In this paper, we describe soliton transmission experiments at 20-40 Gbit/s over 1000 km and new soliton transmission technologies. The experimental setup for the soliton data transmission is shown. 20 Gbit/s pulses were obtained by using an optical multiplexing technique with two 3 dB fiber couplers. For the 40 Gbit/s transmission experiment, a polarization multiplexing technique was used, which enabled the bit rate to be doubled (20 Gbit/sx2). The EDFA repeater spacing was 50 km. After propagation over 2000 km, the output soliton at 20 Gbit/s was optically demultiplexed to a 10 Gbit/ s signal by using LiNbO3 intensity modulators and a clock extraction circuit. The 10 Gbit/s signals were then detected with an InGaAs PIN photodiode and the bit error rate (BER) was measured.