| 摘要 |
A system for determining an optical loss of a device under test DUT includes a fiber coupler for receiving an optical input power (Ps) at a first input, coupling out a stimulus signal at a first output derived from the optical input power (Ps), receiving a response signal on the applied stimulus signal, and for providing a returning optical power (P) at a third output derived from the received response signal. For calibration, a reference cable with a reflectivity Rref is coupled to the first output of the fiber coupler and a value Pref of the returning optical power is measured. The reference cable is exchanged for a customer cable, whereby an end of the customer cable is provided in a way that no, or substantially no, reflection occurs, and a value Ppara of the returning optical power is measured. The calibration uses the values Rref, Pref, and Ppara. For obtaining the return loss of the DUT, the customer cable is coupled between the first output of the fiber coupler and the DUT, whereby an end of the DUT is provided in a way that no, or substantially no, reflection occurs, and a value PDUT of the returning optical power is measured. The return loss of the DUT can then be determined using the values Rref, Pref, Ppara, and PDUT.
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