Gigahertz-clocked Generation of Highly Indistinguishable Photons at C-band Wavelengths

TL;DR

This paper demonstrates the generation of highly indistinguishable single photons at a 2.5 GHz clock rate in the telecom C-band using a semiconductor quantum dot, advancing quantum communication capabilities.

Contribution

It reports a novel high-speed photon source with near-theoretical indistinguishability, suitable for quantum communication at unprecedented data rates.

Findings

Photon generation at 2.5 GHz clock rate with high indistinguishability

Strong multiphoton suppression with g^{(2)}(0) < 4%

High two-photon interference visibility > 85%

Abstract

High-performance single-photon sources at telecom C-band wavelentghs are key building blocks for applications in long-distance quantum communication. Here, we report the generation of highly indistinguishable, single photons at a clock-rate of 2.5 GHz. This is achieved by coherently driving the biexciton transition ($T_1^\mathrm{XX}=64(1)\,$ps) of a semiconductor quantum dot embedded in a microcavity with strong asymmetric Purcell enhancement. Employing pulsed two-photon resonant excitation, strong multiphoton suppression with $g^{(2)}(0) < 4\%$ and high two-photon-interference visibility of $V_\mathrm{raw}> 85\%$ is observed. The observed photon indistinguishability is close to the theoretical limit expected for the photonically engineered radiative cascade and matches values obtained at lower repetition rates. Our results show a substantial advancement towards interference-based quantum information protocols at unprecedented data rates in the telecom C-Band.