Interface between path and orbital angular momentum entanglement for high-dimensional photonic quantum information

Area of Science:

• Quantum Information Science
• Integrated Photonics
• Quantum Optics

Background:

• Integrated optical circuits are crucial for scaling quantum information science.
• Encoding information on photonic chips often uses paths.
• High-dimensional quantum states need robust flying carriers for long-distance distribution, such as orbital angular momentum modes.

Purpose of the Study:

• To demonstrate a quantum interface between integrated photonic paths and spatial modes.
• To enable the transfer of quantum entanglement between different degrees of freedom.
• To facilitate the creation and distribution of high-dimensional spatial mode entanglement.

Main Methods:

• Generated three-dimensional path entanglement between two photons using a nonlinear crystal.
• Employed a mode sorter as a quantum interface.
• Transferred the entanglement from the path degree of freedom to the orbital angular momentum degree of freedom.

Main Results:

• Successfully demonstrated a quantum interface between path-encoded and orbital angular momentum-encoded photonic states.
• Achieved flexible creation of high-dimensional spatial mode entanglement.
• Established a method for transferring quantum entanglement between distinct photonic degrees of freedom.

Conclusions:

• The developed quantum interface provides a flexible method for generating high-dimensional spatial mode entanglement.
• This work lays the foundation for complex quantum networks capable of distributing high-dimensional entangled states over long distances.
• Enables the integration of different photonic quantum information processing schemes.