Lam, Timothy T-YGray, Malcolm BShaddock, Daniel AMcClelland, David EChow, Jong H2016-05-162016-05-160146-9592http://hdl.handle.net/1885/101246Laser 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.This research was supported by the Australian Research Council funding schemes for Discovery Projects and Linkage Projects.© 2012 Optical Society of AmericaKeywords: Fiber sensing; Fiber strain sensors; Frequency fluctuation; Frequency noise; High resolution; Laser frequency; Nanostrain; Noise floor; Noise signals; Orders of magnitude; Strain sensitivity; Strain sensors; Strain signal; Time-delay interferometry; Inter2012-06-0110.1364/OL.37.0021692016-06-14