光子太赫兹：大容量高可靠星地传输的新途径

摘要：面向大容量高可靠星地传输需求，建立600 km低轨地—星上行模型，以140 GHz太赫兹和1 550 nm空间激光为对象，比较晴空、云雾及降雨条件下的衰减与误码性能，分析大气湍流对链路稳定性的影响，并建立地地—星地等效传输距离映射。结果表明，太赫兹在浓雾和云层环境中更具鲁棒性，对湍流起伏较不敏感，但对降雨更敏感。在终端实现方面，光子太赫兹面临的相位噪声与调制非线性会增加功率需求，空间激光则可通过光束漂移补偿减轻湍流影响。上述传播优势的发挥还需结合收发终端设计与优化。光子太赫兹兼具超宽带传输潜力及云雾、湍流环境下的传播鲁棒性，有望降低高速星地业务对时间和地域条件的依赖，为大容量高可靠星地传输提供新途径。

关键词：光子太赫兹；星地通信；空间激光通信；大气湍流；误码率

Abstract: To address the need for high-capacity, reliable satellite–ground transmission, a 600-km low-Earth-orbit (LEO) ground-to-satellite uplink model is established for 140 GHz THz and 1 550-nm free-space optical (FSO) links. Attenuation and bit-error-rate (BER) performance are compared under clear-air, fog, cloud, and rain conditions, the effects of atmospheric turbulence on link stability are analyzed, and a ground-to-ground (G2G)/ground-to-satellite (G2S) equivalent-distance mapping is developed. THz is more robust in dense fog and cloud environments and is less sensitive to turbulence-induced fluctuations, but more sensitive to rain. At the terminal level, phase noise and modulation nonlinearity in photonic THz front ends increase power requirements, while beam-wander compensation can mitigate turbulence effects in FSO links. Realizing these propagation advantages also requires transceiver design and optimization. Combining ultra-wideband transmission potential with resilient propagation through cloud/fog and turbulence, photonic THz offers a promising path toward high-capacity, reliable satellite–ground transmission with reduced temporal and geographical constraints on high-speed services.

Keywords: photonic terahertz; satellite–ground communication; free-space optical communication; atmospheric turbulence; bit-error rate