Design of a novel hybrid multimode interferometer operating with both TE and TM polarizations for sensing applications

Yuri H Isayama; Hugo E Hernández-Figueroa

doi:10.1007/s11082-023-04751-7

Design of a novel hybrid multimode interferometer operating with both TE and TM polarizations for sensing applications

Opt Quantum Electron. 2023;55(5):454. doi: 10.1007/s11082-023-04751-7. Epub 2023 Mar 31.

Authors

Yuri H Isayama¹, Hugo E Hernández-Figueroa²

Affiliations

¹ Center for Semiconductor Components and Nanotechnology, University of Campinas, Campinas, Sao Paulo, 13083-870 Brazil.
² School of Electrical and Computer Engineering, Univeristy of Campinas, Campinas, Sao Paulo, 13083-852 Brazil.

Abstract

A novel hybrid multimode interferometer for sensing applications operating with both TE and TM polarizations simultaneously is proposed and numerically demonstrated. The simulations were performed assuming an operating wavelength of 633 nm with the goal of future use as a biosensor, but its applications extend beyond that area and could be adapted for any wavelength or application of interest. By designing the mutimode waveguide core with a low aspect ratio, the confinement characteristics of TE modes and TM modes become very distinct and their interaction with the sample in the sensing area becomes very different as well, resulting in high device sensitivity. In addition, an excitation structure is presented, that allows good control over power distribution between the desired modes while also restricting the power coupled to other undesired modes. This new hybrid TE/TM approach produced a bulk sensitivity per sensor length of 1.798 rad $\cdot {RIU}^{- 1} \cdot μ m^{- 1}$ and a bulk sensitivity per sensor area of 2.140 rad $\cdot {RIU}^{- 1} \cdot μ m^{- 2}$ , which represents a much smaller footprint when compared to other MMI sensors, contributing to a higher level of integration, while also opening possibilities for a new range of MMI devices.

Keywords: Interferometry; Multimode interferometer; Optical sensors; Optical waveguides.

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