Title :
Stabilized extrinsic fiber-optic Fizeau sensor for surface acoustic wave detection
Author :
Tran, Tuan A. ; Miller, William V., III ; Murphy, Kent A. ; Vengsarkar, Ashish M. ; Claus, Richard O.
Author_Institution :
Bradley Dept. of Electr. Eng., Virginia Polytech. Inst. & State Univ., Blacksburg, VA, USA
fDate :
10/1/1992 12:00:00 AM
Abstract :
A surface acoustic wave sensor based on an in-line extrinsic Fizeau interferometer is described. A single-mode fiber, used as the input/output fiber, and a multimode fiber, used solely as a reflector, form an air-gap that acts as a low-finesse Fabry-Perot or Fizeau cavity. The Fresnel reference reflection from the glass/air interface at the front of the air-gap interferes with the sensing reflection from the air/glass interface at the far end of the air-gap. Strains in the thin-walled silica tube housing the two fibers change the length of the air-gap, thereby altering the phase difference between the reference and sensing reflections. A theoretical analysis of the interaction between the strain induced by elastic stress wave fields and the fiber sensor housing is presented
Keywords :
acoustic variables measurement; fibre optic sensors; light interferometers; optical resonators; surface acoustic waves; Fizeau cavity; Fizeau interferometer; Fresnel reference reflection; SAW sensor; air-gap; elastic stress wave fields; extrinsic fiber-optic Fizeau sensor; fiber sensor housing; glass/air interface; input/output fiber; low-finesse Fabry-Perot cavities; multimode fiber; phase difference; reference reflections; reflector; sensing reflections; single-mode fiber; surface acoustic wave detection; thin-walled silica tube; tube strained; Acoustic sensors; Acoustic waves; Air gaps; Capacitive sensors; Fabry-Perot; Fresnel reflection; Glass; Optical fiber sensors; Sensor phenomena and characterization; Surface acoustic waves;
Journal_Title :
Lightwave Technology, Journal of
