Fig. 3: High-speed THz wireless transmission results.

a, Schematic of the UWB all-optical THz wireless transmission set-up. The blue and purple lines indicate the electrical and optical links, respectively. The carrier frequency used in the experiment is 180 GHz. All of the data are collected and processed offline. BNF, band notch filter; MUTC-PD, modified UTC-PD; OMA, optical modulation analyser; PC, polarization controller. b,c, BER results (b) and constellation diagrams (c) at different symbol rates (10–90 Gbaud) with the baseline DSP method. All results are under the given SD-FEC threshold. Constellation diagrams are only shown at the highest symbol rates for different modulation formats. Other results can be found in Supplementary Note 4. d, Architecture of the proposed complex-biGRU algorithm. For each equalization, the network parameters are initially optimized using one set of data, followed by inference generation on another dataset. e,f, BER results (e) and constellation diagrams (f) at different symbol rates (40–100 Gbaud) with the complex-biGRU algorithm. All results are far below the SD-FEC threshold, showing a marked enhancement brought by the complex-biGRU algorithm.