Diffraction Grating Fabricated on Chalcogenide Glass Fiber End Surfaces With Femtosecond Laser Direct Writing

Chalcogenide glass (ChG) optical fibers have excellent transmission performance in the mid-infrared range, and microstructured devices prepared on ChG fibers play an important role in the field of infrared sensing and optical integration. In this study, high-quality chalcogenide optical fibers were prepared, and grating structures were produced on their end surfaces. An easy-to-use FC cable was first prepared and polished to high flatness with the surface roughness of less than 0.08 mu m. 1- and 2-D diffraction gratings were then prepared on the end surfaces of the chalcogenide fibers via femtosecond laser line-by-line direct writing technology. The ChG fiber end surface gratings prepared with optimized femtosecond laser parameters exhibited high diffraction efficiency and clear diffraction pattern, indicating that they had excellent optical performance. The performance of the grating was tested by using a laser source with wavelengths covering the visible to the near-infrared regions. This measurement showed that the first-order diffraction efficiency of the grating on the end face could reach close to 50% at 1550 nm.