The development of highly linear
The development of highly linear distributed feedback (DFB) lasers allowed CATV systems to be converted to analog optical systems. CATV companies "overbuild" with fiber. They connect their headends with fiber and then take fiber into the neighborhood. They lash the fiber cable onto the aerial "hardline" coax used for the rest of the network or pull it in the same conduit underground. The fiber allows them to break their network into smaller service areas, typically fewer than 4 amplifiers deep, that prevent large numbers of customers from being affected in an outage, making their network more reliable and easier to troubleshoot, providing better service and customer relations.
The fiber also gives CATV operators a return path which they use for Internet and telephone connections, increasing their revenue potential. Most current CATV systems still use AM (analog) systems which simply convert the electrical TV signals into optical signals. Look for them to convert to more digital transmission in the future.
December 3, 2011