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arXiv · 2104.11508

Superconducting Acousto-optic Phase Modulator

Ayato Okada·Rekishu Yamazaki·Maria Fuwa·Atsushi Noguchi·Yuya Yamaguchi·Atsushi Kanno·Naokatsu Yamamoto·Yuji Hishida·Hirotaka Terai·Yutaka Tabuchi·Koji Usami·Yasunobu Nakamura
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Abstract

We report the development of a superconducting acousto-optic phase modulator fabricated on a lithium niobate substrate. A titanium-diffused optical waveguide is placed in a surface acoustic wave resonator, where the electrodes for mirrors and an interdigitated transducer are made of a superconducting niobium titanium nitride thin film. The device performance is evaluated as a substitute for the current electro-optic modulators, with the same fiber coupling scheme and comparable device size. Operating the device at a cryogenic temperature (T=8K), we observe the length-half-wave-voltage (length-$V_\pi$) product of 1.78 V$\cdot$cm. Numerical simulation is conducted to reproduce and extrapolate the performance of the device. An optical cavity with mirror coating on the input/output facets of the optical waveguide is tested for further enhancement of the modulation efficiency. A simple extension of the current device is estimated to achieve an efficient modulation with $V_\pi=$ 0.27 V.

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Ayato Okada, Rekishu Yamazaki, Maria Fuwa, Atsushi Noguchi, Yuya Yamaguchi, Atsushi Kanno, Naokatsu Yamamoto, Yuji Hishida, Hirotaka Terai, Yutaka Tabuchi, Koji Usami, Yasunobu Nakamura. 2021-04-23. Superconducting Acousto-optic Phase Modulator. https://doi.org/10.1364/oe.426371

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