Orbital angular momentum and beyond in free-space optical communications

Area of Science:

• Optics and Photonics
• Optical Communications
• Quantum Science

Background:

• Orbital angular momentum (OAM) describes light with a helical phase structure, enabling diverse applications.
• OAM beams possess inherent orthogonality and unbounded states, ideal for scaling optical communication capacity.

Purpose of the Study:

• To provide a comprehensive overview of OAM and structured light in free-space optical communications.
• To review advancements in OAM modulation, multiplexing, multicasting, and communication in turbulent environments.

Main Methods:

• Review of fundamental OAM concepts and communication strategies.
• Analysis of OAM modulation techniques, including spatial light modulators and array modulation.
• Exploration of OAM multiplexing, multicasting, and performance in turbulence using adaptive optics and digital signal processing.

Main Results:

• OAM enables spectrally efficient, high-capacity, and long-distance free-space optical communication.
• Structured light beyond OAM, such as Bessel and Airy beams, offers further communication enhancements.
• Techniques for turbulence mitigation and adaptive multicasting are crucial for robust OAM communications.

Conclusions:

• OAM and beyond represent a promising frontier for diverse and robust optical communication systems.
• Future opportunities lie in exploiting general structured light for advanced applications.
• Continued research is needed to address challenges and unlock the full potential of OAM in communications.