Precision time transfer systems and methods in optical networks

A node that communicates with a second node, and the node is configured to determine a difference in time from the second node, the node comprising:

• one or more line ports communicatively coupled to the second node;
• and
• a controller communicatively coupled to the one or more line ports, wherein the controller is configured to
• receive a departure time, TD-A, from the second node, wherein the departure time, TD-A, is determined by the second node based on detecting a timing marker in a Forward Error Correction (FEC) frame,
• determine an arrival time, TA-B, based on detecting the timing marker in the FEC frame, and
• determine a time difference based on the departure time and the arrival time,
• wherein the timing marker is detected at a last point in a transmitter of the second node and at a first point in a receiver of a line port, during FEC processing.

An optical modem, configured to determine precise time information regardless of timing uncertainties due to Forward Error Correction (FEC) processing and adaptation therein, the optical modem comprising:

• a FEC encoder configured to encode FEC for an encoded signal;
• a transmitter configured to optically transmit the encoded signal;
• a receiving configured to optically receive a signal;
• and
• a FEC decode configured to decode FEC on the received signal;
• wherein the encoded signal and the received signal have one or more timing markers included therewith that are detected by the FEC encoder or the FEC decoder, and wherein, responsive to detecting the one or more timing markers, the FEC encoder and the FEC decoder are configured to cause a timing determination.