Photonic Bandgap Fibre Based Gas Sensing: Current Status and Future Possibilities

A development of gas concentration sensing systems based on a photonic bandgap fiber (PBGF) is described. Several types of PBG fibers of various parameters and core diameters ranging from 10.9 to 26.25 microns have been designed and tested. The capillary gas flow rate within the fiber has been simulated and measured. A new method for cutting the fiber using focused ion beam in a vacuumed chamber for fine milling was tested to obtain the required angle of the fiber’s end, to avoid the destruction of the cladding structure and to create a novel low-loss splice for use between PBGF and the conventional solid-core fiber. The measurement results obtained using proposed systems for selected types of gases are presented. The experimental results clearly indicated a high overlap between the propagating light and filled gas inside the PBGF. Therefore, these studies can contribute to highly sensitive gas sensing, higher accuracy of wavelength references, and other applications.