Faraday rotator and magneto-optical element

Abstract

Provided are a Faraday rotator and a magneto-optical device which stably provide a Faraday rotation angle of 45° and achieve further size reduction. A Faraday rotator comprises: a magnetic circuit 2 including first to third magnetic materials 11 to 13 each provided with a through hole through which light passes; and a Faraday element 14 disposed in the through hole 2a and made of a paramagnetic material capable of transmitting light therethrough, wherein when a direction where light passes through the through hole 2a is defined as a direction of an optical axis, the first magnetic material 11 is magnetized in a direction perpendicular to the direction of the optical axis to have a north pole located toward the through hole, the second magnetic material 12 is magnetized in a direction parallel to the direction of the optical axis to have a north pole located toward the first magnetic material 11, and the third magnetic material 13 is magnetized in a direction perpendicular to the direction of the optical axis to have a south pole located toward the through hole, a length of the second magnetic material 12 along the direction of the optical axis is equal to or more than 0.5 times a length of the Faraday element 14 along the direction of the optical axis, and the first and third magnetic materials 11, 13 are shorter than the length of the second magnetic material 12 along the direction of the optical axis.

Dependencies are inferred from the claim text.