  We propose a method for generation of a single-cycle squeezed light by
parametric down-conversion in a chirped quasi-phase-matched nonlinear crystal.
We find an exact quantum solution for this process valid for an arbitrary
parametric gain, and discover an ultrabroadband squeezing in the down-converted
light with flat squeezing spectrum comprising the full optical octave. We
describe a scheme for observation of this kind of squeezing using
second-harmonic generation as an ultrafast correlator.
