TY - JOUR AU - Babai-Hemati, Jonas AU - vom Bruch, Felix AU - Herrmann, Harald AU - Silberhorn, Christine ID - 51339 JF - Optics Express KW - Atomic and Molecular Physics KW - and Optics SN - 1094-4087 TI - Tailored second harmonic generation inTi-diffused PPLN waveguides usingmicro-heaters ER - TY - JOUR AB - Abstract Lithium niobate has emerged as a promising platform for integrated quantum optics, enabling efficient generation, manipulation, and detection of quantum states of light. However, integrating single-photon detectors requires cryogenic operating temperatures, since the best performing detectors are based on narrow superconducting wires. While previous studies have demonstrated the operation of quantum light sources and electro-optic modulators in LiNbO3 at cryogenic temperatures, the thermal transition between room temperature and cryogenic conditions introduces additional effects that can significantly influence device performance. In this paper, we investigate the generation of pyroelectric charges and their impact on the optical properties of lithium niobate waveguides when changing from room temperature to 25 K, and vice versa. We measure the generated pyroelectric charge flow and correlate this with fast changes in the birefringence acquired through the Sénarmont-method. Both electrical and optical influence of the pyroelectric effect occur predominantly at temperatures above 100 K. AU - Thiele, Frederik AU - Hummel, Thomas AU - Lange, Nina Amelie AU - Dreher, Felix AU - Protte, Maximilian AU - Bruch, Felix vom AU - Lengeling, Sebastian AU - Herrmann, Harald AU - Eigner, Christof AU - Silberhorn, Christine AU - Bartley, Tim ID - 51356 IS - 1 JF - Materials for Quantum Technology KW - General Earth and Planetary Sciences KW - General Environmental Science SN - 2633-4356 TI - Pyroelectric influence on lithium niobate during the thermal transition for cryogenic integrated photonics VL - 4 ER - 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 AB - This work reports a fully guided setup for single-mode squeezing on integrated titanium-indiffused periodically poled nonlinear resonators. A continuous-wave laser beam is delivered and the squeezed field is collected by single-mode fibers; up to −3.17(9) dB of useful squeezing is available in fibers. To showcase the usefulness of such a fiber-coupled device, we applied the generated squeezed light in a fiber-based phase sensing experiment, showing a quantum enhancement in the signal-to-noise ratio of 0.35 dB. Moreover, our investigation of the effect of photorefraction on the cavity resonance condition suggests that it causes system instabilities at high powers. AU - Domeneguetti, Renato AU - Stefszky, Michael AU - Herrmann, Harald AU - Silberhorn, Christine AU - Andersen, Ulrik L. AU - Neergaard-Nielsen, Jonas S. AU - Gehring, Tobias ID - 46138 IS - 11 JF - Optics Letters KW - Atomic and Molecular Physics KW - and Optics SN - 0146-9592 TI - Fully guided and phase locked Ti:PPLN waveguide squeezing for applications in quantum sensing VL - 48 ER - TY - JOUR AB - 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 what we believe to be 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 810 nm (signal) and 1550 nm (idler) are generated via parametric down-conversion pumped at 532 nm in the LiNbO3 waveguide. The pairs are split in the polymer board and routed to separate output ports. The module has a size of (2 × 1) cm^2 and is fully fiber-coupled with one pump input fiber and two output fibers. We measure a heralded second-order correlation function of g_h(2)=0.05 with a heralding efficiency of η_h=3.5% at low pump powers AU - Kießler, Christian AU - Conradi, Hauke AU - Kleinert, Moritz AU - Quiring, Viktor AU - Herrmann, Harald AU - Silberhorn, Christine ID - 46644 IS - 14 JF - Optics Express KW - Atomic and Molecular Physics KW - and Optics SN - 1094-4087 TI - Fiber-coupled plug-and-play heralded single photon source based on Ti:LiNbO3 and polymer technology VL - 31 ER - TY - JOUR AB - Abstract Lithium niobate is a promising platform for integrated quantum optics. In this platform, we aim to efficiently manipulate and detect quantum states by combining superconducting single photon detectors and modulators. The cryogenic operation of a superconducting single photon detector dictates the optimisation of the electro-optic modulators under the same operating conditions. To that end, we characterise a phase modulator, directional coupler, and polarisation converter at both ambient and cryogenic temperatures. The operation voltage V π / 2 of these modulators increases, due to the decrease in the electro-optic effect, by 74% for the phase modulator, 84% for the directional coupler and 35% for the polarisation converter below 8.5 K . The phase modulator preserves its broadband nature and modulates light in the characterised wavelength range. The unbiased bar state of the directional coupler changed by a wavelength shift of 85 n m while cooling the device down to 5 K . The polarisation converter uses periodic poling to phasematch the two orthogonal polarisations. The phasematched wavelength of the utilised poling changes by 112 n m when cooling to 5 K . AU - Thiele, Frederik AU - vom Bruch, Felix AU - Brockmeier, Julian AU - Protte, Maximilian AU - Hummel, Thomas AU - Ricken, Raimund AU - Quiring, Viktor AU - Lengeling, Sebastian AU - Herrmann, Harald AU - Eigner, Christof AU - Silberhorn, Christine AU - Bartley, Tim ID - 33672 IS - 3 JF - Journal of Physics: Photonics KW - Electrical and Electronic Engineering KW - Atomic and Molecular Physics KW - and Optics KW - Electronic KW - Optical and Magnetic Materials SN - 2515-7647 TI - Cryogenic electro-optic modulation in titanium in-diffused lithium niobate waveguides VL - 4 ER - TY - JOUR AU - Trenti, Alessandro AU - Achleitner, Martin AU - Prawits, Florian AU - Schrenk, Bernhard AU - Conradi, Hauke AU - Kleinert, Moritz AU - Incoronato, Alfonso AU - Zanetto, Francesco AU - Zappa, Franco AU - Luch, Ilaria Di AU - Cirkinoglu, Ozan AU - Leijtens, Xaveer AU - Bonardi, Antonio AU - Bruynsteen, Cedric AU - Yin, Xin AU - Kießler, Christian AU - Herrmann, Harald AU - Silberhorn, Christine AU - Bozzio, Mathieu AU - Walther, Philip AU - Thiel, Hannah C. AU - Weihs, Gregor AU - Hubel, Hannes ID - 38532 IS - 23 JF - Journal of Lightwave Technology KW - General Engineering SN - 0733-8724 TI - On-Chip Quantum Communication Devices VL - 40 ER - TY - JOUR AU - Bartnick, Moritz AU - Santandrea, Matteo AU - Höpker, Jan Philipp AU - Thiele, Frederik AU - Ricken, Raimund AU - Quiring, Viktor AU - Eigner, Christof AU - Herrmann, Harald AU - Silberhorn, Christine AU - Bartley, Tim ID - 26221 JF - Physical Review Applied SN - 2331-7019 TI - Cryogenic Second-Harmonic Generation in Periodically Poled Lithium Niobate Waveguides ER - TY - CONF AB - We experimentally investigate the generation of continuous-wave optical squeezing from a titanium-indiffused lithium niobate waveguide resonator at low and high frequencies. The device promises integration with different platform chips for more complex optical systems. AU - Domeneguetti, Renato R. AU - Conradi, Hauke AU - Kleinert, Moritz AU - Kießler, Christian AU - Stefszky, Michael AU - Herrmann, Harald AU - Silberhorn, Christine AU - Andersen, Ulrik L. AU - Neergaard-Nielsen, Jonas Schou AU - Gehring, Tobias ID - 39027 KW - Optical systems KW - Polymer waveguides KW - Quantum key distribution KW - Quantum light sources KW - Squeezed states KW - Waveguides T2 - 2021 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference TI - Nonlinear waveguides for integrated quantum light source ER - TY - CONF AB - 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. AU - Ferreri, A. AU - Santandrea, Matteo AU - Stefszky, Michael AU - Luo, Kai Hong AU - Herrmann, Harald AU - Silberhorn, Christine AU - Sharapova, Polina ID - 40374 T2 - Conference on Lasers and Electro-Optics TI - Multimode integrated SU(1,1) interferometer ER - TY - JOUR AB - 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. AU - Ferreri, Alessandro AU - Santandrea, Matteo AU - Stefszky, Michael AU - Luo, Kai Hong AU - Herrmann, Harald AU - Silberhorn, Christine AU - Sharapova, Polina R. ID - 26077 JF - Quantum SN - 2521-327X TI - Spectrally multimode integrated SU(1,1) interferometer 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 - Stefszky, Michael AU - Santandrea, Matteo AU - vom Bruch, Felix AU - Krapick, S. AU - Eigner, Christof AU - Ricken, R. AU - Quiring, V. AU - Herrmann, Harald AU - Silberhorn, Christine ID - 22771 JF - Optics Express SN - 1094-4087 TI - Waveguide resonator with an integrated phase modulator for second harmonic generation ER - TY - JOUR AU - Thiele, Frederik AU - vom Bruch, Felix AU - Quiring, Victor AU - Ricken, Raimund AU - Herrmann, Harald AU - Eigner, Christof AU - Silberhorn, Christine AU - Bartley, Tim ID - 20157 JF - Optics Express SN - 1094-4087 TI - Cryogenic electro-optic polarisation conversion in titanium in-diffused lithium niobate waveguides ER - TY - JOUR AU - Vergyris, Panagiotis AU - Babin, Charles AU - Nold, Raphael AU - Gouzien, Elie AU - Herrmann, Harald AU - Silberhorn, Christine AU - Alibart, Olivier AU - Tanzilli, Sébastien AU - Kaiser, Florian ID - 40271 IS - 2 JF - Applied Physics Letters KW - Physics and Astronomy (miscellaneous) SN - 0003-6951 TI - Two-photon phase-sensing with single-photon detection VL - 117 ER - TY - JOUR AU - Eigner, Christof AU - Padberg, Laura AU - Santandrea, Matteo AU - Herrmann, Harald AU - Brecht, Benjamin AU - Silberhorn, Christine ID - 21025 IS - 22 JF - Optics Express SN - 1094-4087 TI - Spatially single mode photon pair source at 800 nm in periodically poled Rubidium exchanged KTP waveguides VL - 28 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 - CONF AU - Meyer-Scott, Evan AU - Prasannan, Nidhin AU - Montaut, Nicola AU - Tiedau, Johannes AU - Eigner, Christof AU - Harder, Georg AU - Sansoni, Linda AU - Nitsche, Thomas AU - Herrmann, Harald AU - Ricken, Raimund AU - Quiring, Viktor AU - Bartley, Tim AU - Barkhofen, Sonja AU - Silberhorn, Christine ED - Hasan, Zameer U. ED - Hemmer, Philip R. ED - Migdall, Alan L. ID - 9635 SN - 9781510625082 T2 - Advances in Photonics of Quantum Computing, Memory, and Communication XII TI - Engineering integrated photon pair sources and multiplexed detectors (Conference Presentation) 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 -