Modeling and performance analysis for few-mode free-space optical communication reception based on optical-domain...

Area of Science:

• Optical Communications
• Free-Space Optics (FSO)
• Signal Processing

Background:

• Free-space optical communication (FSOC) systems face challenges from atmospheric turbulence and mode coupling.
• Existing FSOC reception methods can be complex and prone to noise accumulation.

Purpose of the Study:

• To develop a theoretical model for few-mode FSOC reception utilizing optical-domain coherent beam combining.
• To establish a comprehensive framework integrating atmospheric turbulence, mode coupling, and beam combining effects.

Main Methods:

• Analysis of few-mode fiber coupling efficiency to model atmospheric turbulence effects.
• Quantitative evaluation of bit error rate (BER) performance by including device losses and combining efficiency.
• Development of a theoretical framework encompassing the entire signal transmission chain.

Main Results:

• The proposed scheme shows a 1-3 dB improvement in receiver sensitivity compared to single-mode FSOC at a BER of 3.8×10^-3.
• Performance is comparable to mode diversity reception systems, within 1 dB.
• Significant reduction in hardware complexity and noise by using a single local oscillator and detector.

Conclusions:

• The theoretical model provides a robust framework for understanding and optimizing few-mode FSOC reception.
• Coherent beam combining offers a promising approach for enhanced FSOC performance with reduced complexity.
• The findings pave the way for more efficient and practical free-space optical communication systems.