Optical measuring apparatus, optical level measuring system and optical level measuring method

摘要

This invention concerns measuring optical power in a passive optical network (PON) employing time division multiplexing (TDM). At an optical line terminal (OLT), the optical levels of signals transmitted froth multiple optical network units (ONU)s is measured. In ordinary operation each ONU is assigned a band permission time in which it can transmit data to the OLT. However, the duration of the band permission time (left hand 50, Fig. 2) may be shorter than the time required to make an optical level measurement (51, Fig. 2). If this is the case, the measurement time period is extended by assigning an additional dedicated band (right hand 50, Fig. 2) to the affected ONU immediately before or after the band permission time.