Ultra-broadband light source for optical coherence tomography by fiber matching

摘要

In this paper, an ultra-broadband all fiber light source for optical coherence tomography was obtained. This light source was obtained by supercontinuum (SC) generated in matched fibers with different characteristics. It was showed that the spectrum quality was affected by dispersion and nonlinear characteristics of the fiber pumped firstly. SC spectrum flatness on the short wavelength side of pumping wavelength was affected by characteristic of the fiber pumped secondly. Dispersion shifted fiber (DSF) was connected after highly nonlinear fiber (HNLF) to optimize spectral shape. Widely broadened SC spectrum was generated in the combination of 120m HNLF+4.5km DSF+2km single mode fiber (SMF) with 55 mW average pump power. 140.6nm 3 dB bandwidth spectrum on the short wavelength was obtained. About 4.1 urn longitudinal resolution could be obtained theoretically around ～1300nm by using this SC spectrum as the light source of optical coherence tomography system. A Fourier-domain OCT (FD-OCT) system was set up by using this light source. Dielectric film plane mirror, a three-layer microscope cover glass with 160um thick and onion scarfskin were used as test sample and their depth signal at one point was obtained respectively.