In this paper we investigate the quantum statistical properties in a cascade laser system with the lower transition being in a #LAMBDA# quantum-beat configuration. It is shown that a type of three-mode squeezing may be generated. The fluctuations of the intensity difference between the sum-mode from the quantum-beat and the cascade single mode may be reduced below the shot-noise limit. The best achievable noise reduction is up to 50. Good squeezing occurs when the sum mode and the cascade single mode have normalized intensities much larger than unity and the intensity difference is much smaller than the respective intensity.
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