This document provides an overview of GPON (Gigabit-capable Passive Optical Networks) technology. It describes the basic concepts and architecture of PON networks, including how they use passive splitters and wavelength division multiplexing. GPON is introduced as the choice for carriers due to its ability to support high-bandwidth, long-reach transmission over fiber for triple-play services. The document then covers GPON principles such as downstream broadcast and upstream TDMA transmission, as well as standards, performance parameters, and network protection modes.