Patent ID: 6480636
Filing Date: 2002-11-12
Classification: G02F

Abstract:
An optical isolator including a Faraday rotator of a magnetic garnet thick film and a field-application magnet for generating a magnetic field applied to magnetize said magnetic garnet thick film, wherein said field-application magnet is selected from the group consisting of an iron-chromium-cobalt (Feâ€”Crâ€”Co) magnet, a Cunife magnet made of a copper-nickel-iron (Cuâ€”Niâ€”Fe) alloy, a platinum (Pt) alloy magnet made of a Ptâ€”Co alloy or a Ptâ€”Fe alloy, and a Cunico magnet made of a copper-nickel-cobalt (Cuâ€”Niâ€”Co) alloy,wherein said field-application magnet has a U-frame shape and a dimension such that the relationship tÂ·(S)âˆ’Â½&gE;0.7 is satisfied where S represents a sectional area of said magnet in a plane perpendicular to a magnetized direction thereof and t represents the length of said magnet in the magnetizing direction.