TY - GEN
T1 - Reflective SOA-based fiber Bragg grating ultrasonic sensing system with two wave mixing interferometric demodulation
AU - Wei, Heming
AU - Krishnaswamy, Sridhar
N1 - Publisher Copyright:
© 2017 SPIE.
PY - 2017
Y1 - 2017
N2 - Damages such as cracking or impact loading in civil, aerospace, and mechanical structures generate transient ultrasonic waves, which can be used to reveal the structural health condition. Hence, it is necessary to find a practical tool based on ultrasonic detection for structural health monitoring. In this work, we describe an intelligent fiber-optic ultrasonic sensing system, which is designed based on a fiber Bragg grating (FBG) and a reflective semiconductor optical amplifier (RSOA) used as an adaptive source, and demodulated by an adaptive photorefractive two wave mixing (TWM) technique without any active compensation of quasi-static strains and temperature. As the wavelength of the FBG shifts due to the excited ultrasonic waves, the wavelength of the optical output from the fiber cavity laser shifts accordingly. With regard to the shift of the FBG reflective spectrum, the adaptivity of the RSOA-based laser is analyzed theoretically and verified by the TWM demodulator. Additionally, due to the response time of the photorefractive crystal, the TWM demodulator is insensitive to low frequency-FBG spectral shift. The results demonstrate that this proposed FBG ultrasonic sensing system has high sensitivity and can respond the ultrasonic waves into the megahertz frequency range, which shows a potential for acoustic emission detection in practical applications.
AB - Damages such as cracking or impact loading in civil, aerospace, and mechanical structures generate transient ultrasonic waves, which can be used to reveal the structural health condition. Hence, it is necessary to find a practical tool based on ultrasonic detection for structural health monitoring. In this work, we describe an intelligent fiber-optic ultrasonic sensing system, which is designed based on a fiber Bragg grating (FBG) and a reflective semiconductor optical amplifier (RSOA) used as an adaptive source, and demodulated by an adaptive photorefractive two wave mixing (TWM) technique without any active compensation of quasi-static strains and temperature. As the wavelength of the FBG shifts due to the excited ultrasonic waves, the wavelength of the optical output from the fiber cavity laser shifts accordingly. With regard to the shift of the FBG reflective spectrum, the adaptivity of the RSOA-based laser is analyzed theoretically and verified by the TWM demodulator. Additionally, due to the response time of the photorefractive crystal, the TWM demodulator is insensitive to low frequency-FBG spectral shift. The results demonstrate that this proposed FBG ultrasonic sensing system has high sensitivity and can respond the ultrasonic waves into the megahertz frequency range, which shows a potential for acoustic emission detection in practical applications.
KW - Fiber Bragg grating
KW - Optical fiber sensor
KW - Reflective SOA
KW - Two wave mixing demodulation
KW - Ultrasound
UR - http://www.scopus.com/inward/record.url?scp=85020504162&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85020504162&partnerID=8YFLogxK
U2 - 10.1117/12.2256362
DO - 10.1117/12.2256362
M3 - Conference contribution
AN - SCOPUS:85020504162
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Health Monitoring of Structural and Biological Systems 2017
A2 - Kundu, Tribikram
PB - SPIE
T2 - Health Monitoring of Structural and Biological Systems 2017
Y2 - 26 March 2017 through 29 March 2017
ER -