Adaptive optics model characterizing turbulence mitigation for free space optical communications link budgets

Area of Science:

• Optical Engineering
• Atmospheric Physics
• Telecommunications

Background:

• Free-space optical communications (FSOC) are crucial for high-data-rate atmospheric and space-based networks.
• Atmospheric turbulence significantly degrades FSOC link performance, necessitating mitigation strategies for reliable operation.
• Adaptive optics (AO) is a proposed technology to counteract turbulence effects, but validated performance models are scarce.

Purpose of the Study:

• To review the Strehl ratio for the Andrews AO model in the context of FSOC.
• To compare predicted AO-based FSOC link budgets with measured field trial performance.
• To assess the practical effectiveness of AO systems in mitigating turbulence for FSOC links.

Main Methods:

• Review of the Andrews AO model and Strehl ratio calculations.
• Comparison of theoretical AO-based FSOC link budgets with empirical data from field trials.
• Analysis of FSOC link performance under varying turbulence conditions and ranges.

Main Results:

• AO systems demonstrate effectiveness in weak turbulence or short-range FSOC links (under 10 km).
• In moderate turbulence, AO provides only limited tip/tilt correction, with performance degrading at longer ranges.
• Under high/saturation regime turbulence and at longer ranges, AO offers no significant performance gain, and proximity to the ground can further degrade performance.

Conclusions:

• Current AO systems offer limited benefits for long-range, high-turbulence FSOC links.
• Field-validated models are essential for deploying reliable AO-assisted FSOC systems.
• Further research is needed to enhance AO performance in challenging atmospheric conditions for FSOC applications.