Optical mixing effects in a turbulent atmosphere

Measurements were made of the signal/noise ratio under optical homodyne conditions at a wavelength of 0.63 μ when a reference signal traveled along the same path as a data signal, and also when the signals were spatially separated and the fronts were not matched. The measurements were carried out over a 200-m strongly turbulent horizontal path using a helium-neon laser with an unstabilized frequency.