An optical isolator is discussed which is suitable for use in high-gain optical isolators. After a brief discussion of the necessary properties of such an isolator, a particular design is discussed. Measurements on a breadboard model using a He-Ne laser operating at 6328 Å indicate an isolation greater than 40 dB and insertion loss of 27% (1.1 dB). The model discussed uses the Faraday rotation principle in flint glass in a Lummer-Gehrcke configuration. Modification of this model to other wavelengths is discussed.
Paul C. Fletcher and David L. Weisman, "Circulators for Optical Radar Systems," Appl. Opt. 4, 867-873 (1965)