OEO versus All-Optical Networks

The first key assumption, that OEO regenerators were prohibitively expensive, led to the widescale development of an entire suite of ULH transport technologies. Key amongst these was Raman assisted EDFA amplification, in order to extended optical reach to 3,000 to 4,000 km without the need for regeneration. Along with this came the necessity to develop a suite of all-optical technologies in order to manage "analog" optical waves along the entire optical reach distance. These include dispersion compensation technologies dynamic PMD compensators, dynamic gain flatness, optical monitors, all-optical switching, and tunable lasers and receivers in order to avoid wavelength blocking limitation along the network. Inclusion of all of these technologies and components led to high overall network costs which could only be partially justified at extremely long network distances and high capacities