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Norin, Lars
Publications (10 of 10) Show all publications
Engholm, M. & Norin, L. (2008). Materials optimization for ytterbium-doped high power fiber lasers. In: 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9: . Paper presented at Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference, may 04-09, 2008, San Jose, CA (pp. 232-233). New York: IEEE conference proceedings
Open this publication in new window or tab >>Materials optimization for ytterbium-doped high power fiber lasers
2008 (English)In: 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9, New York: IEEE conference proceedings, 2008, p. 232-233Conference paper, Published paper (Refereed)
Abstract [en]

In this paper we will present paths to reduce the extent of photodarkening in ytterbium. doped fiber lasers based on the aluminosilicate glass matrix. This will enable higher powers and longer operating lifetimes.

Place, publisher, year, edition, pages
New York: IEEE conference proceedings, 2008
Keywords
photodarkening, ytterbium
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-4496 (URN)000260498400117 ()2-s2.0-51349090170 (Scopus ID)5541 (Local ID)978-1-55752-859-9 (ISBN)5541 (Archive number)5541 (OAI)
Conference
Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference, may 04-09, 2008, San Jose, CA
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2017-10-18Bibliographically approved
Engholm, M. & Norin, L. (2008). Preventing Photodarkening in Ytterbium-Doped High Power Fiber Lasers; Correlation to the UV-Transparency of the Core Glass. Optics Express, 16(2), 1260-1268
Open this publication in new window or tab >>Preventing Photodarkening in Ytterbium-Doped High Power Fiber Lasers; Correlation to the UV-Transparency of the Core Glass
2008 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 16, no 2, p. 1260-1268Article in journal (Refereed) Published
Abstract [en]

 

Photodarkening experiments are performed on ytterbium-doped silicate glass

samples. A strong charge-transfer (CT) absorption band near 230nm in

aluminosilicate glass is found to be correlated to the mechanism of induced

color center formation. Excitation into the CT-absorption band generates

similar color centers as observed in ytterbium-doped fiber lasers under

915nm high power diode pumping. The position of the CT-absorption band is

compositional dependent and is shifted to shorter wavelengths in ytterbium

doped phosphosilicate glass. Very low levels of photodarkening is observed

for the ytterbium doped phosphosilicate glass composition under 915nm high

power diode pumping. Possible excitation routes to reach the CT-absorption

band under 915nm pumping are discussed.

 

Keywords
Photodarkening, charge-transfer, ytterbium
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-4491 (URN)10.1364/OE.16.001260 (DOI)000252479700077 ()18542200 (PubMedID)2-s2.0-38549163196 (Scopus ID)5538 (Local ID)5538 (Archive number)5538 (OAI)
Available from: 2008-11-29 Created: 2008-11-29 Last updated: 2017-12-12Bibliographically approved
Engholm, M. & Norin, L. (2008). Reduction of photodarkening in Yb/Al-doped fiber lasers. In: Proceedings of SPIE - The International Society for Optical Engineering: . Paper presented at Conference on Fiber Lasers V, Jan 21-24, 2008, San Jose CA (pp. U269-U276). SPIE - International Society for Optical Engineering
Open this publication in new window or tab >>Reduction of photodarkening in Yb/Al-doped fiber lasers
2008 (English)In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE - International Society for Optical Engineering, 2008, p. U269-U276Conference paper, Published paper (Refereed)
Abstract [en]

A strong charge-transfer band at UV-wavelengths is found to play a major role for the observed induced optical losses (photodarkening) in ytterbium doped high-power fiber lasers. This is correlated to the valence stability of the ytterbium ion in the silicate glass matrix, which we believe is the origin of photodarkening. We have performed UV-irradiation experiments on ytterbium-doped preform samples and accelerated photodarkening experiments on Yb-doped fibers, by using 915nm high power diodes. Our results show that photodarkening can be reduced, to low levels, either by preparing the preform glass in a reducing atmosphere or by hydrogen loading the fiber in a pressure chamber at room temperature.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2008
Series
PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, ISSN 0277-786X ; 6873
Keywords
Ytterbium, valence stability, photodarkening; ytterbium; fiber lasers; charge-transfer
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-5974 (URN)10.1117/12.763218 (DOI)000255547100041 ()2-s2.0-44949237937 (Scopus ID)5539 (Local ID)978-0-8194-7048-5 (ISBN)5539 (Archive number)5539 (OAI)
Conference
Conference on Fiber Lasers V, Jan 21-24, 2008, San Jose CA
Available from: 2008-11-19 Created: 2008-11-19 Last updated: 2017-10-20Bibliographically approved
Engholm, M. & Norin, L. (2007). Comment on:"Photodarkeningin Yb-doped aluminosilicate fiber induced by 488nm irradiation". Optical Letter, 33(11), 1216.
Open this publication in new window or tab >>Comment on:"Photodarkeningin Yb-doped aluminosilicate fiber induced by 488nm irradiation"
2007 (English)In: Optical Letter, ISSN 0146-9592, Vol. 33, no 11, p. 1216.-Article in journal (Refereed) Published
Abstract [en]

We present some strong evidence against the assignment of an ytterbium-related oxygen deficiency center (ODC) near 230 nm in Yb-doped aluminosilicate glass in the Letter by Yoo

Keywords
Charge-transfer
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-4495 (URN)5540 (Local ID)5540 (Archive number)5540 (OAI)
Available from: 2008-09-30 Created: 2008-12-17 Last updated: 2011-05-29Bibliographically approved
Engholm, M. & Norin, L. (2007). Divalent Ytterbium in Ytterbium Doped Aluminosilicate Glass - Aspects on Photodarkening in Fiber Lasers. In: 2007 CONFERENCE ON LASERS & ELECTRO-OPTICS/QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2007), VOLS 1-5: . Paper presented at Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference, may 06-11, 2007, Baltimore, MD (pp. 1902-1903). New York: IEEE conference proceedings
Open this publication in new window or tab >>Divalent Ytterbium in Ytterbium Doped Aluminosilicate Glass - Aspects on Photodarkening in Fiber Lasers
2007 (English)In: 2007 CONFERENCE ON LASERS & ELECTRO-OPTICS/QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2007), VOLS 1-5, New York: IEEE conference proceedings, 2007, p. 1902-1903Conference paper, Published paper (Refereed)
Abstract [en]

We show that divalent ytterbium ions are present in ytterbium doped aluminosilicate glass. The presence of Yb^2+-ions may influence the formation of induced color centers in ytterbium doped fiber lasers leading to reduced performance.

Place, publisher, year, edition, pages
New York: IEEE conference proceedings, 2007
Keywords
Photodarkening
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-6393 (URN)000268751001394 ()2-s2.0-82955193210 (Scopus ID)4615 (Local ID)978-1-4244-3590-6 (ISBN)4615 (Archive number)4615 (OAI)
Conference
Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference, may 06-11, 2007, Baltimore, MD
Available from: 2009-02-23 Created: 2009-02-23 Last updated: 2017-11-02Bibliographically approved
Engholm, M. & Norin, L. (2007). Strong UV absorption and visible luminescence in ytterbium-doped aluminosilicate glass under UV excitation. Optics Letters, 32(22), 3352-3354
Open this publication in new window or tab >>Strong UV absorption and visible luminescence in ytterbium-doped aluminosilicate glass under UV excitation
2007 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 32, no 22, p. 3352-3354Article in journal (Refereed) Published
Abstract [en]

A broad visible luminescence band and characteristic IR luminescence of Yb3+ ions are observed under UV excitation in ytterbium-doped aluminosilicate glass. Samples made under both oxidizing and reducing conditions are analyzed. A strong charge-transfer absorption band in the UV range is observed for glass samples containing ytterbium. Additional absorption bands are observed for the sample made under reducing conditions, which are associated with f�d transitions of divalent ytterbium. The visible luminescence band is attributed to 5d�4f emission from Yb2+ ions, and the IR luminescence is concluded to originate from a relaxed charge-transfer transition. The findings are important to explain induced optical losses (photodarkening) in high-power fiber lasers.

Keywords
Ytterbium, Silica, Charge transfer, valence stability
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-4380 (URN)10.1364/OL.32.003352 (DOI)000251747600044 ()2-s2.0-38549100491 (Scopus ID)4261 (Local ID)4261 (Archive number)4261 (OAI)
Available from: 2008-12-09 Created: 2008-12-09 Last updated: 2017-12-12Bibliographically approved
Engholm, M., Norin, L., Edvardsson, S., Lashgari, K. & Westin, G. (2006). A structural investigation of a synthesized precursor for fiber optical applications; the heterobimetallic ErNb_2(OPr^i)_13. Optical materials (Amsterdam), 29(4), 386-391
Open this publication in new window or tab >>A structural investigation of a synthesized precursor for fiber optical applications; the heterobimetallic ErNb_2(OPr^i)_13
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2006 (English)In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 29, no 4, p. 386-391Article in journal (Refereed) Published
Abstract [en]

A structural investigation of a synthesized precursor in a silica glass matrix is performed. Silica soot samples are doped with the heterobimetallic precursor ErNb2(OPri)13 by using a conventional solution doping technique and heat treatments to different temperatures. The precursor has also been introduced into a silica fiber preform by using the modified chemical vapor deposition technique. Analyses are made by using ultraviolet–visible–near infrared absorption spectroscopy, scanning electron microscopy, energy dispersive spectroscopy and powder X-ray diffraction. It is concluded that an immiscible system of ErNbO4 crystallites and Nb2O5 is formed in the silica soot samples at high temperatures. Colloidal particles of ErNbO4 are also formed in the silica glass fiber preform showing interesting features.

Keywords
Precursor, optical fiber, glass-ceramics
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-3307 (URN)10.1016/j.optmat.2005.11.004 (DOI)000242647600006 ()2-s2.0-33750693980 (Scopus ID)3242 (Local ID)3242 (Archive number)3242 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2017-12-12Bibliographically approved
Lashgari, K., Kritikos, M., Engholm, M., Norin, L., Edvardsson, S. & Westin, G. (2006). Sol-gel preparation of Er-doped planar and fibre wave-guides using heterometallic. In: SPIE conference, San Diego (2006)..
Open this publication in new window or tab >>Sol-gel preparation of Er-doped planar and fibre wave-guides using heterometallic
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2006 (English)In: SPIE conference, San Diego (2006)., 2006Conference paper, Published paper (Other academic)
Keywords
erbium, wave guides
National Category
Natural Sciences
Identifiers
urn:nbn:se:miun:diva-4689 (URN)5914 (Local ID)5914 (Archive number)5914 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2011-05-29Bibliographically approved
Engholm, M., Lashgari, K., Edvardsson, S., Westin, G. & Norin, L. (2005). Atomically designed precursors in optical fiber amplifiers: The thermal stability of the heteroimetallic ErAl_3(OPri)_12 in a solution-coated silica soot. Journal of Applied Physics, 97(11), 113104
Open this publication in new window or tab >>Atomically designed precursors in optical fiber amplifiers: The thermal stability of the heteroimetallic ErAl_3(OPri)_12 in a solution-coated silica soot
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2005 (English)In: Journal of Applied Physics, ISSN 0021-8979, Vol. 97, no 11, p. 113104-Article in journal (Refereed) Published
Keywords
EDFA, silica, sol-gel, cluster
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-682 (URN)10.1063/1.1922087 (DOI)000229804700005 ()2471 (Local ID)2471 (Archive number)2471 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2011-05-29Bibliographically approved
Engholm, M., Vanin, E. & Norin, L. Characterization of Erbiuim Crystallites Embedded in Silica Glass.
Open this publication in new window or tab >>Characterization of Erbiuim Crystallites Embedded in Silica Glass
(English)Manuscript (Other (popular science, discussion, etc.))
Keywords
Crystallites, Erbium
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-6367 (URN)4260 (Local ID)4260 (Archive number)4260 (OAI)
Available from: 2009-02-18 Created: 2009-02-18 Last updated: 2011-05-29Bibliographically approved
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