High-Speed Photo-Diode with Advanced Driver/Control Circuits

This chapter focuses on high-speed photodetectors (PDs) and their integration into advanced driver/control circuits, particularly analog radio-over-fiber communications configured for point-to-point or point-to-multipoint access in 5G/beyond-5G networks. Compared with digital-based radio-over-fiber, analog radio-over-fiber technology provides high-data-rate and low-latency wireless communications. High-speed PDs are essential components of radio-over-fiber technologies. In section “Introduction,” several types of PDs are described. Sections “Photodetector’s Basic” and “Surface/Side Illuminated Photodetector” describe the fundamental PIN-PD structure and theories based on surface and edge illumination. In addition to the fundamental PD, an avalanche photodetector (APD) is introduced to increase responsivity in section “Avalanche Photodetector.” In section “Uni-travelling Carrier Photodetector,” the fundamental theories for high-speed designing using a uni-traveling carrier photodetector (UTC-PD), including the major factors of carrier traveling, carrier drifting, and the CR time constant, are explained. To improve the output photocurrent and output radio frequency (RF) power, section “High Photocurrent and High RF Output Power Photodetector” reviews the electric field screening and thermal impedance effects at the junction. State-of-the-art high-speed and high-power PDs in the 100 GHz range from previous reports are reviewed in section “State of the Art of High-Power Photodetector.” In section “Fabrication of UTC-photodetector,” UTC-PD fabrication and characteristics are discussed with a nonbias UTC-PD as an example. Advanced driver/control circuits, optical-to-electrical (O/E) package designs, implementations for hybrid integrations, and their applications to fiber wireless communication are discussed in section “Advanced Driver/Control Circuits” for a 100 GHz optical-to-radio converter module. A demonstration using high-data-rate fiber wireless communication using an optical-to-radio converter module is also described.