---
_id: '60891'
abstract:
- lang: eng
  text: Straight dielectric waveguide channels made from slabs of thin-film lithium
    niobate (TFLN), or lithium niobate on insulator (LNOI), are investigated in the
    linear regime, for channels of rib and strip type with common trapezoidal cross
    sections, in Z-cut and X-cut samples at varying on-chip orientation. We clarify
    the theoretical basis for the waveguides with potentially non-diagonal core permittivity.
    Symmetry classes can be distinguished that differ in their consequences for potential
    modal degeneracy and polarization conversion. Our rigorous numerical analysis
    by means of a finite-element solver takes the anisotropy of the lithium niobate
    cores rigorously into account. We discuss extensive data for effective indices,
    polarization properties, and hybridization of guided modes, in single- and multimode
    channels. Scans over the waveguide width and orientation as primary parameters
    are complemented by a series of illustrations of vectorial mode profiles. These
    turn out to be essentially complex in cases of X-cut channels at non-crystal-axis-aligned
    orientations.
author:
- first_name: Manfred
  full_name: Hammer, Manfred
  id: '48077'
  last_name: Hammer
  orcid: 0000-0002-6331-9348
- first_name: Shahriar
  full_name: Khan, Shahriar
  last_name: Khan
- first_name: Behnood
  full_name: Taheri, Behnood
  last_name: Taheri
- first_name: Henna
  full_name: Farheen, Henna
  id: '53444'
  last_name: Farheen
  orcid: 0000-0001-7730-3489
- first_name: Jens
  full_name: Förstner, Jens
  id: '158'
  last_name: Förstner
  orcid: 0000-0001-7059-9862
citation:
  ama: 'Hammer M, Khan S, Taheri B, Farheen H, Förstner J. TFLN channel waveguides
    of rib and strip type: Properties of guided modes. <i>Optics Continuum</i>. 2025;4(10):2356.
    doi:<a href="https://doi.org/10.1364/optcon.569959">10.1364/optcon.569959</a>'
  apa: 'Hammer, M., Khan, S., Taheri, B., Farheen, H., &#38; Förstner, J. (2025).
    TFLN channel waveguides of rib and strip type: Properties of guided modes. <i>Optics
    Continuum</i>, <i>4</i>(10), 2356. <a href="https://doi.org/10.1364/optcon.569959">https://doi.org/10.1364/optcon.569959</a>'
  bibtex: '@article{Hammer_Khan_Taheri_Farheen_Förstner_2025, title={TFLN channel
    waveguides of rib and strip type: Properties of guided modes}, volume={4}, DOI={<a
    href="https://doi.org/10.1364/optcon.569959">10.1364/optcon.569959</a>}, number={10},
    journal={Optics Continuum}, publisher={Optica Publishing Group}, author={Hammer,
    Manfred and Khan, Shahriar and Taheri, Behnood and Farheen, Henna and Förstner,
    Jens}, year={2025}, pages={2356} }'
  chicago: 'Hammer, Manfred, Shahriar Khan, Behnood Taheri, Henna Farheen, and Jens
    Förstner. “TFLN Channel Waveguides of Rib and Strip Type: Properties of Guided
    Modes.” <i>Optics Continuum</i> 4, no. 10 (2025): 2356. <a href="https://doi.org/10.1364/optcon.569959">https://doi.org/10.1364/optcon.569959</a>.'
  ieee: 'M. Hammer, S. Khan, B. Taheri, H. Farheen, and J. Förstner, “TFLN channel
    waveguides of rib and strip type: Properties of guided modes,” <i>Optics Continuum</i>,
    vol. 4, no. 10, p. 2356, 2025, doi: <a href="https://doi.org/10.1364/optcon.569959">10.1364/optcon.569959</a>.'
  mla: 'Hammer, Manfred, et al. “TFLN Channel Waveguides of Rib and Strip Type: Properties
    of Guided Modes.” <i>Optics Continuum</i>, vol. 4, no. 10, Optica Publishing Group,
    2025, p. 2356, doi:<a href="https://doi.org/10.1364/optcon.569959">10.1364/optcon.569959</a>.'
  short: M. Hammer, S. Khan, B. Taheri, H. Farheen, J. Förstner, Optics Continuum
    4 (2025) 2356.
date_created: 2025-08-06T09:36:30Z
date_updated: 2025-10-05T11:52:55Z
ddc:
- '530'
department:
- _id: '61'
- _id: '230'
- _id: '429'
- _id: '623'
doi: 10.1364/optcon.569959
file:
- access_level: closed
  content_type: application/pdf
  creator: fossie
  date_created: 2025-10-05T11:48:25Z
  date_updated: 2025-10-05T11:48:25Z
  file_id: '61516'
  file_name: 2025-08 Hammer - Optics Continuum - TFLN channel waveguides of rib and
    strip type. Properties of guided modes (official version).pdf
  file_size: 5417636
  relation: main_file
  success: 1
file_date_updated: 2025-10-05T11:48:25Z
has_accepted_license: '1'
intvolume: '         4'
issue: '10'
keyword:
- tet_topic_waveguide
language:
- iso: eng
page: '2356'
publication: Optics Continuum
publication_identifier:
  issn:
  - 2770-0208
publication_status: published
publisher: Optica Publishing Group
status: public
title: 'TFLN channel waveguides of rib and strip type: Properties of guided modes'
type: journal_article
user_id: '158'
volume: 4
year: '2025'
...
---
_id: '59069'
abstract:
- lang: eng
  text: <jats:p>Stable and bright single photon sources are key components for future
    quantum applications. A simple fabrication method is an important requirement
    for such sources. Here, we present a single photon source based on diced ridge
    waveguides in titanium indiffused LiNbO<jats:sub>3</jats:sub>. These waveguides
    can be easily fabricated by combining planar titanium in-diffusion without lithographic
    patterning and easy-to-handle precision dicing. Such devices have the potential
    to generate high single photon rates because ridge structures are typically less
    prone to the photorefractive effect. We achieve waveguide propagation losses &lt;0.4dBcm
    and a SHG conversion efficiency of about 81%Wcm<jats:sup>2</jats:sup>. Harnessing
    a type-0 SPDC process to generate 1550 nm photons, we obtain a SPDC brightness
    of 3⋅10<jats:sup>5</jats:sup>1s⋅mW⋅nm, with a heralding efficiency of <jats:italic>η</jats:italic><jats:sub>h</jats:sub>=45%
    (<jats:italic>η</jats:italic><jats:sub>h,wg</jats:sub>=77.5% for the waveguide
    itself excluded setup losses) and a heralded second-order correlation function
    of <jats:italic>g</jats:italic><jats:sub>h</jats:sub><jats:sup>2</jats:sup>(0)&lt;0.003
    at low pump powers.</jats:p>
article_number: '593'
article_type: original
author:
- first_name: Christian
  full_name: Kießler, Christian
  id: '44252'
  last_name: Kießler
- first_name: Michelle
  full_name: Kirsch, Michelle
  id: '69553'
  last_name: Kirsch
- first_name: Sebastian
  full_name: Lengeling, Sebastian
  id: '44373'
  last_name: Lengeling
- first_name: Harald
  full_name: Herrmann, Harald
  id: '216'
  last_name: Herrmann
- first_name: Christine
  full_name: Silberhorn, Christine
  id: '26263'
  last_name: Silberhorn
citation:
  ama: Kießler C, Kirsch M, Lengeling S, Herrmann H, Silberhorn C. SPDC single-photon
    source in Ti-indiffused diced ridge LiNbO<sub>3</sub> waveguides. <i>Optics Continuum</i>.
    2025;4(3). doi:<a href="https://doi.org/10.1364/optcon.557439">10.1364/optcon.557439</a>
  apa: Kießler, C., Kirsch, M., Lengeling, S., Herrmann, H., &#38; Silberhorn, C.
    (2025). SPDC single-photon source in Ti-indiffused diced ridge LiNbO<sub>3</sub>
    waveguides. <i>Optics Continuum</i>, <i>4</i>(3), Article 593. <a href="https://doi.org/10.1364/optcon.557439">https://doi.org/10.1364/optcon.557439</a>
  bibtex: '@article{Kießler_Kirsch_Lengeling_Herrmann_Silberhorn_2025, title={SPDC
    single-photon source in Ti-indiffused diced ridge LiNbO<sub>3</sub> waveguides},
    volume={4}, DOI={<a href="https://doi.org/10.1364/optcon.557439">10.1364/optcon.557439</a>},
    number={3593}, journal={Optics Continuum}, publisher={Optica Publishing Group},
    author={Kießler, Christian and Kirsch, Michelle and Lengeling, Sebastian and Herrmann,
    Harald and Silberhorn, Christine}, year={2025} }'
  chicago: Kießler, Christian, Michelle Kirsch, Sebastian Lengeling, Harald Herrmann,
    and Christine Silberhorn. “SPDC Single-Photon Source in Ti-Indiffused Diced Ridge
    LiNbO<sub>3</sub> Waveguides.” <i>Optics Continuum</i> 4, no. 3 (2025). <a href="https://doi.org/10.1364/optcon.557439">https://doi.org/10.1364/optcon.557439</a>.
  ieee: 'C. Kießler, M. Kirsch, S. Lengeling, H. Herrmann, and C. Silberhorn, “SPDC
    single-photon source in Ti-indiffused diced ridge LiNbO<sub>3</sub> waveguides,”
    <i>Optics Continuum</i>, vol. 4, no. 3, Art. no. 593, 2025, doi: <a href="https://doi.org/10.1364/optcon.557439">10.1364/optcon.557439</a>.'
  mla: Kießler, Christian, et al. “SPDC Single-Photon Source in Ti-Indiffused Diced
    Ridge LiNbO<sub>3</sub> Waveguides.” <i>Optics Continuum</i>, vol. 4, no. 3, 593,
    Optica Publishing Group, 2025, doi:<a href="https://doi.org/10.1364/optcon.557439">10.1364/optcon.557439</a>.
  short: C. Kießler, M. Kirsch, S. Lengeling, H. Herrmann, C. Silberhorn, Optics Continuum
    4 (2025).
date_created: 2025-03-19T10:56:04Z
date_updated: 2025-03-19T16:03:25Z
department:
- _id: '15'
- _id: '623'
- _id: '288'
doi: 10.1364/optcon.557439
intvolume: '         4'
issue: '3'
language:
- iso: eng
publication: Optics Continuum
publication_identifier:
  issn:
  - 2770-0208
publication_status: published
publisher: Optica Publishing Group
status: public
title: SPDC single-photon source in Ti-indiffused diced ridge LiNbO<sub>3</sub> waveguides
type: journal_article
user_id: '216'
volume: 4
year: '2025'
...
---
_id: '56193'
abstract:
- lang: eng
  text: 'Dielectric slab waveguides made of thin-film-lithium-niobate (TFLN) media
    are consid-ered, for operation in the linear regime. We outline and implement
    a largely analytic procedure forrigorous modal analysis of three-layer slabs with
    birefringent, anisotropic core. For Z-cut wave-guides, the slab eigenmode problem
    separates into uncoupled sets of scalar equations for TE andTM modes. Slabs in
    X-cut configuration support mostly mildly hybrid eigenmodes, with clear pre-dominant
    TE or TM polarization, and with effective indices that depend on the propagation
    directionof the modes, relative to the crystal axes. Strong hybridization can
    be observed for near degeneratemodes in singular configurations without vertical
    symmetry, or in symmetric slabs where two nearlydegenerate modes are of the same
    symmetry class. Dispersion curves for slab thickness and propa-gation angle are
    discussed, for slabs with oxide and air cover. '
author:
- first_name: Manfred
  full_name: Hammer, Manfred
  id: '48077'
  last_name: Hammer
  orcid: 0000-0002-6331-9348
- first_name: Henna
  full_name: Farheen, Henna
  id: '53444'
  last_name: Farheen
  orcid: 0000-0001-7730-3489
- first_name: Jens
  full_name: Förstner, Jens
  id: '158'
  last_name: Förstner
  orcid: 0000-0001-7059-9862
citation:
  ama: Hammer M, Farheen H, Förstner J. Guided modes of thin-film lithium niobate
    slabs. <i>Optics Continuum</i>. Published online 2024:532822. doi:<a href="https://doi.org/10.1364/optcon.532822">10.1364/optcon.532822</a>
  apa: Hammer, M., Farheen, H., &#38; Förstner, J. (2024). Guided modes of thin-film
    lithium niobate slabs. <i>Optics Continuum</i>, 532822. <a href="https://doi.org/10.1364/optcon.532822">https://doi.org/10.1364/optcon.532822</a>
  bibtex: '@article{Hammer_Farheen_Förstner_2024, title={Guided modes of thin-film
    lithium niobate slabs}, DOI={<a href="https://doi.org/10.1364/optcon.532822">10.1364/optcon.532822</a>},
    journal={Optics Continuum}, publisher={Optica Publishing Group}, author={Hammer,
    Manfred and Farheen, Henna and Förstner, Jens}, year={2024}, pages={532822} }'
  chicago: Hammer, Manfred, Henna Farheen, and Jens Förstner. “Guided Modes of Thin-Film
    Lithium Niobate Slabs.” <i>Optics Continuum</i>, 2024, 532822. <a href="https://doi.org/10.1364/optcon.532822">https://doi.org/10.1364/optcon.532822</a>.
  ieee: 'M. Hammer, H. Farheen, and J. Förstner, “Guided modes of thin-film lithium
    niobate slabs,” <i>Optics Continuum</i>, p. 532822, 2024, doi: <a href="https://doi.org/10.1364/optcon.532822">10.1364/optcon.532822</a>.'
  mla: Hammer, Manfred, et al. “Guided Modes of Thin-Film Lithium Niobate Slabs.”
    <i>Optics Continuum</i>, Optica Publishing Group, 2024, p. 532822, doi:<a href="https://doi.org/10.1364/optcon.532822">10.1364/optcon.532822</a>.
  short: M. Hammer, H. Farheen, J. Förstner, Optics Continuum (2024) 532822.
date_created: 2024-09-21T09:17:16Z
date_updated: 2024-11-04T17:07:27Z
ddc:
- '530'
department:
- _id: '61'
- _id: '230'
- _id: '429'
doi: 10.1364/optcon.532822
file:
- access_level: closed
  content_type: application/pdf
  creator: fossie
  date_created: 2024-11-04T17:05:30Z
  date_updated: 2024-11-04T17:05:30Z
  file_id: '56864'
  file_name: 2024-11 Hammer - Optics Continuum - Guided modes of thin-film lithium
    niobate slabs.pdf
  file_size: 4399685
  relation: main_file
  success: 1
file_date_updated: 2024-11-04T17:05:30Z
has_accepted_license: '1'
keyword:
- tet_topic_waveguide
language:
- iso: eng
page: '532822'
project:
- _id: '266'
  grant_number: PROFILNRW-2020-067
  name: 'PhoQC: PhoQC: Photonisches Quantencomputing'
- _id: '167'
  grant_number: '231447078'
  name: 'TRR 142 - B06: TRR 142 - Ultraschnelle kohärente opto-elektronische Kontrolle
    eines photonischen Quantensystems (B06*)'
- _id: '53'
  grant_number: '231447078'
  name: 'TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden
    Konzepten zu funktionellen Strukturen'
publication: Optics Continuum
publication_identifier:
  issn:
  - 2770-0208
publication_status: published
publisher: Optica Publishing Group
status: public
title: Guided modes of thin-film lithium niobate slabs
type: journal_article
user_id: '158'
year: '2024'
...