This paper describes a compact Faraday rotation isolator using terbium aluminum garnet (TAG) as the Faraday rotation material and small high field permanent magnets made of copper—rare earth alloys. The nominal isolation is 26 dB with a 0.4-dB forward loss. The present isolator can be adjusted to provide effective isolation from 4880 Å to 5145 Å. Details of the design, fabrication, and performance of the isolator are presented.
F. J. Sansalone, "Compact Optical Isolator," Appl. Opt. 10, 2329-2331 (1971)