Agilent / HP / Keysight 81534A

This unit is ideal for making measurements on fast telecommunications systems, such as filters, multiplexers, cross connects, amplifiers and whole systems under test.

Return loss measurements can be made using this Optical Return Loss Module.

It contains a sensitive detector and a directional coupler.

The source illuminates the test device, while the directional coupler and detector sense only the power that is traveling in the reverse direction.

This system is best suited for accurate measurement of devices with a single reflection such as connectors, splices and attenuators. It is also used to measure the aggregate or total return loss of a device with multiple reflections.