Integrated optical transceivers: architectures, key technologies, and applications

As electrical I/O approaches inherent bottlenecks in reach, energy efficiency, and bandwidth density, integrated optical transceivers are becoming critical enablers for scaling data center and accelerator interconnects. In this review, we systematically explore their development through three aspects: transceiver architectures, key enabling technologies, and target applications. At the architectural level, we outline the entire integration-driven progression trend of optical transceivers, from pluggable modules to co-packaged optics and chiplet-based engines. Regrading key implemented technologies, we survey various commonly employed optical transmitter solutions, in which the key modulation components are severally vertical-cavity surface-emitting laser (VCSEL), electro-absorption modulated laser (EML), Mach-Zehnder modulator (MZM) and microring modulators; optical receiver schemes based on single and balanced photodetectors; as well as the associated electronic CMOS/SiGe driver and transimpedance amplifier (TIA) circuits. Currently, optical transceivers already serve as essential components in data center and high-performance computing (HPC) fabrics, high-bandwidth memory and accelerator links. They could also support other emerging computing, sensing, and communication applications in near future, including short-reach free-space links, IoT/edge systems, autonomous vehicles, and quantum communication. Moving forward, next-generation optical transceivers are increasingly progressing toward much higher energy efficiency, bandwidth density, and scalability, driven by the new advancements in architectural design, powerful cell devices and chiplet packaging.