Fig. 1. Two transmission schemes for the IM/DD MIMO communication system. (a) Transmission scheme without polarization multiplexing. (b) Transmission scheme with polarization multiplexing.

Fig. 2. Experimental setup of photonics-assisted D-band MIMO wireless communication system. Photos of (a) transmitter, (b) transmission link, and (c) receiver. (d) Tx DSP block diagram. (e) Rx DSP block diagram.

Fig. 3. (a) Baseband signal spectrum captured by OSC. (b) Baseband signal spectrum after resampling.

Fig. 4. (a) Estimated SNR on each subcarrier of the DMT-QPSK signal. (b) Constellation of the recovered QPSK before DD-LMS. (c) Constellation of the recovered QPSK after DD-LMS. (d) Estimated SNR on each subcarrier of the DMT-16QAM signal. (e) Constellation of the recovered 16QAM before DD-LMS. (f) Constellation of recovered 16QAM after DD-LMS.

Fig. 5. Measured BER of the DMT-QPSK versus different input optical powers into UTC-PD. (a) Constellation of the QPSK recovered from the 10-GBaud DMT signal at 5-dBm input optical power into UTC-PD. (b) Constellation of the QPSK recovered from the 15-GBaud DMT signal at 5-dBm input optical power into UTC-PD.

Fig. 6. Measured BER of the DMT-16QAM versus different input optical powers into the UTC-PD.

Fig. 7. Waveforms of the DMT-16QAM signals when the input optical powers into the UTC-PD are 5 and 5.5 dBm.