Patent ID: 8705955

Claim:
An optical access network comprising: a first network side termination node comprising a first transceiver arrangement, including a first modulator, coupled to a first optical link comprising at least one optical fiber and sending, when the first network side termination node is active, a first data signal and a first pilot tone of a first specific wavelength generated by the modulator via the first optical link, the first network side termination node further comprising a first link failure detector tuned to the pilot tone; a second network side termination node comprising a second transceiver arrangement, including a second modulator, connected to a second optical link comprising at least one optical fiber and sending, when the second network side termination node is active, a second data signal and a second pilot tone of a second specific wavelength generated by the second modulator via the second optical link, the second network side termination node further comprising a second link failure detector tuned to the first pilot tone; a customer side termination node having a transceiver and a reflecting mechanism coupled to a third optical link, comprising at least one optical fiber; and a remote node between the customer side termination node and the network side termination nodes, the remote node coupled to the first, the second and the third optical links; wherein, with the first network side termination node active, the first data signal modulated with the pilot tone is sent via the first optical link to the remote node, and thence via the third optical link to the customer side termination node, where the reflector mechanism reflects a portion of at least the pilot tone back into the third optical link, thence to the remote node, and from the remote node via the first optical link back to the first network side termination node, where the first link failure detector senses the presence or absence of the pilot tone, and in the absence of the pilot tone, indicating a link failure in the path between the first network side termination node and the customer side termination node, deactivates the transceiver arrangement of the first network side termination node.