While 3-D microelectromechanical systems (MEMS) allow switching between a large number of ports in optical telecommunication networks, the development of such systems often suffers from design, fabrication and packaging constraints due to the complex structures, the wafer bonding processes involved, and the tight alignment tolerances between different components. In this work, we present a 2-D translational MEMS platform capable of highly efficient planar optical switching through integration with silicon nitride (SiN) based optical waveguides. The discrete lateral displacement provided by simple parallel plate actuators on opposite sides of the central platform enables switching between different input and output waveguides. The proposed structure can displace the central platform by 3.37 µm in two directions at an actuation voltage of 65 V. Additionally, the parallel plate actuator designed for closing completely the 4.26 µm air gap between the fixed and moving waveguides operates at just 50 V. Eigenmode expansion analysis shows over 99% butt-coupling efficiency the between the SiN waveguides when the gap is closed. Also, 2.5 finite-difference time-domain analysis demonstrates zero cross talk between two parallel SiN waveguides across the length of the platform for a 3.5 µm separation between adjacent waveguides enabling multiple waveguide configuration onto the platform. Different MEMS designs were simulated using static structural analysis in ANSYS. These designs were fabricated with a custom process by AEPONYX Inc. (Montreal, QC, Canada) and through the PiezoMUMPs process of MEMSCAP (Durham, NC, USA).

This work demonstrates a hybrid MEMS actuator platform that combines electrostatic and piezoelectric actuators to displace a suspended MEMS platform along 3 degrees-of-freedom (DOF). The prototype MEMS actuator tested produces maximum displacements of 8.8 $\upmu$ m along the positive X-axis, and 8.5 $\upmu$ m along the negative X-axis, with digital control. Analog control produces maximum displacements of 5.9 $\upmu$ m along the positive X-axis, and 5.8 $\upmu$ m along the negative X-axis. It can also provide 2.2 $\upmu$ m of in-plane displacement along the negative Y-axis with analog control. The electrostatic actuator used for displacement along the negative Y-axis also compensates for any out-of-plane misalignment between the suspended MEMS platform and fixed silicon due to the significant residual stress caused by deposited piezoelectric material layers. In addition, up to 550 nm of misalignment compensation using the electrostatic actuator before electrostatic pull-in is demonstrated. The piezoelectric actuator provides fine alignment capability with a maximum out-of-plane displacement of 200 nm and 100 nm with analog control along the positive and negative Z-axis, respectively. This hybrid MEMS actuator can be integrated with channel waveguides for efficient planar optical switching applications. 2023-0121

We demonstrate a microelectromechanical system (MEMS) based 1 x 5 optical switch with integrated silicon nitride channel waveguides. Our MEMS actuator allows analog control for fine alignment in three switching positions. The other two switching positions rely upon electrostatic pull-in phenomena for digital switching. The samples tested demonstrate the broadband capability of the optical switch over the wavelength range of 1540 nm to 1625 nm. A minimum average insertion loss of 2.2 dB and a maximum average insertion loss of 7.1 dB was recorded for these devices in different switching positions. A custom microfabrication process developed by AEPONYX Inc was used to fabricate the devices.

We report the first 1 x 3 silicon nitride optical switch using silicon electrostatic MEMS actuator with a 4.97 dB average insertion loss over the 1530 nm to 1580 nm wavelength range.