Photoparametric amplifier frequency converters

This paper reviews the use of a photoparametric amplifier as a versatile yet elegant solution to the optical to electrical conversion stage found within optical communication systems. Basic operational principles are described along with application examples, in particular focusing on point-to-point free space links and indoor optical wireless scenarios. Broader applications, such as subcarrier multiplexing fiber systems and radio over fiber links, are also highlighted. Gain equations for upconversion and baseband detection are presented, along with a novel baseband detection double heterodyne photoparametric amplifier.