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US5757540A
Expired / Lapsed
US
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Long-period fiber grating devices packaged for temperature stability
Assignee: Nokia of America Corp
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Filing: 1996-09-06
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Granted: 1998-05-26
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Expires: 2016-09-06
Abstract
Abstract The present applicants have discovered that one can fabricate a long-period grating wherein the grating peak wavelength λ p will be shifted in different directions when the grating is subject to temperature and tensile strain, respectively. Accordingly, a long-period grating can be designed and packaged such that a temperature-induced shift in λ p is compensated by a corresponding strain-induced shift arising from a single packaging material. Thus, by proper design of the grating and choice of the packaging material expansion coefficient, a temperature stable grating having temperature sensitivity of less than 4 nm per 100° C. can comprise a grating fiber encased in or attached to a package comprising a single material such as glass, polymer or metal. Such designs permit the use of long-period grating devices without temperature control.
Inventors
- 👤 Justin Boyd Judkins
- 👤 Paul Joseph Lemaire
- 👤 Ashish Madhukar Vengsarkar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:49
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/02057; G02B6/02076; G02B6/0208; G02B6/02085; G02B6/02095; G02B6/02171; G02B6/02176; G02B6/0218; G02B6/0219; H; H01; H01S; H01S2301/00; H01S2301/04
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
130 words
A fiber long-period grating device having enhanced stability to variations in temperature comprising: an optical fiber comprising a core and a cladding having a lower index of refraction for transmitting light of wavelength λ in a guided mode, said fiber having a plurality of perturbations in its refractive index, said perturbations spaced apart by distances at least 10λ to form a long-period grating with a center wavelength λ p , said center wavelength exhibiting a variation with temperature dλ p /dT and a variation with stress dλ p /dε which are opposite in sign; and said grating mechanically coupled to a body of material having a thermal expansion coefficient such that said grating will be stretched as the temperature increases to thereby reduce the variation of λ p with temperature.
Claim 2
Dependent Claim
130 words
A fiber long-period grating device having enhanced stability to variations in temperature comprising: an optical fiber comprising a core and a cladding having a lower index of refraction for transmitting light of wavelength λ in a guided mode, said fiber having a plurality of perturbations in its refractive index, said perturbations spaced apart by distances at least 10λ to form a long-period grating with a center wavelength λ p , said center wavelength exhibiting a variation with temperature dλ p /dT and a variation with stress dλ p /dε which are opposite in sign; and said grating mechanically coupled to a body of material having a thermal expansion coefficient such that said grating will be stretched as the temperature increases to thereby reduce the variation of λ p with temperature.
Claim 3
Dependent Claim
30 words
A device according to claim 1 wherein said material has a thermal expansion coefficient such that the stretching of said grating substantially offsets the change in λ p with temperature.
Claim 4
Dependent Claim
19 words
A device according to claim 1 wherein said perturbations are spaced apart by distances in the range 15-1500 micrometers.
Claim 5
Dependent Claim
18 words
A device according to claim 1 wherein said fiber core comprises germanium-doped silica and said cladding comprises silica.
Claim 6
Dependent Claim
112 words
An optical fiber communications system comprising: a source of an optical signal; optically coupled to said source, an optical signal path comprising length of optical fiber for transmitting said optical signal; disposed in said optical signal path, an optical amplifier for amplifying said optical signal; a pair of pumping sources for pumping said optical amplifier with optical pumping energy of wavelengths λ p1 and λ p2 ; disposed in the path of the energy from each pumping source after said pumping energy has passed through said amplifier unused, a spectral shaping a device for removing said unused pumping energy from said optical path comprising a long-period grating device according to claim 1.
Claim 7
Dependent Claim
17 words
A communications system according to claim 5 wherein said optical amplifier comprises an erbium-doped optical fiber amplifier.
Claim 8
Dependent Claim
103 words
An optical fiber communications system comprising: a source of at least one optical signal; optically coupled to said source, an optical signal path comprising a length of optical fiber for transmitting said optical signal; disposed in said optical signal path, an optical amplifier having a gain spectral dependence with one or more peak regions providing different gain for different wavelengths; disposed in said optical signal path, a spectral shaping device comprising a long-period grating device according to claim 1 for removing energy from the spectral region of one or more of said peak regions in order to provide a more uniform spectral output.
Claim 9
Dependent Claim
17 words
A communications system according to claim 7 wherein said optical amplifier comprises an erbium-doped optical fiber amplifier.
Claim 10
Dependent Claim
36 words
An optical fiber amplifier comprising a rare-earth doped length of optical fiber; and a long-period grating device according to claim 1 in the path of said fiber for shaping the spectral gain characteristics of said amplifier.
Claim 11
Dependent Claim
99 words
A fiber grating device capable of temperature stabilization by a single material package comprising: an optical fiber comprising a core and a cladding having lower index of refraction than said core for transmitting light of wavelength λ in a guided mode; said fiber having a plurality of perturbations in its refractive index, said perturbations spaced apart by distances greater than 10λ to form a long period grating with a center wavelength λ p ; and said center wavelength exhibiting a variation with temperature dλ p /dT and a variation with stress dλ p /dε which are opposite in sign.
Claim 12
Dependent Claim
99 words
A fiber grating device capable of temperature stabilization by a single material package comprising: an optical fiber comprising a core and a cladding having lower index of refraction than said core for transmitting light of wavelength λ in a guided mode; said fiber having a plurality of perturbations in its refractive index, said perturbations spaced apart by distances greater than 10λ to form a long period grating with a center wavelength λ p ; and said center wavelength exhibiting a variation with temperature dλ p /dT and a variation with stress dλ p /dε which are opposite in sign.
Claim 13
Dependent Claim
20 words
A fiber grating device according to claim 10 wherein and said core comprises germanosilicate glass and said cladding comprises silica.
Claim 14
Dependent Claim
18 words
A device according to claim 1 wherein said body of material is a body of a single material.
Claim 15
Dependent Claim
16 words
A device according to claim 1 wherein said body of material is glass, polymer or metal.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 2001-05-25 | 2001-11-24 | 2002-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-25 | 2005-11-24 | 2006-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-25 | 2009-11-24 | 2010-05-26 | $7700.00 | Window Closed / Lapsed |