Ultrahigh-Bit-Rate Optical Transmission Research in Japan

Recent progress toward ultrahigh-bit-rate optical fibre transmission systems employing optical time-division multiplexing (TDM) techniques is reviewed. Focus is placed on 100 Gbit s$^{-1}$ optical TDM transmission systems and the related technologies studied in Japan. Successful 100 Gbit s$^{-1}$ TDM transmission experiments over 200-500 km and the key technologies are described, including ultrashort optical pulse generation, all-optical multiplexing-demultiplexing and optical timing extraction techniques, together with state-of-the-art performances and future prospects.