Because of their increased bandwidth characteristics and robustness against noise, fiber optic networks have been proposed as a broadband replacement for a variety of communication systems, such as traditional `copper wire` telephony networks and `add-on` cable television distribution networks (which employ a separate, dedicated coax conductor cable). Unfortunately, proposals to date for implementing multi-service (broadband) optical fiber-based subscriber networks have been very costly. A fundamental factor in the high cost of such proposals has been the fact that they have typically involved the use of a large number of electro-optic and interconnect components, such as source and detector elements, which, when added to the cost of optical connectors and splices for the fiber links, and the quantity of optical fiber itself in the distribution cable between opposite ends of the link severely impact overall system expense. Namely because production requirements of these components are currently low, they are expensive. As a consequence, on a per-subscriber basis, the cost of such components amount to a large fraction of the price tag of an overall system, which, in addition to employing two transmitter/receiver pairs per subscriber, customarily uses a separate, dedicated pair of optical fibers within the distribution cable for each subscriber.
Faced with the costly outlay for the fiber optic components needed for the system, one course of thought has been to design signal processing and communication architectures that can handle a very large number of subscriber lines per unit and employ a highly compressed data format. Unfortunately, this approach is somewhat self-defeating since, in order to spread out the cost of the fiber optic components over a large number of subscribers, the system architecture becomes highly complex and therefore aggravates the cost problem, rather than alleviating it.
USPTO Backgrounds
USPTO Backgrounds