Book excerpt: Developed for an introductory course, this up-to-date text discusses the major building blocks of present-day fibre-optic systems and presents their use in communications and sensing. Starting with easy-to-understand ray propagation in optical fibres, the book progresses towards the more complex topics of wave propagation in planar and cylindrical waveguides. Special emphasis has been given to the treatment of single-mode fibres, the backbone of present-day optical communication systems. It also offers a detailed treatment of the theory behind optoelectronic sources (LEDs and injection laser diodes), detectors, modulators, and optical amplifiers. Contemporary in terms of technology, it presents topics such as erbium-doped fibre amplifiers (EDFAs) and wavelength-division multiplexing (WDM) along with dense WDM. Building upon these fundamental principles, the book introduces the reader to system design considerations for analog and digital fibre-optic communications. Emphasis has also been given to fibre-optic sensors and laser-based systems along with their industrial and other applications. This student-friendly text is suitable for undergraduate students pursuing instrumentation, electronics, and communication engineering. Contents: Preface Introduction Part 1: Fiber Optics Ray Propagation in Optical Fibers Wave Propagation in Planar Waveguides Wave Propagation in Cylindrical Waveguides Single-mode Fibers Optical Fiber Cables and Connections Part 2: Optoelectronics Optoelectronic Sources Optoelectronic Detectors Optoelectronic Modulators Optical Amplifiers Part 3: Applications Wavelength-division Multiplexing Fiber-optic Communication Systems Fiber-optic Sensors Laser-based Systems Part 4: Lab-oriented Projects Index