GPON

What is GPON?

GPON stands for Gigabit Ethernet passive optical network (PON). A GPON system consists of an optical line terminal (OLT) that connects several optical network terminals (ONTs/ONUs) together using a passive optical distribution network (ODN). 

GPON fundamentals and how it works:

GPON is a point-to-mulipoint access network. The main characteristic of GPON is that it uses passive splitters in the fiber optic distribution network (ODN). This allows one single feeding fiber from the Internet service provider (ISP) to serve multiple homes or businesses. 

OLT sends one-point signal > ODN > splitter breaks into multiple signals > multiple ONT/ONUs receive signals. This is a simplified version, but it gives you a high-level idea of what is happening on a GPON system. 

GPON SFP

Modern OLT and ONT/ONU use compact fiber optic modules to achieve the triple-play GPON services. These modules are known as GPON SFP transceivers. GPON SFP is one type of gigabit optical transceivers that are used in GPON system, which is compliant with ITU-T G.984.2 standard. It is a bidirectional module that has SC receptacle and works over simplex single-mode fiber optic cable over a reach of 20km.

GPON SFP transceivers are categorized into GPON OLT SFP and GPON ONT SFP or GPON ONU SFP depending on the devices they are used in. And there are Class B+ GPON SFP and Class C+ GPON SFP. The major differences between them are the transmit power and the receive sensitivity.