  We demonstrate that the cubic gain applied in a localized region, which is
embedded into a bulk waveguide with the cubic-quintic nonlinearity and uniform
linear losses, supports stable spatial solitons in the absence of the quintic
dissipation. The system, featuring the bistability between the solitons and
zero state (which are separated by a family of unstable solitons), may be used
as a nonlinear amplifier for optical and plasmonic solitons, which, on the
contrary to previously known settings, does not require gain saturation. The
results are obtained in an analytical form and corroborated by the numerical
analysis.
