Joint spectral characterization of SPDC photon pairs near 2 $\mu$m in (Al)GaAs-on-insulator waveguides

arXiv:2608.03950v1 Announce Type: cross Abstract: Integrated photon-pair sources are a core component of chip-based quantum computing, communication, and metrology. Although such sources have been demonstrated at conventional telecom wavelengths, the 2 $\mu$m band remains comparatively less explored, despite offering advantages for free-space quantum communication, low-loss transmission in emerging fiber networks, and integration with silicon photonic platforms. In this paper, we demonstrate spontaneous parametric down-conversion (SPDC) in straight GaAs- and AlGaAs-on-insulator waveguides. This platform offers strong second-order nonlinearity and geometry-tunable dispersion, which are advantageous for efficient on-chip pair generation. Measurements of the joint spectral intensity and heralded second-order correlation function show broadband emission around 2 $\mu$m with strong spectral anti-correlations. To our knowledge, this is the first direct joint-spectral characterization of an integrated SPDC source in this wavelength regime.

Authors:Alexandre Z. Leger, Emil Z. Ulsig, Samuel E. Fontaine, Dileep V. Reddy, Eric J. Stanton, Lynden K. Shalm, Richard P. Mirin, Martin J. Stevens, J. E. Sipe, Nicolas Volet, Deny R. Hamel

Abstract:Integrated photon-pair sources are a core component of chip-based quantum computing, communication, and metrology. Although such sources have been demonstrated at conventional telecom wavelengths, the 2 $\mu$m band remains comparatively less explored, despite offering advantages for free-space quantum communication, low-loss transmission in emerging fiber networks, and integration with silicon photonic platforms. In this paper, we demonstrate spontaneous parametric down-conversion (SPDC) in straight GaAs- and AlGaAs-on-insulator waveguides. This platform offers strong second-order nonlinearity and geometry-tunable dispersion, which are advantageous for efficient on-chip pair generation. Measurements of the joint spectral intensity and heralded second-order correlation function show broadband emission around 2 $\mu$m with strong spectral anti-correlations. To our knowledge, this is the first direct joint-spectral characterization of an integrated SPDC source in this wavelength regime.

Optics (physics.optics); Quantum Physics (quant-ph)

arXiv:2608.03950 [physics.optics]

(or arXiv:2608.03950v1 [physics.optics] for this version)

https://doi.org/10.48550/arXiv.2608.03950 arXiv-issued DOI via DataCite (pending registration)

From: Alexandre Z. Leger [view email] [v1] Tue, 4 Aug 2026 17:14:20 UTC (670 KB)

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Joint spectral characterization of SPDC photon pairs near 2 $\mu$m in (Al)GaAs-on-insulator waveguides

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