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 Monday, June 18, 2007

Another step towards all optical networks (AON) has been achieved with the consent of the new Recommendation G.680 by ITU-T's Study Group 15.

The Recommendation will allow operators to take optical add/drop multiplexers (OADMs) and photonic cross-connects (PXCs) from different vendors and integrate them in to an all optical network without having to add expensive optical/electrical/optical conversion (O/E/Os).

This achievement is made possible as the Rec gives operators a way to evaluate the end-to-end quality of a signal where photonic cross-connects (PXC) and optical add/drop multiplexers (OADMs) are deployed. In addition, experts say that the evolution towards an AON could significantly reduce costs for operators by reducing the need for costly optical/electrical/electrical (O/E/O) conversion. As optical transport networks (OTN) evolve, the number of - expensive - O/E/O conversions within their boundaries is coming down.

The two main reasons for the reduction in the number of O/E/O conversions are that DWDM systems are becoming capable of carrying light signals for thousands of kilometers without electrical regeneration and that PXCs and OADMs are becoming available with the capacity, space requirements, power consumption, reliability and cost, suitable for their use in the telecommunication networks. With this evolution experts predict that AONs could extend to all potential routes of the backbone network of a medium size country - optical paths up to around 2,000 km.

The Recommendation defines a "degradation function" of optical network elements (ONEs) such as photonic cross connects (PXCs), optical add-drop multiplexers (OADMs), etc. making up an optical network. It enables the degradation of the signal quality in an all-optical network consisting of ONEs including DWDM line segments to be assessed.