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US 7,095,923 B1Granted
Wavelength selective optical filter
AssigneeNortel Networks Limited
InventorJames Whiteaway
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AssigneeNortel Networks Limited
InventorJames Whiteaway
Estimating the term…
The invention is directed to an improved wavelength selective optical filter component having an optical path therethrough and comprising a first and a second optical port, a multimode interference region and a wavelength selective element. The first optical port and the multimode interference region each have an axis of symmetry relative to the optical path. The optical path enables light to travel through the multimode interference region and the wavelength selective element from the first or second optical port to the other optical port, and wherein the axis of symmetry of the multimode interference region is not aligned with the axis of symmetry of the first optical port. An advantage of arranging the multimode interference region and first optical port such that their axes of symmetry are not aligned is that this introduces a slope in the pass band of the device which can be chosen at the design stage to meet a specific slope requirement or can be used to cancel a pre-existing slope to give a resultant flat pass band.
An optical filter component having an optical path therethrough and comprising a first and a second optical port, said first optical port having an axis of symmetry relative to the optical path, a multimode element having an axis of symmetry relative to the optical path and a wavelength selective element, wherein the optical path enables light to travel through the multimode element and the wavelength selective element from one of said first or second optical ports to said other of said first or second optical ports, and wherein the axis of symmetry of the multimode element is not aligned with the axis of symmetry of the first optical port.
A method of reducing the passband slope of an optical filter component, said optical filter component having an optical path therethrough and comprising a first and a second optical port, said first optical port having an axis of symmetry relative to the optical path, a multimode element having an axis of symmetry relative to the optical path and a wavelength selective element, wherein the optical path enables light to travel through the multimode element and the wavelength selective element from one of said first or second optical ports to said other of said first or second optical ports, and wherein the axis of symmetry of the multimode element is not aligned with the axis of symmetry of the first optical port.
An optical communications system containing an optical filter component, said filter component having an optical path therethrough and comprising a first and a second optical port, said first optical port having an axis of symmetry relative to the optical path, a multimode element having an axis of symmetry relative to the optical path and a wavelength selective element, wherein the optical path enables light to travel through the multimode element and the wavelength selective element from one of said first or second optical ports to said other of said first or second optical ports, and wherein the axis of symmetry of the multimode element is not aligned with the axis of symmetry of the first optical port.
Dependencies are inferred from the claim text.