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arXiv · 2603.20139

Heisenberg-scaling characterization of a two-channel optical network via two-port homodyne detection

Atmadev Rai·Paolo Facchi·Vincenzo Tamma
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Abstract

We present a fully Gaussian and experimentally feasible scheme for the simultaneous estimation of the four real parameters that characterize a two-channel optical network. The scheme utilizes a two-mode squeezed probe and balanced homodyne detection at both output ports, for which we derive the complete classical Fisher information matrix analytically. Our scheme achieves the Heisenberg-scaling sensitivity for all four parameters simultaneously, enabling full multiparameter characterization of the two-channel interferometric network. We further show, by maximum-likelihood estimation, that the corresponding multiparameter Cram\'er-Rao bounds are saturated with a modest number of experimental repetitions and for low photon number. The scheme establishes a practical route to Heisenberg-scaling multiparameter Gaussian metrology for a two-channel network, with direct relevance to calibration and sensing in integrated photonics and distributed quantum-enhanced measurement architectures.

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Atmadev Rai, Paolo Facchi, Vincenzo Tamma. 2026-03-20. Heisenberg-scaling characterization of a two-channel optical network via two-port homodyne detection. https://doi.org/10.1103/y9wq-hhg2

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