Comparison of Optical Fiber With Coaxial Cables

In the late 1960's and early 1970's scientists and engineers began exploring how to overcome some of the limitations of communicating using metallic links(wires and cables).Using the principle of total internal reflection discovered over 200 years earlier,fiber optics based systems allows many benefits that cannot be achieved with any other type of medium.In such a system,the electronic data signals are converted to light pulses and sent through a hair thin  glass or plastic fiber to a detector at the far end,where they are reconverted back to electronic signals.Although this seems to be an extremely simple concept,many practical problems have been solved thoroughly that fiber optic systems are now being used in many application instead of traditional wires and cables.

Both conventional electronic signals and light are electromagnetic  waves and follow the same basic laws of physics.However,the extremely high frequencies and short wavelength of light have dramatically different implications for signal transmission than do those of lower frequency waves,including microwaves.Note that the frequencies in use are around 360 megahertz,compared to the 1 GHz at the beginning of the microwave region.At these frequencies it is easier to use wavelength value as a measure.Fiber optics systems use the wavelength between 600 and 1500 nanometers,often referred to as 0.6 to 1.5 µ m or microns.Visible light spans 430 to 690 nm; so fiber optics system wavelength use a part of the visible spectrum as well as the longer wavelength region;the invisible in infrared spectrum.