title: Mode-locked thulium-bismuth codoped fiber laser using graphene saturable absorber in ring cavity: comment.
abstract: We comment on a recent paper [Appl. Opt.52, 1226 (2013)]. We believe that this paper reports significant errors regarding the autocorrelation measurement of output pulses and the associated analysis of their temporal and spectral characteristics.
authors: Minwan
authors: M
authors: Jung
authors: Ju Han
authors: JH
authors: Lee