Relay apparatus and relay method for passive optical network

A relay method for a passive optical network using an apparatus of relaying optical signals of an OLT and an ONT using a pair of optical transceivers, the relay method comprising:

• recovering, by a CDR unit configured in the relay apparatus, OLT clock data from a downstream continuous signal received by the optical transceiver connected to the OLT;
• providing, by a control unit configured in the relay apparatus, a proactive upstream burst frame preamble generated according to the OLT clock recovered by the CDR unit to the OLT-side optical transceiver when the upstream burst signal received by the optical transceiver connected with the ONT is detected or predicted by a signal pattern;
• recovering, by a BCDR unit configured in the relay apparatus, clock data from the upstream burst signal received by the optical transceiver and storing, by an asynchronous buffer unit, the recovered upstream burst frame data using the clock recovered by the BCDR unit as an input clock and the clock recovered by the CDR unit as an output clock;
• and
• selecting, by the control unit, all or some of the recovered upstream burst frame data stored in the asynchronous buffer unit to provide the selected upstream burst frame data to the optical transceiver connected with the OLT according to the OLT clock subsequent to the proactively generated upstream burst frame preamble,
• wherein in the detecting of the upstream burst signal received by the optical transceiver connected with the ONT, the control unit configured in the relay apparatus detects the upstream burst signal received by a signal detector of the relay apparatus that detects the presence of the upstream burst signal earlier than the electrical signal generation preparation time of the optical transceiver.