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 by separately implementing OAM and optical path multiplexing.

Purpose of the Study:

• To enhance free-space optical propagation modes for quantum information applications.
• To combine optical path multiplexing using acoustic-optic deflectors (AODs) with OAM modes.
• To increase the number of multiplexed modes beyond previous achievements.

Main Methods:

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

Main Results:

• The proposed scheme successfully combined AODs and OAM modes for free-space optical multiplexing.
• Orbital angular momentum (OAM) modes maintained high efficiency and a considerable 0.5 dB bandwidth after AOD modulation.
• The number of multiplexed modes achieved is at least one order of magnitude greater than previous works.

Conclusions:

• The combined AOD and OAM approach offers a significant enhancement in free-space optical multiplexing for quantum applications.
• This method provides a substantial increase in mode numbers compared to prior techniques.
• The scheme is expected to enable higher mode numbers in quantum memory through practical advancements.