Design optimization for bright electrically-driven quantum dot single-photon sources emitting in telecom O-band.

Area of Science:

• Optics and Photonics
• Quantum Information Science
• Semiconductor Devices

Background:

• Micro-cavity single-photon sources are crucial for quantum technologies.
• Improving photon extraction efficiency is a key challenge.
• Telecom O-band operation (∼1.3 µm) is desirable for fiber integration.

Purpose of the Study:

• To substantially improve photon extraction efficiency of micro-cavity single-photon sources.
• To achieve broadband emission enhancement in the telecom O-band.
• To enable efficient coupling to various optical fibers.

Main Methods:

• Utilizing advanced light engineering with broadband bottom distributed Bragg reflector (DBR) and top DBR in a dielectric micropillar.
• Incorporating a circular Bragg grating in the lateral plane.
• Designing a doped layer in a pin-configuration for electric carrier injection.
• Employing 3D finite-difference time-domain (FDTD) modeling for efficiency calculations.

Main Results:

• Achieved broadband (∼8-10 nm) emission enhancement.
• Demonstrated an overall photon-extraction efficiency of ∼83% into the upper hemisphere.
• Reported photon-extraction efficiency of ∼79% within numerical aperture NA=0.7.
• Modeled photon coupling efficiencies: 11% for SMF28 (NA=0.12), >22% for 980HP (NA=0.2), and ∼40% for HNA (NA=0.42).

Conclusions:

• The advanced light engineering approach significantly enhances photon extraction efficiency for single-photon sources.
• The designed device shows high efficiency and broadband operation in the telecom O-band.
• The results indicate strong potential for efficient fiber coupling, crucial for practical quantum communication systems.