Performance of an optical wireless communication system as a function of wavelength

Free-space optical communication has attracted considerable attention recently for a variety of applications. Special attention has been paid to how adverse weather conditions and background radiation affect transmission through the atmosphere. Due to these effects, the performance of laser communication (lasercom) systems is extremely dependent on the laser transmission wavelength. Available weather statistic measurements indicate that weather effects can be mitigated by using medium and far-IR laser sources. In that case, the new and versatile quantum cascade lasers (QCLs), which are adjusted to operate within the atmospheric window regions in the mid-wave and long-wave IR (MWIR and LWIR) 3-20 μm wavelength band, can provide a viable solution to this problem. In this work, we analyze the wavelength dependence of lasercom system performance under different weather conditions for the purpose of making recommendations on preferable transmission wavelengths within the 0.4-20 μm band.