Free-space optical multiplexing scheme based on acousto-optic deflector (AOD) with orbital angular momentum

Area of Science:

• Quantum Information Science
• Optical Physics
• Quantum Communication

Background:

• Free-space optical multiplexing is crucial for quantum repeaters in quantum information processing and communication.
• Orbital angular momentum (OAM) modes offer a high-dimensional encoding capacity for spatial degrees of freedom.
• Previous methods achieved hundreds of multiplexed modes using OAM qubits or optical path multiplexing separately.

Purpose of the Study:

• To enhance free-space optical propagation modes by integrating optical path multiplexing with orbital angular momentum (OAM) modes.
• To increase the number of multiplexed modes beyond previous implementations for quantum information applications.

Main Methods:

• Combining optical path multiplexing, utilizing acoustic-optic deflectors (AODs), with orbital angular momentum (OAM) modes.
• Experimentally verifying the efficiency and bandwidth of OAM modes after AODs modulation.

Main Results:

• The proposed scheme successfully combined AOD-based optical path multiplexing with OAM modes.
• Orbital angular momentum (OAM) modes maintained high efficiency and a considerable 0.5 dB bandwidth after AODs modulation.
• The integrated method achieved at least one order of magnitude more mode numbers compared to previous works.

Conclusions:

• The integration of AODs and OAM modes offers a significant advancement in free-space optical multiplexing.
• This scheme is expected to enable higher mode numbers in quantum memory and future quantum communication systems.