Subfrequency noise signal extraction in fiber-optic strain sensors using postprocessing.
Laser frequency fluctuations typically limit the performance of high-resolution interferometric fiber strain sensors. Using time delay interferometry, we demonstrate a frequency noise immune fiber sensing system, where strain signals were extracted well below the noise floor normally imposed by the frequency fluctuations of the laser. Initial measurements show a reduction in the noise floor by a factor of 30, with strain sensitivities of a nanostrain/Hz at 100 mHz and reaching 100 ps/Hz at 1 Hz. Further characterization of the system indicates the potential for at least 4.5 orders of magnitude frequency fluctuation rejection.
Centre for Gravitational Physics, Department of Quantum Science, The Australian National University Building, 38a Science Road, Acton, Australian Capital Territory 0200, Australia. timothy.lam@anu.edu.au
Timothy T-Y
TT
Lam
Malcolm B
MB
Gray
Daniel A
DA
Shaddock
David E
DE
McClelland
Jong H
JH
Chow