SNR enhancement through phase dependent signal reconstruction algorithms for phase separated interferometric signals

Opt Express. 2007 Aug 6;15(16):10103-22. doi: 10.1364/oe.15.010103.

Abstract

We report several signal reconstruction algorithms for processing phase separated homodyne interferometric signals. Methods that take advantage of the phase of the signal are experimentally shown to achieve a signal-to-noise ratio (SNR) improvement of up to 5 dB over commonly used algorithms. To begin, we present a derivation of the SNR resulting from five image reconstruction algorithms in the context of a 3x3 fiber-coupler based homodyne optical coherence tomography (OCT) system, and clearly show the improvement in SNR associated with phase-based algorithms. Finally, we experimentally verify this improvement and demonstrate the enhancement in contrast and improved image quality afforded by these algorithms through homodyne OCT imaging of a Xenopus laevis tadpole. These algorithms can be generally applied in signal extraction processing where multiple phase separated measurements are available.