In-Line Gas Sensor Based on a Photonic Bandgap Fiber With Laser-Drilled Lateral Microchannels

The fabrication, characterization, and gas sensor application of a hollow core photonic bandgap fiber (HC-PBGF) with laser drilled lateral microchannels will be described. The HC-PBGF was tailor-made for gas sensing applications in the near infrared region from 1.5 to 1.7 μm wavelengths, covering the first harmonic absorptions of quite a number of natural gas components. Laser-drilled, lateral microchannels makes access to the light guiding core of the HC-PBGF and offers the ability to realize fast-responding, distributed gas sensor cells with large optical path lengths. The application of those cells in a distributed sensor arrangement using white light spectroscopy combined with chemometrical methods as interrogation method will be demonstrated.