Electrothermal Actuators for SiO₂ Photonic MEMS.

Tjitte-Jelte Peters,Marcel Tichem

doi:10.3390/mi7110200

Abstract

This paper describes the design, fabrication and characterization of electrothermal bimorph actuators consisting of polysilicon on top of thick (>10 ) silicon dioxide beams. This material platform enables the integration of actuators with photonic waveguides, producing mechanically-flexible photonic waveguide structures that are positionable. These structures are explored as part of a novel concept for highly automated, sub-micrometer precision chip-to-chip alignment. In order to prevent residual stress-induced fracturing that is associated with the release of thick oxide structures from a silicon substrate, a special reinforcement method is applied to create suspended silicon dioxide beam structures. The characterization includes measurements of the post-release deformation (i.e., without actuation), as well as the deflection resulting from quasi-static and dynamic actuation. The post-release deformation reveals a curvature, resulting in the free ends of 800 long silicon dioxide beams with 5 -thick polysilicon to be situated approximately 80 above the chip surface. Bimorph actuators that are 800 in length produce an out-of-plane deflection of approximately 11 at 60 dissipated power, corresponding to an estimated 240 actuator temperature. The delivered actuation force of the 800 -long bimorph actuators having 5 -thick polysilicon is calculated to be approximately 750 at 120 .

Highlights

Combining suspended photonic waveguides and microactuators enables positionable waveguides, resulting in the photonic switch [1,2,3] and numerous other Micro-Opto-Electro-Mechanical Systems (MOEMS) applications [4,5,6]
The strength of the alignment approach lies in a positionable waveguide array that is locally realized in one of the photonic integrated circuits (PICs) and which is equipped with on-chip MEMS actuators to achieve sub-micrometer precise alignment with the waveguides of the other PIC
The fabricated positionable waveguide arrays have a curved crossbar, which introduces a vertical misalignment in case more than two waveguides need to be aligned with two other waveguides

Summary

Introduction

Combining suspended photonic waveguides and microactuators enables positionable waveguides, resulting in the photonic switch [1,2,3] and numerous other Micro-Opto-Electro-Mechanical Systems (MOEMS) applications [4,5,6]. We have explored the use of suspended SiO2 waveguides with integrated actuators as part of a novel chip-to-chip alignment concept for photonic integrated circuits (PICs). We emphasize that this is only one of many possible applications using positionable waveguides, and in this paper, we focus on the characteristics of the bimorph actuators in general

Objectives

Methods

Results

Conclusion