High-resolution electrostatic analog tunable grating with a single-mask fabrication process

We present the design, modeling, fabrication, and characterization of the microelectromechanical systems (MEMS) analog tunable diffraction grating with the concept of transverse actuation. In contrast to the vertically actuated "digital" tunable grating, our prototype design trades angular tunable range for tuning resolution. The prototype shows an angular tunable range of 250 murad with 1-murad resolution at 10 V. Grating pitch changes corresponding to the full range and resolution are 57 nm and 2.28 Aring, respectively confirmed by experimental measurement and theoretical calculation. Simulation shows that subradian tunable range is feasible with better lithographic design rules or higher actuation voltage. The single-mask fabrication process offers several advantages: 1) Excellent optical flatness; 2) ease of fabrication; and 3) great flexibility of device integration with existing on-chip circuitry. Tunable gratings such as the one presented here can be used for controlling dispersion in optical telecommunications, sensing, etc., applications