Generation of high-purity entangled photon pairs using silicon wire waveguide

Area of Science:

• Quantum optics
• Integrated photonics
• Materials science

Background:

• Spontaneous four-wave mixing (SFWM) is a key process for generating entangled photon pairs.
• Silicon wire waveguides (SWW) offer potential for miniaturized quantum photonic devices.
• Achieving high purity and coincidence rates is crucial for practical quantum applications.

Purpose of the Study:

• To demonstrate high-purity entangled photon pair generation in silicon wire waveguides (SWW).
• To evaluate the performance of SWW for spontaneous four-wave mixing (SFWM) compared to traditional fiber-based sources.
• To characterize the quality of generated time-bin entangled photons.

Main Methods:

• Utilized spontaneous four-wave mixing (SFWM) in a nano-scale silicon waveguide.
• Employed a low-loss mode size converter integrated with the silicon waveguide.
• Measured coincidence to accidental coincidence ratio (CAR) and two-photon interference visibility.

Main Results:

• Generated high-purity correlated and entangled photon pairs with high fidelity.
• Achieved a coincidence to accidental coincidence ratio (CAR) of approximately 200, exceeding dispersion shifted fiber (DSF) by 3.2 times.
• Observed two-photon interference fringes with >95% visibility for time-bin entangled photons without accidental coincidence subtraction.

Conclusions:

• Silicon wire waveguides (SWW) are a promising platform for efficient and high-purity entangled photon generation.
• The demonstrated performance of SWW surpasses conventional fiber sources for quantum applications.
• The results pave the way for scalable integrated quantum photonic systems.