Sensitivity of Laser Attenuation Through Fog to the Wavelength and to the Drop Size Distribution

A comprehensive analysis of the impact of fog DSDs on FSO attenuation at 0.55, 0.85, 1.55 and 10.6 micrometer is presented. Results show that visibility is almost proportional to fog attenuation at short wavelengths but not in the far-IR region where the impact of the DSD is definitely large. Preliminary results show that joint measurements of visibility and liquid water content could be appropriate to identify fog DSDs.