Experimental Evaluation of an Unrepeatered Link Using C, L, and U Transmission Bands

We investigate C+L+U bands unrepeatered transmission of 520 x 24.5 GBaud PM-16QAM signal over 257.1 km. The system uses distributed Raman amplification as well as erbium doped fiber amplifiers for the C+L bands and lumped Raman amplifiers for the U band.