V.E. Ustimchik, J. Kerttula, S.A. Nikitov, A.E. Ulanov, V.N. Filippov, Yu.K. Chamorovskii
Insignificance of mode beating into passive double-clad tapered fiber in presented transmission spectra over wide wavelengths range 900…1400 nm shows that there is no mode coupling into fiber with output core diameter more than 100µm and singlemode input signal.