The vertical-cavity surface-emitting laser (VCSEL) is becoming a key device in high-speed optical local area networks (LANs) and even wide-area networks (WANs). This device is also enabling ultraparallel data transfer in equipment and computer systems, including storage area networks (SANs) and wide optoelectronics fields. In this paper, we will review its physics and the progress of technology covering the spectral band from infrared to ultraviolet by featuring materials and fabrication technology. Performances such as threshold, output power, polarization, modulation, and reliability are introduced. Last, we will touch on its future prospects.