Open AccessMultiplexing fiber-optic ultrasound sensors using laser intensity modulation
Author(s) -
Guigen Liu,
Ming Han
Publication year - 2019
Publication title -
optics letters/optics index
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.44.000751
Subject(s) - optics , demodulation , fiber bragg grating , multiplexing , materials science , intensity modulation , laser , envelope detector , signal (programming language) , modulation (music) , fiber optic sensor , optical filter , optical fiber , optoelectronics , phase modulation , physics , acoustics , computer science , telecommunications , channel (broadcasting) , amplifier , cmos , phase noise , programming language
We propose and demonstrate the use of laser intensity modulation for the multiplexing and demultiplexing of fiber Bragg grating-based ultrasound sensors. The method utilizes an intensity modulator to modulate the output power of the laser with a frequency much higher than that of the ultrasounds. The high-frequency-modulated optical signal serves as a carrier signal. Ultrasonic signals impinged onto the sensor appear as the envelope of the carrier signal. In the frequency domain, the carrier signal and the sidebands encoded with the ultrasonic signal are separated from those of other channels and, thus, can be isolated using an electronic bandpass filter for crosstalk-free ultrasound detection. Each laser can be tuned to demodulate any sensor covered by the wavelength range of the laser, and a common photodetector is used for all channels. Both a theoretical analysis and experimental verification are provided to demonstrate the concept.