EXFO FTB-7000 OTDR for FTB-200 v2 - Manual (Page 46)

Preparing Your OTDR for a Test
32 FTB-7000 Series
Launch Conditions for Multimode Measurements
The table below 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
a 0.1 to 0.3 dB excess loss.