Group delay based phase shifting algorithm on frequency domain optical coherence tomography

The frequency-domain optical coherence tomography (FD-OCT) has the advantages of high acquisition time and high system sensitivity, it makes to obtain cross-section image based on the broadband source or swept source. The phase shifting algorithm always applies to reduce the additional noise within FD-OCT and provide accurate signal process. In this paper, we present a new system structure of group delay based phase shifting by combining diffraction grating pairs in Frequency domain OCT. For the parallel grating pair's property, we separate the spectrum and stretch the optical pulse in time to produce group delay result utilizing diffraction grating pair. It makes the linearly group delay between the different frequencies and provides accurate phase shifting algorithm, promotes the system performance and accuracy.