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OTDR/iOLM Testing

This course teaches attendees how to interpret OTDR measurements based on general reflectometry theory. It also covers the limitations of both the theory and the instrument, as understanding these limitations will enable the attendees to get reliable results from an OTDR. An overview of iOLM features is also available.

1 day
Live online


The optical time-domain reflectometer (OTDR) is one of the most complex instruments in fiber optic testing. To fully understand OTDR measurements, users must first acquire traces, which must then be properly analyzed and interpreted.

The training session also includes more specific testing theory and a hands-on workshop that will show attendees how to operate the instrument and perform manual measurements using markers.

This course covers
  • Basic types of fiber connections
  • Attenuation vs. the event dead zone
  • Calculation of attenuation and event dead zones
  • Causes of reflectance in the fiber
  • Fundamental theory of optical time-domain reflectometry
  • OTDR measurement method based on dynamic range
  • Manual OTDR measurements using markers:
    • Four-point event loss
    • Three-point reflectance
    • Two-point ORL
    • Two-point section attenuation
    • Least square approximation (LSA) section attenuation
  • Parameter settings for fiber link characterization:
    • Distance range
    • Pulse width
    • Averaging time
    • Wavelength
    • Index of refraction (IOR)
  • Helix factor
  • Overview of iOLM features


Basic comprehension of math and physics
Basic fiber optics and loss testing (IL and ORL)


The first part of this course consists of lectures using PowerPoint presentations and demonstrations, while the second part consists of specific hands-on OTDR testing exercises and experiments, including manual testing using markers and trace acquisition for fiber characterization.


Attendees will receive a binder containing copies of presentations and other handouts.