Measuring system based on Photonic Bandgap Fiber (PBGF), which will be able to detect, distinguish and measure the
concentration of various aliphatic hydrocarbons is proposed. Such a system can be applied on each stage of fuel
evaluation, production, distribution and storage of petroleum products. Aliphatic hydrocarbons absorption spectra show
several peaks around 1400-1600 nm wavelength. Thus, tunable lasers with 20 micron core photonic bandgap fiber
matching above wavelengths were chosen for the optical measurement system. Measurements were performed at a low
pressure to eliminate pressure broadening effect and to sharpen the absorption peaks. The sensitivity of measurement
increases with increasing of the fiber's length. Length of fiber was adjusted using several methods. The best results were
obtained using argon ion beam cutting. The angled cut was performed to improve signal to noise ratio.
The Photonic Pandgap fiber was proposed as a new alternative for traditional glass-made gas cell used in spectroscopic
measurements. Several PBG fibers were specially designed and produced for performed experiments. Gas flow within
fiber was simulated and measured and ppm concentrations of ammonia gas were detected with short lengths of fiber.
Final goal of the project is to produce portable and compact device for fast, ppb range measurement. Additionally,
several fiber cutting methods were tested.
New generation of light fibers: Photonic Bandgap fibers (PBG fiber) were applied as gas cells in the concentration
measurement sensor. Several types of PBG fibers of various parameters were designed. Core diameters ranged from 10.9
to 26.25 μm. The precise cutting method for the PBG fiber was proposed. Capillary gas flow rate within the fiber was
simulated and measured. Attenuation of newly produced fibers was investigated and concentration of ammonia gas was
measured using the new type sensing system.