PhD12: Sacha Grelet

Host: NKT Photonics 

Secondment: University of Kent, Applied Optics Group (AOG)

PhD Project: Time Stretched Pulse Supercontinuum (SPSC) swept laser source

During the last years, the progress in All-Normal Dispersion (ANDi) fiber manufacturing lead to a new technique to generate low-noise supercontinuum sources. These broadband lasers can be used in Optical Coherent Tomography (OCT) systems to get high resolution and high sensitivity imaging. Another technique called time-stretch allows overcoming one of the bottlenecks of OCT: the lack of high speed, high sensitivity detector and digitizers. In this project, we aim to build low noise, near-visible IR sources that combine the strength of the ANDi Supercontinuum and Time Stretch to improve the capabilities of OCT systems.

Completed workshops, Seminars, and Conferences:

  • Kick-off Meeting with the beneficiants and collaborators, University of Kent, UK, 20/02/2020 – 21/02/2020
  • Optics and Photonics for Scientific Progress- Student Led Conference, SEPnet, UoKent’s OSA Student, online participation, 13-14/04/2021
  • International Day of Light Conference, 20th – 21st May, 2021, Organizer: Tampere University, Finland
  • CLEO – ECBO conference, Munich, Germany , oral presentation, 20-24/6/21
  • Danish Quantum Community 4th Conference, Denmark, Poster presentation “Fast akinetic swept source for OCT”, 27-28/10/21
  • Danish Optical Society (DOPS) annual meeting, IDA Conference (Copenhagen), Denmark, 17/11/21
  • 1st International Conference on “Advances in 3OM: Opto-Mechatronics, Opto-Mechanics, Optical Metrology” 13 December 2021, Timisoara, Romania
  • NETLAS Winter School, DTU, Denmark, 1-4th March 2022,
  • Celebration of Prof. Adrian Podoleanu’s career. Poster presentation, University of Kent, UK, 26-27/05/2022


  • E. Genier, S. Grelet, R. D. Engelsholm, P. Bowen, P. M. Moselund, O. Bang, J. M. Dudley, and T. Sylvestre, “Ultra-flat, low-noise, and linearly polarized fiber supercontinuum source covering 670–1390 nm,” Opt. Lett. 46, 1820-1823 (2021).
  • S. Grelet, A. Martínez Jiménez, R. D. Engelsholm, P. B. Montague and A. Podoleanu, “40 MHz swept-source optical coherence tomography at 1060 nm using a time-stretch and supercontinuum spectral broadening dynamics,” in IEEE Photonics Journal, VOL. 14, NO. 6 doi: 10.1109/JPHOT.2022.3226820.
  • E. Genier, S. Grelet, R. D. Engelsholm, P. Bowen, P. M. Moselund, O. Bang, J. M. Dudley, and T. Sylvestre, “Generation of an ultra-flat, low-noise and linearly polarized fiber supercontinuum covering 670 nm-1390 nm,” in 2021 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, OSA Technical Digest (Optica Publishing Group, 2021), paper cd_5_1 (2021).
  • S. Grelet, P. Bowen, P.M. Moselund, and A. Podoleanu, “80 MHz swept source operating at 1060 nm based on all-normal-dispersion supercontinuum generation for ultrahigh-speed optical coherence tomography.” In European Conference on Biomedical Optics (pp. ETu3D-5). Optical Society of America (2021).
  • Alejandro Martínez Jiménez; Sacha Grelet; Veronika Tsatourian; Patrick Bowen Montague; Adrian Bradu and Adrian Podoleanu, “400 Hz volume rate swept-source optical coherence tomography at 1060 nm using a KTN deflector” in IEEE Photonics Technology Letters, VOL. 34, NO. 23, 2022, doi: 10.1109/LPT.2022.3212015
  • Sacha Grelet, Patrick Bowen Montague, Adrian Podoleanu, “Towards sub-5 µm axial resolution OCT from a multi-MHz swept source,” Proc. SPIE 12390, High-Speed Biomedical Imaging and Spectroscopy VIII, 123900E (16 March 2023);
  • S. Grelet, P. B. Montague and A. Podoleanu, “10 MHz Swept-Source for Optical Coherence Tomography at 1050 nm,” 2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), Munich, Germany, 2023, pp. 1-1, doi: 10.1109/CLEO/Europe-EQEC57999.2023.10231366.
  • Alejandro Martínez JiménezSacha Grelet, Patrick Bowen Montague, Adrian Bradu, Adrian Podoleanu, “Dual ultrahigh speed swept-source and time domain optical coherence tomography system using a time stretch laser and a KTN deflector,” Proc. SPIE 12632, Optical Coherence Imaging Techniques and Imaging in Scattering Media V, 126320B (11 August 2023);


Sacha obtained his engineering degree from Telecom Saint Etienne (France) with a major in Photonics and minors in Computer Science and Image Processing. He spent his fifth year at the University of Laval (Québec, Canada) to specialize in laser science and nonlinear effects in fiber optics. To complete his education in this field, he did a six months internship at Alphanov (Bordeaux, France) on the design of stable passively mode-locked fiber laser.