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Fiber-Optic Pressure Sensor Based On Π-Phase-Shifted Fiber Bragg Grating On Side-Hole Fiber, Qi Zhang, Nan Liu, Thomas Fink, Hong Li, Wei Peng, Ming Han
Fiber-Optic Pressure Sensor Based On Π-Phase-Shifted Fiber Bragg Grating On Side-Hole Fiber, Qi Zhang, Nan Liu, Thomas Fink, Hong Li, Wei Peng, Ming Han
Department of Electrical and Computer Engineering: Faculty Publications
We present a fiber-optic pressure sensor based on a π-phase-shifted fiber Bragg grating (πFBG) fabricated on a side hole fiber. Due to the resonance effect of a πFBG, its reflection spectrum features two notches that are dramatically narrower than the line width of a regular FBG of similar length. The narrow spectral notches allow high-resolution measurement of their spectral separation, significantly improving the pressure detection limit (defined herein as the minimum detectable pressure change) compared to sensors based on a regular FBG of a similar length and on the same fiber. The πFBG demonstrated in this letter is 8.3 mm …
Analysis Of Π-Phase-Shifted Fiber Bragg Gratings For Ultrasonic Detection, Tongqing Liu, Ming Han
Analysis Of Π-Phase-Shifted Fiber Bragg Gratings For Ultrasonic Detection, Tongqing Liu, Ming Han
Department of Electrical and Computer Engineering: Faculty Publications
Using numerical simulations, we investigated the responses of the π-phase-shifted fiber Bragg gratings (πFBGs) impinged by pressure ultrasonic waves. The effect of the grating length, grating refractive index modification depth, and ultrasonic frequency on the wavelength sensitivity and intensity sensitivity of the πFBG ultrasonic sensor for ultrasonic waves of different wavelengths was analyzed. The directivity of a πFBG sensor was also studied. Our analysis revealed several unique πFBG response characteristics and will be useful in the design and optimization of fiber-optic ultrasonic sensors that use a πFBG as the sensing element.