Telecom band quantum dot technologies for long-distance quantum networks

TL;DR

This paper reviews advances in quantum dot technologies emitting at telecom wavelengths, crucial for enabling long-distance quantum networks and quantum repeaters in fiber-optic systems.

Contribution

It summarizes recent physics and technological developments in epitaxial quantum dots for telecom-band emission, including growth techniques and quantum frequency conversion methods.

Findings

Development of epitaxial QD devices emitting at telecom O- and C-bands

Use of quantum frequency conversion for telecom-band down-conversion

Discussion of challenges and future opportunities in telecom QD device integration

Abstract

A future quantum internet is expected to generate, distribute, store and process quantum bits (qubits) over the globe by linking different quantum nodes via quantum states of light. To facilitate the long-haul operations, quantum repeaters, the building blocks for a long-distance quantum network, have to be operated in the telecom wavelengths to take advantage of both the low-loss fiber network and the well-established technologies for optical communications. Semiconductors quantum dots (QDs) so far have exhibited exceptional performances as key elements, i.e., quantum light sources and spin-photon interfaces, for quantum repeaters, but only in the near-infrared (NIR) regime. Therefore, the development of high-performance telecom-band QD devices is highly desirable for a future solid-state quantum internet based on fiber networks. In this review, we present the physics and the technological developments towards epitaxial QD devices emitting at the telecom O- and C-bands for quantum networks by using advanced epitaxial growth for direct telecom emission, and quantum frequency conversion (QFC) for telecom-band down-conversion. We also discuss the challenges and opportunities in the future to realize telecom QD devices with improved performances and expanded functionalities by taking advantage of hybrid integrations.