[1] NTT Corp, NTT Device Technol Labs, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 2430198, Japan
[2] Fujikura Ltd, Adv Technol Lab, 1440 Mutsuzaki, Sakura, Chiba 2858550, Japan
[3] Osaka Prefecture Univ, Grad Sch Engn, Naka Ku, 1-1 Gakuencho, Sakai, Osaka 5990814, Japan