A novel micro-scaled multi-layered optical stress sensor for force sensing

Abstract: Miniaturization and integration of sensors on chip has become essential with advancements of artificial intelligence and the Internet of Thing. The size of existing microbend optical stress sensors is too large for integration on a chip, necessitating fundamental change of structural design to achieve micron-sized lithography. In this regard, we demonstrate the design and analysis of a multi-layer microbend optical stress sensor using an advanced Multiphysics simulation model that could be potentially embedded on chips after the experimental tests of the basic microbend optical stress sensor units. The sensor architecture is optimized not just in size, but also the materials in the layers. A well-optimized structure of Glass/Ag/SU8/PDMS architecture delivers best comprehensive performance resulting in a sensitivity in one pitch of 110.42 µm which is 0.00935 N⁻¹ with a linearity of R² = 0.99868 at a detectable range of 1200 N–2800 N. This work paves way for embedding microbend optical stress sensors on chips to further accelerate sensors for communication and information technologies. Graphic abstract: [Figure not available: see fulltext.]