High-sensitivity ultrasonic phase-shifted fiber Bragg grating balanced sensing system

Abstract:We theoretically and experimentally demonstrate a fiber-optic ultrasonic sensor system based on a fiber-ring laser whose cavity consisting of a regular fiber Bragg grating (FBG) and a tunable optical band-pass filter (TOBPF). The FBG is the sensing element and the TOBPF is used to set the lasing wavelength at a point on the spectral slope of the FBG. The ultrasonic signal is detected by the variations of the laser output intensity in response to the cold-cavity loss modulations from the ultrasonicallyinduced FBG spectral shift. The system demonstrated here has a simple structure and low cost, making it attractive for acoustic emission detection in structure health monitoring.

Section: Introductionmentioning

confidence: 99%

Intensity-demodulated fiber-ring laser sensor system for acoustic emission detection

Han¹,

Liu²,

Hu³

et al. 2013

“…While the majority of light near the Bragg wavelength is reflected, a narrow band (known as a defect mode) gives rise to a reflection dip or transmission peak [3,6]. Bragg filters with tunable defect modes attract much attention due to their potential abilities for laser cavities [7,8], sensing, communications, and spectroscopy applications [9][10][11][12]. By changing the property of a defect layer, such as its refractive index or thickness, the reflection dip (transmission peak) can be tuned accordingly.…”

Section: Introductionmentioning

confidence: 99%

Tunable Bragg filters with a phase transition material defect layer

Wang¹,

Gong²,

Dong³

et al. 2016

Abstract:We propose an all-solid-state tunable Bragg filter with a phase transition material as the defect layer. Bragg filters based on a vanadium dioxide defect layer sandwiched between silicon dioxide/titanium dioxide Bragg gratings are experimentally demonstrated. Temperature dependent reflection spectroscopy shows the dynamic tunability and hysteresis properties of the Bragg filter. Temperature dependent Raman spectroscopy reveals the connection between the tunability and the phase transition of the vanadium dioxide defect layer. This work paves a new avenue in tunable Bragg filter designs and promises more applications by combining phase transition materials and optical cavities. References and links1. E. Yablonovitch, "Inhibited spontaneous emission in solid-state physics and electronics," Phys. Rev. Lett. 2059-2062 (1987). 2. E. Yablonovitch, "Photonic band-gap structures," J. Opt. Soc. Am. B 10(2), 283-295 (1993) 1039-1263 (1998). 27. J. Wu, Q. Gu, B. S. Guiton, N. P. de Leon, L. Ouyang, and H. Park, "Strain-induced self organization of metal−insulator domains in single-crystalline VO2 nanobeams," Nano Lett. 6(10), 2313-2317 (2006). 28. A. Perucchi, L. Baldassarre, P. Postorino, and S. Lupi, "Optical properties across the insulator to metal transitions in vanadium oxide compounds," J. 58(20),

“…Fiber-optic ultrasonic sensors based on regular fiber Bragg gratings (FBGs) or π-phaseshifted FBGs have received a great deal of attention in the past decades for their potential applications in structural health monitoring such as ultrasonic testing and acoustic emission (AE) detection [1][2][3][4][5][6][7]. A common demodulation method for these sensors is to use a tunable laser whose wavelength is set within a linear range of the grating spectrum.…”

Section: Introductionmentioning

confidence: 99%

Multiplexed fiber-ring laser sensors for ultrasonic detection

Liu¹,

Hu²,

Han³

2013

Abstract:We propose and demonstrate a multiplexing method for ultrasonic sensors based on fiber Bragg gratings (FBGs) that are included inside the laser cavity of a fiber-ring laser. The multiplexing is achieved using add-drop filters to route the light signals, according to their wavelengths, into different optical paths, each of which contains a separate span of erbium-doped fiber (EDF) as the gain medium. Because a specific span of EDF only addresses a single wavelength channel, mode completion is avoided and the FBG ultrasonic sensors can be simultaneously demodulated. The proposed method is experimentally demonstrated using a two-channel system with two sensing FBGs in a single span of fiber. fiber multiwavelength erbium-doped fiber laser functionalized with evanescent field interaction," Laser Phys. ©2013 Optical Society of America