Deep-space and near-Earth optical communications by coded orbital angular momentum (OAM) modulation

Area of Science:

• Optical communications
• Information theory
• Space exploration technology

Background:

• Deep-space communication relies on pulse-position modulation (PPM), requiring extensive time slots for multi-gigabit transmission.
• Future interplanetary missions demand high-bandwidth communication solutions with low cost and power consumption.

Purpose of the Study:

• To explore orbital angular momentum (OAM) as an alternative modulation technique for high-bandwidth deep-space optical communications.
• To address the challenge of maintaining OAM state orthogonality under atmospheric turbulence.

Main Methods:

• Utilizing OAM eigenstates as orthogonal basis functions for N-dimensional signaling.
• Implementing OAM modulation and multiplexing in conjunction with other degrees of freedom.
• Employing Low-Density Parity-Check (LDPC) codes to mitigate atmospheric turbulence effects.

Main Results:

• OAM modulation provides a viable alternative for high-bandwidth interplanetary communication.
• OAM-based schemes demonstrate resilience to atmospheric turbulence when combined with LDPC codes.
• The proposed OAM scheme offers a spectral efficiency improvement of N²/log₂(N) over PPM.

Conclusions:

• OAM modulation is a promising technology for future high-bandwidth optical communication systems in space.
• The integration of OAM with LDPC coding enhances communication reliability in challenging environments like deep space.
• OAM-based communication systems significantly improve spectral efficiency compared to traditional PPM methods.