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Liquid Crystals for nanophotonic applications

Main Researcher: Lukas Van Iseghem

Silicon-on-insulator is an ideal material for passive waveguide components. However, for active functions that require nonlinearities or electrooptic effects the material properties are relatively weak. In nanophotonic waverguides a significant fraction of the light is in the surrounding air. If the air is replaced with a material with very strong electrooptic or nonlinear properties, like Liquid Crystal, active functions can be implemented in SOI.
We explore the possibilities to add a Liquid crystal cladding to SOI nanophotonic waveguides. To do this, we fabricate aLC cell, not unlike those used in displays, but where one glass contact plate is replaced by an SOI waveguide component. The other plate of the cell is a thin glass plate with a gold contact and a polyimide alignment layer. The plates are joined with two stripes of glue and the distance is well controlled with spacers suspended in the glue. Once mounted, the cell is filled with liquid crystal with cappilary forces.
We have measured the change in refractive index in a 3micron wide SOI ridge waveguide. Here, the effect is not very strong, because only a small fraction of the light is in the cladding. Still, we can observe the effect when we measure the transmission of a Fabry-Perot cavity formed by the facets. The results is very close to the predicted theoretical values.

This research is in collaboration with the Liquid Crystal & Photonics Group

Other people involved:

Related Research Projects

PhD thesises

Publications

    International Journals

  1. Y. Xing, T. Ako, J. George, D. Korn, H. Yu, P. Verheyen, M. Pantouvaki, G. Lepage, P. Absil, A. Ruocco, C. Koos, J. Leuthold, K. Neyts, J. Beeckman, W. Bogaerts, Digitally Controlled Phase Shifter using an SOI Slot Waveguide with Liquid Crystal Infiltration, Photonics Technology Letters, doi:10.1109/LPT.2015.2416438  (2015)  Download this Publication (3.8MB).
  2. S. Lambert, W.A.D. De Cort, J. Beeckman, K. Neyts, R. Baets, Trimming of silicon-on-insulator ring resonators with a polymerizable liquid crystal cladding, Optics Letters, 37(9), p.1475-1477 doi:10.1364/ol.37.001475 (2012)  Download this Publication (584KB).
  3. W.A.D. De Cort, J. Beeckman, R. James, F.A. Fernandez, R. Baets, K. Neyts, Tuning silicon-on-insulator ring resonators with in-plane switching liquid crystals, Journal of the Optical Society of America, 28(1), p.79 - 85 doi:10.1364/josab.28.000079 (2011)  Download this Publication (703KB).
  4. J. Beeckman, R. James, F.A. Fernandez, W.A.D. De Cort, P. Vanbrabant, K. Neyts, Calculation of Fully Anisotropic Liquid Crystal Waveguide Modes, Journal of Lightwave Technology, 27(17), p.3812-3819 doi:10.1109/jlt.2009.2016673 (2009)  Download this Publication (958KB).
  5. W.A.D. De Cort, J. Beeckman, R. James, F.A. Fernandez, R. Baets, K. Neyts, Tuning of silicon-on-insulator ring resonators with liquid crystal cladding using the longitudinal field component, Optics Letters, 34(13), p.2054-2056  doi:10.1364/ol.34.002054 (2009)  Download this Publication (229KB).
  6. H. Desmet, K. Neyts, R. Baets, Modeling nematic liquid crystals in the neighborhood of edges, Journal of Applied Physics, 98(12), p.123517 doi:10.1063/1.2143122 (2005).
  7. C. Desimpel, J. Beeckman, H. Desmet, K. Neyts, R. James, F.A. Fernandez, A four-electrode liquid crystal device for 2pi in-plane director rotation, Journal of physics. D, applied physics, 38(21), United Kingdom, p.3976-3984 doi:10.1088/0022-3727/38/21/023 (2005)  Download this Publication (7.6MB).
      International Conferences

    1. L. Van Iseghem, U. Khan, P. Edinger, C. Errando-Herranz, A.Y. Takabayashi, H. Sattari, K.B. Gylfason, N. Quack, J. Beeckman, W. Bogaerts, Liquid crystal phase shifter integrated in a silicon photonics platform, European Conference on Integrated Optics, p.1.3 (2020)  Download this Publication (1.8MB).
    2. Y. Xing, T. Ako, J. George, D. Korn, H. Yu, P. Verheyen, M. Pantouvaki, G. Lepage, P. Absil, C. Koos, J. Leuthold, J. Beeckman, W. Bogaerts, Direct Digital Control of an Efficient Silicon+Liquid Crystal Phase Shifter, 11th International Conference on Group IV Photonics (GFP), France, p.43-44 doi:10.1109/group4.2014.6962029 (2014)  Download this Publication (394KB).
    3. W.A.D. De Cort, J. Beeckman, T. Claes, K. Neyts, R. Baets, Widely Tunable Silicon-On-Insulator Ring Resonators with a Liquid Crystal Cladding, IEEE Photonics 2011 Conference (IPC11), p.541-542 doi:10.1109/pho.2011.6110661 (2011)  Download this Publication (776KB).
    4. W.A.D. De Cort, J. Beeckman, K. Neyts, R. Baets, Tuning silicon-on-insulator ring resonators in in-plane switching liquid crystal cells, 15th European Conference on Integrated Optics (ECIO 2010), United Kingdom, p.WeD7 (2010)  Download this Publication (417KB).
    5. W.A.D. De Cort, N. Hattasan, J. Beeckman, K. Neyts, R. Baets, Tuning SOI filter structures with liquid crystals, Proceedings of the 2009 Annual Symposium of the IEEE Photononics Benelux Chapter, Belgium, p.57-60 (2009)  Download this Publication (314KB).
    6. N. Hattasan, W.A.D. De Cort, J. Beeckman, K. Neyts, R. Baets, Tunable Silicon-on-Insulator based integrated optical filters with liquid crystal cladding, The 22nd Annual Meeting of the IEEE Photonics Society, Turkey, p.189-190 doi:10.1109/leos.2009.5343308 (2009)  Download this Publication (369KB).
    7. K. Neyts, J. Beeckman, W.A.D. De Cort, Non-linear light propagation and bistability in nematic liquid crystals, SPIE Optics and Photonics, 7414, United States, doi:10.1117/12.827015 (2009)  Download this Publication (772KB).
    8. W.A.D. De Cort, J. Beeckman, R. James, F.A. Fernandez, R. Baets, K. Neyts, New wavelength-tuning method in optical ring resonators with liquid crystal cladding: exploiting the longitudinal E-field, SPIE Optics and Photonics, 7414, United States, doi:10.1117/12.825669 (2009)  Download this Publication (716KB).
    9. W.A.D. De Cort, J. Beeckman, K. Neyts, R. Baets, R. James, F. A. Fernandez, Tuning SOI filters with Liquid Crystals, LCP, United Kingdom, (2008)  Download this Publication (171KB).
    10. W.A.D. De Cort, R. Baets, K.Neyts, Liquid crystal technology for wavelength tuning in SOI structures, ePIXnet Spring School 2008, (2008)  Download this Publication (267KB).
    11. W.A.D. De Cort, R. Baets, K. Neyts, Towards a widely tunable laser on silicon with liquid crystal technology, 12th Annual Symposium of the IEEE/LEOS Benelux Chapter, Belgium, p.99-102 (2007)  Download this Publication (2.7MB).
    12. W.A.D. De Cort, H. Desmet, S. Scheerlinck, K. Neyts, R. Baets, Design and realization of an Optical Switch based on Long-Range Surface Plasmon Polaritons and Liquid Crystal , 35. Arbeitstagung Flüssigkristalle (2007, Bayreuth), Germany, (2007)  Download this Publication (104KB).
    13. W.A.D. De Cort, R. Baets, K. Neyts, A silicon laser with gain in doped liquid crystal, ePIXnet Winter School 2007, (2007)  Download this Publication (45KB).
    14. H. Desmet, K. Neyts, D. Van Thourhout, R. Baets, Focused ion beam technology for aligning and switching liquid crystals, 21st International Liquid Crystal Conference, United States, p.704 (2006)  Download this Publication (57KB).
    15. K. Neyts, J. Da Sylva, H. Desmet, H. Azarinia, I. Bartolozzi, E. Schacht, Study of liquid crystal in contact with aqueous solutions for detection of biomolecules, 21st International Liquid Crystal Conference (ILCS 2006), United States, p.428 (2006)  Download this Publication (1.5MB).
    16. H. Desmet, K. Neyts, R. Baets, Liquid crystal orientation on patterns etched in silicon-on-insulator, Integrated Optics, Silicon Photonics, and Photonic Integrated Circuits, 6183, France, p.61831Z doi:10.1117/12.668350 (2006)  Download this Publication (651KB).
    17. H. Desmet, K. Neyts, R. Baets, Liquid crystal orientation on patterns etched in silicon-on-insulator, Proceedings Symposium IEEE/LEOS Benelux Chapter, Belgium, p.293-296 (2005).
    18. C. Desimpel, F. Beunis, H. Desmet, K. Neyts, Experiments on azimuthal degenerated anchoring surfaces, Programme & Abstracts of the 16th Conference on Liquid Crystals (Chemistry, Physics & Applications), Poland, p.69 (2005)  Download this Publication (4MB).
    19. H. Desmet, K. Neyts, R. Baets, Influence of etched silicon patterns on the liquid crystal orientation, Programme & Abstracts of the 16th Conference on Liquid Crystals (Chemistry, Physics & Applications), Poland, p.30 (2005)  Download this Publication (38KB).
    20. H. Desmet, K. Neyts, R. Baets, Nematic Liquid Crystal Behaviour in the Neighbourhood of Edges, 20th International Liquid Crystal Conference, Slovenia, p.783 (2004).
    21. H. Desmet, W. Bogaerts, A. Adamski, J. Beeckman, K. Neyts, R. Baets, Silicon-on-insulator optical waveguides with liquid crystal cladding for switching and tuning, ECOC 2003, 3, Italy, p.430-431 (2003)  Download this Publication (149KB).
        National Conferences

      1. D. Van Thourhout, Novel materials and integration technologies for silicon photonics, Belgian Photonics Online Meetup (bePOM) (invited), Belgium, (2020).
      2. W.A.D. De Cort, R. Baets, K. Neyts, Towards a widely tunable laser on silicon with liquid crystal technology, 8e Ugent - FirW doctoraatssymposium , Belgium, p.48 (2007)  Download this Publication (1MB).

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