In addition to a power meter, you need a test source

In addition to a power meter, you need a test source. The test source should match the type fiber ( generally LED for MM or laser for SM) and wavelength (850, 1300, 1550 nm) that will be used on the fiber optic cable you are testing. If you are testing to some standards, you may need to add some mode conditioning, like a mandrel wrap, to meet the standard launch conditions.

You generally need one or two reference cables, depending on the test we wish to perform. The accuracy of the measurement you make will depend on the quality of your reference cables, since they will be mated to the cable under test. The quality and cleanliness of the connectors on the launch and receive cables is the most important factor in the accuracy of loss measurements. Always test your reference cables by the patchcord or single ended method shown below to make sure they're good before you start testing other cables

Standards groups have not been able to successfully specify the quality of reference cables in terms of tightly toleranced components like the fiber and connectors. The best recommendation for qualifying reference cables is to choose cables with low loss, tested "single-ended" per FOTP-171 below.

December 20, 2011

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