Nonlinear Optics Technology. Phase 3. Volume 2. Phase Conjugated Optical Communication Link

Abstract : A laser communication link that uses phase conjugation (PC) to correct for atmospheric aberrations due to turbulence was investigated. Significant improvements over conventional optical communication links were demonstrated through experiments and analysis. A 1.1 km four wave mixing (FWM) PC optical comm link propagating through the atmosphere was demonstrated and characterized over a range of atmospheric turbulence conditions and compared to the performance of a conventional link. Four wave mixing was performed in sodium vapor near the sodium D2 resonance line, (lambda = 589 nm). Signals with amplitude modulation of 10 kHz to 1 MHz were successfully transmitted and received and received over this link. Measurements of intensity variance demonstrated that the beam returned by the phase conjugator is corrected for atmospheric turbulence, displaying significantly less intensity variance than a beam returned by a conventional mirror. A 30 m FWM PC comm link was tested with a uniform turbulence generator (turbox) in the laboratory and compared to theoretical performance predictions.