of FLW, we introduce suspended waveguides and precisely engineered 2D and 3D microstructures, significantly enhancing thermal isolation and minimizing power dissipation. As a result, our processor operates efficiently at less than 10 W, requiring only a simple thermo-electric cooler for stable thermal management. The device exhibits exceptional performance after calibration, implementing Haar-random unitary transformations with an amplitude fidelity of 99.7 %. This work establishes FLW-based integrated photonics as a scalable and robust platform for advancing quantum computing, communication, and sensing technologies.
Keywords
Cite
@article{arxiv.2505.01609,
title = {A low-loss, 24-mode laser-written universal photonic processor in a glass-based platform},
author = {Andrea Barzaghi and Maëlle Bénéfice and Francesco Ceccarelli and Giacomo Corrielli and Valerio Galli and Marco Gardina and Vittorio Grimaldi and Jakub Kaczorowski and Francesco Malaspina and Roberto Osellame and Ciro Pentangelo and Andrea Rocchetto and Alessandro Rudi},
journal= {arXiv preprint arXiv:2505.01609},
year = {2025}
}
Comments
Updated Haar-random implementation measurements with slightly improved ones. Updated figure 4 with new measurement data