A solid understanding of the polarization characteristics of light waves has now become essential in the use of numerous optical devices in a variety of applications. Optical devices may possess linear, circular, or, in general, elliptical birefringence. While linear birefringence is quite simple to analyze, circular and elliptical birefringencies are more difficult to work with. Jones matrix and Poincaré sphere approaches are two powerful techniques used in polarization-based applications. In optical communication systems, polarization mode dispersion (PMD) is a serious issue for ultrahigh-bit-rate (>10 Gb) data transmission.
A large number of important fiber optic sensors and components have recently been developed, including fiber optic gyroscopes, current sensors, and in-line fiber optic polarization-based components such as polarizers, wave plates, and polarization controllers, all of which use polarization effects in optical fibers. Accordingly, sound knowledge of the polarization characteristics of light waves has become almost essential for all working engineers. This book aims to develop various concepts from first principles so that a working engineer is able to not only understand the basic physics of polarization-based devices, but also to improve on the design and characteristics of these devices.
All electromagnetic phenomena can be said to follow from Maxwell's equations. In Chapter 2, we write these equations and their constitutive relations. We use Maxwell's equations to derive the wave equation and study the consequences. In Chapter 3, we start with the plane wave solutions of Maxwell's equations and discuss the various states of polarization - namely, linear polarization, circular polarization, and elliptical polarization. We discuss methods of producing such polarization states as well as experimental configurations used to analyze them.
When an unpolarized light beam enters an anisotropic medium (such as calcite), it usually splits into two linearly polarized beams. These two linearly polarized waves, in general, propagate with different phase and ray velocities and hence see different refractive indices. This phenomenon is known as double refraction, or birefringence, and is of great importance as it is used to realize many polarization-based devices. In Chapter 4, we study plane wave propagation in an anisotropic medium and discuss some applications.