In an incoherent optical fiber bundle (IOFB), the spatial correspondence of its both ends is not given, which usually complicates its handling. There are, however, medical applications for which IOFBs are well suited: Ultra-high spatial resolution fiber spectroscopy, for example, requires densely packed thin fibers on one side of the bundle, while on the other bundle side a flexible arrangement of the fibers is necessary to prevent overlapping of the individual spectra. To make such IOFBs usable for information transmission, a calibration routine to match input and output of the bundle is necessary. The aim of the present work is to establish a calibration routine for densely packed IOFBs with a single fiber core diameter of 23 μm. A HeNe laser focused to illuminate only one single fiber at a time is forming the basis of the experimental setup. An image of the output side is taken, the respective brightness peak is detected and its coordinates are stored in a look-up table (LUT) to allow the fiber bundle input to be reconstructed from its signal output. Several validation and calibration steps have been established to ensure a reliable fiber assignment. In a test run, 94.3% of the 1,374 fibers of the bundle used for proof of concept could be assigned exactly and used for image transmission.
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