Optical communications with femtosecond lasers

Free space optical communications using 9-10 fs pulses was investigated through aerosol clouds approaching 104 to 105 particles per cm3 in a 15 cm long tube containing aerosol particles 4-5 μm in diameter. This small size is representative of the most difficult situation for the transmission of light through the atmosphere. The ultra fast pulse transmission were compared to continuous wave (cw) transmission through the exact same aerosols clouds and compared to the ultra short pulses. Results indicate that there was increased transmission for the ultra short laser pulses, but was not as high as expected. The results now can be explained by a recent paper demonstrating that deviation from the Beer Lambert law does not occur until the ultra short pulse transverses a longer path length in water. Results will be presented on the pulse dispersion in water and glass.