Computationally efficient long-distance free-space optical simulation using a continuous-scaling angular spectrum...

Area of Science:

• Optics and Photonics
• Optical Communications
• Computational Physics

Background:

• Free-space optical (FSO) communication systems face challenges in simulating long-distance propagation due to computational complexity.
• Conventional angular spectrum (AS) methods require large computational grids, limiting efficiency for extensive simulations.

Purpose of the Study:

• To introduce an efficient simulation method for long-distance free-space optical propagation.
• To reduce the computational cost associated with conventional angular spectrum approaches.

Main Methods:

• Developed a continuous-scaling angular spectrum (CSAS) method combining multistep propagation with updated sampling intervals.
• Implemented an aperture-limited framework preserving only relevant spatial-frequency components contributing to received optical power (ROP).
• Introduced a low-frequency energy ratio to quantify spectral content.

Main Results:

• CSAS demonstrated consistent ROP estimation compared to conventional AS in simulations and a 4.3 km outdoor experiment.
• Achieved approximately 98% reduction in computation time at 4.3 km propagation distance.
• Maintained power estimation performance without degradation.

Conclusions:

• CSAS provides an efficient and accurate framework for simulating long-distance FSO propagation.
• The method is particularly suitable for scenarios involving multi-step turbulence modeling and system-level evaluation.
• CSAS offers significant computational advantages for practical FSO system design and analysis.