When you see “PON” on your router, it stands for Passive Optical Network. Enter the passive optical network (PON), a technology that makes it easier and more affordable for internet service providers to deliver high-speed fiber internet to households. Depending on where the PON terminates, the system can be described as fiber to the curb, fiber to the building or. "PON" stands for Passive Optical Network, which is a technology used in fiber optic communication systems. The "PON light" on a router typically refers to the indicator light that shows the status of the PON connection. While there are many subtle differences, a clear distinction between active optical networking and PON topology is PON's use of a.