Title :
Absolute strain demodulation with acoustooptic scanning low-coherence fiber interferometry
Author :
Sinha, P.G. ; Yoshino, T.
Author_Institution :
Dept. of Electron. Eng., Gunma Univ., Japan
Abstract :
A traveling acoustic pulse in a two-mode fiber can act as a moving beam splitter coupling light from LP/sub 01/ to LP/sub 11/ mode. The intermodal delay varies as the acoustic pulse advances in the fiber. The device can be used in low-coherence interferometry to scan time delay for making a fast extended range absolute measurement without involving complex signal processing. As an illustration, the time delay as a function of axial strain applied to a section of highly birefringent fiber is scanned. Absolute measurement of strain over 900 μ/spl epsiv/ with a resolution of the order of 25 μ/spl epsiv/ is reported.
Keywords :
acousto-optical devices; acousto-optical modulation; birefringence; demodulation; fibre optic sensors; light coherence; light interferometry; measurement errors; strain measurement; strain sensors; LP/sub 01//LP/sub 11/ mode coupling; absolute strain demodulation; acoustic pulse; acoustooptic scanning low-coherence fiber interferometry; axial strain; coupling light; highly birefringent fiber; intermodal delay; low-coherence interferometry; measurement errors; moving beam splitter; resolution; strain measurement; time delay scanning; traveling acoustic pulse; two-mode fiber; Acoustic measurements; Acoustic pulses; Capacitive sensors; Delay effects; Demodulation; Optical coupling; Optical fiber devices; Optical interferometry; Strain measurement; Time measurement;
Journal_Title :
Photonics Technology Letters, IEEE
