Wireless Optical Telecommunications

Foreword

Modern telecommunication, at least in the vicinity of terminals (TV receivers, computers, recorders, smartphones, network games consoles, e-books, etc.), will be “wireless” and high speed: the physical link will not be a copper wire, or made from fiber, silica, or other, but an electromagnetic wave propagating in free space between one transmitter–receiver and another transmitter–receiver.

The most common physical wireless link is the use of radio, an electromagnetic wave in the range of radio spectrum. It is a well-developed technology, but we can see the limitations in terms of speed (bits per second), frequency, power, electromagnetic compatibility, and electromagnetic pollution among others. Regarding transmission of information, we know that the higher the frequency of the electromagnetic transmitted wave, the higher the speed. Hence, current laboratory studies are looking at communication systems operating at frequencies of gigahertz (GHz) to terahertz (THz) and above. For frequencies beyond terahertz, and particularly in the ranges corresponding to optical waves, infrared or visible light (100–1,000 THz), a communication speed in the range of terabits per second can be achieved.

Because of the laser (invented in 1960) and silica fiber (the potential of silica fiber for telecom applications was demonstrated in 1961), optical telecommunications together with the fantastic progress made in the manufacturing technology of lasers and optoelectronic systems, in parallel ...