Fabrication of negative curvature hollow core optical fibers capable of acoustic sensing

Negative curvature hollow-core optical fibers (NCHCFs) are one of the great inventions of modern times, as they are capable of transmitting light over a broad range of wavelengths, from UV to mid-infrared, with losses that can be lower compared to those of standard solid silica fibers. By exploiting an anti-resonance mechanism, low attenuation is achieved within the transmission windows located in the vicinity of wavelengths determined by a capillary thickness. Lately, novel applications have emerged, as these fibers show significant potential to function as distributed acoustic sensors, since their sensitivity to acoustic waves may surpass that of conventional fibers. However, the fabrication of NCHCFs often proves to be complicated due to the difficulty of controlling a fiber’s capillary diameter, fiber core diameter, and capillary wall thickness. In this contribution, we report on the fabrication process of in-house drawn NCHCFs with different structures, the splicing process of NCHCF with conventional solid fibers, and the capability of our NCHCFs to serve as acoustic sensors.