A stable wavelength-tunable triggered source of single photons and cascaded photon pairs at the telecom C-band

TL;DR

This paper presents a stable, wavelength-tunable single-photon and photon-pair source at 1.55 μm using strain-engineered quantum dots on piezoelectric substrates, advancing telecom quantum communication.

Contribution

It introduces a novel, stable, and tunable quantum light source at telecom wavelengths by integrating quantum dots with piezoelectric substrates, enabling spectral overlap of remote sources.

Findings

Achieved 0.25 nm wavelength tuning range.

Demonstrated triggered single-photon emission with 0.097 multiphoton probability.

Produced photon pairs via biexciton-exciton cascade.

Abstract

The implementation of fiber-based long-range quantum communication requires tunable sources of single photons at the telecom C-band. Stable and easy-to-implement wavelength- tunability of individual sources is crucial to (i) bring remote sources into resonance, to (ii) define a wavelength standard and to (iii) ensure scalability to operate a quantum repeater. So far, the most promising sources for true, telecom single photons are semiconductor quantum dots, due to their ability to deterministically and reliably emit single and entangled photons. However, the required wavelength-tunability is hard to attain. Here, we show a stable wavelength-tunable quantum light source by integrating strain-released InAs quantum dots on piezoelectric substrates. We present triggered single-photon emission at 1.55 {\mu}m with a multiphoton emission probability as low as 0.097, as well as photon pair emission from the radiative biexciton-exciton cascade. We achieve a tuning range of 0.25 nm which will allow to spectrally overlap remote quantum dots or tuning distant quantum dots into resonance with quantum memories. This opens up realistic avenues for the implementation of photonic quantum information processing applications at telecom wavelengths.