Spectrometer calibration with reduced dispersion for optical coherence tomography

A wavelength calibration method is proposed for Fourier domain optical coherence tomography. In the present study, the wavelength remapping procedure is based on the spectral phase function determined by the calibration signal. To accomplish high accuracy feature for wavelength calibration, a common-path interferometer is employed. Two autocorrelation interferograms generated from the common-path interferometer are utilized as the calibration signals. The advantage of the interferometer proposed here is that the accurate optical path difference of the calibration signals could be acquired easily. The wavelength distribution in the spectrometer was deduced with the phase signal. The approach was compared to a wavelength-determined approach using a standard light source with a characterized spectrum. With the result that the mean spectrometer calibration error is 0.1 nm, it demonstrates that the proposed method is more superior in spectrometer calibration. Furthermore, the proposed method allows for higher axial imaging resolution and signal-to-noise ratio (SNR) in the FD-OCT system.