Fig. 1. Experimental setup of the photonics-assisted fiber-wireless converged 2 × 2 MIMO communication system based on polarization multiplexing at the THz band. (a) The scene diagram of the 3-m wireless 2 × 2 MIMO links. (b) The scene diagram of the back-to-back (BTB) wireless link.

Fig. 2. Measured optical spectra of the 318 GHz optical THz-wave signals.

Fig. 3. (a) The structure of the four-butterfly MIMO CMA. (b) The schematic diagram of the non-linear equalizer structure based on the second-order Volterra-series. (c) The DSP routine at the transmitter side. (d) The DSP routine at the receiver side.

Fig. 4. X-polarized signal constellation diagrams after (a) GSOP, (b) clock recovery, (c) CMA equalization, (d) CPR, and (e) DD-LMS. Y-polarized signal constellation diagrams after (f) GSOP, (g) clock recovery, (h) CMA equalization, (i) CPR, and (j) DD-LMS.

Fig. 5. (a) Electrical spectra of the X-polarized signals. (b) Electrical spectra of the Y-polarized signals.

Fig. 6. (a) BER versus the input optical power into the UTC-PD in different cases for the X-polarized signals. (b) BER versus the input optical power into the UTC-PD in different cases for the Y-polarized signals.

Fig. 7. BER versus the number of CMA taps in Case 2.

Fig. 8. (a) BER versus the input optical power into the UTC-PD with the VNLE algorithm for X-polarized signals. (b) BER versus the input optical power into the UTC-PD with the VNLE algorithm for Y-polarized signals.