Distribution of fiber parameters computed by 2D autocorrelation. Panel a: frequency difference between absorption-emission peaks (see Fig. 2d). Panel b: frequency drift rate, calculated for the outbound typical fibers (groups 1−37). Panel c: duration at fixed frequency. Panel d: average repetition time. Both panels c and d were calculated at the central frequency for each group. In all panels except panel b data from groups 1−44 of Table A.1 were used, excluding narrowband fibers.