Optical MEMS applied in photonics

Reconfigurable or tunable photonics are essential for photonics applications. Electro-optics, thermo-optics, magneto-optics and free carrier dispersion effect are common approaches for implement tunable photonic devices. However, all those tuning mechanisms are relatively weak or require large power consumption. In our lab, we focus on developing microelectromechanical-system (MEMS) tunable photonics. Through physically "moving" or "actuating" photonic components through electrostatic force, we can achieve a large tuning effect with very small power consumption in a small device footprint. 

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 100000. 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.

MEMS-Actuated Phase Modulators

An optical phase modulator is presented by using micro-electro-mechanical systems to actuate deformable silicon waveguides. Via mechanically stretching the waveguide length, the optical path is extended, resulting in a phase shift. The power consumption is estimated to be smaller than 0.2 mW, mainly resulting from the leakage current.

MEMS-Actuated Movable Optical Probes to Pre-calibrate Phase Errors in a Programmable Photonic Integrated Circuits

We propose a novel approach utilizing microelectromechanical-system (MEMS) optical probes to dynamically monitor the waveguide power of Mach-Zehnder interferometers for phase error calibration in programmable photonic integrated circuits (PICs). 

Reference: Thuy Trinh, The Anh Nguyen, Ming-Chang M. Lee, “On-chip Monitoring Phase Conditions of Tunable Mach-Zehnder Interferometers via Integrated Microelectromechanical-System Optical Probes”, IEEE Access, Vol. 12, pp. 161798 - 161804, 16 Oct. 2024.