OLP6304 is special for the PON/OLT system which was featured as burst mode. By using an effective algorithm patented by Sino-telecom, OLP6304 can accurately detect the optical power in the down-link traffic while neglecting the surge of burst data. If the optical power is detected below the setting threshold, OLP6304 would trigger the switching from the working line to the redundant line within a few sub-microseconds. This solution provides a swift restoring method special for the passive optical networks.