Bc. Buchler et al., Enhancement of quantum nondemolition measurements with an electro-optic feed-forward amplifier, PHYS REV A, 60(6), 1999, pp. 4943-4950
Methods for the enhancement of optical quantum nondemolition (QND) measurem
ents are discussed. We review the use of meter squeezing; as a QND enhancem
ent tool and present a method of QND enhancement using an electro-optic fee
d-forward amplifier. By applying a linearized theory it is shown that these
techniques work very well together. The combined effect of these enhanceme
nt methods is modeled for two QND systems, a squeezed light beam splitter a
nd an optical parametric amplifier. We also discuss the conflict between th
e normal QND criteria and QND systems that involve noiseless amplification.
We use an additional parameter to quantify the problem. A method for corre
cting the effects of noiseless amplification is discussed and modeled. We a
lso discuss a special case of QND that eliminates the optical interaction b
etween the meter and signal input beams. This system is shown to be a very
effective QND device. [S1050-2947(99)06411-2].