Micromirror Actuation Research Articles

Magnet arrays for use in a 3-D MEMS mirror array for optical switching

Magnet arrays for creating regions of high magnetic flux gradient are presented. These high-flux gradient regions are useful for actuation of two-axis micromirrors with quadrupole coils, which are an essential component of some optical switches. Three magnet arrays are presented: a checkerboard array made of individual magnets and two monolithic magnet arrays, an array with filled holes, and an array with raised nubs. Monolithic magnet arrays reduce costs and eliminate the runout introduced from fabrication tolerances of the checkerboard array. Elimination of runout allows the mirrors to be precisely centered over the high-gradient regions. Quadrupole mirror arrays were fabricated and showed performance of 7/spl deg//mA for a monolithic magnet with an array of steel-filled holes.

Self-aligned vertical electrostatic combdrives for micromirror actuation

In this paper, we analyze the effect of misalignment in electrostatic combdrives, and describe a fabrication technology that minimizes misalignment in vertical electrostatic combdrives by creating self-aligned, vertically staggered electrodes. Self-alignment of the interdigitated electrodes simplifies fabrication and minimizes failures due to electrostatic instability, thus enabling fabrication of narrow-gap, high-force actuators with high yield. The process is based on deep-reactive ion etching (DRIE) of buried-patterned silicon-on-insulator (SOI) wafers. Measurements on fabricated combdrives show relative misalignment of less than 0.05 /spl mu/m. This corresponds to less than 0.1% misalignment, which, according to our analysis, results in a travel range of 98% of that for perfectly aligned drives. The validity of the process is demonstrated by fabrication of scanning micromirrors measuring 300 /spl mu/m by 100 /spl mu/m. Optical angular deflections from 4/spl deg/ at low frequency to 40/spl deg/ at resonance were measured for an applied voltage of 75 Vpp. Resonant frequencies ranged from 5 kHz to 15 kHz for these devices, making them suitable for high-speed, high-resolution optical scanning and switching.

Micromechanically controlled GT interferometer for optical-pulse narrowing

A micromechanically controlled Gires–Tournois interferometer (micro-GTI) is proposed for a tunable dispersive medium for use in optical-pulse compression. Its dispersive properties, which are controlled by comb-drive micromirror actuation, were theoretically and experimentally evaluated to verify its capability to generate ultra-short optical pulses. Pulse compression performed using this micro-GTI generated nearly transform-limited pulses with a duration of 0.43 ps.