  We study a microwave superconducting stripline resonator made of NbN on a
Sapphire wafer. Novel, self-sustained modulation of the reflected power off the
resonator, at frequencies of up to 60MHz, has been recently reported. Here we
show experimentally that near the self modulation threshold, the device
exhibits a giant nonlinearity, which manifests itself in an extremely high
intermodulation gain, accompanied by a very strong noise squeezing and period
doubling of various orders. Such a device is highly suitable for serving as a
readout device in quantum data processing systems.
