Optical Distribution Channel: An Almost-All Optical LAN Based on the Field-coding Technique

The very high-speed access requirement that characterizes interactive and real-time high-performance applications like parallel processing, compressed video, or high-quality imaging, initiated a considerable interest in networks that provide a single user with a very high-speed network access. Coupled with this effort is the belief that optical networking can provide very high speed access, in addition to already utilized large aggregated bandwidth. In this paper, we examine the possibility of harvesting the optical spectrum to provide high-speed access networking capability in local-area environment in a way that is economically justifiable. In particular, we describe a design of the physical layer of an “almost-all” optical local-area network that is capable of providing gigabit per second network access. The network design is based on the dual-bus topology, the field-coding technique that was reported by us earlier (in which the header and the data fields are encoded at different rates), and the principle of “almost-all” optical switching. The field-coding technique allows integration of several subnets on the same physical medium. Moreover, we show that because of the field-coding technique, the maximal number of stations on the bus before signal amplification is required is doubled in the limit. Furthermore, we discuss various implementation issues in the design of ODC, like opto-electronic amplification, clock distribution and clock-data synchronization, and reduction in the receiver dynamic range.