  A recent communication [Opt. Commun. doi:10.1016/j.optcom.2010.06.076 (2010)]
presents experimental results in which dark pulses are observed in a
dispersion-managed (DM) net-anomalous dispersion fiber laser. Disagreement on
the formation mechanism proposed in this communication, we would like to
indicate a more accurate explanation in order to clarify some potential
misunderstanding on dark pulses in fiber lasers.
