Devices Based on Co-Integrated MEMS Actuators and Optical Waveguide: A Review

Abstract

The convergence of Micro Electro Mechanical Systems (MEMS) and optics was, at the end of the last century, a fertile ground for a new breed of technological and scientific achievements. The weightlessness of light has been identified very early as a key advantage for micro-actuator application, giving rise to optical free-space MEMS devices. In parallel to these developments, the past 20 years saw the emergence of a less pursued approach relying on guided optical wave, where, pushed by the similarities in fabrication process, researchers explored the possibilities offered by merging integrated optics and MEMS technology. The interest of using guided waves is well known (absence of diffraction, tight light confinement, small size, compatibility with fiber optics) but it was less clear how they could be harnessed with MEMS technology. Actually, it is possible to use MEMS actuators for modifying waveguide properties (length, direction, index of refraction) or for coupling light between waveguide, enabling many new devices for optical telecommunication, astronomy or sensing. With the recent expansion to nanophotonics and optomechanics, it seems that this field still holds a lot of promises.

MEMS for Photonic Integrated Circuits

“…Previous reviews on photonic MEMS have focused on nonintegrated, free-space optical MEMS [19], [20], or on individual devices [21]- [23], MEMS based optical cross connects [24], and optomechanics [25].…”

Tuning of 2D rod-type photonic crystal cavity for optical modulation and impact sensing

“…By changing the field, the effective refractive index of the structure changes and that results in resonant shift of the system or phase shift of the incoming light. Some types use parallel high dielectric waveguides and plate structures [47][48][49][50][51][52][53][54][55][56] and incorporates NEMS actuators to change the coupling between the waveguide, whereas other types use ring resonators and deforms the structure out of plane and in plane [57][58][59][60][61][62] by capacitive actuators. In this work, mechanical perturbation of photonic crystal cavities for on-chip applications is demonstrated.…”

Suspended polarization beam splitter on silicon-on-insulator

“…Recently, devices based on suspended photonic waveguides have attracted significant attention, due to two fundamental aspects. First, suspended waveguides enable coupling between mechanical motion and optical fields, which leads to devices based on optically-induced motion, so-called optomechanics [9], and motion-induced optical tuning, generally called photonic microelectromechanical systems (MEMS) [10]. Second, the suspended solid core can be made very thin, and thus a large fraction of the optical power can propagate outside of the core and be used for sensing of gases or liquids, since suspended waveguides have a perfectly symmetric index difference between the core and the top and bottom claddings [11,12].…”