8. Conclusion

Today, optics is an essential technology in telecommunications. It has enabled the development of networks with capacities that bear no comparison with those of the 1980s, and which carry traffic whose growth is almost entirely linked to the development of the Internet. Clearly, this global network could never have developed without the existence of high-capacity transmission systems offering very low transmission costs compared with the previous situation.

Since 1995, as we have seen, transmission capacities have continued to grow, exploiting the principle of wavelength division multiplexing and using the same transmission medium, namely optical fiber: it is remarkable to observe that the G.652 fiber known as "standard fiber", developed in the 1980s for totally different systems, has finally proved to be an excellent choice for those installed today. But the contribution...