Wavenumber calibration and dispersion compensation for Fourier domain optical coherence tomography by parameterized instantaneous frequency estimation method

A nonlinear chirp is always introduced to an interference fringe in the Fourier domain optical coherence tomography (FD-OCT), which can be regarded as an amplitude-modulated and frequency-modulated nonstationary signal. It is mainly caused by the non-uniform wavenumber sampling and the dispersion mismatch between the sample and the reference arms. It results in the broadening of the axial point spread function and the degradation of the axial resolution. In this paper, the parameterized instantaneous frequency estimation method (PIFEM) is applied to estimate the phase function of the chirped interference fringe to achieve the linear resampling of the wavenumber space and the rebalance of the dispersion mismatch. The proposed method is efficient and convenient that requires only two interference fringes corresponding to a mirror at different depths in the sample arm of the FD-OCT system. In addition, it is proved that the PIFEM is adapted to compensate for the depth-independent dispersion mismatch caused by the sample comprised of layered structures. The experiment results validate the performance of the proposed method.