---
_id: '63091'
abstract:
- lang: eng
text: 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)=(6.7+/-1.1)*10^8-3).
Furthermore, we achieve a high spectral brightness of 0.44·10pairs/(smWGHz) 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.
article_number: '52729'
article_type: original
author:
- first_name: Silia
full_name: Babel, Silia
id: '63231'
last_name: Babel
orcid: https://orcid.org/0000-0002-1568-2580
- first_name: Laura
full_name: Bollmers, Laura
id: '61375'
last_name: Bollmers
- first_name: Franz
full_name: Roeder, Franz
id: '88149'
last_name: Roeder
- first_name: Werner
full_name: Ridder, Werner
id: '63574'
last_name: Ridder
- first_name: Christian
full_name: Golla, Christian
id: '40420'
last_name: Golla
- first_name: Ronja
full_name: Köthemann, Ronja
last_name: Köthemann
- first_name: Bernhard
full_name: Reineke, Bernhard
id: '29821'
last_name: Reineke
- first_name: Harald
full_name: Herrmann, Harald
id: '216'
last_name: Herrmann
- first_name: Benjamin
full_name: Brecht, Benjamin
id: '27150'
last_name: Brecht
orcid: '0000-0003-4140-0556 '
- first_name: Christof
full_name: Eigner, Christof
id: '13244'
last_name: Eigner
orcid: https://orcid.org/0000-0002-5693-3083
- first_name: Laura
full_name: Padberg, Laura
id: '40300'
last_name: Padberg
- first_name: Christine
full_name: Silberhorn, Christine
id: '26263'
last_name: Silberhorn
citation:
ama: Babel S, Bollmers L, Roeder F, et al. Ultrabright, two-color photon pair source
based on thin-film lithium niobate for bridging visible and telecom wavelengths.
Optics Express. 2025;33(25). doi:10.1364/oe.571605
apa: Babel, S., Bollmers, L., Roeder, F., Ridder, W., Golla, C., Köthemann, R.,
Reineke, B., Herrmann, H., Brecht, B., Eigner, C., Padberg, L., & Silberhorn,
C. (2025). Ultrabright, two-color photon pair source based on thin-film lithium
niobate for bridging visible and telecom wavelengths. Optics Express, 33(25),
Article 52729. https://doi.org/10.1364/oe.571605
bibtex: '@article{Babel_Bollmers_Roeder_Ridder_Golla_Köthemann_Reineke_Herrmann_Brecht_Eigner_et
al._2025, title={Ultrabright, two-color photon pair source based on thin-film
lithium niobate for bridging visible and telecom wavelengths}, volume={33}, DOI={10.1364/oe.571605}, number={2552729},
journal={Optics Express}, publisher={Optica Publishing Group}, author={Babel,
Silia and Bollmers, Laura and Roeder, Franz and Ridder, Werner and Golla, Christian
and Köthemann, Ronja and Reineke, Bernhard and Herrmann, Harald and Brecht, Benjamin
and Eigner, Christof and et al.}, year={2025} }'
chicago: Babel, Silia, Laura Bollmers, Franz Roeder, Werner Ridder, Christian Golla,
Ronja Köthemann, Bernhard Reineke, et al. “Ultrabright, Two-Color Photon Pair
Source Based on Thin-Film Lithium Niobate for Bridging Visible and Telecom Wavelengths.”
Optics Express 33, no. 25 (2025). https://doi.org/10.1364/oe.571605.
ieee: 'S. Babel et al., “Ultrabright, two-color photon pair source based
on thin-film lithium niobate for bridging visible and telecom wavelengths,” Optics
Express, vol. 33, no. 25, Art. no. 52729, 2025, doi: 10.1364/oe.571605.'
mla: Babel, Silia, et al. “Ultrabright, Two-Color Photon Pair Source Based on Thin-Film
Lithium Niobate for Bridging Visible and Telecom Wavelengths.” Optics Express,
vol. 33, no. 25, 52729, Optica Publishing Group, 2025, doi:10.1364/oe.571605.
short: S. Babel, L. Bollmers, F. Roeder, W. Ridder, C. Golla, R. Köthemann, B. Reineke,
H. Herrmann, B. Brecht, C. Eigner, L. Padberg, C. Silberhorn, Optics Express 33
(2025).
date_created: 2025-12-15T07:20:36Z
date_updated: 2026-01-07T11:28:35Z
department:
- _id: '288'
- _id: '623'
doi: 10.1364/oe.571605
intvolume: ' 33'
issue: '25'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://opg.optica.org/oe/fulltext.cfm?uri=oe-33-25-52729
oa: '1'
publication: Optics Express
publication_identifier:
issn:
- 1094-4087
publication_status: published
publisher: Optica Publishing Group
status: public
title: Ultrabright, two-color photon pair source based on thin-film lithium niobate
for bridging visible and telecom wavelengths
type: journal_article
user_id: '63231'
volume: 33
year: '2025'
...
---
_id: '54668'
abstract:
- lang: eng
text: Samples of dielectric optical waveguides of rib or strip type in thin-film
lithium niobate (TFLN) technology are characterized with respect to their optical
loss using the Fabry-Pérot method. Attributing the losses mainly to sidewall roughness,
we employ a simple perturbational procedure, based on rigorously computed mode
profiles of idealized channels, to estimate the attenuation for waveguides with
different cross sections. A single fit parameter suffices for an adequate modelling
of the effect of the waveguide geometry on the loss levels.
author:
- first_name: Manfred
full_name: Hammer, Manfred
id: '48077'
last_name: Hammer
orcid: 0000-0002-6331-9348
- first_name: Silia
full_name: Babel, Silia
id: '63231'
last_name: Babel
orcid: https://orcid.org/0000-0002-1568-2580
- first_name: Henna
full_name: Farheen, Henna
id: '53444'
last_name: Farheen
orcid: 0000-0001-7730-3489
- first_name: Laura
full_name: Padberg, Laura
id: '40300'
last_name: Padberg
- first_name: J. Christoph
full_name: Scheytt, J. Christoph
id: '37144'
last_name: Scheytt
orcid: '0000-0002-5950-6618 '
- first_name: Christine
full_name: Silberhorn, Christine
id: '26263'
last_name: Silberhorn
- first_name: Jens
full_name: Förstner, Jens
id: '158'
last_name: Förstner
orcid: 0000-0001-7059-9862
citation:
ama: Hammer M, Babel S, Farheen H, et al. Estimation of losses caused by sidewall
roughness in thin-film lithium niobate rib and strip waveguides. Optics Express.
2024;32(13):22878. doi:10.1364/oe.521766
apa: Hammer, M., Babel, S., Farheen, H., Padberg, L., Scheytt, J. C., Silberhorn,
C., & Förstner, J. (2024). Estimation of losses caused by sidewall roughness
in thin-film lithium niobate rib and strip waveguides. Optics Express,
32(13), 22878. https://doi.org/10.1364/oe.521766
bibtex: '@article{Hammer_Babel_Farheen_Padberg_Scheytt_Silberhorn_Förstner_2024,
title={Estimation of losses caused by sidewall roughness in thin-film lithium
niobate rib and strip waveguides}, volume={32}, DOI={10.1364/oe.521766},
number={13}, journal={Optics Express}, publisher={Optica Publishing Group}, author={Hammer,
Manfred and Babel, Silia and Farheen, Henna and Padberg, Laura and Scheytt, J.
Christoph and Silberhorn, Christine and Förstner, Jens}, year={2024}, pages={22878}
}'
chicago: 'Hammer, Manfred, Silia Babel, Henna Farheen, Laura Padberg, J. Christoph
Scheytt, Christine Silberhorn, and Jens Förstner. “Estimation of Losses Caused
by Sidewall Roughness in Thin-Film Lithium Niobate Rib and Strip Waveguides.”
Optics Express 32, no. 13 (2024): 22878. https://doi.org/10.1364/oe.521766.'
ieee: 'M. Hammer et al., “Estimation of losses caused by sidewall roughness
in thin-film lithium niobate rib and strip waveguides,” Optics Express,
vol. 32, no. 13, p. 22878, 2024, doi: 10.1364/oe.521766.'
mla: Hammer, Manfred, et al. “Estimation of Losses Caused by Sidewall Roughness
in Thin-Film Lithium Niobate Rib and Strip Waveguides.” Optics Express,
vol. 32, no. 13, Optica Publishing Group, 2024, p. 22878, doi:10.1364/oe.521766.
short: M. Hammer, S. Babel, H. Farheen, L. Padberg, J.C. Scheytt, C. Silberhorn,
J. Förstner, Optics Express 32 (2024) 22878.
date_created: 2024-06-10T11:18:06Z
date_updated: 2024-07-22T07:43:02Z
ddc:
- '530'
department:
- _id: '61'
- _id: '429'
- _id: '623'
- _id: '263'
- _id: '288'
doi: 10.1364/oe.521766
file:
- access_level: open_access
content_type: application/pdf
creator: fossie
date_created: 2024-06-10T11:25:00Z
date_updated: 2024-06-10T11:25:00Z
file_id: '54669'
file_name: 2024-06 Hammer - Optics Express - Estimation of losses caused by sidewall
roughness in thin-film lithium niobate rib and strip waveguides.pdf
file_size: 4004782
relation: main_file
file_date_updated: 2024-06-10T11:25:00Z
has_accepted_license: '1'
intvolume: ' 32'
issue: '13'
keyword:
- tet_topic_waveguide
language:
- iso: eng
oa: '1'
page: '22878'
project:
- _id: '53'
grant_number: '231447078'
name: 'TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden
Konzepten zu funktionellen Strukturen'
- _id: '175'
grant_number: '231447078'
name: 'TRR 142 - C11: TRR 142 - Kompakte Photonenpaar-Quelle mit ultraschnellen
Modulatoren auf Basis von CMOS und LNOI (C11*)'
- _id: '167'
grant_number: '231447078'
name: 'TRR 142 - B06: TRR 142 - Ultraschnelle kohärente opto-elektronische Kontrolle
eines photonischen Quantensystems (B06*)'
- _id: '266'
grant_number: PROFILNRW-2020-067
name: 'PhoQC: PhoQC: Photonisches Quantencomputing'
publication: Optics Express
publication_identifier:
issn:
- 1094-4087
publication_status: published
publisher: Optica Publishing Group
status: public
title: Estimation of losses caused by sidewall roughness in thin-film lithium niobate
rib and strip waveguides
type: journal_article
user_id: '158'
volume: 32
year: '2024'
...
---
_id: '45850'
abstract:
- lang: eng
text: 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.
article_number: '23140'
author:
- first_name: Silia
full_name: Babel, Silia
id: '63231'
last_name: Babel
orcid: https://orcid.org/0000-0002-1568-2580
- first_name: Laura
full_name: Bollmers, Laura
id: '61375'
last_name: Bollmers
- first_name: Marcello
full_name: Massaro, Marcello
id: '59545'
last_name: Massaro
orcid: 0000-0002-2539-7652
- first_name: Kai Hong
full_name: Luo, Kai Hong
id: '36389'
last_name: Luo
orcid: 0000-0003-1008-4976
- first_name: Michael
full_name: Stefszky, Michael
id: '42777'
last_name: Stefszky
- first_name: Federico
full_name: Pegoraro, Federico
id: '88928'
last_name: Pegoraro
- first_name: Philip
full_name: Held, Philip
id: '68236'
last_name: Held
- first_name: Harald
full_name: Herrmann, Harald
id: '216'
last_name: Herrmann
- first_name: Christof
full_name: Eigner, Christof
id: '13244'
last_name: Eigner
orcid: https://orcid.org/0000-0002-5693-3083
- first_name: Benjamin
full_name: Brecht, Benjamin
id: '27150'
last_name: Brecht
orcid: '0000-0003-4140-0556 '
- first_name: Laura
full_name: Padberg, Laura
id: '40300'
last_name: Padberg
- first_name: Christine
full_name: Silberhorn, Christine
id: '26263'
last_name: Silberhorn
citation:
ama: Babel S, Bollmers L, Massaro M, et al. Demonstration of Hong-Ou-Mandel interference
in an LNOI directional coupler. Optics Express. 2023;31(14). doi:10.1364/oe.484126
apa: Babel, S., Bollmers, L., Massaro, M., Luo, K. H., Stefszky, M., Pegoraro, F.,
Held, P., Herrmann, H., Eigner, C., Brecht, B., Padberg, L., & Silberhorn,
C. (2023). Demonstration of Hong-Ou-Mandel interference in an LNOI directional
coupler. Optics Express, 31(14), Article 23140. https://doi.org/10.1364/oe.484126
bibtex: '@article{Babel_Bollmers_Massaro_Luo_Stefszky_Pegoraro_Held_Herrmann_Eigner_Brecht_et
al._2023, title={Demonstration of Hong-Ou-Mandel interference in an LNOI directional
coupler}, volume={31}, DOI={10.1364/oe.484126},
number={1423140}, journal={Optics Express}, publisher={Optica Publishing Group},
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 et al.}, year={2023} }'
chicago: Babel, Silia, Laura Bollmers, Marcello Massaro, Kai Hong Luo, Michael Stefszky,
Federico Pegoraro, Philip Held, et al. “Demonstration of Hong-Ou-Mandel Interference
in an LNOI Directional Coupler.” Optics Express 31, no. 14 (2023). https://doi.org/10.1364/oe.484126.
ieee: 'S. Babel et al., “Demonstration of Hong-Ou-Mandel interference in
an LNOI directional coupler,” Optics Express, vol. 31, no. 14, Art. no.
23140, 2023, doi: 10.1364/oe.484126.'
mla: Babel, Silia, et al. “Demonstration of Hong-Ou-Mandel Interference in an LNOI
Directional Coupler.” Optics Express, vol. 31, no. 14, 23140, Optica Publishing
Group, 2023, doi:10.1364/oe.484126.
short: S. Babel, L. Bollmers, M. Massaro, K.H. Luo, M. Stefszky, F. Pegoraro, P.
Held, H. Herrmann, C. Eigner, B. Brecht, L. Padberg, C. Silberhorn, Optics Express
31 (2023).
date_created: 2023-07-03T14:08:36Z
date_updated: 2023-07-05T07:58:31Z
department:
- _id: '15'
- _id: '230'
- _id: '623'
- _id: '288'
doi: 10.1364/oe.484126
intvolume: ' 31'
issue: '14'
keyword:
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: Optics Express
publication_identifier:
issn:
- 1094-4087
publication_status: published
publisher: Optica Publishing Group
status: public
title: Demonstration of Hong-Ou-Mandel interference in an LNOI directional coupler
type: journal_article
user_id: '63231'
volume: 31
year: '2023'
...