Publication

Abstract : As a part of this investigation, we aim to develop a 1 × 2 multimode interferometer (MMI) beam splitter based on chalcogenide waveguides for dual RI profile simultaneous detection applications. The operating principle involves multiplexing transverse magnetic (TM) polarized light into two distinct channels, enabling the simultaneous detection of two RI profiles, which are considered as methane (CH₄) and nitrous oxide (N₂O) in this work. This approach is cost-effective, as the design integrates broadband near-infrared on-chip light emission with dispersive spectroscopic components, making it suitable for dual RI profile simultaneous detection. In this work, we focus on optimizing the width and length of the multimode interference region in the 1 × 2 MI, intending to enhance the imbalance between output ports and improve the contrast ratio. Additionally, the curvature of the S-bend waveguide is optimized to maximize output power while minimizing insertion loss. The spectral transmission characteristics of the MMI diplexer are analyzed with respect to variations in the refractive index (RI) of the sensing layer.