Optical isolators employing oppositely signed faraday rotating materials

Abstract

A Faraday rotator having a first, or central magnet, and first and second tuning magnets a opposite ends of the central magnet. The central magnet and the tuning magnets are of opposite polarities. The central magnet surrounds a first optical element having a positive or negative Verdet constant, and the tuning magnets surround second and third optical elements, respectively. The second and third optical elements each have a Verdet constant of a sign opposite that of the first optical element. Such Faraday rotators require smaller magnet assemblies than Faraday rotators having just one optical element surrounded by the central magnet. There is also provided a Faraday rotator having at least two magnets wherein each magnet of any one pair of contiguous magnets generates a magnetic field in a direction opposite that generated by the other of the any one pair of contiguous magnets. The optical elements surrounded by these magnets have oppositely signed Verdet constants.