Tunable optical filter
First Claim
1. An apparatus comprising a tunable filter for passing one or more selected wavelength from a band of wavelengths, the tunable filter adapted to be tuned to the one or more selected wavelength without physically moving any parts of the tunable filter, the tunable filter reflecting unselected wavelengths;
- wherein the tunable filter has a filter region, a support body and one or more support legs, the filter region formed of first and second mirrors with a layer between them that has a refractive index that changes with temperature, and wherein the one or more support legs are adapted to suspend the filter region away from the support body.
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Accused Products
Abstract
A tunable filter having a top mirror, a bottom mirror, and one or more intervening layers. The one or more intervening layers preferably have a refractive index that changes with temperature. By heating the one or more intervening layers, the wavelength that is selected by the optical filter can be controlled. The one or more intervening layers are preferably heated by passing current through the one or more intervening layers, or by passing current through a separate resistive layer that is thermally coupled to the one or more intervening layers. Such a filter can provide a high degree of wavelength selectivity in a robust and stable manner.
61 Citations
25 Claims
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1. An apparatus comprising a tunable filter for passing one or more selected wavelength from a band of wavelengths, the tunable filter adapted to be tuned to the one or more selected wavelength without physically moving any parts of the tunable filter, the tunable filter reflecting unselected wavelengths;
- wherein the tunable filter has a filter region, a support body and one or more support legs, the filter region formed of first and second mirrors with a layer between them that has a refractive index that changes with temperature, and wherein the one or more support legs are adapted to suspend the filter region away from the support body.
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2. A tunable filter for selecting a desired wavelength from a band of wavelengths, comprising:
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a support structure having one or more support members;
a first mirror;
a second mirror;
a layer situated between the first mirror and the second mirror, the layer having a refractive index that changes with temperature, the refractive index at least partially determining the wavelength that is selected by the tunable filter; and
heating means for providing heat to the layer;
wherein the layer is mechanically supported by the support members, and the layer is spaced from the support structure by the support members. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
tuning the tunable filter of claim 2 to one or more selected wavelength from a band of wavelengths without physically moving any parts of the tunable filter; passing the one or more selected wavelengths through the tunable filter; and
reflecting unselected wavelengths.
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25. An apparatus for selecting a desired wavelength from a band of wavelengths, comprising:
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a tunable filter for passing a selected wavelength, the tunable filter being tuned to a selected wavelength by applying heat to the tunable filter, the tunable filter having a filter region spaced from a support body by air gaps;
heating means for providing heat to the tunable filter; and
a controller for applying a controlled power to the heating means such that the desired wavelength is selected by the tunable filter.
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Specification