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US5287214A
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Fabry-Perot optical filters
Assignee: Benhov GmbH LLC
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Filing: 1992-04-08
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Granted: 1994-02-15
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Expires: 2012-04-08
Abstract
Abstract Simple polarization independent wavelength tuning components (filters) employ a filter element, such as a Fabry-Perot etalon element, which is such that light input thereto undergoes two element transitions with orthogonal polarization states before being output, in order to suppress polarization noise. The element may be mounted for rotation about a single axis. In one arrangement, two etalon filters (20, 21), are separated by a half wave plate (22) providing the necessary polarization rotation. The two etalon filters and the half wave plate comprise a single element rotatable about the single axis.
Inventors
- 👤 Alexander J. Robertson
- 👤 Stephen Day
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:02
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29379; G02B6/2938; G02B27/00; G02B27/28; G02B27/288; G02B5/00; G02B5/30; G02B5/3083; G02B6/27; G02B6/2706; G02B6/29346; G02B6/29358; G02B6/2753; G02B6/2766
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
77 words
An optical filter including a filter element which is such that a light beam including polarisation noise and input to the optical filter undergoes two filter element transitions with a transformation to an orthogonal polarisation state between said two transitions before being output from the optical filter, whereby to suppress the polarisation noise, wherein the filter element is a Fabry-Perot etalon element, and wherein the etalon element is mounted with provision for rotation about a single axis.
Claim 2
Dependent Claim
77 words
An optical filter including a filter element which is such that a light beam including polarisation noise and input to the optical filter undergoes two filter element transitions with a transformation to an orthogonal polarisation state between said two transitions before being output from the optical filter, whereby to suppress the polarisation noise, wherein the filter element is a Fabry-Perot etalon element, and wherein the etalon element is mounted with provision for rotation about a single axis.
Claim 3
Dependent Claim
118 words
An optical filter including a filter element which is such that a light beam including polarisation noise and input to the optical filter undergoes two filter element transitions with a transformation to an orthogonal polarisation state between said two transitions before being output from the optical filter, whereby to suppress the the polarisation noise, and wherein the filter element is a Fabry-Perot etalon element which comprises two etalon filters in series with a half wave plate therebetween whereby to rotate the polarisation state of light output from the first etalon filter through 90° prior to input to the second etalon filter, the etalon filters and the half wave plate comprising a single element rotatable about a single axis.
Claim 4
Dependent Claim
118 words
An optical filter including a filter element which is such that a light beam including polarisation noise and input to the optical filter undergoes two filter element transitions with a transformation to an orthogonal polarisation state between said two transitions before being output from the optical filter, whereby to suppress the the polarisation noise, and wherein the filter element is a Fabry-Perot etalon element which comprises two etalon filters in series with a half wave plate therebetween whereby to rotate the polarisation state of light output from the first etalon filter through 90° prior to input to the second etalon filter, the etalon filters and the half wave plate comprising a single element rotatable about a single axis.
Claim 5
Dependent Claim
116 words
An optical transmission system employing multiwavelength transmission over optical fibre and including a plurality of receivers and transmitters each associated with a respective predetermined wavelength, and wherein associated with each receiver is a respective optical filter passing the respective wavelength, the optical filter including a filter element which is such that a light beam including polarisation noise input to the optical filter undergoes two filter element transitions with a transformation to an orthogonal polarisation state between said two transitions before being output from the optical filter, whereby to suppress the polarisation noise, wherein the filter element is a Fabry-Perot etalon element, and wherein the etalon element is mounted with provision for rotation about a single axis.
Claim 6
Dependent Claim
116 words
An optical transmission system employing multiwavelength transmission over optical fibre and including a plurality of receivers and transmitters each associated with a respective predetermined wavelength, and wherein associated with each receiver is a respective optical filter passing the respective wavelength, the optical filter including a filter element which is such that a light beam including polarisation noise input to the optical filter undergoes two filter element transitions with a transformation to an orthogonal polarisation state between said two transitions before being output from the optical filter, whereby to suppress the polarisation noise, wherein the filter element is a Fabry-Perot etalon element, and wherein the etalon element is mounted with provision for rotation about a single axis.
Claim 7
Dependent Claim
18 words
An optical transmission system as claimed in claim 3 wherein the transmission medium is single mode optical fibre.
References Cited (Backward Citations)
US3471802A
Cited
US3681608A
Cited
US3740144A
Cited
US3802775A
Cited
US3936147A
Cited
US3934210A
Cited
US4196396A
Cited
US4199226A
Cited
US4548506A
Cited
US4508964A
Cited
US4502762A
Cited
US4678287A
Cited
US4969744A
Cited
US4772104A
Cited
US4813756A
Cited
GB2223324A
Cited
US4973120A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-02-14 | 1997-08-16 | 1998-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-14 | 2001-08-16 | 2002-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-14 | 2005-08-16 | 2006-02-15 | $7700.00 | Window Closed / Lapsed |