Patent ID: 7110668

Claim:
An optical node comprising: a first optical line terminal having an all-optical-pass-through port side interface including a plurality of port side transmit ports, each to transmit a respective one of a plurality of optical wavelengths, and a plurality of associated port side receive ports, to receive respective ones of the plurality of optical wavelengths, the first optical line terminal including at least one transponder connected to a predetermined one of the transmit ports and also connected to an associated one of the port side receive ports, the at least one transponder including a loopback mechanism to perform looping back of an optical wavelength received at the associated one of the port side receive ports to the predetermined one of the port side transmit ports; a second optical line terminal having an all-optical-pass-through port side interface including a plurality of port side transmit ports, each to transmit a respective one of the plurality of optical wavelengths, and a plurality of associated port side receive ports, to receive respective ones of the plurality of optical wavelengths, the second optical line terminal including at least one transponder connected to a predetermined one of the port side transmit ports and also connected to an associated one of the port side receive ports, the at least one transponder including a loopback mechanism to perform looping back of an optical wavelength received at the associated one of the port side receive ports to the predetermined one of the port side transmit ports; and an optical connection, optically connecting at least one of the port side transmit ports of the first optical line terminal to at least one of the port side receive ports of the second optical line terminal, and connecting at least one port side receive port of the first optical line terminal to at least one transmit port of the second optical line terminal.