In the 5G era, the demand for high-bandwidth computing, transmission, and storage has led to the development of optoelectronic interconnect technology. This technology has evolved from traditional board-edge optical modules to smaller and more integrated solutions. Co-packaged optics (CPO) has evolved as a solution to meet the growing demand for data. Compared to typical optoelectronic connectivity technology, CPO presents distinct benefits in terms of bandwidth, size, weight, and power consumption. This study presents an overview of CPO, highlighting its fundamental principles, advantages, and distinctive features. Additionally, it examines the current research progress of two distinct approaches utilizing Vertical-Cavity Surface-Emitting Laser (VCSEL) and silicon photonics integration technology. Additionally, it provides a concise overview of the many application situations of CPO. Expanding on this, the analysis focuses on the CPO using 2D, 2.5D, and 3D packaging techniques. Lastly, taking into account the present technological environment, the scientific obstacles encountered by CPO are analyzed, and its future progress is predicted.

Silicon photonics, serving as a cornerstone technology in modern information technology, demonstrates significant application potential in critical scenarios such as high-speed data center interconnects and integrated optical communication systems. Facing the persistent demand for information processing capabilities in the post-Moore era, photonic chips have emerged as a pivotal direction for overcoming the performance bottlenecks of traditional chips, leveraging their advantages of low power consumption, high speed, and high integration density. This review focuses specifically on the optical interconnection and packaging technologies for photonic chips. It comprehensively analyzes the research frontiers and key challenges in packaging technologies, encompassing efficient fiber-to-chip coupling techniques, chip-scale optical interconnection technologies, and 2D, 2.5D, and 3D stacked co-packaged optics technologies. By synthesizing and summarizing recent research advances, this paper aims to provide researchers in related fields with a systematic understanding of photonic integrated circuit technology. Furthermore, it seeks to offer insights for future technological breakthroughs in device optimization, packaging innovation, and system-level applications of photonic integrated circuits.