Error-free 20-Gbit/s soliton transmission over 7150 km through all-optical synchronous phase modulation

In the perspective of ultrahigh bit-rate (>100 Gbit/s) long-haul soliton transmission, synchronous regeneration requires all-optical clock recovery and all-optical modulation. All-optical amplitude and phase modulators have been proposed. However, regeneration based on phase modulators has been demonstrated only at 2.5-Gbit/s data rates. In this paper, an all-optical Kerr modulator has been implemented in a recirculating loop to periodically achieve phase control of 20-Gbit/s soliton data. Error-free propagation over 7150 km is achieved without the help of dispersion-managed fibers.