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Defects in optical fibers can cause severe damage, and thus must be found and repaired/replaced early. Such defects in fibers and their coatings can be detected using an angle-resolved interrogator that exploits the contribution of different ray groups. This approach can also estimate the radial position of defects within the fiber. A demonstration is performed with a femtosecond-laser-induced internal...
Rotational Seismology caused highly interest in investigation of rotational movements generated by earthquake, mines and existing in engineering structures. The most oppressive aspect of research in this field is technical requirements for sensors. However, the instruments basing on the Sagnac effect seem to be the most appropriate to investigate rotational effects due to the fact that they are entirely...
The proposed technique consists in an optical fiber resonator interrogated for sensor characterization, implementing an alternative technique for dynamic range improvement. Such technique relies on the analysis of an added-signal caused by signal saturation, which occurs due to the broadening of the laser pulse. A wide study for different pulse widths is presented in this work, namely for 100 ns,...
We demonstrate three microfluidic chip based microfiber/nanofiber sensors for ultra-sensitive absorption, fluorescence, and femtoliter-scale sensing, respectively. The sensors shown here may open up new opportunities for ultra-sensitive biosensing and single molecule analysis.
A novel Mach-Zehnder interferometer (MZl) based on a pair of long period fiber gratings (LPGs) in an embedded-core hollow optical fiber (ECOF) are proposed and demonstrated experimentally. Two similar LPGs with peak attenuation of approximately 3dB are fabricated in an ECOF by using high-frequency CO2 laser to form an in-fiber MZI. The dependences of the resonant peak on the temperature and the axial...
A variety of optical methods to enhance the process of making optical fibre tapers are explored. A thermal camera was used to both refine the alignment of the optical components and optimize the laser power profile during the tapering process. The fibre transmission was measured to verify that the tapers had the requisite optical characteristics while the strain experienced by the fibre while tapering...
This paper reports on the development, and evaluation, of fiber optic hydrogen sensors based on fiber Bragg gratings (FBG) and an experimental measurement system for long term experiments of fiber optic gas sensors. Two types of palladium metal sensors were manufactured; sputter coated and modified palladium foil with 20 and 100 μm thickness. The responses (at 90 °C with both 1 and 5 % hydrogen) of...
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