  We observe a broadband chaotic signal of Terahertz frequency emitted from a
superconducting junction. The generated radiation has a wide spectrum reaching
0.7 THz and power sufficient to drive on-chip circuit elements. To our
knowledge, this is the first experimental observation of a high-frequency
chaotic signal emitted by a superconducting system which lies inside the
Terahertz gap. Our experimental finding is fully confirmed by the numerical
modeling based on the microscopic theory and reveals the unrealized potential
of superconducting systems in chaos-based Terahertz communication, fast
generation of true random numbers and non-invasive Terahertz spectroscopy
applicable to physical, chemical and biological systems.
