In Flux

摘要

The fact that MM fiber needs modal control to get repeatable measurements has been known for the last 30 years. The measured loss of connectors, splices or even the fiber itself could vary widely according to the mode output of the test source. MM mode control has been included in virtually every test standard ever written, but the methods of specify ing and controlling it has changed many times. The best-known method of mode control is to use a mandrel wrap on the test source reference cable as has been speci fied in most standards for the last 20 years.