On-Demand Generation of Indistinguishable Photons in the Telecom C-Band Using Quantum Dot Devices

Area of Science:

• Quantum Optics
• Materials Science
• Nanotechnology

Background:

• Semiconductor quantum dots (QDs) are crucial for generating single and entangled photons for quantum technologies.
• Directly generating high-quality photons in the telecom C-band (1550 nm) from QDs for fiber-optical quantum communication has been a significant challenge.

Purpose of the Study:

• To demonstrate the coherent, on-demand generation of indistinguishable photons in the telecom C-band from single QD devices.
• To achieve high quantum-optical quality for these telecom C-band photons.

Main Methods:

• Utilized InAs/InP QD-mesa structures heterogeneously integrated with a metallic reflector on a silicon wafer.
• Employed pulsed two-photon resonant excitation of the biexciton-exciton radiative cascade.
• Applied Rabi rotation analysis and photon cross-correlation measurements to assess fidelity and purity.

Main Results:

• Observed Rabi rotations up to 4π, indicating strong coherent control.
• Achieved high single-photon purity with g(2)(0) values of 0.005(1) for exciton and 0.015(1) for biexciton photons.
• Demonstrated preparation fidelities exceeding 80% at the π-pulse and photon indistinguishability up to 35(3)% via Hong-Ou-Mandel interference.

Conclusions:

• Successfully demonstrated coherent, on-demand generation of indistinguishable photons in the telecom C-band from single QD devices.
• The achieved high purity, fidelity, and indistinguishability represent a significant advancement for quantum communication applications.
• This work paves the way for practical quantum communication systems utilizing fiber-optical networks.