Powering the fiber information network

The future of voice, data and video transmission is fiber, but electronics will still be required to translate sounds and images into pulses of light for transmission and back again to electronics for hearing and viewing. And electronics require sources of DC power.The question facing telcos today is "Who will provide this power, and where will it be located?" Traditionally, the telco has maintained an "active" copper network, providing 48V DC power with battery backup to energize copper transmission lines in the Central Office (CO) and at other points along the network to overcome resistance in the copper. Pulses of light carried by fiber optic cables do not require power to overcome resistance.The ultimate long-term goal is to abandon the copper in the ground and replace it with fiber. However, since fiber does not yet reach all the way to most subscribers, at some point, conversion is required from optical to electronic so that it can be carried "the final mile" on existing copper.