Microtomography of the polarization-maintaining fiber by digital holography

• DH is used to record complex transmitted fields under various angles of incidence.
• FDT algorithm is applied to reconstruct the 3-D RI distribution of PMF.
• Geometric parameters can be obtained from RI map by the edge detection algorithm.
• Experimental results prove the feasibility of Microtomography of PMF by DH.

We report the experimental results of structural parameters measurement of the polarization-maintaining fiber (PMF) by the use of digital holographic microtomography. First, digital holography (DH) in microscopy configuration is used to record complex transmitted fields under various angles of incidence, and then the Fourier diffraction tomography algorithm is applied to reconstruct the 3-D refractive index (RI) distribution of the PMF. According to the 3-D map of RI, we can further get geometric parameters of the PMF by the related edge detection algorithm of image processing. The experimental results show that, the diffraction tomography algorithm is superior to the reconstruction algorithm based on Fourier slice theorem in terms of exhibiting reasonable RI distribution and respecting the dimensions of the PMF. It provides a new way for the non-destructive micromeasurement of the PMF.