With the increasing demand for high-speed, reliable, and scalable communication systems, the integration of optical and wireless technologies has emerged as a critical area of research. Optical communication provides unparalleled bandwidth and minimal signal loss over long distances, while wireless communication offers the mobility and flexibility essential for last-mile connectivity. This paper reviews the fundamentals of optical-to-wireless and wireless-to-optical signal conversions, addressing the technical challenges and design considerations inherent in hybrid systems. Various integration methodologies are explored, emphasizing their roles in advancing modern communication networks such as 5G and 6G. Additionally, the potential of optical–wireless integration in supporting satellite-based communication is discussed, particularly in areas such as free-space optical links, radio-over-fiber for ground station connectivity, and hybrid fiber-satellite backhaul solutions. While not the primary focus, these considerations highlight possible future research directions, where optical–wireless technologies may enhance global connectivity and next-generation communication infrastructures.