Fiber Optic Testing, Lesson 3: Visual Inspection, Tracing And Fault Location
Objectives: From this self-study lesson you should learn:
- What can be tested using visual methods in fiber optics?
- How does a visual fault locator (VFL) differ from a fiber tracer?
- What are other uses for a VFL?
- What can you learn from inspecting connectors with a microscope?
Your
eye can be a very useful tool in testing fiber optics. A visual light
source can be used to trace fibers, ensure connections are correct and
even find faults. A microscope lets you inspect connectors to confirm
proper termination or determine if the connector is dirty and needs
cleaning. Since most fiber optic networks use infrared light, your eye
is not very good at detecting system light and if the power is high, you
have no warning that it could be harmful (see "Eye Safety" below.) But
many digital cameras can see infrared light and can be used to detect
system light when you don't have an optical power meter. This lesson
will cover all those topics.
Eye Safety: A note on using any fiber optic source:
Fiber optic sources, including test equipment, are generally too low in
power to cause any eye damage, but it's still advisable to check
connectors with a power meter or a digital camera before looking into
it. Besides, most fiber optic sources are at infrared wavelengths that
are invisible to the eye, making them more dangerous because you cannot
see the light even when the power level could be dangerous. Connector
inspection microscopes focus all the light into the eye and can increase
the danger. Some telco DWDM and CATV systems have very high power and
they could be harmful, so better safe than sorry. Read our page on
Safety.
The course leads you to read online or printed
materials (with an emphasis on the online using the FOA Guide), watch
FOA YouTube Videos, complete some activities and take the quizzes. Each
lesson plan is self-contained. Lesson plans open in new pages so the
course overview page stays open to lead you to the next lesson or you
may use the link at the bottom of the page.
Student Assignment
Read the references, watch the videos and take the quizzes (Test Your Knowledge)
Videos
FOA YouTube Videos:
FOA Lecture 13: Testing Fiber Visually (An overview of visual testing)
FOA Lecture 21 Visual Fault Locator Demonstration (How to use visual tracers and fault locators)
FOA Lecture 57: Connector Inspection and Cleaning
The Fiber Optic Tester In Your Pocket (How to use old cell phone or digital cameras to "see" invisible infrared light.)
Online FOA Guide
FOA Reference Guide to Fiber Optics:
Visual tracing & fault location (How to use visual tracers and fault locators)
Microscope Inspection And Cleaningof Connectors
(Using microscopes to inspect connectors for proper polishing during
termination and finding dirty or damaged connectors in the field.)
Reference Textbook
FOA Reference Guide to Fiber Optic Testing, Chapter 5
Testing is also covered in these FOA textbooks in a more abbreviated form:
FOA
Reference Guide to Fiber Optics, Chapter 8
FOA
Reference Guide to Outside Plant Fiber Optics, Chapter 8
Reference Textbook
FOA Reference Guide to Fiber Optic Testing, Chapters 5,
Testing is also covered in these FOA textbooks in a more abbreviated form:
FOA
Reference Guide to Fiber Optics, Chapter 8
FOA
Reference Guide to Outside Plant Fiber Optics, Chapter 8
Test Your Knowledge
Online Quiz
Next Lesson: #4 Testing the cable plant, insertion Loss Testing
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