Source: http://www.google.com/patents/US7062137?dq=6,460,050
Timestamp: 2017-12-18 13:17:26
Document Index: 442521214

Matched Legal Cases: ['art 583', 'art 585', 'art 583', 'art 585', 'art 583', 'art 583', 'art 585']

Patent US7062137 - Fiber optic article including fluorine - Google Patents
A fiber optic article, such as an optical fiber or an optical preform, can include a core comprising a concentration of erbium, a concentration of fluorine and a concentration of ytterbium for sensitizing the erbium by absorbing pump light and transferring energy to the erbium. The erbium can provide...http://www.google.com/patents/US7062137?utm_source=gb-gplus-sharePatent US7062137 - Fiber optic article including fluorine
Publication number US7062137 B2
Application number US 10/912,666
Also published as US20060029344, US20060245714
Publication number 10912666, 912666, US 7062137 B2, US 7062137B2, US-B2-7062137, US7062137 B2, US7062137B2
Inventors Julia A. Farroni, Upendra H. Manyam, Nils Jacobson, Kanishka Tankala, Adrian Carter
Patent Citations (47), Non-Patent Citations (3), Referenced by (21), Classifications (20), Legal Events (10)
Fiber optic article including fluorine
US 7062137 B2
A fiber optic article, such as an optical fiber or an optical preform, can include a core comprising a concentration of erbium, a concentration of fluorine and a concentration of ytterbium for sensitizing the erbium by absorbing pump light and transferring energy to the erbium. The erbium can provide light having a second wavelength different than the wavelength of the pump light. The article can also include a concentration of phosphorus. The fiber optic article can include a cladding disposed about the core, where the cladding has an index of refraction that is less than the index of refraction of the core, and a second cladding disposed about the first cladding, where the second cladding includes an index of refraction than is less than the index of refraction of the cladding. The fiber optic article can be elongate along a longitudinal axis and can include a longitudinally extending region for providing birefringence.
a core comprising a host material comprising a concentration of erbium, a concentration of phosphorus, a concentration of ytterbium and a concentration of fluorine for reducing the index of refraction of the host material comprising said concentrations of erbium, phosphorus and ytterbium, said concentration of ytterbium for sensitizing said erbium by absorbing pump light and transferring energy to said erbium, said erbium providing light having a second wavelength different than the wavelength of the pump light;
a cladding disposed about said core and having inner and outer perimeters spaced by a thickness therebetween, said cladding having an index of refraction that is less than an index of refraction of said core; and wherein
said core has a V-number at said second wavelength of greater than 2.405 and a numerical aperture of less than 0.12 relative to said cladding, and said thickness is larger than a thickness of a region, if present, disposed between said cladding and said core.
2. The optical fiber of claim 1 wherein said cladding is a pump cladding for receiving the pump light and wherein said optical fiber includes a second cladding disposed about said cladding.
3. The optical fiber of claim 1 wherein said concentration of fluorine is at least 1% by weight.
4. The optical fiber of claim 1 wherein said V-number is at least 3.
5. The optical fiber of claim 1 wherein said numerical aperture is no greater than 0.09.
6. The optical fiber of claim 1 wherein said core comprises a diameter of at least 12 microns.
7. The optical fiber of claim 1 wherein said core comprises a diameter of at least 15 microns.
8. The optical fiber of claim 1 wherein said core comprises a diameter of at least 25 microns.
9. The optical fiber of claim 1 wherein said core comprises at least 60% by weight of silica.
10. The optical fiber of claim 1 comprising at least one longitudinally extending region for providing said core of said fiber with a selected birefringence at said second wavelength.
11. The optical fiber of claim 10 wherein said selected birefringence is no less than 1×10−4.
12. The optical fiber of claim 10 wherein said at least one longitudinally extending region comprises a pair of longitudinally extending regions each having a substantially circular outer perimeter, said cladding having a substantially circular outer perimeter and being a pump cladding for receiving the pump light, and said optical fiber comprising a second cladding disposed about said cladding.
13. The optical fiber of claim 12 wherein said selected birefringence is no less than 1×10−4.
14. The optical fiber of claim 1 comprising said region disposed between said cladding and said core, said region having an index of refraction that is less than an index of refraction of said core and wherein said cladding comprises an index of refraction that is less than said index of refraction of said region.
15. The optical fiber of claim 14 comprising at least one longitudinally extending region for providing said core of said fiber with a selected birefringence at said second wavelength.
16. The optical fiber of claim 14 wherein said region has a non-circular outer perimeter.
Fermann et al. in “Efficient Operation of an Yb-Sensitised Er Fibre Laser at 1.56 μm”, Electronics Letters, Vol. 24, No. 18, pp. 1135–1136 (1988) teach that an optical fiber comprising erbium and ytterbium can be very useful, as the ytterbium can make pumping the erbium more practical, and the erbium can provide light at the useful wavelength of, for example, 1560 nm. In the Fermann et al. article, the core of the fiber includes phosphorus and aluminum in addition to erbium and ytterbium. In certain instances the NA of such a core can be higher than desired. For example, the core may not provide the desired larger MFD, especially where the cladding is formed from tube-derived silica glass, as is common in the modified chemical vapor deposition (MCVD) process for forming the preform from which an optical fiber is drawn.
Vienne et al., in the article entitled “Fabrication and Characterization of Yb3+:Er3+ Phosphosilicate Fiber for Lasers”, Journal of Lightwave Technology, Vol. 16, No. 11, pp. 1990–2001 (1998), provides teaching related to erbium-ytterbium co-doped fibers.
Typically the fiber (e.g., the core of the fiber) will comprise from 10% to 25% by weight of P2O5; from 0.5% to 5% by weight of Yb203; from 0% to 0.7% by weight of Er203; and from 0.1% to 3.5% by weight of F. In certain embodiments, a fiber optic article (e.g., the core of an optical fiber) can comprise at least 1%, at least 3%, or at least 5% by weight of fluorine. A glass host material, (e.g., SiO2) typically makes up any remainder of material one or more of the foregoing. The core may be essentially free of aluminum. In one embodiment of the invention, the fiber (e.g., the core of the fiber) can comprise from 0 to 4.9×1019 erbium atoms (e.g., Er3+ ions) per cubic centimeter and from 3.3×1019 to 3.4×1020 ytterbium atoms (e.g., Yb3+ ions) per cubic centimeter. Such a fiber can also include a concentration of phosphorus, which can be incorporated into a compound, such as, for example, P2O5. Typically, the concentration of ytterbium atoms or ions is higher than the concentration of erbium atoms or ions. The ratio of ytterbium ions to erbium ions can be, for example, at least 2:1, at least 6:1, at least 10:1; at least 12:1, at least 15:1; or at least 20:1. The concentration in weight percent of Er2O3 is typically higher than the concentration in weight percent of Yb2O3.
FIG. 2 schematically illustrates one example of a possible index of refraction profile 150 taken across a selected diameter of the cross section of the optical fiber 112 of FIG. 1. The index of refraction profile 150 includes a section 152 corresponding generally to the core 120 and hence representing ncoree; sections 156 corresponding generally to the cladding 124 and hence representing nclad; and sections 158 corresponding generally to the second cladding 128 and hence representing nclad2.
The fiber optic article 212 can include a cladding 224 disposed about the inner region 270. A second cladding 228 can be disposed about the cladding 224. The fiber optic article 212 can also comprise another region 240 disposed about the second cladding 228 and having an outer perimeter 248. The region 240 can be a third cladding having an index of refraction nclad3 that is less than nclad2, which is in turn less than nclad, which is in turn less than nregn, which is less than ncore. It can be advantageous to include an additional cladding, especially where a fiber according to the invention will receive higher levels of pump power. Additional claddings can share the duty of confining the pump power. For example, in one embodiment of the invention, the cladding 224 can comprise undoped fused silica, or can consist essentially of or consist of fused silica. The cladding 224 can be derived, for example, from a commercially available silica tube that can be part of the preform from which the fiber is drawn. Such tubes are available from vendors such as Heraeus Arnersil. The second cladding 228 can comprise “down doped” fused silica, such as silica glass that is doped with fluorine, or can consist essentially of or consist of fluorine-doped silica. The second cladding 228 can be derived, for example, from a fluorinated silica glass tube that can be part of the preform from which the fiber is drawn. Fluorinated glass tubes are also understood to be available from Heraeus Amersil.
Both of the foregoing can be applicable. For example, the inner part 583 can include a first selected material (e.g., P in the form of P2O5) that is also included in the outer part 585 but in a substantially different concentration (e.g., the inner part 583 can comprise 10–20 weight % of P2O5 and the outer part can comprise 0–10 weight % of P2O5 and the outer part 585 can comprise a second selected material (e.g., 0–10 weight of GeO2) of which the inner part 583 is substantially free. Preferably, the inner part 583 of the inner region 570 comprises an index of refraction that is substantially the same as an index of refraction comprised by the outer part 585 of the inner region 570. This can be achieved by proper selection of the concentrations of the material in each of the inner and outer parts of the inner region 570.
The core of a fiber according to the invention (e.g., a fiber as shown in FIGS. 1–12) can have a diameter (e.g., Dcore in FIG. 1) of at least 10 microns; at least 15 microns; at least 25 microns; at least 40 microns; at least 60 microns; at least 80 microns; and at least 90 microns. Other useful ranges for a core diameter include from 10 microns to 100 microns; from 20 microns to 90 microns; from 25 microns to 85 microns; from 30 microns to 80 microns; and from 40 microns to 70 microns.
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Cooperative Classification G02B6/02033, H01S3/094007, G02B6/105, G02B6/03638, G02B6/02009, G02B6/03688, H01S3/06729, G02B6/03661, G02B6/03694, G02B6/024
European Classification G02B6/10P, G02B6/024, G02B6/036U, G02B6/036L4, G02B6/036L5, G02B6/036L3
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Free format text: CONFIRMATORY LICENSE;ASSIGNOR:NUFERN, PRIME CONTRACTOR;REEL/FRAME:021640/0400