Optical systems: A review: Fiber-optics applications include power monitoring, video transmission, data links, and public communications

The advantages of fiber-optic communications have been demonstrated by experimental optical waveguide systems throughout the world. Among the important features stimulating research and development in fiber-optical communications are these: • Low transmission loss (greater distance between repeaters). • Wide transmission bandwidth. • Potential low cost. • Insensitivity to electromagnetic and radio-frequency interference. • Improved security compared with electronic cabling (no cross-talk among parallel cables). • Relatively small size, light weight, high strength, and flexibility. • Elimination of combustion or sparks caused by short circuits. • Flexibility in upgrading system capacity without need to install new cables. • Immunity to ground-loop problems. • Suitability for digital communications and pulsemodulation methods (fiber-optic cable losses are independent of transmission frequency). • Fewer government regulatory difficulties (because of the elimination of frequency allocation). • Suitability for relatively high temperature.