Efficient fiber-coupled single-photon source based on quantum dots in a photonic-crystal waveguide.

Area of Science:

• Photonics
• Quantum Information Science
• Solid-State Physics

Background:

• Photonic quantum information processing requires high-brightness, fiber-coupled single-photon sources.
• Existing sources often face limitations in efficiency and fiber integration.

Purpose of the Study:

• To present a novel fiber-coupled single-photon source based on photonic-crystal waveguides.
• To enhance the efficiency and reliability of planar chip-based single-photon sources.

Main Methods:

• Evanescent coupling of light from a tapered out-coupler to an optical fiber.
• Two-step approach: performance measurement of out-coupler with on-chip reflector, followed by detailed characterization of the integrated source.
• Reflection measurements and efficiency quantification.

Main Results:

• Chip-to-fiber coupling efficiency exceeds 80%.
• Overall single-photon source efficiency of 10.9% ± 2.3% achieved.
• The out-coupling method demonstrates robustness, stability, and broadband operation (tens of nanometers).

Conclusions:

• The developed tapered out-coupler significantly improves fiber coupling for photonic-crystal waveguide single-photon sources.
• This approach offers a promising pathway for efficient and reliable planar chip-based quantum photonics.
• The method's robustness and broadband characteristics are key advantages for practical applications.