Suppression of turbulence-induced scintillation in free-space optical communication systems using saturated optical amplifiers

A laboratory-simulated free-space optical link under various turbulence levels is implemented to propose and experimentally demonstrate the use of saturated optical amplifiers as a simple and efficient approach for suppression of scintillation due to atmospheric turbulence. The use of erbium-doped fiber amplifier (EDFA) or semiconductor optical amplifier (SOA) re- quires the received signal be coupled into a fiber. The system performance of receiver structures employing a saturated EDFA and a SOA (in saturation and conversion modes) are measured and compared to that of fiberless direct detection (DD). It is shown that in higher turbulence levels, where no data transmission can be achieved by DD, remarkable eye opening results when using saturated amplifiers.