On the basis of the nondegenerate Λ quantum-beat laser model, we introduce a coherent field which drives the transition between the upper lasing level and an auxiliary level. We demonstrate that such a four-level system can produce squeezed two-mode lasei without and with inversion. When the laser is operated well above threshold, the intensity fluctuation in the average mode is reduced below the shot noise with an optimum Mandel parameter Q = -1/2. At the same time, the noises in the relative amplitude and the relative phase drop to their vac...
