[1] NTT Corp, NTT Network Innovat Labs, Hyperphoton Component Lab, Fiber Amplifiers Res Grp, Atsugi, Kanagawa 2430198, Japan
[2] NTT Corp, NTT Network Innovat Labs, Photon Transport Network Lab, High Speed Lightwave Transport Syst Res Grp, Yokosuka, Kanagawa 2390847, Japan