  We demonstrate that the amplitudes of optical solitons in nonlinear
multisequence optical waveguide coupler systems with weak linear and cubic
gain-loss exhibit large stable oscillations along ultra-long distances. The
large stable oscillations are caused by supercritical Hopf bifurcations of the
equilibrium states of the Lotka-Volterra (LV) models for dynamics of soliton
amplitudes. The predictions of the LV models are confirmed by numerical
simulations with the coupled cubic nonlinear Schr\"odinger (NLS) propagation
models with $2 \le N \le 4$ pulse sequences. Thus, we provide the first
demonstration of intermediate nonlinear amplitude dynamics in multisequence
soliton systems, described by the cubic NLS equation. Our findings are also an
important step towards realization of spatio-temporal chaos with multiple
periodic sequences of colliding NLS solitons.
