Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:quant-ph/0601067 · Metrologia

Optimizing single-photon-source heralding efficiency and detection efficiency metrology at 1550 nm using periodically poled lithium niobate

Stefania Castelletto, Ivo Pietro Degiovanni, Valentina Schettini, Alan L. Migdall

Published Mar 23, 2006• 30 citations
arXivHTMLPDF

Abstract

We explore the feasibility of using high conversion-efficiency periodically-poled crystals to produce photon pairs for photon-counting detector calibrations at 1550 nm. The goal is the development of an appropriate parametric down-conversion (PDC) source at telecom wavelengths meeting the requirements of high-efficiency pair production and collection in single spectral and spatial modes (single-mode fibres). We propose a protocol to optimize the photon collection, noise levels and the uncertainty evaluation. This study ties together the results of our efforts to model the single-mode heralding efficiency of a two-photon PDC source and to estimate the heralding uncertainty of such a source.

DOI
10.1088/0026-1394/43/2/s12

Related papers

MHz rate and efficient synchronous heralding of single photons at telecom wavelengths

Enrico Pomarico, Bruno Sanguinetti, Thiago Guerreiro +2 more

We report on the realization of a synchronous source of heralded single photons at telecom wavelengths with MHz heralding rates and high heralding efficiency. This source is based on the generation of photon pairs at 810 and 1550 nm via Spontaneous Parametric Down Conversion (SPDC) in a 1 cm periodically poled lithium niobate (PPLN) crystal pumped by a 532 nm pulsed laser. As high rates are fundamental for multi-photon experiments, we show that single telecom photons can be announced at 4.4 MHz rate with 45% heralding efficiency. When we focus only on the optimization of the coupling of the heralded photon, the heralding efficiency can be increased up to 80%. Furthermore, we experimentally observe that group velocity mismatch inside long crystals pumped in a pulsed mode affects the spectrum of the emitted photons and their fibre coupling efficiency. The length of the crystal in this source has been chosen as a trade off between high brightness and high coupling efficiency.

arXiv:1207.0441•Optics Express•Oct 2, 2012•45 citations

MHz rate and efficient synchronous heralding of single photons at telecom wavelengths

Enrico Pomarico, Bruno Sanguinetti, Barbosa Dos Santos Guerreiro, Thiago +2 more

We report on the realization of a synchronous source of heralded single photons at telecom wavelengths with MHz heralding rates and high heralding efficiency. This source is based on the generation of photon pairs at 810 and 1550 nm via Spontaneous Parametric Down Conversion (SPDC) in a 1 cm periodically poled lithium niobate (PPLN) crystal pumped by a 532 nm pulsed laser. As high rates are fundamental for multi-photon experiments, we show that single telecom photons can be announced at 4.4 MHz rate with 45% heralding efficiency. When we focus only on the optimization of the coupling of the heralded photon, the heralding efficiency can be increased up to 80%. Furthermore, we experimentally observe that group velocity mismatch inside long crystals pumped in a pulsed mode affects the spectrum of the emitted photons and their fibre coupling efficiency. The length of the crystal in this source has been chosen as a trade off between high brightness and high coupling efficiency.

•Jan 1, 2012•31 citations

Degenerate parametric down-conversion at 1570 nm by periodically poled lithium niobate waveguide: a route to single photon source and photon entanglement

Stefania Castelletto, Ivo Pietro Degiovanni, Valentina Schettini +4 more

In this paper we measure the efficiency of photon pair production from parametric downconversion at the photon counting level, generated in a laboratory prototype of PPLN waveguide at 1572 nm. The aim is to enhance the brightness of an heralded single photon source and to improve compactness for quantum communication applications, namely quantum key distribution. We observed a maximum of the conversion efficiency corresponding to 7.9 106 photon pairs/s for a pump power of 28 μW. This value is compared with the measured pairs production in a classical experiment of difference frequency generation, realized with the same sample by analogue classical detection. We highlight the advantages of using the waveguide versus a bulk PPLN for such applications and we foresee further possible improvements by adopting waveguide in a single photon level experimental setup.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 21, 2006•0 citations

Spatial and spectral mode selection of heralded single photons from parametric down-conversion in bulk and PPLN

Stefania Castelletto, Ivo Pietro Degiovanni, Alan L. Migdall +1 more

We describe two experiments in which photon pairs from a parametric down-conversion source are efficiently coupled into single-mode fibers, and estimation of the heralding efficiency is attempted. One experiment is based on a pulsed pump configuration in a bulk crystal and the other experiment on a CW periodically poled downconverter. The heralding and heralded photons were analyzed spectrally by a monochromator to determine the effect of the correlation between spectral and spatial mode-matching in the heralding efficiency. Moreover, we theoretically model the heralding efficiency of both bulk and periodically poled crystals. Analysis of spatial and spectral mode selection, and their mutual correlation, allows controlled engineering of the spectral and spatial emission modes of PDC single photons.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 18, 2005•2 citations

A highly efficient integrated two-color source for heralded single photons

Stephan Krapick, Harald Herrmann, Benjamin Brecht +3 more

Summary form only given. Recent progress in quantum information processing has highlighted the benefits of integrated optic devices for quantum applications (e.g.[l]). The miniaturization of systems with increased complexity drastically reduces the required space and paves the way for future commercialization.In the past five years, several groups have demonstrated promising approaches to achieve quantum interference and photonic gates on-chip (e.g.[2]). However, in all of these experiments the preparation of the photon pairs has been performed outside the integrated devices employing bulk crystal parametric down-conversion (PDC) sources, while the efficient coupling between these sources and the integrated circuit remains as a bottleneck for the design of systems with increasing complexity. On the other hand remarkable efforts have been devoted to the development of integrated PDC sources for photon pair generation inside channel waveguides [3]. The main benefits of guided-wave PDC processes include high conversion efficiencies and spatial mode control. We combine the prospects of an efficient type-I PDC source based on Titanium-indiffused periodically poled Z-cut Lithium Niobate waveguides (Ti:PPLN) with a passive wavelength division demultiplexing coupler on-chip, shown in Figure 1. The coupler allows for excellent spatial separation generated photon pairs. The non-degenerate decay of pump photons at 532 nm into signal and idler photons provides us with a photon pair at wavelengths of 1575 nm and 800 nm, respectively. Thus low-loss fiber transmission of the prepared states at 1575 nm can be accomplished on the one hand, while on the other hand efficient heralding of conditioned states can be implemented with off-the-shelf silicon-based detectors. The quality and efficiency of our source was improved by the deposition of endface-coatings. This allows for the efficient launching of pump light into the waveguide and it simultaneously provides a close-toperfect transmission of signal and idler at the output of our source, reflecting the pump light by more than 99%. In conditioned coincidence measurements in the picosecond pulsed regime we achieved heralding of single photons with almost no influence of background radiation, expressed by high coincidences-toaccidentals ratios up to CAR > 7400. The preparation exceeded 60% of efficiency in the low pump power regime, accompanied with ultra-low second-order correlation functions of g(2) (0) <; 4.10-3. These figures of merit in conjunction with the integration of active and passive elements make our source a candidate for a basic building block in more complex and miniaturized quantum network realizations in the future.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•May 1, 2013•1 citation

Ultrabright, two-color photon pair source based on thin-film lithium niobate for bridging visible and telecom wavelengths

Silia Babel, Laura Bollmers, Franz Roeder +9 more

We present the design and characterization of a guided-wave, bright, and highly frequency non-degenerate parametric down-conversion (PDC) source in thin-film lithium niobate. The source generates photon pairs with wavelengths of 815 nm and 1550 nm, linking the visible wavelength regime with telecommunication wavelengths. We confirm the high quality of the generated single photons by determining a value for the heralded second-order correlation function as low as g h (2) (0)=(6.7±1.1)⋅10 −3 . Furthermore, we achieve a high spectral brightness of 0.44·10 7 pairss⋅mW⋅GHz which is two orders of magnitude higher than sources based on weakly guiding waveguides. The shape of the PDC spectrum and the strong agreement between the effective and nominal bandwidth highlight our high fabrication quality of periodically poled waveguides. The good agreement between the measured and simulated spectral characteristics of our source demonstrates our excellent understanding of the PDC process. Our result is a valuable step towards practical and scalable quantum communication networks as well as photonic quantum computing.

arXiv:2506.18609•Optics Express•Oct 22, 2025•2 citations
We explore the feasibility of using high conversion-efficiency periodically-poled crystals to produce photon pairs for photon-counting detector calibrations at 1550 nm. The goal is the development of an appropriate parametric down-conversion (PDC) source at telecom wavelengths meeting the requirements of high-efficiency pair production and collection in single spectral and spatial modes (single-mode fibres). We propose a protocol to optimize the photon collection, noise levels and the uncertainty evaluation. This study ties together the results of our efforts to model the single-mode heralding efficiency of a two-photon PDC source and to estimate the heralding uncertainty of such a source.
We report on the realization of a synchronous source of heralded single photons at telecom wavelengths with MHz heralding rates and high heralding efficiency. This source is based on the generation of photon pairs at 810 and 1550 nm via Spontaneous Parametric Down Conversion (SPDC) in a 1 cm periodically poled lithium niobate (PPLN) crystal pumped by a 532 nm pulsed laser. As high rates are fundamental for multi-photon experiments, we show that single telecom photons can be announced at 4.4 MHz rate with 45% heralding efficiency. When we focus only on the optimization of the coupling of the heralded photon, the heralding efficiency can be increased up to 80%. Furthermore, we experimentally observe that group velocity mismatch inside long crystals pumped in a pulsed mode affects the spectrum of the emitted photons and their fibre coupling efficiency. The length of the crystal in this source has been chosen as a trade off between high brightness and high coupling efficiency.
We report on the realization of a synchronous source of heralded single photons at telecom wavelengths with MHz heralding rates and high heralding efficiency. This source is based on the generation of photon pairs at 810 and 1550 nm via Spontaneous Parametric Down Conversion (SPDC) in a 1 cm periodically poled lithium niobate (PPLN) crystal pumped by a 532 nm pulsed laser. As high rates are fundamental for multi-photon experiments, we show that single telecom photons can be announced at 4.4 MHz rate with 45% heralding efficiency. When we focus only on the optimization of the coupling of the heralded photon, the heralding efficiency can be increased up to 80%. Furthermore, we experimentally observe that group velocity mismatch inside long crystals pumped in a pulsed mode affects the spectrum of the emitted photons and their fibre coupling efficiency. The length of the crystal in this source has been chosen as a trade off between high brightness and high coupling efficiency.
In this paper we measure the efficiency of photon pair production from parametric downconversion at the photon counting level, generated in a laboratory prototype of PPLN waveguide at 1572 nm. The aim is to enhance the brightness of an heralded single photon source and to improve compactness for quantum communication applications, namely quantum key distribution. We observed a maximum of the conversion efficiency corresponding to 7.9 106 photon pairs/s for a pump power of 28 μW. This value is compared with the measured pairs production in a classical experiment of difference frequency generation, realized with the same sample by analogue classical detection. We highlight the advantages of using the waveguide versus a bulk PPLN for such applications and we foresee further possible improvements by adopting waveguide in a single photon level experimental setup.
We describe two experiments in which photon pairs from a parametric down-conversion source are efficiently coupled into single-mode fibers, and estimation of the heralding efficiency is attempted. One experiment is based on a pulsed pump configuration in a bulk crystal and the other experiment on a CW periodically poled downconverter. The heralding and heralded photons were analyzed spectrally by a monochromator to determine the effect of the correlation between spectral and spatial mode-matching in the heralding efficiency. Moreover, we theoretically model the heralding efficiency of both bulk and periodically poled crystals. Analysis of spatial and spectral mode selection, and their mutual correlation, allows controlled engineering of the spectral and spatial emission modes of PDC single photons.
Summary form only given. Recent progress in quantum information processing has highlighted the benefits of integrated optic devices for quantum applications (e.g.[l]). The miniaturization of systems with increased complexity drastically reduces the required space and paves the way for future commercialization.In the past five years, several groups have demonstrated promising approaches to achieve quantum interference and photonic gates on-chip (e.g.[2]). However, in all of these experiments the preparation of the photon pairs has been performed outside the integrated devices employing bulk crystal parametric down-conversion (PDC) sources, while the efficient coupling between these sources and the integrated circuit remains as a bottleneck for the design of systems with increasing complexity. On the other hand remarkable efforts have been devoted to the development of integrated PDC sources for photon pair generation inside channel waveguides [3]. The main benefits of guided-wave PDC processes include high conversion efficiencies and spatial mode control. We combine the prospects of an efficient type-I PDC source based on Titanium-indiffused periodically poled Z-cut Lithium Niobate waveguides (Ti:PPLN) with a passive wavelength division demultiplexing coupler on-chip, shown in Figure 1. The coupler allows for excellent spatial separation generated photon pairs. The non-degenerate decay of pump photons at 532 nm into signal and idler photons provides us with a photon pair at wavelengths of 1575 nm and 800 nm, respectively. Thus low-loss fiber transmission of the prepared states at 1575 nm can be accomplished on the one hand, while on the other hand efficient heralding of conditioned states can be implemented with off-the-shelf silicon-based detectors. The quality and efficiency of our source was improved by the deposition of endface-coatings. This allows for the efficient launching of pump light into the waveguide and it simultaneously provides a close-toperfect transmission of signal and idler at the output of our source, reflecting the pump light by more than 99%. In conditioned coincidence measurements in the picosecond pulsed regime we achieved heralding of single photons with almost no influence of background radiation, expressed by high coincidences-toaccidentals ratios up to CAR > 7400. The preparation exceeded 60% of efficiency in the low pump power regime, accompanied with ultra-low second-order correlation functions of g(2) (0) <; 4.10-3. These figures of merit in conjunction with the integration of active and passive elements make our source a candidate for a basic building block in more complex and miniaturized quantum network realizations in the future.
We present the design and characterization of a guided-wave, bright, and highly frequency non-degenerate parametric down-conversion (PDC) source in thin-film lithium niobate. The source generates photon pairs with wavelengths of 815 nm and 1550 nm, linking the visible wavelength regime with telecommunication wavelengths. We confirm the high quality of the generated single photons by determining a value for the heralded second-order correlation function as low as g h (2) (0)=(6.7±1.1)⋅10 −3 . Furthermore, we achieve a high spectral brightness of 0.44·10 7 pairss⋅mW⋅GHz which is two orders of magnitude higher than sources based on weakly guiding waveguides. The shape of the PDC spectrum and the strong agreement between the effective and nominal bandwidth highlight our high fabrication quality of periodically poled waveguides. The good agreement between the measured and simulated spectral characteristics of our source demonstrates our excellent understanding of the PDC process. Our result is a valuable step towards practical and scalable quantum communication networks as well as photonic quantum computing.