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The aim of the project ELENE is to experimentally prove the feasibility of all-optical conversion using LNOI waveguides, and theoretically evaluate the beneficial effects that such converters can have for optical networks.
Goal 1: develop new skills for LNOI waveguides.
Goal 2: develop new ideas and devices for wavelength conversion.
Goal 3: prove a disruptive prototype for telecom of the future.
Goal 4: envision a step forward for optical networks.

ELENE is part of Spoke 1 – Pervasive and Photonic Network Technologies and Infrastructures

Project PI: Stefan Wabnitz

[M1 - M9]
Overall, the key results achieved until September 2023 are:
  • start-up of the technical activities;
  • theoretically studied how phase-matching of third-harmonic generation in a Kerr micro-resonator can be used to extend frequency conversion into new spectral regions, far from the pump wavelength;
  • investigated temporally dispersive dual-comb generation of phase-matched combs with broad bandwidth and anomalous dispersion of the fundamental field;
  • set up a simulation workflow for LNOI waveguides, linking numerical simulations at the device level with theoretical modelling, layout design and future experimental characterization;
  • designed experimental setup based on a soliton waveguide in a LNOI sample for wavelength conversion.
[M9 - today]

  • Set up a simulation workflow for lithium niobate (LNOI) waveguides.
  • Investigated various parameters for frequency converters.
  • Designed an experimental setup for wavelength conversion, emphasizing telecom compatibility.
  • Studied the effect of combined quadratic and cubic nonlinearity on optical soliton frequency comb stability.
  • Found that cubic nonlinearity increases the stability region of quadratic soliton optical frequency combs.
  • Studied different methods for modeling conversion processes in X-cut and Z-cut LNOI waveguides.
  • Analyzed the fundamental mode at 1550nm and SHG at 775nm through modal analysis.

  • Reviewed existing literature and conducted numerical simulations.
  • Procured a laser source for 850-band experiments.
  • Assembled and aligned an experimental setup for nonlinear wavelength conversion.
  • Planned to shift focus to the O and C bands in alignment with project specifications.
  • Ongoing extended experiments for down-conversion from 400nm to 875+815.

Up to June 2024, the scientific outcome of the ELENE focused project has resulted in one journal publication (1) and two conference oral presentations (2-3).  

The outcome has been limited to the work of Sapienza University of Rome research unit only, since the two other units that have been foreseen for carrying out the planned research have not been selected yet by the RESTART Consortium, even though the technical and scientific criteria for determining the tasks to be assigned to the additional units via a call for proposals were already outlined by the PI of ELENE in the month of July 2023. 
  • Developed a mean-field model for optical frequency comb generation in a nonlinear cavity system.
  • Explored dual-comb generation with broad bandwidth and anomalous dispersion.
  • Achieved coexistence of bistable cavity solitons
  • Enabled telecom pump lasers to access both near-infrared and visible regions.
  • Beneficial for optical clocks and sensing applications
  • Conducted experiments with a relatively thick film in the first transparency window of fibers.
  • Received a new set of thin film LNOI waveguides.
  • Initiated new experiments with the thin film waveguides.

Hamed Tari, Alessandro Bile, Arif Nabizada, and Eugenio Fazio, "Immobilization of photorefractive solitons by charge anchoring on conductive walls," Opt. Lett. 48, 6508-6511 (2023) 

Francesco Rinaldo Talenti, Stefan Wabnitz, Yifan Sun, Tobias Hansson, Pedro Parra-Rivas, Multipeak dissipative solitons in  χ(2) + χ(3) optical cavites, Italian conference on optics and photonics, Firenze 17-19 June 2024 

Francesco Rinaldo Talenti, Luca Lovisolo, Andrea Gerini, Pedro Parra-Rivas, Tobias Hansson, Stefan Wabnitz, Laurent Vivien, Carlos Alonso-Ramos, and Giuseppe Leo, Frequency comb generation dynamics in χ(2) + χ(3) AlGaAs micro-resonators, European Optical Society Annual Meeting, Napoli, September 9-13, 2024 
Scientific KPIs

1- Publications
  • Expected: >=1 journal publication/partner during the first year
  • Accomplished: 1 journal publication
  • Readiness: 100%
2- Joint Publications
  • Expected: 0% joint publications during Y1
  • Accomplished: 0
  • Readiness: 100%
3- Demo/PoC
  • Expected: 0 (2 PoCs expected by the end of the project)
  • Accomplished: 0
  • Readiness: 100% (work according to plan)
4- Project meetings
  • Expected: 6 meetings
  • Accomplished: 6 meetings
  • Readiness: 100%
1. Milestone M1: Harmonic frequency conversion in solitonic waveguide (due date: M18)
  • Expected: 0
  • Accomplished: 0
  • Readiness level: 100%
2. Milestone M2: LNOI waveguide design completed (due date: M18)
  • Expected: 0
  • Accomplished: 0
  • Readiness level: 100%
3. Milestone M3: Demonstration of frequency conversion with LNOI waveguides (M36)
  • Expected: 0
  • Accomplished: 0
  • Readiness level: 100%
It is envisaged that the two additional partners will be formally selected in the next few weeks. If this happens, it might be possible to catch up with most of the delay incurred, in such a way that the main objectives of the project can still be achieved, albeit over a much shortened time scale. 

However, we anticipate that a re-definition of the timing and content of the milestones and deliverables might be necessary.

Collaboration proposals:
For any proposal of collaboration within the project please contact the project PI.