Laser frequency noise cancelation in a phase-shifted fiber Bragg grating ultrasonic sensor system using a reference grating channel

Lingling Hu, Guigen Liu, Yupeng Zhu, Xiangyu Luo, Ming Han

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

In an ultrasonic sensor system based on π phase-shifted fiber Bragg gratings (πFBGs), a cost-effective way for sensor demodulation is to set the laser wavelength at the center of the steep spectral slope of the πFBG refection spectrum. Frequency noise of the laser source ultimately limits the signal-to-noise ratio (SNR) of the sensor system. Here, we demonstrate a noise cancelation method based on a pair of πFBGs, which is capable of improving the SNR of system beyond the limitation set by the laser frequency noise. In this method, one of the gratings is used as the sensor to detect the acoustic signal, and the other grating, isolated from the signal, is used as a reference that gives the noise information. Employing a data postprocessing method, the noise is subtracted from the original detected signal. We show that the SNR of the sensor system can be improved by up to 20 dB using this method.

Original languageEnglish (US)
Article number7400917
JournalIEEE Photonics Journal
Volume8
Issue number1
DOIs
StatePublished - Feb 2016

Keywords

  • Diode lasers
  • Fiber gratings
  • Sensors

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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