dBm
20.00
-
850
nm
Fiber Loss
Definition:
during the calculation of an optical loss budget, the amount of optical loss attributed to the optical fiber in the link
under test. Fiber loss is specified by cabling standards that base link budget calculation on the passive components of the link
under test; examples of this type of standard are the TIA-568 and the ISO IEC 11801.
Units:
dB per kilometer; loss values are different for different wavelengths and different fiber types
Calculation:
(fiber length in kilometers) x (dB loss per kilometer)
Light Source Reference Power
Definition:
the amount of absolute optical power being received directly from the light source by the power meter during the
setting of the optical reference. Light Source Reference Power is used as a reference, or starting point, on which a standards-
based optical reference is set.
Units:
dBm
Calculation:
none; Light Source Reference Power is measured via a single patch cord of the appropriate type.
OWL REPORTER
INTERPRETING OWL REPORTER SCREENS AND REPORTS, cont.
Patch
Panel
Patch
Panel
Link Under Test
testing standards require multimode reference
cables to be wrapped around a device called a mandrel,
which is used to filter high-order modes and achieve EMD,
or Equilibrium Mode Distribution (shown here).
Singlemode test jumpers do NOT require this mandrel.
Light
Source
Reference
Power (dBm)
INVALID
OPERATING
MARGIN **
Minimum
Required
Power (dBm)
Measured
Power (dBm)
PASS
OPERATING MARGIN
or
SYSTEM OVERHEAD
Optical Loss
FAIL
Total Allowable System Loss
39
