Coherent Optical Array Receivers For The Mitigation Of Atmospheric Turbulence And Speckle Effects
Title - Alternative
Coherent Optical Array Receivers; Heterodyne Arrays; Space Diversity; Receivers; Coherent Optical Communications; Atmospheric Turbulence; Compensation; Electro-Optic Phase-Locked Loop; Heterodyne Detector Array; Lidar; Optics
A description is given of the design, operation, and test over a 2-km path (roundtrip) of a continuous wave, coherent laser array receiver that uses two independent aperture-receivers whose intermediate frequencies are electro-optically co-phased in real time and then added as a proposed way to overcome effective aperture limitations imposed by atmospheric turbulence and to mitigate signal fading associated with atmospheric turbulence and speckle effects. The experiment resulted in a mean carrier-to-noise ratio increase of 1.8, which is within 1% of the theoretical predictions, when the two signals were phase locked, versus no increase without phase locking. Further, the carrier fading strength, or normalized carrier-to-noise ratio variance, was reduced by a factor of 0.53, which is within 2% of the theoretical prediction. The bandwidth of the electro-optic phase-locked loop was measured to be of the order of 600 Hz, which is adequate to compensate for atmospheric refractive turbulence fluctuations. (C) 1996 Optical Society of America
Gatt, P.; Costello, T. P.; Heimmermann, D. A.; Castellanos, D. C.; Weeks, A. R.; and Stickley, C. M., "Coherent Optical Array Receivers For The Mitigation Of Atmospheric Turbulence And Speckle Effects" (1995). Faculty Bibliography. 1486.