High-mobility 40-Gbps free-space optical link by a three-stage high-speed beam stabilizer and 2-D photodetector array...

Area of Science:

• Optical Communications
• Wireless Technology
• Robotics

Background:

• Free-space optical (FSO) systems face challenges with misalignment and wavefront distortion, limiting mobility and performance.
• Existing FSO systems often lack the wide field-of-view and robust mobility required for dynamic applications.
• Future 6G indoor environments demand high-speed, reliable wireless communication solutions that support mobile devices.

Purpose of the Study:

• To experimentally demonstrate a mobile free-space optical link with enhanced stability and reception capabilities.
• To investigate the effectiveness of a three-stage optical beam stabilizer and a 2-D photodetector array for diversity reception.
• To enable high-speed data transmission in a mobile FSO system suitable for 6G indoor applications.

Main Methods:

• Implemented a three-stage high-speed optical beam stabilizer to counteract system vibrations and movement.
• Utilized a 2-D photodetector array for spatial diversity reception to improve signal quality.
• Employed maximum-ratio combining digital signal processing to mitigate residual misalignment and wavefront distortions.

Main Results:

• Successfully demonstrated a mobile free-space optical link with an angular moving speed of 11.5°/s.
• Achieved a data transmission rate of 40 Gbps over a 2.1-m free-space distance.
• The diversity reception and signal processing effectively mitigated performance impacts from misalignment and distortion.

Conclusions:

• The proposed mobile FSO system offers a wide field-of-view and robust mobility support.
• This technology is well-suited for future 6G indoor applications, particularly those involving mobile robots.
• The integration of beam stabilization and diversity reception significantly enhances FSO system performance for mobile scenarios.