PON SYSTEM, OLT, ONU AND OPTICAL SIGNAL TRANSMISSION/RECEPTION CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To maintain communication quality of a signal of a downward direction.SOLUTION: An OLT 1 comprises: a PRBS transmitter unit 15 for generating a pseudo random signal to transmit to an ONU 2; and based on a parameter related to a transmission loss measured by the ONU 2, an instruction generator unit 13 for instructing the ONU 2 to adjust an APD application voltage. The ONU 2 comprises: an optical signal transmission/reception unit 21 for transmitting and receiving optical signals between with the OLT 1; a PRBS receiver unit 25 for measuring a bit error rate using the pseudo random signal received by the optical signal transmission/reception unit 21; an instruction transmitter unit 26 for transmitting to the OLT 1 a bit error rate measured by the PRBS receiver unit 25; and according to the instruction from the instruction generator unit 13, a bias adjustment unit 28 for adjusting the APD application voltage of the optical signal transmission/reception unit 21.