A fiber optic connector that puts out more power than it receives? Sounds like a miracle, but it’s actually a mistake. Read about the infamous “gainer” and why it’s not a good thing. Gainers can show up when using an OTDR to measure loss from one end of a fiber link, and they occur due to the way in which an OTDR measures reflected light along the length of the fiber. An OTDR assumes that fiber characteristics such as core and cladding size are consistent along the length with no variations, and it calculates signal loss based on the amount of reflected light, or backscatter, that it detects.
Sourced through Scoop.it from: www.flukenetworks.com