A reliable, but cost-effective generation of single-photon states is key for practical quantum communication systems. For real-world deployment, waveguide sources offer optimum compatibility with fiber networks and can be embedded in hybrid integrated modules. Here, we present the first chip-size fully integrated fiber-coupled Heralded Single Photon Source (HSPS) module based on a hybrid integration of a nonlinear lithium niobate waveguide into a polymer board. Photon pairs at 810nm (signal) and 1550nm (idler) are generated via parametric down-conversion pumped at 532nm in the LiNbO3 waveguide. The pairs are splitted in the polymer board and routed to separate output ports. The module has a size of (2×1)cm2 and is fully fiber-coupled with one pump input fiber and two output fibers. We measure a heralded second-order correlation function of gh(2)=0.05 with a heralding efficiency of ηh=4.5% at low pump powers.
@article{arxiv.2302.10976,
title = {Fiber-coupled plug-and-play heralded single photon source based on Ti:LiNbO$_3$ and polymer technology},
author = {Christian Kießler and Hauke Conradi and Moritz Kleinert and Viktor Quiring and Harald Herrmann and Christine Silberhorn},
journal= {arXiv preprint arXiv:2302.10976},
year = {2023}
}