Experimental Demonstration of an Optimized 16-ary Four-Dimensional Modulation Format Using Optical OFDM

We experimentally demonstrate the best known 16-ary modulation format in four dimensions at 25.6 Gb/s using coherent optical OFDM, achieving an OSNR gain of 0.58 dB over PDM-QPSK at a symbol error rate of 1E-2. We also evaluate its performance under optimal coding.