Photonics-assisted fully integrated high-power transmitter for compact fiber-to-millimeter-wave wireless links

The technique of Radio over Fiber provides breakthroughs for information penetration in the millimeter-wave (mmWave) and terahertz era. The next generation of mobile networks demands dense, high-speed, and energy-efficient wireless systems, driving an urgent need for integrated and miniaturized transmitters. However, constrained by limited power handling capabilities and high radiation losses of on-chip systems, current systems still rely on bulky components and devices to fulfill the desired functions, resulting in high power consumption and increased complexity. Here, we demonstrate a fully integrated fiber-to-mmWave wireless transmitter chip by integrating a high-power silicon-germanium photodiode with a bowtie antenna on a standard silicon-on-insulator (SOI) platform. The saturated input optical power of the transmitter is significantly enhanced (>17 dBm) through the special design of the light absorption region. Furthermore, the high-resistivity substrate of the SOI process effectively reduces radiation losses, achieving a 1.75 dBi maximum gain of the antenna. As a proof-of-concept demonstration, the transmitter chip achieves 1.2 Gbps wireless communication at 26 GHz and successfully achieves high-definition video transmission at a distance of 5.5 m.