Strain-Controlled Quantum Dot Fine Structure for Entangled Photon Generation at 1550 nm

Area of Science:

• Quantum optics
• Materials science
• Telecommunications

Background:

• Entangled photon generation at 1550 nm is crucial for long-distance quantum communication using existing fiber infrastructure.
• Indium Arsenide (InAs) quantum dots offer on-demand entangled photon sources in the telecom C-band.
• Fine-structure splitting in quantum dots currently limits the fidelity of entangled states.

Purpose of the Study:

• To demonstrate fine-structure suppression in InAs quantum dots.
• To achieve high-fidelity entangled photon generation at 1550 nm.
• To enable practical quantum communication applications.

Main Methods:

• Utilized micromachined piezoelectric actuators for fine-structure control in InAs quantum dots.
• Generated entangled photons at 1550 nm.
• Characterized photon entanglement fidelity and concurrence.

Main Results:

• Achieved significant fine-structure suppression in InAs quantum dots.
• Demonstrated generation of highly entangled photons at 1550 nm with a maximum fidelity of 90.0 ± 2.7%.
• Obtained high concurrence values (up to 87.5 ± 3.1%) even with temporal filtering.

Conclusions:

• Micromachined piezoelectric actuators effectively control fine-structure splitting in InAs quantum dots.
• This control enables high-fidelity entangled photon generation for quantum communication.
• The technology paves the way for using quantum dots in fiber-based quantum communication protocols.