Showing papers by "Jeffrey H. Shapiro published in 1979"

Generation and detection of two-photon coherent states in degenerate four-wave mixing.

Abstract: It is shown that degenerate four-wave mixing generates two-photon coherent states (TCS) of the radiation field for modes that are proper combinations of the output object and image waves. TCS light has novel quantum behavior, which can be probed by homodyne detection, intensity interferometry, or photocount statistics. Numerical estimates indicate that the generation and detection of TCS light via degenerate four-wave mixing and homodyne detection can be accomplished with current technology.

Optical communication with two-photon coherent states--Part II: Photoemissive detection and structured receiver performance

Abstract: In Part I of this three-part study, it was shown that novel quantum states, called two-photon coherent states (TCS), have significant potential for improving free-space optical communications. Because TCS radiation does not possess a classical analog, i.e., its diagonal P -representation is highly singular, the semiclassical conditional Poisson process model for direct detection is not applicable to TCS reception. In this paper, photoemissive detection of arbitrary quantized radiation fields is studied with incorporation of the nontrivial effects of detector quantum efficiency. General theorems are derived permitting the application of classical point process results to the detection and estimation of signals in arbitrary quantum states. These general theorems are applied to determining the performance of TCS optical communication systems that employ direct, heterodyne, or homodyne detection in binary decision as well as in linear modulation problems. It is shown that the use of TCS radiation with direct detection or heterodyne detection results in minimal performance increments over comparable coherent-state systems. Homodyne detection, however, can achieve the full TCS signal-to-noise ratio improvement predicted in Part I of this study. The increase in homodyne signal-to-noise ratio obtained by use of TCS radiation yields significant performance gains in both linear modulation and antipodal signal detection.

Turbulence Effects on the Receiver Operating Characteristics of a Heterodyne-Reception Optical Radar.

Abstract: : The theory of atmospheric turbulence effects on the receiver operating characteristics of coherent optical radars is reviewed and the theoretical results for the target detection probability are numerically evaluated. Graphs and tables are presented of the glint target and speckle target detection probabilities as a function of the carrier-to-noise ratio at various false alarm probabilities for different turbulence log-amplitude variances. Experimental turbulence strength measurements are reviewed and used to determine typical log-amplitude variances. These results are combined with the detection probability calculations to predict the performance of a realistic infrared radar under a variety of turbulent propagation conditions. (Author)