EXFO AXS-100 Series OTDR - Manual (Page 59)

Testing Fibers
OTDR 51
Launch Conditions for Multimode Measurements
The table on fiber types gives information about tests with the 50 μm and
62.5 μm fibers.
Fiber type Recommended mode filter Remarks
50 μm Perform a five-turn
mandrel-wrap (wrapping the
patchcord a minimum of five
turns around the mandrel tool)
on the patchcord connecting
the OTDR to the fiber under
test.
As per FOTP-34:
³
For fibers with 3 mm
jacket: use a mandrel tool
with a diameter of 25 mm.
³
For fibers without jacket:
use a mandrel tool with a
diameter of 22 mm.
Nominal launch conditions are
overfilled.
Loss measurements can be
slightly pessimistic (higher loss)
when compared to loss
measurements done with a
50 MMF source compliant to
FOTP34, Method A2.
62.5 μm No mode filter required. Loss measurements similar to
those obtained with a power
meter and a source that is
conditioned according to
FOTP34, Method A2.
I
MPORTANT
If you test with 50-μm fibers, EXFO recommends that you use a
mode filter (mandrel-wrap). Otherwise, you may obtain results with
an excess loss value of 0.1 to 0.3 dB.