The optical carrier is fundamental to modern high-speed data transmission, serving as the foundation for global communication. This technology. This Technical Paper provides a comprehensive overview of the optical transport network (OTN), which is the current generation technology used in telecommunication networks for transporting various client signals including Ethernet and legacy protocols. Each wavelength acts like an independent “virtual fibre” carrying its own traffic — Ethernet, OTN, Fibre. The Optical Transport Network (OTN) is an internationally standardized set of protocols that define how digital signals are encapsulated, multiplexed, and transported across optical fiber infrastructure.