Fiber interferometry limitations due to parasitic optical cavities

Light propagating in a fiber core undergoes reflections at fiber interfaces which create parasitic cavities and can degrade the performance of a fiber interferometric sensor. Such cavities can stem from poor splices, unused fiber ends or reflection from other sensors in a fiber array. We demonstrate the deleterious effects of a Fabry-Perot (FP) cavity on the output of a Michelson interferometer. The increase in amplitude and phase noise is analyzed and correlated with experimental data, and we achieve over 40 dB reduction of the parasitic FP effects