Simultaneously measuring the refractive index and thickness of an optical sample by using improved fiber-based optical coherence tomography

An improved structure for the optical coherence tomography (OCT) scheme based on a 4 x 4 fiber coupler for simultaneously measuring the refractive index and thickness of optical samples is presented. The proposed structure incorporates the optical path length difference of interference light and is used to calculate the refractive index and thickness of an unknown sample without any prior knowledge of the sample parameters. Two methods (time-domain and Fourier-domain OCT) of obtaining information about an unknown sample are proposed, and a high-speed high-resolution OCT system was developed. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.