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Silicon optomechanics

Research Area: Integrated nonlinear optics

Main Researcher: Dries Van Thourhout

The high refractive index contrast and excellent mechanical properties of monocrystalline silicon make SOI a suitable platform for mechanical nanophotonic structures. Typically a part of a nanophotonic waveguide is underetched such that it is able to move. Additionally in a nanophotonic waveguide light is confined in such a way that strong spatial field gradients exist which give rise to strong optical gradient forces. The nature of this force is related to the forces used for free space optical tweezing and trapping of microparticles.

Underetched parallel waveguide pair
Underetched parallel waveguide pair

On chip however this novel actuation force enables a new class of integrated optomechanical devices (Micro-optomechanical systems = MOMS vs. classical Micro-electro-mechanical systems=MEMS). We demonstrated this on-chip optical force between waveguides in several experiments including attractive force between two nanophotonics waveguides and optical force in a slotted waveguide. Typically these forces are of the gap closing type just like the standard capacitive closing gap actuation found in classical MEMS.

A few years age we were able to demonstrate that with optomechanical actuation an extra degree of freedom is available and that it is possible to tune the sign of the force from attractive to repulsive. For this purpose the structure shown in the picture was designed and fabricated. The region labeled “waveguide string pair” consists of two parallel waveguides.
The rest of the structure is basically a construction which enables us to alter the distribution of light energy between the parallel waveguides when sweeping wavelength. Finally the force arising between the parallel waveguides could be tuned from attractive to repulsive with wavelength. To detect and quantify this ultra-small force also the development of calibration schemes and accurate optical sensing techniques were required. The experiment can be considered a breakthrough of both fundamental and practical importance

Waveguide string pair in an unbalanced Mach Zehnder Interferometer configuration
Waveguide string pair in an unbalanced Mach Zehnder Interferometer configuration

Currently we are investigating different application of on-chip optomechanical chips, including broadband sensing and parametric amplification

Other people involved:

PhD thesises


    International Journals

  1. R. Van Laer, C. J. Sarabalis, R. Baets, D. Van Thourhout, A. H. Safavi-Naeini, Thermal Brillouin noise observed in silicon optomechanical waveguide, Journal of Optics, 19(4), p.044002 (2017)  Download this Publication (587KB).
  2. R. Van Laer, R. Baets, D. Van Thourhout, Unifying Brillouin scattering and cavity optomechanics, Physical Review A, 93(5), p.1-15 (2016)  Download this Publication (388KB).
  3. R. Van Laer, B. Kuyken, D. Van Thourhout, R. Baets, Interaction between light and highly confined hypersound in a silicon photonic nanowire, Nature Photonics, 9(3), p.199-203 (2015)  Download this Publication (3.1MB).
  4. J. Roels, B. Maes, W. Bogaerts, R. Baets, D. Van Thourhout, Parametric instability of an integrated micromechanical oscillator by means of active optomechanical feedback, Optics Express, 19(14), p.13081-13088 (2011)  Download this Publication (3.4MB).
  5. J. Roels, I. De Vlaminck, L. Lagae, B. Maes, D. Van Thourhout, R. Baets, Tunable optical forces between nanophotonic waveguides, Nature Nanotechnology, 4, p.510-513 (2009).
      International Conferences

    1. P. Tiebot, B. Kuyken, D. Van Thourhout, Design for hybrid SOI/Silicon Nitride high cooperativity optomechanical cavity, Proceedings Symposium IEEE Photonics Society Benelux, Belgium, p.223-226 (2016)  Download this Publication (1.3MB).
    2. Z. Wang, Marianna Pantouvaki, G. Morthier, Clement Merckling, Joris Van Campenhout, D. Van Thourhout, G. Roelkens, Heterogeneous Integration of InP Devices on Silicon, the 28th International Conference on Indium Phosphide and Related Materials (IPRM) (invited), Japan, p.paper ThD1-1 (2016)  Download this Publication (379KB).
    3. P. Tiebot, R. Van Laer, B. Kuyken, D. Van Thourhout, Silicon socket layer for highly tunable phonon-phonon coupling in integrated circuits , Conference on Lasers and Electro-Optics (CLEO), (2016)  Download this Publication (831KB).
    4. P. Tiebot, B. Kuyken, D. Van Thourhout, CMOS compatible cavities based on TM ring resonators, ITN-cQOM workshop , (2015).
    5. J.M.O. Håkansson, D. Van Thourhout, Optomechanically actuated slot cantilever for mass sensing., Proceedings of the 2013 Annual Symposium of the IEEE Photonics Society Belenux Chapter, Netherlands, (2013).
    6. J. Roels, B. Maes, R. Baets, D. Van Thourhout, Integrated optomechanical circuits, Integrated Photonics Research, Silicon and Nano Photonics (IPR) 2010 (invited), United States, (2010)  Download this Publication (234KB).
    7. J. Roels, B. Maes, R. Baets, D. Van Thourhout, Silicon Optomechanics, 2010 IEEE Photonics Society Summer Topicals (invited), Mexico, p.90-91 (2010)  Download this Publication (193KB).

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