A Bragg grating is successfully inscribed in a piece of strongly coupled seven-core fiber (SCF). There are two separate Bragg resonance notches observed in the transmission spectrum, corresponding to backward coupling of HE-like and HE-like supermodes of the SCF. The mode coupling mechanism of the Bragg grating is theoretically investigated via modeling and analyzing modal properties of the SCF. The theoretical results agree well with the experimental results. Since the SCF is spliced between two standard single mode fibers with central alignments at both ends, the transmission spectrum of the device also contains a set of interference fringe due to modal interference between the supermodes. The device's responses to temperature and curvature are experimentally measured, respectively. The obtained temperature sensitivities and curvature sensitivities of the supermode Bragg grating notches are 9.55 pm/°C and 9.55 pm/°C, -1.8 pm/m and -112.3 pm/m, respectively. The obtained temperature sensitivity and curvature sensitivity of one of the interference spectrum dips are 11.8 pm/°C and -3909.8 pm/m, respectively. This device is potentially useful for simultaneous measurement of temperature and curvature.
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http://dx.doi.org/10.1364/OE.480929 | DOI Listing |
Sci Rep
January 2025
Institute of Electro-Optical Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan.
In this paper, we demonstrated a novel bidirectional high-speed transmission system integrating a free-space optical (FSO) communication with a 5G wireless link, utilizing a high-power erbium-doped fibre amplifier (EDFA) for enhanced loss compensation. The system supports downlink rates of 1-Gb/s/4.5-GHz and 10-Gb/s at 24-GHz and 39-GHz, and an uplink rate of 10-Gb/s/28-GHz.
View Article and Find Full Text PDFA wavelength demodulation method for ultra-short fiber Bragg grating (US-FBG) sensors based on an arrayed waveguide grating (AWG) and a convex optimization algorithm is proposed and demonstrated. Instead of measuring the output power ratio of the two adjacent AWG channels as previously done, in this work the wavelength demodulation is realized by reconstructing the US-FBG spectrum. The principle of spectral reconstruction involves using an AWG to sample the spectral information of US-FBG and constructing underdetermined matrix equations with the obtained prior information on transmission responses and the detected output power from multiple AWG channels.
View Article and Find Full Text PDFSensors (Basel)
November 2024
School of Information Engineering, Wuhan University of Technology, Wuhan 430070, China.
Monitoring of real-time flow and defects in the vacuum-assisted resin infusion (VARI) process can provide important guidelines for full impregnation of dry reinforcement. A weak fiber Bragg grating array was employed to obtain quasi-distributed monitoring results in real-time. Sensitivity testing of different kinds of coated optical fiber sensors (OFs) was carried out first, and the polyacrylate-coated OF showed a greater wavelength-shift response than the polyimide-coated one.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Photonics Research Group, Department of Electrical and Information Engineering, Politecnico di Bari, 70126 Bari, Italy.
This study explores the achievement of a tunable true time-delay (TTD) system for a microwave phased-array antenna (MPAA) by incorporating the reversible phase-transition property of phase-change material (PCM) with Bragg gratings (BGs) and a cascade of three phase-shifted Bragg grating resonators (CPSBGRs). The goal was to design a low-power-consuming, non-volatile highly tunable compact TTD system for beam steering. A programmable on/off reflector was designed by changing a PCM-incorporated BG/CPSBGR from one phase to another.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Optics and Photonics Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
A respiration rate (RR) monitoring system was created by integrating a Fibre Bragg Grating (FBG) optical fibre sensor into a respirator mask. The system exploits the sensitivity of an FBG to temperature to identify an individual's RR by measuring airflow temperature variation near the nostrils and mouth. To monitor the FBG response, a portable, battery-powered, wireless miniature interrogator system was developed to replace a relatively bulky benchtop interrogator used in previous studies.
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