Optical microphone with fiber Bragg grating and signal processing techniques

Daniele Tosi, Massimo Olivero, Guido Perrone

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

In this paper, we discuss the realization of an optical microphone array using fiber Bragg gratings as sensing elements. The wavelength shift induced by acoustic waves perturbing the sensing Bragg grating is transduced into an intensity modulation. The interrogation unit is based on a fixed-wavelength laser source and - as receiver - a photodetector with proper amplification; the system has been implemented using devices for standard optical communications, achieving a low-cost interrogator. One of the advantages of the proposed approach is that no voltage-to-strain calibration is required for tracking dynamic shifts. The optical sensor is complemented by signal processing tools, including a data-dependent frequency estimator and adaptive filters, in order to improve the frequency-domain analysis and mitigate the effects of disturbances. Feasibility and performances of the optical system have been tested measuring the output of a loudspeaker. With this configuration, the sensor is capable of correctly detecting sounds up to 3 kHz, with a frequency response that exhibits a top sensitivity within the range 200-500 Hz; single-frequency input sounds inducing an axial strain higher than ∼10nε are correctly detected. The repeatability range is ∼0.1%. The sensor has also been applied for the detection of pulsed stimuli generated from a metronome.

Original languageEnglish
Title of host publicationEighth International Conference on Vibration Measurements by Laser Techniques
Subtitle of host publicationAdvances and Applications
DOIs
Publication statusPublished - Sep 1 2008
Externally publishedYes
Event8th International Conference on Vibration Measurements by Laser Techniques: Advances and Applications - Ancona, Italy
Duration: Jun 18 2008Jun 20 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7098
ISSN (Print)0277-786X

Other

Other8th International Conference on Vibration Measurements by Laser Techniques: Advances and Applications
CountryItaly
CityAncona
Period6/18/086/20/08

Keywords

  • Adaptive signal processing
  • Fiber Bragg gratings
  • Fiber optic sensors
  • Frequency estimation
  • Multisensor system
  • Optical instrumentation
  • Optical microphone
  • Vibro-acoustic sensor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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