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Updated: Jun 3, 2026

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Polarization-entangled photon pairs from a periodically poled crystalline waveguide
Zachary H Levine1, Jingyun Fan, Jun Chen
1Optical Technology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8441, USA. zlevine@nist.gov
Researchers propose a method for generating polarization-entangled photon pairs using periodically poled crystals, achieving high efficiency and entanglement. This technique, suitable for waveguides, demonstrates practical viability with high fidelity results.
Area of Science:
- Quantum optics
- Nonlinear optics
- Photonics
Background:
- Entangled photon pairs are crucial for quantum information processing.
- Existing methods for generating entangled photons face challenges in efficiency and stability.
Purpose of the Study:
- To propose a novel method for generating polarization-entangled photon pairs.
- To achieve high collection efficiency, high entanglement fidelity, and stable operation.
Main Methods:
- Theoretical formulation for collinear propagation in waveguides.
- Utilizing type II phase matching with +1 and -1 diffraction orders in periodically poled crystals.
- Investigating the use of a HeNe pump laser with a periodically poled rubidium-doped potassium titanyl phosphate (Rb:KTP) waveguide.
Main Results:
- The proposed method allows for high collection efficiency and entanglement.
- Practical operating conditions were identified, demonstrating feasibility.
- Fidelities of 0.98 are achievable under these practical conditions.
Conclusions:
- The proposed periodically poled crystal approach offers a promising route for generating high-fidelity polarization-entangled photon pairs.
- This method is well-suited for integration into waveguide structures for scalable quantum applications.
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