Fiber U Basics

Lesson 5: Optical Fiber

how optical fiber works
From "Fiber Optics - Live"FOA YouTube Video in Lesson 1
Objectives: From this lesson you should learn:
What is Optical Fiber?
How optical fiber transmits light
Types of fiber
Physical characteristics of various types of fibers
Fiber performance specifications

In this lesson you will learn what optical fiber is, how it transmits light and all the types of fiber available.

Optical fiber is the communications medium that works by sending optical (light) signals down extremely pure hair-thin strands of glass or plastic fiber. The light is “guided” down the center of the fiber which is called the “core”. The core is surrounded by a optical material called the “cladding” that traps the light in the core using an optical technique called “total internal reflection.”  The fiber itself is coated by a “buffer” to protect the fiber from moisture and physical damage.


The buffer is what one strips off the fiber for termination or splicing.

Fiber is specified by size (core/cladding)
and core design which determines whether it is multimode or singlemode and its performance parameters. This lesson will cover all those topics.

Fiber Trivia: Although glass optical fibers are made of a material that everyone assumes is weak and fragile, it's made from ultra pure glass and is actually quite flexible, 3 times stronger than steel and 6 times stronger than titanium (according to the largest manufacturer of optical fiber, Corning.)

Student Assignment:
Watch the videos, read the references and take the quizzes (Test Your Comprehension)

FOA YouTube Video:
         FOA Lecture 3: Optical Fiber 

Fiber Optics - Live!  A series of videos that use lab demonstrations to show how optical fiber works. 

Online FOA Reference:
Optical Fiber  
Plastic Optical Fiber 

Book Chapter:
FOA Reference Guide to Fiber Optics, Chapter 5

Test Your Knowledge:
Online Quiz
Take the Quiz at the end of Chapter 5 and check your answers

Optional - Extra Credit Reading
How fiber is manufactured  
Measuring Loss in Fiber Optics  
Plastic Optical Fiber  
Singlemode fiber nomenclature and standards  

Next: Lesson 6: Fiber Optic Cables   

Return to Lesson Plan


Table of Contents: The FOA Reference Guide To Fiber Optics

(C)2012-20, The Fiber Optic Association, Inc.