Generating polarization-entangled photon pairs using cross-spliced birefringent fibers

Area of Science:

• Quantum optics
• Photonics
• Fiber optics

Background:

• Entangled photon-pair sources are crucial for quantum information processing.
• Current sources often rely on bulk optics, limiting miniaturization and stability.
• Developing fiber-based sources offers advantages in integration and robustness.

Purpose of the Study:

• To demonstrate a novel polarization-entangled photon-pair source using standard birefringent polarization-maintaining optical fiber.
• To explore the potential for a fully fiber-based entangled photon source, replacing bulk optics with in-fiber equivalents.
• To achieve high-fidelity entangled states suitable for quantum applications.

Main Methods:

• Utilizing two stretches of polarization-maintaining optical fiber spliced with perpendicular polarization axes.
• Modeling temporal walk-off in the fibers to ensure indistinguishable photon creation processes.
• Implementing compensation techniques to optimize entanglement quality.

Main Results:

• Demonstration of a novel, compact polarization-entangled photon-pair source.
• Achieved a high fidelity of (92.2 ± 0.2)% with a maximally entangled Bell state.
• Validated the potential for a fully fiber-based system with in-fiber components.

Conclusions:

• The developed fiber-based source offers a promising platform for generating high-quality entangled photons.
• This technology advances the development of integrated photonic quantum devices.
• The approach minimizes the need for bulk optical components, enhancing scalability and practicality.