TY - JOUR AB - Interference between single photons is key for many quantum optics experiments and applications in quantum technologies, such as quantum communication or computation. It is advantageous to operate the systems at telecommunication wavelengths and to integrate the setups for these applications in order to improve stability, compactness and scalability. A new promising material platform for integrated quantum optics is lithium niobate on insulator (LNOI). Here, we realise Hong-Ou-Mandel (HOM) interference between telecom photons from an engineered parametric down-conversion source in an LNOI directional coupler. The coupler has been designed and fabricated in house and provides close to perfect balanced beam splitting. We obtain a raw HOM visibility of (93.5 ± 0.7) %, limited mainly by the source performance and in good agreement with off-chip measurements. This lays the foundation for more sophisticated quantum experiments in LNOI. AU - Babel, Silia AU - Bollmers, Laura AU - Massaro, Marcello AU - Luo, Kai Hong AU - Stefszky, Michael AU - Pegoraro, Federico AU - Held, Philip AU - Herrmann, Harald AU - Eigner, Christof AU - Brecht, Benjamin AU - Padberg, Laura AU - Silberhorn, Christine ID - 45850 IS - 14 JF - Optics Express KW - Atomic and Molecular Physics KW - and Optics SN - 1094-4087 TI - Demonstration of Hong-Ou-Mandel interference in an LNOI directional coupler VL - 31 ER - TY - JOUR AU - Luo, Kai Hong AU - Santandrea, Matteo AU - Stefszky, Michael AU - Sperling, Jan AU - Massaro, Marcello AU - Ferreri, Alessandro AU - Sharapova, Polina AU - Herrmann, Harald AU - Silberhorn, Christine ID - 26889 JF - Physical Review A SN - 2469-9926 TI - Quantum optical coherence: From linear to nonlinear interferometers ER - TY - JOUR AU - Massaro, Marcello AU - Meyer-Scott, Evan AU - Montaut, Nicola AU - Herrmann, Harald AU - Silberhorn, Christine ID - 25038 JF - New Journal of Physics SN - 1367-2630 TI - Improving SPDC single-photon sources via extended heralding and feed-forward control ER - TY - JOUR AU - Luo, Kai-Hong AU - Ansari, Vahid AU - Massaro, Marcello AU - Santandrea, Matteo AU - Eigner, Christof AU - Ricken, Raimund AU - Herrmann, Harald AU - Silberhorn, Christine ID - 26237 JF - Optics Express SN - 1094-4087 TI - Counter-propagating photon pair generation in a nonlinear waveguide ER - TY - JOUR AU - Georgi, Philip AU - Massaro, Marcello AU - Luo, Kai Hong AU - Sain, Basudeb AU - Montaut, Nicola AU - Herrmann, Harald AU - Weiss, Thomas AU - Li, Guixin AU - Silberhorn, Christine AU - Zentgraf, Thomas ID - 12919 JF - Light: Science & Applications SN - 2047-7538 TI - Metasurface interferometry toward quantum sensors VL - 8 ER - TY - JOUR AU - Luo, Kai Hong AU - Ansari, Vahid AU - Massaro, Marcello AU - Santandrea, Matteo AU - Eigner, Christof AU - Ricken, Raimund AU - Herrmann, Harald AU - Silberhorn, Christine ID - 26052 JF - Optics Express SN - 1094-4087 TI - Counter-propagating photon pair generation in a nonlinear waveguide ER -