Fig. 5. Data modulation testing.
a Experimental setup for coherent data transmission. AWG: arbitrary waveform generator, LO: local oscillator, OMA: optical modulation analyser, PC: polarisation controller. b–g Constellation diagram for QPSK signals with symbol rates of 60, 80, 100, and 110 Gbaud and 16 QAM signals with symbol rates of 60 and 80 Gbaud. h Measured curve of BER versus the received optical power for 60 Gbaud 16 QAM signal.