Passive Optical Network (PON) is a type of fiber-optic network architecture that enables multiple end-users to share a single optical fiber for data transmission. The key characteristic of PON is that it utilizes passive optical splitters to divide the optical signal among multiple end-users. This means that the splitting of the signal is done passively, without the need for active components such as amplifiers or repeaters.

In a typical PON deployment, a single optical line terminal (OLT) at the service provider's central office or data center connects to multiple optical network units (ONUs) or optical network terminals (ONTs) at the end-users' premises. The OLT communicates with the ONUs/ONTs by sending optical signals downstream (from the service provider to the end-users) and receiving optical signals upstream (from the end-users to the service provider).

The passive optical splitter located between the OLT and the ONUs/ONTs divides the downstream optical signal into multiple paths, allowing it to be distributed to multiple end-users. Similarly, the upstream signals from different end-users are combined by the splitter and sent back to the OLT.

PON technology offers several advantages, including:

1. Cost-effectiveness: Since PON utilizes passive components, it requires less active equipment, leading to lower deployment and maintenance costs.

2. Scalability: PON can easily accommodate additional end-users by adding more ONUs/ONTs without significant upgrades to the central office equipment.

3. Efficient use of fiber: PON enables the efficient sharing of a single optical fiber among multiple users, maximizing the utilization of fiber infrastructure.

4. High bandwidth: PON supports high-speed data transmission, making it suitable for delivering broadband services such as internet access, voice, and video.

PON is widely deployed in Fiber-to-the-Home (FTTH), Fiber-to-the-Premises (FTTP), and Fiber-to-the-Building (FTTB) applications, where it provides high-speed broadband access to residential and business customers.