Calibration protocol for Fourier-domain OCT using optical fiber gratings

We present a calibration protocol to get the alignment factors of a custom-made spectrometer and the nonlinear fitting function between the measured CCD pixel domain and the wavelength domain to apply the Fourier-domain optical coherence tomography (FD-OCT) using optical fiber gratings. We have used 5 different center wavelength gratings covered the broadband source spectral range with a narrow spectral bandwidth (<0.05 nm) and the same reflectivity (>92 %) to calibrate and align the custom-made spectrometer. The implemented SD-OCT system following the proposed protocol showed the alignment factors as 44.37o incident angle, 53.11o diffraction angle, and 70.0 mm focal length. The spectral resolution of 0.187 nm was recalculated from the alignment factors.