With the rapid development of new services such as 5G mobile Internet and Internet of Things, the transmission capacity, transmission speed and bit error rate of future communication system are required to be higher. Terahertz(THz) band, which is between millimeter wave and far-infrared light, has the advantages of both microwave and light wave like low quantum energy, large bandwidth and good penetration. THz communication system has become one of the research hotspots in recent years. However, terahertz wireless communication has the disadvantages of line of sight propagation and large path loss. It is important to combine wireless link with wired link. This paper analyzes the devices and technologies involved in the process of photonic terahertz signal generation, photonic terahertz wireless link transmission and fiber link transmission, and focuses on the research status of terahertz cable transmission. Finally, the experiment shows the great potential of terahertz wired transmission through real-time transmission of 1 m terahertz fiber with transmission rate of 1.485 GBaud and carrier wave of 350 GHz based on intensity modulation and direct detection.