Entropy-Loading Enhanced 300 GHz DP-IM/DD Photonic-Assisted THz Wireless Interconnect

We propose and experimentally demonstrate an entropy-loading enhanced 300 GHz dual-polarization intensity-modulation/direct-detection (DP-IM/DD) photonic-assisted terahertz (THz) wireless interconnect architecture. Motivated by severe frequency selectivity and deep spectral notches arising from the cumulative imperfections of broadband modulators, uni-traveling-carrier photodiodes (UTC-PDs), antennas, and TIAs, we adopt an entropy-loading based probabilistically shaped discrete multi-tone (PCS-DMT) modulation to match sub-carrier symbol probabilities to their instantaneous signal-to-noise ratios (SNR). Unlike conventional uniform modulation, the entropy-loaded scheme precisely adapts to frequency-selective channel impairments, significantly enhancing performance and robustness. Experimental results indicate that the proposed approach achieves normalized generalized mutual information (NGMI) gains of up to 0.20 compared with the uniform constellation approach at identical transmit powers. The demonstration reaches a record spectral efficiency of 7.0 bit/s/Hz, delivering a gross data rate of 271.8 Gbps (net 230.9 Gbps) over 33 GHz bandwidth at 0.1 m, surpassing existing direct-detection THz links and approaching coherent system performance with substantially reduced complexity.