Title :
Unambiguous sawtooth fringe counting for an active homodyne demodulated interferometric strain gauge
Author :
Furstenau, Norbert ; Schiffer, Frank ; Schmidt, Walter
Author_Institution :
Inst. for Flight Guidance, German Aerosp. Res. Establ., Braunschweig, Germany
fDate :
7/1/1995 12:00:00 AM
Abstract :
Source wavelength modulation by feedback of the interference signal of an unbalanced fiber-optic Michelson interferometer to the driver of the semiconductor laser source gives rise to sawtooth-shaped fringe´s under fiber strain. The fringe asymmetry is utilized for elimination of the fringe counting directional ambiguity via differentiation of the closed-loop interference signal. Initial results of quantitative strain measurements agree reasonably well with the readout of a resistive strain gauge as well as with the theoretically predicted sensitivity
Keywords :
Michelson interferometers; demodulation; fibre optic sensors; light interferometry; optical feedback; strain gauges; strain measurement; active homodyne demodulation; closed-loop interference signal; differentiation; driver; feedback; quantitative strain measurements; sawtooth fringe counting; semiconductor laser; sensitivity; source wavelength modulation; strain gauge; unbalanced fiber-optic Michelson interferometer; Capacitive sensors; Interference; Laser feedback; Optical feedback; Optical fiber cables; Optical fiber polarization; Optical fiber sensors; Optical interferometry; Optical refraction; Strain measurement;
Journal_Title :
Lightwave Technology, Journal of
