  Nanoelectromechanical systems offer unique functionalities in photonics: The
ability to elastically and reversibly deform dielectric beams with
subwavelength dimensions enable electrical control of the propagation of light
with a power consumption orders of magnitude below that of competing
technologies, such as thermo-optic tuning. We present a study of the design,
fabrication, and characterization of compact electrostatic comb-drive actuators
tailored for integrated nanoelectromechanical silicon photonic circuits. Our
design has a footprint of $1.2 \times 10^{3} \mu$m$^{2}$ and is found to reach
displacements beyond 50 nm at 5 V with a mechanical resonance above 200 kHz,
or, using different spring constants and skeletonization, a mechanical
resonance above 2.5 MHz with displacements beyond 50 nm at 28 V. This is
sufficient to induce very large phase shifts and other optical effects in
nanoelectromechanical reconfigurable photonic circuits.
