Novel calibration method for optical coherence tomography instruments using multiple spectrometers

Abstract

In this report, a novel calibration method is introduced, which can be used in camera-based Optical Coherence Tomography (OCT) instruments employing several spectrometers. To ensure that all spectrometers are calibrated, i.e. they sense the same spectral range and the distribution of the optical frequencies across the pixels of the cameras is the same, a hybrid method was used involving (i) a hardware procedure for an initial estimation of the edges of the spectra and (ii) a numerical Monte-Carlo based technique. The utility of such a procedure is demonstrated in an OCT system using a Balance-Detection (BD) scheme. The OCT system employs a single transmission diffraction grating and is driven by a supercontinuum source operating in the visible spectral range. Spectral alignment is paramount in producing high-sensitivity images free of artefacts. To ensure correct calibration, and speed up the calibration procedure, the Master-Slave (MS) technique of generating axial reflectivity profiles is employed. Preliminary results show an improvement of the signal of ~ 3dB and a mitigation of the background noise of over 5 dB.