Sub-Minute Response Time of a Hollow-Core Photonic Bandgap Fiber Gas Sensor

A hollow-core photonic bandgap (PBG) fiber sensing configuration for optical absorption spectroscopy of multiple-component gas samples absent of a vacuum environment is presented. Pressure-driven sensor response times that are shorter in duration compared to diffusion-limited filling times for fiber lengths >1 m are reported. Reduced filling times that approach the sub-minute regime are possible for a ~2 meter length of commercially available PBG fiber with a 12.5 micron core diameter at a pressure <15 Psi. The spectroscopy measurements were limited to the near-IR region for sample gases that include acetylene and carbon dioxide. Using the techniques presented, the detection of concentrations <100 ppm for acetylene gas at pressures <15 Psi is possible.