Cost-Effective Vector THz Signal Generation Technique Enabled by Photonic Frequency Multiplication and Probabilistic Shaping

Terahertz (THz) communications are seen as promising candidates for next-generation mobile data communication systems, owing to their inherently large bandwidth. Taking a step forward, the THz Integrated Sensing and Communication (ISAC) system enables unprecedented data rates while achieving millimeter-level precision in sensing. However, the complexity of generating a THz signal remains significant at present. Still, the complexity involved in generating a THz signal remains considerable at present. In this work, we showcase a cost-effective scheme for generating and detecting vector quadrature amplitude modulation (QAM) signals in the THz band. This is achieved through photonic frequency multiplication utilizing a single-drive Mach–Zehnder Modulator (MZM) in conjunction with optical filtering. The simulation results show that the bit-error ratio (BER) of 4 Gbaud probabilistic shaping-64QAM (PS-64QAM) at 100 GHz can reach the hard-decision forward-error-correction (HD-FEC) threshold of 3.8 × 10^–3.