Quantum-Limited Optical Vector Analysis

arXiv:2509.25950v2 Announce Type: cross Abstract: Optical Vector Analysers (OVA) are critical for emerging technologies such as integrated photonics and optical positioning. Achieving a sensitivity near the Standard Quantum Limit (SQL) while acquiring a wide spectrum allows an accurate measurement of targets that are fragile, non-linear, or that scatter most of the probe light away. Existing OVAs operate with a sensitivity orders of magnitude below the SQL. In this paper, we use a free-running interferometer with a frequency range of 20 THz as an OVA. We introduce novel methods to mitigate the phase noise and obtain a unit signal-to-noise ratio for powers at the fW level. We apply this technique towards quantifying the fabrication quality of microring resonators in thin-film Lithium Niobate. Our characterisation yields a signal-to-noise ratio above 1 with much less than 1 circulating photon and reveals a quality factor above 5 millions, unambiguously attributed to low internal losses.

Abstract:Optical Vector Analysers (OVA) are critical for emerging technologies such as integrated photonics and optical positioning. Achieving a sensitivity near the Standard Quantum Limit (SQL) while acquiring a wide spectrum allows an accurate measurement of targets that are fragile, non-linear, or that scatter most of the probe light away. Existing OVAs operate with a sensitivity orders of magnitude below the SQL. In this paper, we use a free-running interferometer with a frequency range of 20 THz as an OVA. We introduce novel methods to mitigate the phase noise and obtain a unit signal-to-noise ratio for powers at the fW level. We apply this technique towards quantifying the fabrication quality of microring resonators in thin-film Lithium Niobate. Our characterisation yields a signal-to-noise ratio above 1 with much less than 1 circulating photon and reveals a quality factor above 5 millions, unambiguously attributed to low internal losses.

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

arXiv:2509.25950 [physics.optics]

(or arXiv:2509.25950v2 [physics.optics] for this version)

K. Dasigi, P. A. Dmitriev, K. Jen Wo, F. Hanamura, L. Kong and S. Touzard, "Quantum-Limited Optical Vector Analysis," in IEEE Transactions on Instrumentation and Measurement, vol. 75, pp. 7004404-7004404, 2026, Art no. 7004404

https://doi.org/10.1109/TIM.2026.3699774 DOI(s) linking to related resources

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Quantum-Limited Optical Vector Analysis

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