Regensburg 2007 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 35: Devices
HL 35.8: Talk
Thursday, March 29, 2007, 12:00–12:15, H13
Acoustically driven integrated Mach-Zehnder-Interferometer — Markus Beck1, Mauricio de Lima2, Rudolf Hey1, and •Paulo Santos1 — 1Paul–Drude–Institut für Festkörperelktronik, Hausvogteiplatz 5-7, D-10117 Berlin, Germany — 2Materials Science Institute, University of Valencia, P. O. Box 22085, E-46071 Valencia, Spain
We demonstrate a compact modulator based on conventional ridge waveguides (WGs) monolithically fabricated on GaAs. The modulator consists of a Mach-Zehnder interferometer (MZI) driven by a surface acoustic wave (SAW) in the GHz range, which modulates the refractive index in the two arms of the interferometer. The effect on the interference is maximized by choosing the spatial separation between the arms to be an odd multiple of the acoustic wavelength λSAW in order to modulate the arms with opposite phases. The modulated waveguide length is minimized by using a focusing interdigital transducer to generate a narrow and intense acoustic beam. Peak-to-peak modulation exceeding 90% of the average transmission is demonstrated with a modulated waveguide length of approximately 15 µm, which is significantly shorter than for comparable approaches.