Fiber-coupled broadband quantum memory for polarization-encoded photonic qubits

Area of Science:

• Quantum Information Science
• Optics and Photonics
• Quantum Networking

Background:

• Quantum networking requires efficient and reliable quantum memory devices.
• Fiber-coupled photonic quantum memories are essential for integrating quantum devices into existing infrastructure.
• Low-loss and high-efficiency quantum memories are critical for near-term quantum networking applications.

Purpose of the Study:

• To demonstrate a fiber-coupled loop-and-switch quantum memory platform.
• To characterize the efficiency and performance of the quantum memory for different storage cycles.
• To investigate the trade-off between memory lifetime and qubit accessibility.

Main Methods:

• Implementation of a fiber-coupled loop-and-switch architecture for quantum memory.
• Measurement of pass-through efficiency and storage efficiency scaling with the number of cycles (N).
• Testing storage and retrieval fidelity of ultra-broadband single-photon polarization qubits using different storage cycle times (~40 ns and ~0.5 μs).

Main Results:

• Achieved a pass-through efficiency of approximately 54%.
• Demonstrated an overall storage efficiency that scales as ~0.5^(N+1), where N is the number of storage cycles.
• Showcased high-fidelity storage and retrieval of single-photon polarization qubits for both short (~40 ns) and long (~0.5 μs) storage cycle times.

Conclusions:

• The demonstrated fiber-coupled quantum memory platform offers a promising solution for near-term quantum networking applications.
• The platform exhibits a trade-off between memory lifetime and qubit accessibility, which can be managed by adjusting storage cycle times.
• High-fidelity qubit operations are achievable, paving the way for robust quantum communication systems.