This work is concerned with experimental research of laser beam profile dependence on micro-lensed optical fiber configuration. We considered prepared lensed and tapered cone optical fiber samples and tested them on developed experimental setup to analyze laser beam profile from the output of the lensed optical fiber end. Some comparison results of detected spatial distribution patterns of laser source emission from the end of cleaved and lensed optical fiber ends are presented.
We present results of experimental research and comparison of differential mode delay (DMD) maps measured for silica graded index multimode optical fibers (MMFs) with strong and weak diameter variation. Preliminary for two synthesized by MCVD fiber preforms were selected by criterion of expected strong DMD due to great profile dip in the core center. Then two lengths of MFMs were drawn. The first one was manufactured according typical operations with automatic control of technological processes, while the second one was drawn under manual maintenance. Therefore two samples of MMFs of ISO/IEC Cat. OM2 with length about 1 km were manufactured with diameter variation ± 0.3 μm and ± 1.2 μm respectively. At the next stage we performed DMD map measurement of described two MMF 50/125 samples by DMD analyzer lab kit R2D2 according to ratified standards TIA-455-220-A/FOTP-220 and IEC 60793-2-10 to research and analyze influence of fiber diameter variation on mode coupling in the form of additional DMD distortions during laser-excited optical pulse propagation over MMF under a few-mode regime.