128×10.66 Gbit/s transmission over 840 km standard SMF with 140 km optical repeater spacing (30.4 dB loss) employing dual-band distributed Raman amplification

Ultrabroad-band Raman amplifiers pumped and gain-equalized by wavelength-division-multiplexed high-power laser diodes

“…Also, Raman amplifiers play an important role in transoceanic multi-terabit-per-second WDM transmission [23]. An interesting use of the power budget margin is to extend the fiber span distance between amplifiers up to 250 km [24], 140 km [25], and 160 km [26]. Some attempts have been made to increase the bit rate of single channel up to 320 Gb/s [27].…”