Harmonizing an Opaque Core Network with Transparent Optical Elements

摘要

Over the last decade, deployed core telecom networks have migrated from being based on single-channel SONET regeneration links to multi-span, multi-channel optically amplified systems. More recently, the industry has been aggressively pursuing a natural extension of this philosophy towards all-optical "analog" core networks, with each traffic demand touching electrical digital circuitry only at the in/egress nodes. This trend produced a substantial elimination of regeneration costs, increase in network capacity, and notionally simpler operation and service turn-up. At the same time, the optical "analog" network requires a large amount of sophisticated hardware and software for monitoring and manipulating high bit rate optical signals. The primary goal for current equipment suppliers is to provide cost effective system designs that are simple to deploy and operate. This paper will examine the trade-offs inherent in the technology and architecture choices needed to reach this goal through the "analog" transmission/all-optical ideal and concludes that it is difficult to improve on the present approach which uses a mix of transparent and opaque network elements.