Wireless Optical Telecommunications

Introduction

Telecom operators are finding themselves confronted by a growing demand for a higher volume of information to be transmitted (voice, data, pictures, etc.). The increasing frequency in the systems used is a solution because it is able to offer higher bandwidth and allow higher flow rates. In the field of wireless communications, the use of links in the range of optical wavelengths, visible, ultraviolet, and infrared constitutes a form of wireless transmission of a few kilobits per second to hundreds of gigabits per second. They can be implemented either over short distances, limited to one room (office, living room, car, airplane cabin, etc.), or over medium distances (a few tens of meters to several kilometers) outside (atmospheric optical links or free-space optics — FSO), or over large distances in space (high-altitude platform — HAP, planes, drones, intersatellite, etc.).

This technique is not new. Over thousands of years, well before the work of the Abbot Claude Chappe, communication processes, although very primitive, were implementing optical transmission. But the amount of information provided remained low. Optical communications over long distances did not really start until the late 18th Century with the optical telegraph. But the quality of service (QoS) was low; the transmitters and receivers, men and materials’ lack of reproducibility and reliability; and the transmission medium, the air, was changeable.

Soon, electricity (electrical charges) and copper ...