Passive Optical Networks: The Future of Networking

Passive optical networks (PONs) set the new standard for high-speed network architecture that brings fiber cabling and signals to a user based upon a point-to-multipoint design that enables a single optical fiber to serve multiple devices. The architecture uses passive (unpowered) optical splitters, reducing the cost of equipment compared to copper-based architectures that require signals to be "refreshed" every 100 meters.

PONs architecture are designed to be very efficient, as they provide telephone, video, and data traffic over a single strand of optical fiber for up to 64 users. Compare this to a traditional copper-based architecture which require three separate copper cabling infrastructures (one for voice traffic, one for video traffic, and one for data/Internet traffic). In fact, a typical 7-story building with 1,000 employees will require about 18,000 lbs of copper cabling for all of the phone lines, data/ethernet connections, and CATV connections. That same building can be serviced using less than 3,000 lbs of fiber optic cabling. Not only is there a deadweight savings of 15,000 lbs, but there is a huge savings in copper which is a natural resource that is being depleted from of planet by huge copper mines.

A PON implementation uses lasers and wave division multiplexing to simultaneously transmit and receive all voice, video, and data signals across the network. By using fiber optic cabling coupled with unpowered optical splitters, a properly installed PON infrastructure can support end-users up to 24 miles away without the use of repeaters or amplifiers. Compare this to a copper-based network infrastructure that relies upon workgroup switches every 100 meters (That's less than 330 feet!).

So, by using a PON infrastructure an organization can save on the cabling as well as eliminate the workgroup switches from every IDF/Telco room. This paradigm shift in networking infrastructure is far reaching in many different aspects. Here are some of the benefits:

1. Replace the three different copper cabling infrastructures (telephone, video, and data) with a single fiber optic cabling infrastructure.

2. Reduce the deadweight in a building by replacing the dense and heavy copper cabling with very light fiber optic cabling.

3. Eliminate the workgroup switches from every IDF/Telco room, which means saving the cost of purchasing that equipment.

4. Reduce/eliminate the dedicated HVAC used for cooling the IDF/Telco rooms. Since the workgroup switches are eliminated, it also reduces and/or eliminates the need for dedicated HVAC to keep those rooms cool.

5. Because a PON fiber optic network can provide higher bandwidth, it is able to offer higher efficiency using larger, variable-length packets. This permits efficient packaging of user traffic, with frame segmentation allowing higher quality of service (QoS) for delay-sensitive voice and video communications traffic.

The benefits presented in this article for a PON infrastructure touch upon technical superiority, plus savings in space, weight and power. All of these factors contribute towards lower capital costs as well as reduced operating expense for a network infrastructure