Abstract

As was originally pointed out by Caves, squeezed light can be used to increase the accuracy of interferometric phase measurements. This analysis was carried further by Yurke, McCall, and Klauder, who used group theory to examine the ultimate sensitivity of conventional interferometers and also those constructed from four-wave mixers. Here we consider interferometers composed of mixtures of beam splitters, four-wave mixers, and degenerate parametric amplifiers. We show that each interferometer can be characterized by an uncertainty relation whose minimum uncertainty states can be used to explore its ultimate accuracy. The variables in the uncertainty relation are quadratic in the mode operators, which allows us to connect the study of improved interferometric measurements to recent work on higher-order squeezing.

© 1992 Optical Society of America