LAUSR

A hollow-core photonic bandgap fiber for gas sensing with high sensitivity was designed. Some undesirable parameters like mode interference and propagation losses can deteriorate the performance of PBF. By selecting an accurate and reasonable size of the fiber core, consequently modification the shape and size of the first row of holes surrounding the hollow-core, we could improve light intensity profile in the fiber core. According to the simulation results, at a reasonable core radius the relative sensitivity of gas sensor was improved to 96.57%. In addition, by mode interference suppression, we could minimize the effect of mode mismatch. Furthermore, by optimization of fiber structural parameters like lattice constant and air holes diameter, the PBF was single-mode. Considering the operation wavelength λ = 1.55 µm which is approximately equal to the acetylene gas absorption line, this fiber is suitable to be a high sensitivity gas sensor to detect absorbing gases.