Patent ID: 8139937

Claim:
A method for automatically controlling optical power in an OLT (optical line terminal) of a PON (passive optical network), the method comprising the steps of: measuring an allowable range of the optical power allowing a normal network operation on the PON; setting an optimum optical signal level within the measured allowable range of the optical power; adjusting a power level of a transmitter to the set optimum optical signal level, wherein the setting an optimum optical signal level comprises: setting the optimum optical signal level at a minimum power level within the allowable range of the optical power; adding the set optimum optical signal level and an offset power level for ONUs to be additionally connected to the PON, wherein the offset power level is defined as a fraction of transmission power times a maximum allowable distance between an ONU located at the shortest distance from the OLT and an ONU located at the longest distance from the OLT in the corresponding PON; performing an ONU (optical network unit) activation procedure of discovering ONUs operating in every predetermined period and registering the discovered ONUs when the OLT operates; checking the number of the activated ONUs after the ONU activation procedure; and performing a power saving mode of turning off power of the transmitter if the number of the activated ONUs is O.