Highly spectral efficient transmission of 183 + 24.5 GBaud 256-QAM spatial super channels over 55 km three-mode fiber

We investigate the data-rate increase of 256-QAM over 64-QAM signals in few-mode fiber transmission. Simulations and experimental validation indicate an increased total data throughput by applying 256-QAM, achieving 146 Tbit/s total data-rate at an average spectral efficiency of 10.67 bit/s/Hz/mode over the entire C-band.