Wavelength selection for optical wireless communications systems

Eye safety, link performance, and technology infrastructure issues related to Optical Wireless (OW), also known as Free Space Optics (FSO), communication systems are examined relative to wavelength dependence. It is found that 1550 nm systems have compelling advantages over 800 nm systems in the areas of laser eye safety, reduced solar background radiation, and existing technology infrastructure. 1550 nm has somewhat better receiver sensitivity for PIN detectors, while 800 mn has somewhat better sensitivity for APDs. Overall, the factor of 50 greater eye-safe laser power at 1550 nm provides up to 17 dB additional margin for higher data rates or penetrating fog at longer ranges. The availability of high power, low cost semiconductor lasers at 1550 nm allows these advantages to be exploited in commercially available systems.