@article{54544,
  abstract     = {{The biphoton correlation time, a measure for the conditional uncertainty in the temporal arrival of two photons from a photon pair source, is a key performance identifier for many quantum spectroscopy applications, with shorter correlation times typically yielding better performance. Furthermore, it provides fundamental insight into the effects of dispersion on the biphoton state. Here, we show that a characteristic dependence of the width of the temporal interferogram can be exploited to obtain insights into the amount of second-order dispersion inside the interferometer and to retrieve actual and Fourier-limited ultrashort biphoton correlation times of around 100 fs. In the presented scheme, we simultaneously measure spectral and temporal interferograms at the output of an SU(1,1) interferometer based on an integrated broadband parametric down conversion source in a Ti:LiNbO3 waveguide.}},
  author       = {{Roeder, Franz and Pollmann, René and Stefszky, Michael and Santandrea, Matteo and Luo, Kai Hong and Quiring, V. and Ricken, Raimund and Eigner, Christof and Brecht, Benjamin and Silberhorn, Christine}},
  issn         = {{2691-3399}},
  journal      = {{PRX Quantum}},
  number       = {{2}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Measurement of Ultrashort Biphoton Correlation Times with an Integrated Two-Color Broadband SU(1,1)-Interferometer}}},
  doi          = {{10.1103/prxquantum.5.020350}},
  volume       = {{5}},
  year         = {{2024}},
}

@article{45850,
  abstract     = {{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.}},
  author       = {{Babel, Silia and Bollmers, Laura and Massaro, Marcello and Luo, Kai Hong and Stefszky, Michael and Pegoraro, Federico and Held, Philip and Herrmann, Harald and Eigner, Christof and Brecht, Benjamin and Padberg, Laura and Silberhorn, Christine}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  keywords     = {{Atomic and Molecular Physics, and Optics}},
  number       = {{14}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Demonstration of Hong-Ou-Mandel interference in an LNOI directional coupler}}},
  doi          = {{10.1364/oe.484126}},
  volume       = {{31}},
  year         = {{2023}},
}

@article{26889,
  author       = {{Luo, Kai Hong and Santandrea, Matteo and Stefszky, Michael and Sperling, Jan and Massaro, Marcello and Ferreri, Alessandro and Sharapova, Polina and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  title        = {{{Quantum optical coherence: From linear to nonlinear interferometers}}},
  doi          = {{10.1103/physreva.104.043707}},
  year         = {{2021}},
}

@article{26077,
  abstract     = {{<jats:p>Nonlinear SU(1,1) interferometers are fruitful and promising tools for spectral engineering and precise measurements with phase sensitivity below the classical bound. Such interferometers have been successfully realized in bulk and fiber-based configurations. However, rapidly developing integrated technologies provide higher efficiencies, smaller footprints, and pave the way to quantum-enhanced on-chip interferometry. In this work, we theoretically realised an integrated architecture of the multimode SU(1,1) interferometer which can be applied to various integrated platforms. The presented interferometer includes a polarization converter between two photon sources and utilizes a continuous-wave (CW) pump. Based on the potassium titanyl phosphate (KTP) platform, we show that this configuration results in almost perfect destructive interference at the output and supersensitivity regions below the classical limit. In addition, we discuss the fundamental difference between single-mode and highly multimode SU(1,1) interferometers in the properties of phase sensitivity and its limits. Finally, we explore how to improve the phase sensitivity by filtering the output radiation and using different seeding states in different modes with various detection strategies.</jats:p>}},
  author       = {{Ferreri, Alessandro and Santandrea, Matteo and Stefszky, Michael and Luo, Kai Hong and Herrmann, Harald and Silberhorn, Christine and Sharapova, Polina R.}},
  issn         = {{2521-327X}},
  journal      = {{Quantum}},
  title        = {{{Spectrally multimode integrated SU(1,1) interferometer}}},
  doi          = {{10.22331/q-2021-05-27-461}},
  year         = {{2021}},
}

@inproceedings{40374,
  abstract     = {{<jats:p>We present a frequency multimode integrated SU (1,1) interferometer with a polarization converter and strong signal-idler photon correlations. Phase sensitivity below the shot noise limit is demonstrated, various filtering and seeding strategies are discussed.</jats:p>}},
  author       = {{Ferreri, A. and Santandrea, Matteo and Stefszky, Michael and Luo, Kai Hong and Herrmann, Harald and Silberhorn, Christine and Sharapova, Polina}},
  booktitle    = {{Conference on Lasers and Electro-Optics}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Multimode integrated SU(1,1) interferometer}}},
  doi          = {{10.1364/cleo_qels.2021.ftu1n.6}},
  year         = {{2021}},
}

@article{12919,
  author       = {{Georgi, Philip and Massaro, Marcello and Luo, Kai Hong and Sain, Basudeb and Montaut, Nicola and Herrmann, Harald and Weiss, Thomas and Li, Guixin and Silberhorn, Christine and Zentgraf, Thomas}},
  issn         = {{2047-7538}},
  journal      = {{Light: Science & Applications}},
  pages        = {{70}},
  title        = {{{Metasurface interferometry toward quantum sensors}}},
  doi          = {{10.1038/s41377-019-0182-6}},
  volume       = {{8}},
  year         = {{2019}},
}

@article{38047,
  author       = {{Xie, Zhenda and Luo, Kai Hong and Chang, Kai Chi and Panoiu, Nicolae C. and Herrmann, Harald and Silberhorn, Christine and Wong, Chee Wei}},
  issn         = {{1559-128X}},
  journal      = {{Applied Optics}},
  keywords     = {{Atomic and Molecular Physics, and Optics, Engineering (miscellaneous), Electrical and Electronic Engineering}},
  number       = {{22}},
  publisher    = {{The Optical Society}},
  title        = {{{Efficient C-band single-photon upconversion with chip-scale Ti-indiffused pp-LiNbO<sub>3</sub> waveguides}}},
  doi          = {{10.1364/ao.58.005910}},
  volume       = {{58}},
  year         = {{2019}},
}

@article{26052,
  author       = {{Luo, Kai Hong and Ansari, Vahid and Massaro, Marcello and Santandrea, Matteo and Eigner, Christof and Ricken, Raimund and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  title        = {{{Counter-propagating photon pair generation in a nonlinear waveguide}}},
  doi          = {{10.1364/oe.378789}},
  year         = {{2019}},
}

@inproceedings{16959,
  author       = {{Ferreri, A. and Sharapova, P. and Luo, Kai Hong and Herrmann, H. and Silberhorn, C.}},
  booktitle    = {{Quantum Information and Measurement (QIM) V: Quantum Technologies}},
  isbn         = {{9781943580569}},
  keywords     = {{pc2-ressources}},
  title        = {{{Theoretical description of a multimode SU(1,1) interferometer}}},
  doi          = {{10.1364/qim.2019.t5a.35}},
  year         = {{2019}},
}

@article{37288,
  abstract     = {{<jats:p>An integrated chip with quantum state generation, active polarization manipulation, and precise time control is demonstrated.</jats:p>}},
  author       = {{Luo, Kai-Hong and Brauner, Sebastian and Eigner, Christof and Sharapova, Polina and Ricken, Raimund and Meier, Torsten and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{2375-2548}},
  journal      = {{Science Advances}},
  keywords     = {{Multidisciplinary}},
  number       = {{1}},
  publisher    = {{American Association for the Advancement of Science (AAAS)}},
  title        = {{{Nonlinear integrated quantum electro-optic circuits}}},
  doi          = {{10.1126/sciadv.aat1451}},
  volume       = {{5}},
  year         = {{2019}},
}

@inproceedings{40388,
  author       = {{Luo, Kai Hong and Brauner, Sebastian and Eigner, Christof and Sharapova, Polina and Ricken, Raimund and Meier, Torsten and Herrmann, Harald and Silberhorn, Christine}},
  booktitle    = {{Conference on Lasers and Electro-Optics}},
  isbn         = {{978-1-943580-42-2}},
  location     = {{San Jose, California United States}},
  publisher    = {{OSA}},
  title        = {{{Monolithically Integrated Hong-Ou-Mandel Experiment in LiNbO3}}},
  doi          = {{10.1364/cleo_qels.2018.fm1g.3}},
  year         = {{2018}},
}

@inproceedings{40386,
  author       = {{Sharapova, Polina and Luo, Kai Hong and Herrmann, Harald and Reichelt, Matthias and Silberhorn, Christine and Meier, Torsten}},
  booktitle    = {{Conference on Lasers and Electro-Optics}},
  isbn         = {{978-1-943580-42-2}},
  location     = {{San Jose, California United States}},
  publisher    = {{OSA}},
  title        = {{{Manipulation of Two-Photon Interference by Entanglement}}},
  doi          = {{10.1364/cleo_qels.2018.ff1b.8}},
  year         = {{2018}},
}

@article{26058,
  author       = {{Luo, Kai Hong and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{2058-9565}},
  journal      = {{Quantum Science and Technology}},
  title        = {{{Temporal correlations of spectrally narrowband photon pair sources}}},
  doi          = {{10.1088/2058-9565/aa6b8e}},
  year         = {{2017}},
}

@article{26059,
  author       = {{Rütz, Helge and Luo, Kai Hong and Suche, Hubertus and Silberhorn, Christine}},
  issn         = {{2331-7019}},
  journal      = {{Physical Review Applied}},
  title        = {{{Quantum Frequency Conversion between Infrared and Ultraviolet}}},
  doi          = {{10.1103/physrevapplied.7.024021}},
  year         = {{2017}},
}

@article{9685,
  author       = {{Sansoni, Linda and Luo, Kai Hong and Eigner, Christof and Ricken, Raimund and Quiring, Viktor and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{2056-6387}},
  journal      = {{npj Quantum Information}},
  title        = {{{A two-channel, spectrally degenerate polarization entangled source on chip}}},
  doi          = {{10.1038/s41534-016-0005-z}},
  year         = {{2017}},
}

@article{13906,
  author       = {{Sharapova, Polina and Luo, Kai Hong and Herrmann, Harald and Reichelt, Matthias and Meier, Torsten and Silberhorn, Christine}},
  issn         = {{1367-2630}},
  journal      = {{New Journal of Physics}},
  number       = {{12}},
  publisher    = {{IOP Publishing}},
  title        = {{{Toolbox for the design of LiNbO3-based passive and active integrated quantum circuits}}},
  doi          = {{10.1088/1367-2630/aa9033}},
  volume       = {{19}},
  year         = {{2017}},
}

@article{13905,
  author       = {{Sharapova, Polina and Luo, Kai Hong and Herrmann, Harald and Reichelt, Matthias and Silberhorn, Christine and Meier, Torsten}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  number       = {{4}},
  pages        = {{043857}},
  publisher    = {{American Physical Society}},
  title        = {{{Modified two-photon interference achieved by the manipulation of entanglement}}},
  doi          = {{10.1103/physreva.96.043857}},
  volume       = {{96}},
  year         = {{2017}},
}

@article{26061,
  author       = {{Sharapova, Polina and Luo, Kai Hong and Herrmann, Harald and Reichelt, Matthias and Meier, Torsten and Silberhorn, Christine}},
  issn         = {{1367-2630}},
  journal      = {{New Journal of Physics}},
  number       = {{12}},
  publisher    = {{IOP Publishing}},
  title        = {{{Toolbox for the design of LiNbO3-based passive and active integrated quantum circuits}}},
  doi          = {{10.1088/1367-2630/aa9033}},
  volume       = {{19}},
  year         = {{2017}},
}

@article{26063,
  author       = {{Brecht, Benjamin and Luo, Kai Hong and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{0946-2171}},
  journal      = {{Applied Physics B}},
  title        = {{{A versatile design for resonant guided-wave parametric down-conversion sources for quantum repeaters}}},
  doi          = {{10.1007/s00340-016-6381-4}},
  year         = {{2016}},
}

@article{26065,
  author       = {{Luo, Kai Hong and Herrmann, Harald and Krapick, Stephan and Brecht, Benjamin and Ricken, Raimund and Quiring, Viktor and Suche, Hubertus and Sohler, Wolfgang and Silberhorn, Christine}},
  issn         = {{1367-2630}},
  journal      = {{New Journal of Physics}},
  title        = {{{Direct generation of genuine single-longitudinal-mode narrowband photon pairs}}},
  doi          = {{10.1088/1367-2630/17/7/073039}},
  year         = {{2015}},
}