Tunable Micromirror Switches Using (110) Silicon Wafer

A frequency-tunable silicon micromirror has been fabricated and tested for applications to optomechanical switching devices. A high-aspect-ratio single crystal silicon micromirror has been fabricated by an anisotropic etching of (110) silicon wafers. The micromirror, vertical to the substrates, is suspended by two pairs of boron-diffused microflexures. Static and dynamic optical switching functions have been obtained by an electrostatic drive of the micromirror in the direction parallel to the substrate. In the static mirror operation, a threshold deflection of 26.5 μm has been obtained at the DC drive voltage of 330 V. In the dynamic test, the resonant frequency of the suspended micromirror has been measured as 590 Hz. The resonant switching frequency of the micromirror has been tuned in the range of 585-450 Hz by varying the DC bias voltage in the range of 50-300 V