Terahertz direct modulation techniques for high-speed communication systems

Terahertz communication technology can provide abundant frequency resources, strong confidentiality, antijamming capability, communication tracking capability and the ability to achieve high-speed data transmissions and can serve as an important technical method for high-speed communications in the future. Among these terahertz communication technologies, terahertz direct modulation technology is a key means to achieve low system complexity and power consumption. In this paper, a review and outlook of terahertz direct modulation technology are proposed from the aspects of high-electron-mobility-transistor-based terahertz direct modulation, parallel-switch terahertz direct modulation, diode-based terahertz direct modulation, quantum cascade laser-based terahertz direct modulation and new-material-based terahertz direct modulation. We hope through this paper that more readers can gain knowledge about the development and challenges of terahertz direct modulation technology for high-speed communication systems, thus promoting the development of high-speed terahertz communication technology based on direct modulation.