Validation of pre-compensation under point-ahead-angle in a 1 km free-space propagation experiment.

Adaptive optical pre-compensation is seen as crucial for free-space laser communication in order to overcome the influence of atmospheric turbulence, particularly with respect to Earth-to-GEO feederlinks. This paper presents an experimental investigation into adaptive optical pre-compensation under large point-ahead-angles. We detail the design and realization of a free-space laser communication experiment over a 1.0 km horizontal path using a divergent beacon beam and a focussed signal beam, propagating in opposite directions. We describe the design and development of our experimental setup and measurement campaign using real turbulence. The median isoplanatic angle was calculated to be 0.16 mrad, while an increase in the received optical power through pre-compensation could be demonstrated for point-ahead-angles in the range of 0.13 mrad to 0.27 mrad.

[1]  David L Fried,et al.  Optimal control of laser beams for propagation through a turbulent medium. , 2002, Journal of the Optical Society of America. A, Optics, image science, and vision.

[2]  Chao Liu,et al.  Performance verification of adaptive optics for satellite-to-ground coherent optical communications at large zenith angle. , 2018, Optics express.

[3]  Guang-ming Dai,et al.  Orthonormal polynomials in wavefront analysis: analytical solution , 2007 .

[4]  R. Noll.  Zernike polynomials and atmospheric turbulence , 1976 .

[5]  Ramona Eberhardt,et al.  Experimental validation of phase-only pre-compensation over 494  m free-space propagation. , 2017, Optics letters.

[6]  Jacopo Mocci,et al.  Real-time adaptive optics testbed to investigate point-ahead angle in pre-compensation of Earth-to-GEO optical communication. , 2016, Optics express.

[7]  Marie-Thérèse Velluet,et al.  Mitigation of atmospheric effects by adaptive optics for free-space optical communications , 2009, LASE.

[8]  Mikhail A Vorontsov,et al.  Atmospheric compensation with a speckle beacon in strong scintillation conditions: directed energy and laser communication applications. , 2005, Applied optics.

[9]  Marie-Thérèse Velluet,et al.  Experimental demonstration of the full-wave iterative compensation in free space optical communications. , 2013, Optics letters.

[10]  J. Shapiro.  Reciprocity of the Turbulent Atmosphere , 1971 .

[11]  Jean-Marc Conan,et al.  Impact of turbulence on high-precision ground-satellite frequency transfer with two-way coherent optical links , 2016 .

[12]  J. J. Fuensalida,et al.  Statistical structure of the atmospheric optical turbulence at Teide Observatory from recalibrated generalized SCIDAR data , 2011 .

[13]  R. Tyson,et al.  Adaptive optics and ground-to-space laser communications. , 1996, Applied optics.