  Dissipative solitons are non-dispersive localized waves that exhibit
intriguing dynamics. In optical systems, the discovery of new soliton dynamics
and how to accurately manipulate dissipative solitons are still largely
unexplored and challenging in the ultrafast fiber laser community. Herein, we
unveil a new type of dissipative soliton behavior in a net-normal-dispersion
bidirectional ultrafast fiber laser. That is, the bidirectional dissipative
solitons will always reveal similar spectral and temporal characteristics
through common gain and loss modulation, even if the transient instability is
involved. The behavioral similarity enables us to accurately design the soliton
patterns by introducing seed pulses through loss modulation. As a
proof-of-concept application, the precise and flexible manipulation of
multi-soliton patterns is demonstrated. These findings will shed new insights
into the complex dissipative soliton dynamics, and also beneficial for
designing ultrafast lasers with desirable soliton patterns for practical
applications.
