Experimental comparison between Hybrid-QPSK/8QAM and 4D-32SP-16QAM formats at 31.2 GBaud using Nyquist pulse shaping

We report on the performance comparison between two modulation formats carrying each 2.5 bits per transmitted 2D-symbol. Using Nyquist pulse shaping and a 33-GHz spacing grid, we show that the 4D-32SP-16QAM format outperforms the Hybrid-QPSK/8QAM format over a transmission link made of standard single mode fiber.