Sagnac interferometer based stable phase demodulation system for diaphragm based acoustic sensor

Jun Ma, Yongqin Yu, Wei Jin

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review


A modified fiber-optic Sagnac interferometer with a stable π/2 phase bias is demonstrated for the demodulation of diaphragm-based acoustic sensors. The phase bias is obtained by introducing a nonreciprocal frequency shift between the counter-propagating waves. The system is passive and without complicated servo-control for phase stabilization. Interrogated by the proposed demodulation system, a 100 nm-thick graphite diaphragm-based acoustic sensor demonstrated a minimum detectable pressure level of ∼ 450 μPa/Hz1/2at the frequency of 5 kHz and the output signal stability is less than 0.35 dB over an 8-hour period.
Original languageEnglish
Title of host publicationFifth Asia-Pacific Optical Sensors Conference, APOS 2015
ISBN (Electronic)9781628418651
Publication statusPublished - 1 Jan 2015
Event5th Asia-Pacific Optical Sensors Conference, APOS 2015 - Lotte City Hotel Jeju, Jeju, Korea, Republic of
Duration: 20 May 201522 May 2015


Conference5th Asia-Pacific Optical Sensors Conference, APOS 2015
Country/TerritoryKorea, Republic of


  • acoustic sensor
  • graphite diaphragm
  • Optical fiber sensor
  • Sagnac interferometer

ASJC Scopus subject areas

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

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