Quantum-Cascade Lasers in Atmospheric Optical Communication Lines: Challenges and Prospects (Review)

The parameters of prospective samples of atmospheric optical communication lines (AOCL) or free-space optics (FSO) based on quantum-cascade lasers (QCL) as compared to those of existing commercial systems are analyzed. The results indicate that the use of QCL in FSO has significant advantages over existing systems, due largely to longwave radiation and the QCL modulation dynamics, which are limited by the picosecond lifetime of current carriers that provides the fundamental possibility of obtaining an inherent bandwidth of >= 100 GHz. Possible applications of FSO based on IR QCL and THz QCL are discussed taking into account the experimental data and unique properties of QCL radiation. Also, the use of non-traditional methods to eliminate the influence of turbulence and increase the capacity of the information transmission channel is discussed.