Author Affiliations

Tomoya Akatsuka,^1,* Hiromitsu Imai,¹ Masao Takamoto,² Ichiro Ushijima,^2,3 Takashi Goh,⁴ Toshikazu Hashimoto,⁵ Hidetoshi Katori,^2,3 Katsuya Oguri,¹ and Tetsuomi Sogawa⁶

¹NTT Basic Research Laboratories, Nippon Telegraph and Telephone Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan

²Quantum Metrology Laboratory, RTKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

³Department of Applied Physics, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

⁴NTT Device Innovation Center, Nippon Telegraph and Telephone Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan

⁵NTT Device Technology Laboratories, Nippon Telegraph and Telephone Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan

⁶NTT Science and Core Technology Laboratory Group, Nippon Telegraph and Telephone Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan

^*Corresponding author: tomoya.akatsuka.kv@hco.ntt.co.jp