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arXiv · 2201.13333

Quantifying n-photon indistinguishability with a cyclic integrated interferometer

Mathias Pont·Riccardo Albiero·Sarah E. Thomas·Nicolò Spagnolo·Francesco Ceccarelli·Giacomo Corrielli·Alexandre Brieussel·Niccolo Somaschi·Hêlio Huet·Abdelmounaim Harouri·Aristide Lemaître·Isabelle Sagnes·Nadia Belabas·Fabio Sciarrino·Roberto Osellame·Pascale Senellart·Andrea Crespi
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Abstract

We report on a universal method to measure the genuine indistinguishability of n-photons - a crucial parameter that determines the accuracy of optical quantum computing. Our approach relies on a low-depth cyclic multiport interferometer with N = 2n modes, leading to a quantum interference fringe whose visibility is a direct measurement of the genuine n-photon indistinguishability. We experimentally demonstrate this technique for a 8-mode integrated interferometer fabricated using femtosecond laser micromachining and four photons from a quantum dot single-photon source. We measure a four-photon indistinguishability up to 0.81$\pm$0.03. This value decreases as we intentionally alter the photon pairwise indistinguishability. The low-depth and low-loss multiport interferometer design provides an efficient and scalable path to evaluate the genuine indistinguishability of resource states of increasing photon number.

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Mathias Pont, Riccardo Albiero, Sarah E. Thomas, Nicolò Spagnolo, Francesco Ceccarelli, Giacomo Corrielli, Alexandre Brieussel, Niccolo Somaschi, Hêlio Huet, Abdelmounaim Harouri, Aristide Lemaître, Isabelle Sagnes, Nadia Belabas, Fabio Sciarrino, Roberto Osellame, Pascale Senellart, Andrea Crespi. 2022-01-31. Quantifying n-photon indistinguishability with a cyclic integrated interferometer. https://doi.org/10.1103/physrevx.12.031033

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