A time delay correction technique for SS-OCT

K-trigger signals from light source or external Mach-Zehnder interferometer are commonly used in swept source optical coherence tomography (SS-OCT) to achieve interference signal sampling and resolution enhancement. But extra signal transmission time is required due to the increased complexity of interference system using k-trigger signals, resulting in a misalignment (a.k.a., time delay) between the k-trigger and the interference signals.

The objective of this paper is to propose a numerical technique to correct the time delay between these two signals.

The time delay is iterated in this technique and each iterated correction result is evaluated through calculating the full width at half maximum (FWHM) of peaks in time-domain. The precise alignment between the k-trigger and interference signals coincides with the minimum value of FWHM.

The experimental results show that the FWHM can be improved by up to 50% using this time delay correction technique.

The proposed technique assists to provide precise sample tomography, thus enhancing the way of understanding sample characteristic.