Wideband and ultra-dense WDM transmission technologies toward over 10-Tb/s capacity

Summary form only given. We have discussed three topics for achieving over-10-Tb/s WDM systems, which are spectral efficiency, wideband optical amplifier, and transmission issues. The polarization division multiplexing/demultiplexing, the gain-shifted Tm-doped fiber amplifier (GS-TDFA) S-band amplifiers and the distributed Raman amplification for S-band excess loss compensation demonstrated their effectiveness up to 10-Tb/s capacity transmission. The inter-band Raman scattering was pointed out to be the ultimate issue in ultrawideband WDM system. Further technology progress, such as advanced Raman effect control, will hopefully open the path to 100-Tb/s capacity which was recently discussed to be an upper bound capacity of single optical fiber within 15-THz bandwidth based on information theory.