Optical isolators employing wavelength tuning
First Claim
1. In a method of rotating the plane of polarization of polarized light in a Faraday rotator, said Faraday rotator including (i) an optical element having an optical axis, said optical element being formed from a composition including at least one ferromagnetic material, and said optical element being formed from at least one substrate in the form of a disc, and each of said at least one disc(s) is coated with an iron-and oxygen-containing film, and (ii) at least one permanent magnet for generating a magnetic field along the optical axis of the optical element, the improvement comprising:
- varying the strength of magnetic fiels generated along the optical axis of the optical element by moving said at least one permanent magnet with respect to said optical element such that the strength of the magnetic field in said at least one ferromagnetic material is maintained at a level below the saturation point for said at least one ferromagnetic material in order to respond to changes in the wavelength of said polarized light.
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Accused Products
Abstract
An improvement in a method of rotating the plane of polarization of polarized light in a Faraday rotator, having an optical element which includes a ferromagnetic material, which comprises varying the strength of the magnetic field generated along the optical axis of the optical element in response to changes in the wavelength of the polarized light. The magnet employed in the Faraday rotator may be at least one permanent magnet or an electromagnet. Preferred optical elements are made of disc having a gadolinium-gallium-garnet (GGG) or large lattice constant (LLC) substrate, and the substrate is coated with an oxygen--and iron--containing film.
16 Citations
14 Claims
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1. In a method of rotating the plane of polarization of polarized light in a Faraday rotator, said Faraday rotator including (i) an optical element having an optical axis, said optical element being formed from a composition including at least one ferromagnetic material, and said optical element being formed from at least one substrate in the form of a disc, and each of said at least one disc(s) is coated with an iron-and oxygen-containing film, and (ii) at least one permanent magnet for generating a magnetic field along the optical axis of the optical element, the improvement comprising:
varying the strength of magnetic fiels generated along the optical axis of the optical element by moving said at least one permanent magnet with respect to said optical element such that the strength of the magnetic field in said at least one ferromagnetic material is maintained at a level below the saturation point for said at least one ferromagnetic material in order to respond to changes in the wavelength of said polarized light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
Specification