The integration of optical fiber into today's cable television networks

摘要

The tree-and-branch architecture of today's cable television systems is optimized for broadband, broadcast video delivery. A key characteristic of coaxial cable is its relatively high transmission loss, about 1 dB per 100 ft at 550 MHz. The advent of low-cost, single-mode optical fiber and broadband analog optoelectronic devices allows the constructions of hybrid fiber/coaxial systems where fiber is used for trunking over relatively long distances, and coaxial cable is used for 'the last mile' to the home. This approach of overlaying an existing coaxial system with fiber trunking is referred to as fiber backbone. The integration of the fiber backbone structure into existing CATV systems allows a dramatic increase in system reliability, delivery signal quality, and channel capacity. Fiber backbone is also the first step in an evolution to a cost-effective, two-way communications system, ultimately capable of delivering switched video services on demand to the consumer.