EP0156558A2
Expired / Lapsed
EP
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Stable fiber optic polarizer
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1985-03-07
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Granted: —
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Expires: 2005-03-07
Abstract
Abstract This invention relates to fiber optic apparatus and methods for polarizing light for use in fiber optic devices, such as rotation sensors. A phase grating (52) formed of alternating layers of dielectrics (54,56) having different indices of refraction is placed adjacent a half coupler (12) that includes a fiber (20,22) having a cladding thickness which forms an interaction region. The evanescent field of light of a selected polarization interacts with the phase grating (52) to couple out of the fiber (20,22) while light of a second selected polarization remains in the fiber (20,22).
Inventors
- 👤 George A. Pavlath
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 04:13
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/27; G02B6/2726; G02B6/2733; G02B6/2753; G02B6/276
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
173 words
A stable fiber optic polarizer for receiving an input optical signal having an arbitrary polarization and providing an output optical signal having only a single selected polarization, mode comprising: a length of fiber optic material having a core and a cladding surrounding the core, a portion of the cladding having a thickness to form an interaction region; the cladding having a predetermined index of refraction; a phase grating positioned adjacent the interaction region, the phase grating including at least .one layer of a first dielectric material having a first index of refraction and at least one layer of a second dielectric material having a second index of refraction, the first and second indices of refraction being different from the refractive index of the cladding, the indices of refraction of said phase grating and said length of fiber optic material being such that light of the selected polarization propagates in the fiber optic material and other polarizations interact with the phase grating at the interaction region to couple out of the fiber optic material.
Claim 2
Dependent Claim
173 words
A stable fiber optic polarizer for receiving an input optical signal having an arbitrary polarization and providing an output optical signal having only a single selected polarization, mode comprising: a length of fiber optic material having a core and a cladding surrounding the core, a portion of the cladding having a thickness to form an interaction region; the cladding having a predetermined index of refraction; a phase grating positioned adjacent the interaction region, the phase grating including at least .one layer of a first dielectric material having a first index of refraction and at least one layer of a second dielectric material having a second index of refraction, the first and second indices of refraction being different from the refractive index of the cladding, the indices of refraction of said phase grating and said length of fiber optic material being such that light of the selected polarization propagates in the fiber optic material and other polarizations interact with the phase grating at the interaction region to couple out of the fiber optic material.
Claim 3
Dependent Claim
36 words
The stable fiber optic polarizer of claim 1 wherein said phase grating includes a plurality of alternating layers of the first dielectric material having a first thickness and the second dielectric material having a second thickness.
Claim 4
Dependent Claim
31 words
The stable fiber optic polarizer of claim 2 wherein the selected polarization mode to be propagated in the fiber optic material is perpendicular to the phase grating at the interaction region.
Claim 5
Dependent Claim
44 words
The stable fiber optic polarizer of claim 3 comprising a base having a slot therein, said length of fiber optic material being mounted within said slot so that the cladding forms a generally planar surface facing outwardly from the slot at the interaction region.
Claim 6
Dependent Claim
31 words
The stable fiber optic polarizer of claim 1 wherein the indices of refraction of the phase grating have substantially the same temperature dependence as the index of refraction of the cladding.
Claim 7
Independent Claim
127 words
A method for polarizing light, comprising the steps of: forming a length of fiber optic material having a core and a cladding surrounding the core with a portion of the cladding having a thickness selected to form an interaction region; placing a layer of a first dielectric material having a first index of refraction adjacent the interaction region; and placing at least one layer of a second dielectric material having a second index of refraction adjacent the first layer of dielectric material, the layers of the first and second dielectric materials forming a composite dielectric structure having an index of refraction such that a first selected polarization mode propagates in the fiber optic material while light of a second polarization couples out of the fiber optic material.
Claim 8
Independent Claim
127 words
A method for polarizing light, comprising the steps of: forming a length of fiber optic material having a core and a cladding surrounding the core with a portion of the cladding having a thickness selected to form an interaction region; placing a layer of a first dielectric material having a first index of refraction adjacent the interaction region; and placing at least one layer of a second dielectric material having a second index of refraction adjacent the first layer of dielectric material, the layers of the first and second dielectric materials forming a composite dielectric structure having an index of refraction such that a first selected polarization mode propagates in the fiber optic material while light of a second polarization couples out of the fiber optic material.
Claim 9
Dependent Claim
61 words
The method of claim 8, further including the step of forming the phase grating from dielectric materials having refractive indices having temperature dependence substantially the same as the temperature dependence of the index of refraction of the cladding so that temperature fluctuations within a predetermined range have substantially no effect upon the polarization of light which propagate beyond the interaction region.
Claim 10
Independent Claim
107 words
A method for polarizing light comprising the steps of: forming a length of fiber optic material having a core and a cladding surrounding the core with a portion of the cladding having a thickness selected to form an interaction region; placing a phase grating adjacent the interaction region having the phase grating indices of refraction for light of a first polarization mode and a second polarization mode, respectively chosen such that light of the first polarization propagates in the fiber while light of the second polarization interacts with the phase grating at 'the interaction region to couple out of the fiber optic material into the phase grating.
Claim 11
Independent Claim
107 words
A method for polarizing light comprising the steps of: forming a length of fiber optic material having a core and a cladding surrounding the core with a portion of the cladding having a thickness selected to form an interaction region; placing a phase grating adjacent the interaction region having the phase grating indices of refraction for light of a first polarization mode and a second polarization mode, respectively chosen such that light of the first polarization propagates in the fiber while light of the second polarization interacts with the phase grating at 'the interaction region to couple out of the fiber optic material into the phase grating.
Claim 12
Dependent Claim
66 words
The method of claim 9 further including the step of forming the phase grating from dielectric materials having refractive indices having temperature dependences substantially the same as the temperature dependence of the index of refraction of the cladding so that temperature fluctuations within a predetermined range have substantially no effect upon the polarization of light that propagates in the fiber optic material beyond the interaction region.
References Cited (Backward Citations)
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