Semiconductor Bragg-reflection waveguides are well-established sources of correlated photon pairs as well as promising candidates for building up integrated quantum optics devices. Here, we use such a source with optimized non-linearity for preparing time-bin entangled photons in the telecommunication wavelength range. By taking advantage of pulsed state preparation and efficient free-running single-photon detection, we drive our source at low pump powers, which results in a strong photon-pair correlation. The tomographic reconstruction of the state's density matrix reveals that our source exhibits a high degree of entanglement. We extract a concurrence of 88.9±1.8% and a fidelity of 94.2±0.9% with respect to a Bell state.
@article{arxiv.1804.11108,
title = {High-concurrence time-bin entangled photon pairs from optimized Bragg-reflection waveguides},
author = {Huan Chen and Silke Auchter and Maximilian Prilmüller and Alexander Schlager and Thomas Kauten and Kaisa Laiho and Benedikt Pressl and Holger Suchomel and Martin Kamp and Sven Höfling and Christian Schneider and Gregor Weihs},
journal= {arXiv preprint arXiv:1804.11108},
year = {2018}
}