Low-nonlinearity single-transverse-mode ytterbium-doped photonic crystal fiber amplifier Limpert, J. ; Liem, A. ; Reich, M. ; Schreiber, T. ; Nolte, S. ; Zellmer, H. ; T�nnermann, A. ; Broeng, J. ; Petersson, A. ; Jakobsen, C. Abstract Publication: Optics Express Pub Date: April 2004 DOI: 10.1364/OPEX.12.001313 Bibcode: 2004OExpr..12.1313L