1. Active optoelectronic components

Since wavelengths can be multiplexed for parallel transmission of several channels, they have been standardized by an international organization — International Telecommunication Union (ITU). This ITU 100 GHz grid is generally associated with high unit speeds, 10 Gb/s or even 40 Gb/s, while 2.5 Gb/s speeds are compatible with the 50 GHz grid. Until now, high data rates (in excess of tens of Gb/s) have been used for long-distance transmissions (several tens of kilometers), and external modulation has been preferred to avoid distortion caused by the fiber's chromatic dispersion. This is why the main suppliers of active optoelectronic components offer, on the one hand, continuous optical sources equipped with a polarization-maintaining seed fiber placed in front of an external Mach-Zehnder-type modulator, and, on the other hand, optical sources integrating a continuous laser and an electroabsorption...