Summary: The text discusses various cases and applications of optical fibers in telecommunication networks, highlighting different types of fiber optic cables and their functionalities. It describes the importance of fiber optic technology in providing high-speed data transmission, emphasizing the use of fiber optics for long-distance communication and faster internet connectivity. Additionally, the text mentions the different components and configurations of fiber optic networks, including single-mode and multi-mode fibers, as well as the significance of fiber optic splitters and connectors. It also touches on the challenges associated with fiber optic networks, such as attenuation and dispersion, and emphasizes the need for advanced testing methods to ensure optimal performance.