On-Chip Positionable Waveguides for Submicrometric Photonic Alignment

Abstract

In this paper, we present positionable photonic waveguide arrays that are developed for optical chip-to-chip alignment. Partly suspended photonic structures, based on the Si3N4/SiO2 material platform, are equipped with thermal actuators enabling the free end of the structures to be positioned with submicrometer accuracy. A finite-element model is developed to provide insight in the way the design of the system affects the performance. The modeling results show that the expected vertical deflection and rotation are highly dependent on the array design. Measurements of fabricated devices confirm the trends that follow from the model and are used to assess the positioning performance. Moreover, the finite-element analysis gives guidelines for the design parameters of an optimal positionable photonic waveguide array. By following these guidelines, all the requirements for the intended photonic alignment can be fulfilled, which is validated by measurements. The stability over time of the positioning system is experimentally determined and is also sufficient. Measured mode field profiles of partly suspended waveguide beams with 1 $\mu \text{m} \,\, \times 220$ nm (width $\times $ thickness) sized waveguide cores show correct waveguiding functionality. Finally, an alignment experiment demonstrates how three adjacent waveguide beams within a positionable waveguide array can be actively aligned with the channels of another photonic chip. [2017-0046]