Photomixing Optical-Microwave Transformer Coupled with High-TC Josephson Junctions.

Abstract

A new type of optical-microwave conversion system has been developed as an interface between optical systems and high-speed electric circuits. The microwave was generated by mixing two optical beams in a photodiode and radiated from a rod antenna, which was placed beside a high-Tc grain boundary Josephson junction detector. Since frequencies of radiated microwaves correspond to the frequency differences between the two optical beams, the wavelength information of the beams is reflected in the current-voltage and differential resistance-voltage properties of the Josephson junction. System operation up to 20 GHz was demonstrated by changing the wavelength of the two beams and the temperature of the Josephson junction. The relation between the frequency differences and measured Shapiro step intervals suggests that the system can be utilized for a highly sensitive optical-microwave conversion.