Both Light Source and Power Meter are being used to measure the actual fiber optics losses from point A to point B.
The total measuread fiber optics signal lossess included following losses :-
a. Fiber optics loss
b. Splicing loss
c. Connector loss
The measured readings shall be compared with calculated maximum allowable fiber optics loss from point A to point B or link loss budget as per TIA-568 specification.
Should the measured readings is above the calculated maximum loss then troubleshooting steps need to established in order to pinpoint the actual fiber optics components that are giving high losses.
Generally the high losses could be attributed to one or more of the followings problems :-
a. excessive fiber optics bending
b. high loss splicing workmanship
c. dirty connector
d. dirty adapter
e. improper pulling of fiber optics cable
I have been in the field of fiber optics since early 1990s. I gained fiber optics skills and knowledge via my working experience as end-user, main contractor and sub-contractor and finally as an optical fiber enterpreneur.