A tunable optomechanical micromirror switch

Abstract

The paper presents the electromechanical analysis, design, fabrication and characterization of a bulk-micromachined electrostatic micromirror device, whose optomechanical switching frequency is electrically tunable after fabrication. The silicon micromirror, fabricated via anisotropic etching of (110) silicon wafers, was suspended by two pairs of boron-diffused microflexures. The optical switching function was obtained by an electrostatic translational motion of the micromirror in the direction parallel to the substrate. In a static performance test, stable translational motion of the micromirror was observed up to the threshold deflection of 26.5 mu m at the DC threshold voltage of 330 V. In dynamic operation, resonant switching frequencies were electrically tuned in the range of 585-450 Hz using the DC bias voltage in the range of 50 - 300 V for an AC drive voltage of 10 V.