24-hour measurement of squeezed light using automated stable fiber system

Tomohiro Nakamura; Takefumi Nomura; Mamoru Endo; Atsushi Sakaguchi; He Ruofan; Takahiro Kashiwazaki; Takeshi Umeki; Kan Takase; Warit Asavanant; Jun-ichi Yoshikawa; Akira Furusawa

arXiv · 2401.17533

24-hour measurement of squeezed light using automated stable fiber system

Tomohiro Nakamura·Takefumi Nomura·Mamoru Endo·Atsushi Sakaguchi·He Ruofan·Takahiro Kashiwazaki·Takeshi Umeki·Kan Takase·Warit Asavanant·Jun-ichi Yoshikawa·Akira Furusawa

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Abstract

In order to provide a cloud service of optical quantum computing, it is inevitable to stabilize the optical system for many hours. It is advantageous to construct a fiber-based system, which does not require spatial alignment. However, fiber-based systems are instead subject to fiber-specific instabilities. For instance, there are phase drifts due to ambient temperature changes and external disturbances, and polarization fluctuations due to the finite polarization extinction ratio of fiber components. Here, we report the success of measuring squeezed light with a fiber system for 24 hours. To do this, we introduce stabilization mechanics to suppress fluctuations in the fiber system, and integrated controller to automatically align the entire system. The squeezed light at the wavelength of 1545.3 nm is measured every 2 minutes, where automated alignments are inserted every 30 minutes. The squeezing levels with the average of -4.42 dB are recorded with an extremely small standard deviation of 0.08 dB over 24 hours.

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Tomohiro Nakamura, Takefumi Nomura, Mamoru Endo, Atsushi Sakaguchi, He Ruofan, Takahiro Kashiwazaki, Takeshi Umeki, Kan Takase, Warit Asavanant, Jun-ichi Yoshikawa, Akira Furusawa. 2024-01-31. 24-hour measurement of squeezed light using automated stable fiber system. https://arxiv.org/abs/2401.17533

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