  We present a mechanism of amplification of phonons by phonons on the basis of
nonlinear band-gap transmission phenomenon. As a concept the idea may be
applied to the various number of systems, however we introduce the specific
idea of creating amplification scenario in the chain of coupled cantilever
arrays. One chain is driven at the constant frequency located in the upper band
of the ladder system, thus no wave enters the system. However the frequency is
specifically chosen to be very close to the maximum value of frequency
corresponding to dispersion relation of the system. Amplification scenario
happens when a counter phase pulse of same frequency with a small amplitude is
introduced to the second chain. If both signals exceed a threshold amplitude
for the band-gap transmission a large amplitude soliton enters the system -
therefore we have an amplifier. Although the concept may be applied in a
variety of contexts - all optical or all-magnonic systems, we choose the system
of coupled cantilever arrays and represent a clear example of the application
of presented conceptual idea. Logical operations is the other probable field,
where such mechanism could be used, which might significantly broaden the
horizon of considered applications of band-gap soliton dynamics.
