Systems and methods for coherent optics ranging and sensing

An optical line terminal (OLT) for an optical network communication system, the OLT comprising:

• a downstream transmitter configured to provide a coherent downlink transmission and one or more downstream parameters to a downstream receiver of a first optical network unit (ONU) of a plurality of ONUs disposed opposite the OLT with respect to an optical communication medium coupling the OLT to the plurality of ONUs;
• an upstream receiver configured to receive upstream communications from an upstream transmitter of the first ONU;
• a processor;
• and
• a memory containing computer-executable instructions, which, when executed by the processor, cause the OLT to:
• receive, during a time corresponding to a detectable contention transmit opportunity within a contention period enabling access to the OLT by the plurality of ONUs, a first upstream adjustment request message from the first ONU including a coarse ranging request message (CRRM);
• communicate to the first ONU a first downstream acknowledgement in response to the upstream first adjustment request message;
• schedule a dedicated time window subsequent to the contention window;
• and
• receive, during the dedicated time window, a second upstream adjustment request message, based on the first downstream acknowledgement, including a fine ranging request message (FRRM).