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KEY TEST PARAMETERS
Encircled Flux (EF) is a recent evolution in standards-based multimode fiber testing developed as an attempt to further decrease
uncertainty between optical loss measurements taken with different manufacturer’s test equipment, or with the same test equipment
but at a different time.
EF-compliant testing requires
a special multimode reference
cable called a Mode Controller
that ensures light exiting any
EF-compliant Mode Controller
reference cable always has a
consistent modal pattern, no matter
which manufacturer’s multimode
light source was used.
The use of EF-compliant test
cables is typically focused on testing OM3/OM4 multimode fiber networks running at 10-gigabit or greater, and usually only when
a cabling standard specifies it. Technicians should consult customer documents or applicable cabling standards to verify if EF-
compliant testing is required.
However, EF-compliant testing can be performed on any multimode network provided the correct mode controller cable is used.
NOTE: the TIA 568-3.D cabling standard requires EF compliance when testing any multimode network.
Mode Controller Cable Maintenance.
If the output endface of an EF mode controller cable becomes damaged, it is no longer
compliant to EF requirements. Due to the fragile nature of these endfaces and the extremely high cost of EF Mode Controllers, it
is vitally important to protect the output endface from damage.
Encircled Flux extender cords are
low-loss reference grade patch
cables that provide two economical
advantages:
1) EF extender cords act as
sacrificial cords that protect the
fragile output endface of the more
expensive mode controller cable
from damage
i.e. replacing
extender cords costs less than
replacing EF mode controllers; and
2) adapt the EF Mode Controller
output to different connector types
i.e. one mode controller and several
extender cords are less expensive
than multiple mode controllers
ENCIRCLED FLUX
