超高速時間領域光フーリエ変換法による1.28Tbit／s／ch-525km 単一偏波DQPSK伝送

摘要

サブピコ秒パルスを用いた超高速光信号の長距離伝送においては，波長分散，偏波分散（PMD）に加え，高次PMDとその時間変動が伝送性能を射ヒさせる要因となる．我々はこれまで時間領域フーリエ変換法により歪みの時間変動を抑制し，320～640Gbit／s-500km の安定な長距離超高速伝送を実現してきた．今回，サブピコ秒パルス用の超高速光フーリエ変換器を往復型構成の光位相変調器により新たに実現し，さらにDQPSK方式を用いることにより，単一偏波1.28Tbit／s／ch-525km 伝送に初めて成功したので報告する．%We demonstrate a single-channel 1.28 Tbit/s-525 km transmission using OTDM of subpicosecond DQPSK signals. In order to cope with transmission impairments due to time-varying higher-order PMD, which is one of the major limiting factors in such a long-haul ultrahigh-speed transmission, we newly developed an ultrafast time-domain optical Fourier transformation technique in a round-trip configuration. By applying this technique to subpicosecond pulses, transmission impairments were greatly reduced, and BER performance below FEC limit was obtained with increased system margin.