Performance of an Optical Wireless Communication System as a Function of Wavelength

Optical wireless communication (OWC) is gaining acceptance in an increasing number of sectors of science and industry, owing to its unique combination of features: extremely high bandwidth, rapid deployment time, license- and tariff-free bandwidth allocation, and low power consumption, weight, and size. However, the major drawback of OWC in terrestrial applications is the threat of downtime caused by adverse weather conditions, such as fog and haze. Several researchers have proposed and developed communication systems that use far-IR radiation to mitigate weather effects. In this study we analyze the performance of a short-distance terrestrial OWC system as a function of wavelength. A mathematical model for OWC link performance is derived. Using this model, we perform a simulation of our system under different weather conditions. From the results of our calculations, the improvement of link availability for 10 (mu)m compared with 0.785 -1.55 (mu)m for a distance of 1-km propagation is 0.2% (99.6 -99.8%). This modest improvement should be considered relative to the complexity and cost of quantum cascade laser transmitters and far-IR receivers.