Strain-tunable entangled-light-emitting diodes with high yield and fast operation speed

TL;DR

This paper introduces strain-tunable entangled-light-emitting diodes (S-ELEDs) that use piezoelectric strain to enhance quantum dot entanglement, achieving high fidelity and fast operation speeds suitable for quantum communication.

Contribution

The study presents the first strain-tunable ELEDs that significantly improve the probability of entangled-photon emission and operate at record high speeds.

Findings

Up to 30% of QDs emit entangled photon pairs with high fidelity.

Achieved operation speed of 400 MHz, the highest reported.

Demonstrated effective strain tuning to enhance entanglement quality.

Abstract

Triggered sources of entangled photons play crucial roles in almost any existing protocol of quantum information science. The possibility to generate these non-classical states of light with high speed and using electrical pulses could revolutionize the field. Entangled-light-emitting-diodes (ELEDs) based on semiconductor quantum dots (QDs) are at present the only devices that can address this task 5. However, ELEDs are plagued by a source of randomness that hampers their practical exploitation in the foreseen applications: the very low probability (~10-2) of finding QDs with sufficiently small fine-structure-splitting for entangled-photon-generation. Here, we overcome this hurdle by introducing the first strain-tunable ELEDs (S-ELEDs) that exploit piezoelectric-induced strains to tune QDs for entangled-photon-generation. We demonstrate that up to 30% of the QDs in S-ELEDs emit polarization-entangled photon pairs with entanglement-fidelities as high as f+ = 0.83(5). Driven at the highest operation speed of 400 MHz ever reported so far, S-ELEDs emerge as unique devices for high-data rate entangled-photon applications.