Micro bimorph cantilever switches for tuning integrated optical systems

S.M. Chakkalakkal Abdulla, L.J. Kauppinen, Mindert Dijkstra, Meint J. de Boer, R.M. de Ridder, Gijsbertus J.M. Krijnen

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    We propose to use a self aligning technology (Figure 1) to integrate micro bimorph cantilevers with tips with respect to e.g. the holes in a photonic band gap (PBG) microresonator coupling section in order to perturb its evanescent field [1]. Using a simplified process, we first fabricated bimorph cantilevers on top of silicon, by surface micromachining techniques in which the upper electrode is a thin layer of Chromium on the top of a thick layer of dielectric material which is Silicon Rich Nitride (SiN). The resonance frequencies and pull in voltages of these electrostatically actuated bimorph cantilevers with off-state deflection [2] are analysed and it is found that the higher resonance frequencies come at the price of larger switching voltages (Figure 2-3). This allows for fabrication of relative stiff cantilevers with resonance frequencies in the MHz range to interact with the evanescent field of PBG crystals in which the mechanical elements start to play a role typically with a distance <400 nanometers. We have also fabricated bimorph cantilevers without tips, integrated on top of various optical systems like ring resonators, photonic crystals and planar waveguides. Analytical and numerical models are developed to predict the resonance frequencies and the pull-in voltages of these switches, including the effect of undercut and validated it with experimental data. We have observed selective wavelength on/off switching by perturbing the near band edge resonance of a waveguide grating with a 20 μm wide silicon nitride AFM cantilever, without using its tip area (Figure 4). The observed mechanical perturbation allows 15 dB on/off switching of a specific wavelength and a wavelength tuning of approximately 60 pm. In conclusion, here we describe the technology for fabricating integrated bimorph switches, the optimization studies of the cantilever designs and measurements of mechano-optical interactions using an AFM based cantilever. These optical switches have potential application in the field of elecommunication networks.
    Original languageUndefined
    Title of host publicationThe Sense of Contact 12
    Place of PublicationZeist
    PublisherFHI - Federatie Van Technologiebranches
    Number of pages2
    ISBN (Print)978-90-74702-56-0
    Publication statusPublished - 8 Apr 2010
    Event12th Sensor Technology Conference Sense of Contact 2010 - Conferentiecentrum Woudschoten, Zeist, Netherlands
    Duration: 8 Apr 20108 Apr 2010
    Conference number: 12

    Publication series

    PublisherFHI Federatie Van Technologiebranches


    Workshop12th Sensor Technology Conference Sense of Contact 2010


    • IR-75941
    • EWI-19575
    • METIS-275929

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