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 AU - Barkhofen, Sonja AU - Brecht, Benjamin AU - Silberhorn, Christine ID - 38541 IS - 1 JF - Physik in unserer Zeit TI - Verschränkung wie am Fließband VL - 54 ER - TY - JOUR AU - Lüders, Carolin AU - Gil-Lopez, Jano AU - Allgaier, Markus AU - Brecht, Benjamin AU - Aßmann, Marc AU - Silberhorn, Christine AU - Bayer, Manfred ID - 42158 IS - 1 JF - Physical Review Applied KW - General Physics and Astronomy SN - 2331-7019 TI - Tailored Frequency Conversion Makes Infrared Light Visible for Streak Cameras VL - 19 ER - TY - JOUR AB - In real photonic quantum systems losses are an unavoidable factor limiting the scalability to many modes and particles, restraining their application in fields as quantum information and communication. For this reason, a considerable amount of engineering effort has been taken in order to improve the quality of particle sources and system components. At the same time, data analysis and collection methods based on post-selection have been used to mitigate the effect of particle losses. This has allowed for investigating experimentally multi-particle evolutions where the observer lacks knowledge about the system's intermediate propagation states. Nonetheless, the fundamental question how losses affect the behaviour of the surviving subset of a multi-particle system has not been investigated so far. For this reason, here we study the impact of particle losses in a quantum walk of two photons reconstructing the output probability distributions for one photon conditioned on the loss of the other in a known mode and temporal step of our evolution network. We present the underlying theoretical scheme that we have devised in order to model controlled particle losses, we describe an experimental platform capable of implementing our theory in a time multiplexing encoding. In the end we show how localized particle losses change the output distributions without altering their asymptotic spreading properties. Finally we devise a quantum civilization problem, a two walker generalisation of single particle recurrence processes. AU - Pegoraro, Federico AU - Held, Philip AU - Barkhofen, Sonja AU - Brecht, Benjamin AU - Silberhorn, Christine ID - 42648 IS - 3 JF - Physica Scripta SN - 0031-8949 TI - Dynamic conditioning of two particle discrete-time quantum walks VL - 98 ER - TY - CONF AB - We demonstrate the numerical and experimental realization of optimized optical traveling-wave antennas made of low-loss dielectric materials. These antennas exhibit highly directive radiation patterns and our studies reveal that this nature comes from two dominant guided TE modes excited in the waveguide-like director of the antenna, in addition to the leaky modes. The optimized antennas possess a broadband nature and have a nearunity radiation efficiency at an operational wavelength of 780 nm. Compared to the previously studied plasmonic antennas for photon emission, our all-dielectric approach demonstrates a new class of highly directional, low-loss, and broadband optical antennas. AU - Farheen, Henna AU - Yan, Lok-Yee AU - Leuteritz, Till AU - Qiao, Siqi AU - Spreyer, Florian AU - Schlickriede, Christian AU - Quiring, Viktor AU - Eigner, Christof AU - Silberhorn, Christine AU - Zentgraf, Thomas AU - Linden, Stefan AU - Myroshnychenko, Viktor AU - Förstner, Jens ED - García-Blanco, Sonia M. ED - Cheben, Pavel ID - 43051 KW - tet_topic_opticalantenna T2 - Integrated Optics: Devices, Materials, and Technologies XXVII TI - Tailoring the directive nature of optical waveguide antennas ER - TY - JOUR AU - Serino, Laura AU - Gil López, Jano AU - Stefszky, Michael AU - Ricken, Raimund AU - Eigner, Christof AU - Brecht, Benjamin AU - Silberhorn, Christine ID - 44081 IS - 2 JF - PRX Quantum KW - General Physics and Astronomy KW - Mathematical Physics KW - Applied Mathematics KW - Electronic KW - Optical and Magnetic Materials KW - Electrical and Electronic Engineering KW - General Computer Science SN - 2691-3399 TI - Realization of a Multi-Output Quantum Pulse Gate for Decoding High-Dimensional Temporal Modes of Single-Photon States VL - 4 ER - TY - JOUR AU - Kruse, Stephan AU - Serino, Laura AU - Folge, Patrick Fabian AU - Echeverria Oviedo, Dana AU - Bhattacharjee, Abhinandan AU - Stefszky, Michael AU - Scheytt, J. Christoph AU - Brecht, Benjamin AU - Silberhorn, Christine ID - 45485 IS - 14 JF - IEEE Photonics Technology Letters KW - Electrical and Electronic Engineering KW - Atomic and Molecular Physics KW - and Optics KW - Electronic KW - Optical and Magnetic Materials SN - 1041-1135 TI - A Pulsed Lidar System With Ultimate Quantum Range Accuracy VL - 35 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 - CONF AB - A frequency-flexible Nyquist pulse synthesizer is presented with optical pulse bandwidths up to fopt=100 GHz and repetition rates equal to fopt/9, fabricated in an electronic-photonic co-integrated platform utilizing linear on-chip drivers. AU - Kress, Christian AU - Schwabe, Tobias AU - Silberhorn, Christine AU - Scheytt, J. Christoph ID - 45578 T2 - Conference on Lasers and Electro-Optics (CLEO) 2023 TI - Generation of 100 GHz Periodic Nyquist Pulses using Cascaded Mach-Zehnder Modulators in a Silicon Electronic-Photonic Platform 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 - The crystal family of potassium titanyl phosphate (KTiOPO4) is a promising material group for applications in quantum and nonlinear optics. The fabrication of low-loss optical waveguides, as well as high-grade periodically poled ferroelectric domain structures, requires a profound understanding of the material properties and crystal structure. In this regard, Raman spectroscopy offers the possibility to study and visualize domain structures, strain, defects, and the local stoichiometry, which are all factors impacting device performance. However, the accurate interpretation of Raman spectra and their changes with respect to extrinsic and intrinsic defects requires a thorough assignment of the Raman modes to their respective crystal features, which to date is only partly conducted based on phenomenological modelling. To address this issue, we calculated the phonon spectra of potassium titanyl phosphate and the related compounds rubidium titanyl phosphate (RbTiOPO4) and potassium titanyl arsenate (KTiOAsO4) based on density functional theory and compared them with experimental data. Overall, this allows us to assign various spectral features to eigenmodes of lattice substructures with improved detail compared to previous assignments. Nevertheless, the analysis also shows that not all features of the spectra can unambigiously be explained yet. A possible explanation might be that defects or long range fields not included in the modeling play a crucial rule for the resulting Raman spectrum. In conclusion, this work provides an improved foundation into the vibrational properties in the KTiOPO4 material family. AU - Neufeld, Sergej AU - Gerstmann, Uwe AU - Padberg, Laura AU - Eigner, Christof AU - Berth, Gerhard AU - Silberhorn, Christine AU - Eng, Lukas M. AU - Schmidt, Wolf Gero AU - Rüsing, Michael ID - 47997 IS - 10 JF - Crystals KW - Inorganic Chemistry KW - Condensed Matter Physics KW - General Materials Science KW - General Chemical Engineering SN - 2073-4352 TI - Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family VL - 13 ER - TY - JOUR AB - Quantum photonic processing via electro-optic components typically requires electronic links across different operation environments, especially when interfacing cryogenic components such as superconducting single photon detectors with room-temperature control and readout electronics. However, readout and driving electronics can introduce detrimental parasitic effects. Here we show an all-optical control and readout of a superconducting nanowire single photon detector (SNSPD), completely electrically decoupled from room temperature electronics. We provide the operation power for the superconducting detector via a cryogenic photodiode, and readout single photon detection signals via a cryogenic electro-optic modulator in the same cryostat. This method opens the possibility for control and readout of superconducting circuits, and feedforward for photonic quantum computing. AU - Thiele, Frederik AU - Hummel, Thomas AU - McCaughan, Adam N. AU - Brockmeier, Julian AU - Protte, Maximilian AU - Quiring, Victor AU - Lengeling, Sebastian AU - Eigner, Christof AU - Silberhorn, Christine AU - Bartley, Tim ID - 48399 IS - 20 JF - Optics Express KW - Atomic and Molecular Physics KW - and Optics SN - 1094-4087 TI - All optical operation of a superconducting photonic interface VL - 31 ER - TY - JOUR AU - Lange, Nina Amelie AU - Höpker, Jan Philipp AU - Ricken, Raimund AU - Quiring, Viktor AU - Eigner, Christof AU - Silberhorn, Christine AU - Bartley, Tim ID - 30342 IS - 1 JF - Optica KW - Atomic and Molecular Physics KW - and Optics KW - Electronic KW - Optical and Magnetic Materials SN - 2334-2536 TI - Cryogenic integrated spontaneous parametric down-conversion VL - 9 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 - Meyer-Scott, Evan AU - Prasannan, Nidhin AU - Dhand, Ish AU - Eigner, Christof AU - Quiring, Viktor AU - Barkhofen, Sonja AU - Brecht, Benjamin AU - Plenio, Martin B. AU - Silberhorn, Christine ID - 39025 IS - 15 JF - Physical Review Letters KW - General Physics and Astronomy SN - 0031-9007 TI - Scalable Generation of Multiphoton Entangled States by Active Feed-Forward and Multiplexing VL - 129 ER - TY - JOUR AU - Meyer-Scott, Evan AU - Prasannan, Nidhin AU - Dhand, Ish AU - Eigner, Christof AU - Quiring, Viktor AU - Barkhofen, Sonja AU - Brecht, Benjamin AU - Plenio, Martin B. AU - Silberhorn, Christine ID - 40273 IS - 15 JF - Physical Review Letters KW - General Physics and Astronomy SN - 0031-9007 TI - Scalable Generation of Multiphoton Entangled States by Active Feed-Forward and Multiplexing VL - 129 ER - TY - JOUR AU - Hamilton, Craig S. AU - Christ, Regina AU - Barkhofen, Sonja AU - Barnett, Stephen M. AU - Jex, Igor AU - Silberhorn, Christine ID - 33450 IS - 4 JF - Physical Review A SN - 2469-9926 TI - Quantum-state creation in nonlinear-waveguide arrays VL - 105 ER -