Cisco Technology, Inc.

Aldo Aprile

Valerio Viscardi

Fulvio Arecco

Massimo Cambiaghi

In an optical network a 1+1 bidirectional protection system is presented. Each node across a link has photodiodes to monitor the power of signals received by the node on receiving working and protection optical fibers and also optical switches connected to transmission working and protection optical fibers to modulate signals to its counterpart node across the link. When a node detects a fault in the receiving working optical fiber, not only does the node switch to the receiving protection optical fiber, but it also switches to the transmission protection optical fiber to signal the fault to the node across the link. The optical switches on transmission working and protection optical fibers allow the two nodes across the link to signal each other at a protocol-less or primary protocol level for the link to revert back to its initial state.

Protocol-less all-optical 1+1 bidirectional revertive linear protection system

A WDM communication system that includes links traversing substantially inaccessible regions may tolerate multiple failures. In one implementation, a primary link spanning such a region is protected by a backup link. To provide further fault tolerance diverse paths may be provided to and from this backup link. The region may be, for example, an ocean.

Highly resilient architecture for DWDM networks providing 1+1 optical Channel Protection

An autoprotected optical communication ring network includes a first and a second optical carrier having opposite transmission directions and a plurality of optically reconfigurable nodes optically connected along the first and the second optical carrier and adapted to communicate in pairs on links susceptible to failure, the ring network having a normal operative condition in which the nodes of each pair are optically configured so as to exchange optical signals on a working arc path at a respective first wavelength (&#x3bb;) on the first carrier and at a respective second wavelength (&#x3bb;) different from the first wavelength (&#x3bb;) on the second carrier, the working path having a complementary arc path defining a protection arc path in which the first wavelength (&#x3bb;) on the first carrier and the second wavelength (&#x3bb;) on the second carrier can be used for further links.

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Milan, Italy

Aldo Aprile