In this work we experimentally validate and characterize the first phase-shifted polymer optical fiber Bragg gratings (PS-POFBGs) produced using a single pulse from a 248 nm krypton fluoride laser. A single-mode poly (methyl methacrylate) optical fiber with a core doped with benzyl dimethyl ketal for photosensitivity improvement was used. A uniform phase mask customized for 850 nm grating inscription was used to inscribe these Bragg structures. The phase shift defect was created directly during the grating inscription process by placing a narrow blocking aperture in the center of the UV beam. The produced high-quality Bragg grating structures, presenting a double dips, reject 16.3 dB (97.6% reflectivity) and 13.2 dB (95.2% reflectivity) of the transmitted power, being therefore appropriate for sensing or other photonic applications. Its transmission spectrum possesses two sharp transmission notches, allowing a significant increase in measurement resolution compared to direct interrogation of a single grating. The reflection and transmission spectra when multiple phase shifts are introduced in the FBG structure are also shown. The PS-POFBG's strain, temperature, pressure, and humidity characteristics have been experimentally analyzed in detail to assess their potential usage as sensors.
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Funding: Fundac¸ ˜ao para a Ciˆencia e Tecnologia (FCT)/MEC through national funds and when applicable co-funded by FEDER – PT2020 partnership agreement under Project UID/EEA/50008/2013, FCT through the fellowships SFRH/BPD/109458/2015 and SFRH/BPD/101372/2014
- Fiber Bragg gratings
- Fiber gratings
- Fiber lasers
- notch filter
- Optical fiber sensors
- Optical fibers
- optical filtering
- Polymer optical fiber sensors
- ultrasonic detection