Development of Mid-IR Fiber Bundle for Thermal Imaging

We present and discuss the fabrication and characterization of a Mid-Infrared (Mid-IR) transparent flexible bundle based on 1200 fibers whose cores consist of a Ge30As13Se32Te25 chalcogenide glass and the cladding of a Fluorinated Ethylene Propylene (FEP). The Mid-IR fiber bundle was manufactured using the stack and draw method. The high index contrast between the glass and the cladding allows for strong field confinement of the well guided modes within the chalcogenide glass core transparent across the Mid-IR. Higher order modes, which could be prone to cross talk, suffered high losses thanks to the high attenuation offered by the polymer cladding. Additionally, the FEP cladding confers the bundle mechanical flexibility. Following a qualitative thermal imaging assessment, we also present and discuss the experimental loss measurements of the fiber bundle and we compare them to values obtained through modelling to conclude on the potential prospect of the manufactured bundle and its possible improvements.