Degenerate three-level cascade laser with the cavity mode driven by coherent light

We present the quantum statistical properties of the light produced by a degenerate three-level cascade laser with the cavity mode driven by coherent light. In this system three-level atoms in a cascade configuration, initially prepared in a coherent superposition of the top and bottom levels, are injected into a cavity coupled a vacuum reservoir. We find that although the driving coherent light has no effect on the degree of squeezing, it increases the mean photon number considerably. Therefore, this quantum optical system can be taken as a source of a bright squeezed light.