Title :
Theoretical and Experimental Investigation of an Intensity-Demodulated Fiber-Ring-Laser Ultrasonic Sensor System
Author :
Guigen Liu ; Sandfort, Elliot ; Lingling Hu ; Tongqing Liu ; Ming Han
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Nebraska-Lincoln, Lincoln, NE, USA
Abstract :
We theoretically and experimentally investigate the performance of an ultrasound detection system based on a fiber ring laser (FRL) whose cavity includes a pair of fiber Bragg gratings. The ultrasonic detection is achieved by the FRL power variations in response to the ultrasound-induced cold-cavity loss modulation of the FRL. The effects of key FRL parameters, including pump power, laser cold-cavity loss, and laser cavity length, on the system signal-to-noise ratio (SNR) performance have been investigated. It is found that the maximum SNR is achieved when the frequency of the ultrasound is the same as that of the FRL relaxation oscillation (RO). Harmonic generations are more prominent when the ultrasonic frequency is at the RO frequency and highly dependent on the strength of the ultrasonic signal. The analysis provides a useful tool for the understanding and optimization of such ultrasonic sensor systems.
Keywords :
Bragg gratings; acoustic intensity measurement; fibre lasers; fibre optic sensors; intensity modulation; optical fibre losses; optical loss measurement; optical modulation; relaxation oscillators; ring lasers; ultrasonic transducers; FRL; RO; SNR; fiber Bragg grating; harmonic generation; intensity-demodulated fiber-ring-laser ultrasonic sensor system; laser cavity length; laser cold-cavity loss; optimization; pump power; relaxation oscillation; signal-to-noise ratio; ultrasonic detection; ultrasound detection system; ultrasound-induced cold-cavity loss modulation; Acoustics; Cavity resonators; Optical fiber sensors; Sensor systems; Signal to noise ratio; Ultrasonic imaging; Fiber Bragg gratings; Fiber lasers; Fiber-optic sensors; fiber Bragg gratings; fiber lasers; nondestructive testing; nondestructive testings;
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2014.2378536