Tunable coupling regimes of silicon microdisk resonators using MEMS actuators

Abstract

Tunable coupling regimes of a silicon microdisk resonator controlled by MEMS (microelectromechanical system) actuation are demonstrated for the first time. By varying the gap spacing between the waveguide and the disk, this microresonator can dynamically operate in either under-, ciritcal or over-coupling regime. The waveguide transmittance is suppressed by 30 dB in critical coupling, and the quality factor of the microdisk is measured to be as high as 10(5). Additionally, the microdisk presents tunable group delay from 27 ps to 65 ps, and tunable group velocity dispersion from 185 ps/nm to 1200 ps/nm. Waveguides, microdisks and actuators are all integrated on a silicon-on-insulator (SOI) substrate. This compact device exhibits the promise to construct resonator-based reconfigurable photonic integrated circuits.

Optical MEMS for Lightwave Communication

“…Lee and Wu reported a silicon tunable microdisk resonator with tunable optical coupling using MEMS actuators [168]. The SEM of the device is shown in Fig.…”

“…The group delay and group velocity dispersion can be tuned by varying the gap spacing. A delay time tunable from 27 to 65 ps and dispersion from 185 to 1200 ps/nm have been experimentally demonstrated [168]. By actuating both input and output waveguides, a reconfigurable optical add/drop multiplexer (ROADM) [176] has also been realized.…”

Design of dual-core optical fibers with NEMS functionality

“…Comb actuators are usually used for moving sub-micron sized guiding beams and waveguides on chips [14]. However, other methods have been recently introduced, including electrostatic actuation by means of a voltage applied directly to the waveguides [13] or by placing them in a non-uniform electric field created by nearby electrodes [15]. We demonstrate that the latter method gives a direct way to control light propagation in the dual-core fiber, leading to NEMS-type functionality in the system.…”

Oscillatory Vertical Coupling between a Whispering-Gallery Resonator and a Bus Waveguide

“…While several experimental realizations of vertically coupled resonator/waveguide systems have been reported [8][9][10][11], no specific study of the influence of the vertical gap on the coupling efficiency has been performed yet. The issue of the vertical RWC has been discussed in Ref.…”