Parametric down-converters for large frequency ratios

Ladislav Mišta

József Janszky, Yu. Ya. Yushin

Leland Lovell Long

Yu. N. Yashkir

Fluctuation-dissipation theory is developed for parametric noise in a four-photon frequency upcon verter of infrared signals. General analytic formulas are obtained for the parametric converter efficiency, as well as for the signal/noise ratio and the threshold sensitivity. The most important dependences of these characteristics on the parameters of the problem are analyzed and the optimal conditions for the realization of a parametric converter are determined.

Chih‐Sung Chuu, Chun-Yao Yang, Jim Jr-Min Lin +3 more

Colin J. McKinstrie, Nikola Alić

In this paper, studies are made of the information efficiencies of optical amplifiers, attenuators, and frequency convertors. Attenuators always reduce the amount of information carried by a signal. In contrast, parametric amplifiers and frequency convertors redistribute information between the signal and idler sidebands, but preserve the total information. Homodyne detection of the sideband quadratures degrades their signal-to-noise ratios. Detection always reduces the back-to-back and converted information capacities by moderate amounts, which do not depend on how the input information is encoded. The effects of detection on the amplified information capacity can be small or large, depending on how the input information is encoded. For (standard) two-sideband amplifiers, it is best to encode correlated information in both sidebands.