Poster

PUBDB-2024-06507

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Ultra-broadband multimode waveguide dispersion measurement

Fan, W.CFEL*DESY* ; Ayhan, F. ; Villanueva, L. G. ; Herr, T. (Corresponding author)CFEL*DESY* ; Ludwig, M.Extern*

2024

Abstract: Integrated photonic waveguides offer a highly efficient platform for nonlinear optics owing to their strong light confinement and highly nonlinear materials properties. Key applications in this domain critically depend on the waveguide dispersion and include nonlinear pulse compression and supercontinuum generation. Therefore, the ability to tailor waveguide dispersion is a key factor in achieving functional devices. While numerical dispersion modelling based on catalogued refractive index data is a powerful tool in photonic design, it is of importance to establish methods for measuring and validating the dispersion in fabricated devices, e.g. to investigate the impact of fabrication tolerances and process dependent material properties.The ability to quantify waveguide dispersion experimentally also provides a valuable resource for the iteration of waveguide design and fabrication. Although optical waveguides have found numerous applications spanning from astronomy in the ultraviolet regime to spectroscopy at around 5 $\mathrm{\mu}$m, most of previous experimental techniques based on scanning continuous wave laser or white light interferometry only evaluated the dispersion of the fabricated waveguides in a narrow wavelength range. In this study, we demonstrate white light interferometry over more than two-octave spectral range from visible to the mid-infrared region. In addition, we show that it is possible to simultaneously measure the dispersion of multiple waveguide modes in a single experiment. The entire setup consists of dispersionless optics to avoid complex calibration and rule out chromatic effects. In this way, the complex dispersion characteristics of integrated waveguides can be obtained rapidly and without any model assumptions. As an example, the dispersion of both silicon nitride and lithium niobate integrated waveguides is extracted by using only 5 mm long waveguides. Our method in principle is applicable for any wavelength regime where there are suitable light sources and detectors.

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Contributing Institute(s):

1. FS-CFEL-2-UMP (FS-CFEL-2-UMP)

Research Program(s):

1. 631 - Matter – Dynamics, Mechanisms and Control (POF4-631) (POF4-631)
2. iSenseDNA - Computation driven development of novel vivo-like-DNA-nanotransducers for biomolecules structure identification (101046920) (101046920)
3. STARCHIP - Microphotonics-based frequency combs for habitable exoplanet detection (853564) (853564)
4. VH-NG-1404 - Ultra-fast nonlinear microphotonics (G:(DE-HGF)2019_VH-NG-1404) (G:(DE-HGF)2019_VH-NG-1404)

Experiment(s):

1. Experiments at CFEL

Appears in the scientific report 2024

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