The squeezing generated in a lossless nondegenerate parametric amplifier with pump quantization has been numerically simulated in a previous paper [G. Drobný and I. Jex, Phys. Rev. A 46, 499 (1992)]. The report squeezing in a quadrature of up to 90%. We give analytic and numeric results that show that the quadratures studied by Drobný and Jex do not exhibit squeezing if the standard technique of homodyne detection is employed. This is simply shown by a calculation that reveals that the variance in both quadratures is equal for all times. On the other hand, if homodyne detection is not used, the variance would oscillate at the optical carrier frequency—hence, squeezing would be unobservable. We believe that this illustrates the importance of using analytical and physical checks of computer-generated results.
- Received 9 November 1993
©1995 American Physical Society