It is well known that different loss information is likely to be obtained when OTDR measurements
are performed from opposite ends of a fiber. Therefore, for calculating the true splice loss as an
average figure and for accuracy reasons, installation and acceptance test procedures for optical
fiber links require OTDR loss measurements to be conducted from both directions.
This application note describes a new OTDR measurement technique that offers the advantage of
yielding the two-way average splice loss by taking only one measurement from only one end of
the fiber. This approach saves the network installer time, reduces the risk of misinterpreting the
measurement results, and even allows for the examination of fiber segments that are hidden by
the OTDR’s dead zone.