The lasers in the OLT emit optical signals, while the photodetectors in the ONU detect and convert incoming optical signals into electrical signals. In a Passive Optical Network (PON) architecture, a single OLT can support multiple ONUs through a shared optical fiber. Operating at the physical layer of the OSI model, optical modules are core devices in optical. orchestration of OLT (Optical Line Terminal) and ONU (Optical Network Unit) optical modules in networking is fundamental to the efficient and reliable operation of fiber-optic communication systems. This article provides a brief introduction to both. The OLT is responsible not only for transmitting data from the core network to user terminals but also for managing bandwidth. A Gigabit Ethernet Passive Optical Network (GEPON) system is generally composed of an optical line terminal (OLT) at the service provider's central office and a number of optical network units (ONUs) or optical network terminals (ONTs) near end users, as well as the optical splitter.
