Chapter 2
Optical Fiber Structures and Light
Guiding Principles
Abstract Photonics technology is the basic indispensible tool and foundation for
optical fiber communications. To understand how light signals travel along an optical
fiber, this chapter first describes the fundamental nature of light and discusses how
light propagates in a dielectric medium such as glass. The discussion then examines
the structure of optical fibers and presents two mechanisms that show how light
travels along an optical fiber.
The operational characteristics of an optical fiber largely determine the overall
performance of a lightwave transmission system. Some of the questions that arise
concerning optical fibers are
1. What is the structure of an optical fiber?
2. How does light propagate along a fiber?
3. Of what materials are fibers made?
4. How is the fiber fabricated?
5. How are fibers incorporated into cable structures?
6. What is the signal loss or attenuation mechanism in a fiber?
7. Why and to what degree does a signal get distorted as it travels along a fiber?
The purpose of this chapter is to present some of the fundamental answers to the
first five questions in order to attain a good understanding of the physical structure
and waveguiding properties of optical fibers. Questions 6 and 7 are answered in
Chap. 3. The discussions address both conventional silica and photonic crystal fibers.
Chapter 12 addresses additional nonlinear distortion effects that can arise in multiplewavelength optical networks.
Fiber optics technology involves the emission, transmission, and detection of
light, so the discussion first considers the nature of light and then reviews a few basic
laws and definitions of optics. Following a description of the structure of optical
fibers, two methods are used to describe how an optical fiber guides light. The first
approach uses the geometrical or ray optics concept of light reflection and refraction
to provide an intuitive picture of the propagation mechanisms. In the second approach,
light is treated as an electromagnetic wave that propagates along the optical fiber
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
G. Keiser, Fiber Optic Communications,
https://doi.org/10.1007/978-981-33-4665-9_2
31
Optical Fiber Structures and Light
Guiding Principles
Abstract Photonics technology is the basic indispensible tool and foundation for
optical fiber communications. To understand how light signals travel along an optical
fiber, this chapter first describes the fundamental nature of light and discusses how
light propagates in a dielectric medium such as glass. The discussion then examines
the structure of optical fibers and presents two mechanisms that show how light
travels along an optical fiber.
The operational characteristics of an optical fiber largely determine the overall
performance of a lightwave transmission system. Some of the questions that arise
concerning optical fibers are
1. What is the structure of an optical fiber?
2. How does light propagate along a fiber?
3. Of what materials are fibers made?
4. How is the fiber fabricated?
5. How are fibers incorporated into cable structures?
6. What is the signal loss or attenuation mechanism in a fiber?
7. Why and to what degree does a signal get distorted as it travels along a fiber?
The purpose of this chapter is to present some of the fundamental answers to the
first five questions in order to attain a good understanding of the physical structure
and waveguiding properties of optical fibers. Questions 6 and 7 are answered in
Chap. 3. The discussions address both conventional silica and photonic crystal fibers.
Chapter 12 addresses additional nonlinear distortion effects that can arise in multiplewavelength optical networks.
Fiber optics technology involves the emission, transmission, and detection of
light, so the discussion first considers the nature of light and then reviews a few basic
laws and definitions of optics. Following a description of the structure of optical
fibers, two methods are used to describe how an optical fiber guides light. The first
approach uses the geometrical or ray optics concept of light reflection and refraction
to provide an intuitive picture of the propagation mechanisms. In the second approach,
light is treated as an electromagnetic wave that propagates along the optical fiber
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
G. Keiser, Fiber Optic Communications,
https://doi.org/10.1007/978-981-33-4665-9_2
31