Experimental validation of phase-only pre-compensation over 494  m free-space propagation

Area of Science:

• Optical Engineering
• Atmospheric Optics
• Laser Communications

Background:

• Ground-to-geostationary orbit (GEO) laser communication faces challenges from atmospheric turbulence.
• Pre-compensation of atmospheric turbulence is theoretically feasible but lacks extensive free-space validation.

Purpose of the Study:

• To experimentally validate adaptive optics (AO) pre-compensation for ground-to-GEO laser communication.
• To assess the effectiveness of an AO-box in pre-compensating uplink laser beams.

Main Methods:

• Designed and implemented an AO-box for pre-compensating outgoing laser beams (uplink).
• Utilized measurements from an incoming beam (downlink) to control the AO-box.
• Conducted experiments over a 0.5 km horizontal test range simulating a ground-to-satellite scenario.

Main Results:

• Successfully focused the uplink laser beam onto a simulated satellite terminal using AO.
• Achieved beam focusing under a point-ahead angle of 28 microradians.
• Demonstrated a significant increase in the intensity of the received laser beam at the satellite terminal.

Conclusions:

• Adaptive optics pre-compensation is a viable technique for enhancing Earth-to-GEO optical communication.
• Experimental validation confirms the effectiveness of AO in mitigating atmospheric turbulence effects.
• The developed AO-box system shows promise for future free-space optical communication applications.