All-optical millimeter wave generation and its applications in 5G communication systems

With the increase of data volume and the shortage of frequency band resources in sub6 band, it is difficult to meet the communication requirements for the existing mobile communication systems. It is worth noting that, the 5G millimeter wave communication technology has the advantages of fast speed, large bandwidth and low delay, which can meet the demands of future mobile communication. How to generate millimeter wave with high quality is the key technology. In this paper, 5G millimeter wave communication systems and several all-optical millimeter wave generation technologies are discussed, including direct modulation method, optical heterodyne method, frequency up-conversion method, external modulation method and four-wave mixing (FWM) method. Furthermore, the advantages and limitations of different methods are compared and analyzed. In addition, the promising future applications of 5G millimeter wave communication systems are discussed, and the potential application value of 5G millimeter wave communication systems in digital twin, mobile edge computing and other fields is summarized.