Fluke Versiv Series Technical Reference Handbook page 611

Table 22. Settings for Custom Fiber Types (continued)
Setting
IOR
(Index of refraction)
Backscatter
(fibers for OTDR tests
only)
Chapter 19: Custom Media and Test Limits
The tester uses the index of refraction to calculate
the optical length of the fiber. Optical length
usually differs slightly from the length of the fiber
jacket. This occurs because fibers are often curved
inside their jackets and because there are small
variations in the IOR of the fibers.
Each fiber type includes a default value, which is
the IOR specified by the manufacturer.
When you increase the IOR value, the calculated
length decreases. The tester accepts
between 1.000 and 1.700.
Enter the value specified by the fiber
manufacturer. If you are not sure of the value, and
the accuracy of length measurements is not very
important, use the default value. See "About the
Index of Refraction" on page 576.
The backscatter coefficient is a measurement of the
quantity of light that the fiber reflects back to the
OTDR when the OTDR uses a 1 ns pulse. The tester
uses this value to calculate the reflectance of events
for OTDR tests and the overall ORL for the link.
Each fiber type includes a default value, which is
the backscatter coefficient specified by the
manufacturer.
Enter the value specified by the fiber manufacturer.
If you are not sure of the value, use the default
value
Make a Custom Fiber Type
Description
IOR
values
575