Patent ID: 6760496
Filing Date: 2004-07-06
Classification: G02B

Abstract:
An optical isolator comprising:a waveguide that includes: a core having a first end, a second end, and a boundary surface, the core operable to allow a light wave incident the first end of the core to propagate from the first end of the core to the second end of the core, which defines a positive propagation direction, and operable to allow a light wave incident the second end of the core to propagate from the second end of the core to the first end of the core, which defines a negative propagation direction, and a cladding provided relative the boundary surface of the core, wherein a thinned segment of the cladding having a cladding thickness operable to allow an optical field penetration through the thinned segment of the cladding by a light wave that propagates in the positive propagation direction of the core, the thinned segment operable to allow the optical field penetration through the thinned segment of the cladding by a light wave that propagates in the negative propagation direction of the core, and the thinned segment of the cladding having a length that extends relative to a portion of the core; and a magnetic-composite material provided in the presence of an externally applied magnetic field with at least a component of the externally applied magnetic field oriented in a direction perpendicular to the positive propagation direction of the core and parallel to the magnetic vector of the optical field, the magnetic-composite material positioned relative the thinned segment of the cladding of the waveguide to receive the optical field penetration through the thinned segment of the cladding, the magnetic-composite material having a thickness and an index of refraction to attenuate a light wave that propagates in the portion of the core in the negative propagation direction by an amount greater than the attenuation of a light wave that propagates in the portion of the core in the positive propagation direction.