ABSTRACT
In the years following the invention of the transistor in 1947 [1] electrical engineers developed highly sophisticated electronic systems to perform such functions as telecommunications, digital computation, radio detection and ranging (radar), cable television (CATV), medical diagnosis and treatment, military ordnance delivery, and manufacturing process control. In all of these systems the information signal was carried by a current of electrons flowing in an electrically conducting material or by electromagnetic “radio” waves traveling through the air or in a waveguide. As electronic systems reached maturity, with performance being limited by fundamental asymptotes, engineers began to search for new ways to improve system performance further. They found that by using lightwaves to carry the information signal rather than an electric current or radio wave they could surpass the limitations of purely electronic systems in many applications.
