Spatially resolved in-core temperature measurement in rare-earth doped fibers during pumping

We demonstrate a spatially distributed measurement technique to observe temperature changes along a pumped Ybdoped fiber. The technique is based on an array of fiber Bragg gratings acting as temperature sensor line. The Bragg gratings are inscribed directly into the actively doped fiber core using high intensity laser pulses and an interferometric setup. We studied the temperature evolution in differently doped fibers under pumping conditions and find different effects contributing to the observed temperature increase. To avoid an additional heating caused by pump-induced photodarkening, we measure the spatially resolved temperature profile during pumping along a photodarkening-reduced, cerium co-doped fiber.

[1]  Stephan Grimm,et al.  Highly efficient Yb-doped silica fibers prepared by powder sinter technology. , 2011, Optics letters.

[2]  K. Schuster,et al.  High-reflectivity draw-tower fiber Bragg gratings—arrays and single gratings of type II , 2005 .

[3]  R. Windeler,et al.  Effect of heat and H2 gas on the photo-darkening of Yb+3 fibers , 2006, 2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference.

[4]  K. Hill,et al.  Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication , 1978 .

[5]  S. Unger,et al.  Efficient Yb laser fibers with low photodarkening by optimization of the core composition. , 2008, Optics express.

[6]  T. C. Newell,et al.  Temperature effects on the emission properties of Yb-doped optical fibers , 2007 .

[7]  W H Loh,et al.  Efficient single-frequency fiber lasers with novel photosensitive Er/Yb optical fibers. , 1997, Optics letters.

[8]  Hartmut Bartelt,et al.  UV-induced photodarkening and photobleaching in UV-femtosecond-pulse-written fibre Bragg gratings , 2013 .

[9]  Jens Limpert,et al.  Erbium fiber laser based on intracore femtosecond-written fiber Bragg grating. , 2006, Optics letters.

[10]  Hartmut Bartelt,et al.  Femtosecond pulse-induced fiber Bragg gratings for in-core temperature measurement in optically pumped Yb-doped silica fibers , 2012 .

[11]  S. Unger,et al.  Photodarkening in Yb doped fibers: experimental evidence of equilibrium states depending on the pump power. , 2007, Optics express.

[12]  S. Mihailov,et al.  Formation of Type I-IR and Type II-IR gratings with an ultrafast IR laser and a phase mask. , 2005, Optics express.

[13]  David N. Nikogosyan,et al.  Multi-photon high-excitation-energy approach to fibre grating inscription , 2006 .

[14]  Johannes Kirchhof,et al.  Temperature influence on the photodarkening kinetics in Yb-doped silica fibers , 2011 .

[15]  Nemanja Jovanovic,et al.  Stable high-power continuous-wave Yb(3+)-doped silica fiber laser utilizing a point-by-point inscribed fiber Bragg grating. , 2007, Optics letters.

[16]  John Canning,et al.  Photodarkening study of gratings written into rare-earth doped optical fibres using a femtosecond laser , 2007, SPIE Micro + Nano Materials, Devices, and Applications.

[17]  Hartmut Bartelt,et al.  Towards a monolithic fiber laser with deep UV femtosecond-induced fiber Bragg gratings , 2011 .

[18]  I. Bennion,et al.  Investigation of Ultrafast Laser--Photonic Material Interactions: Challenges for Directly Written Glass Photonics , 2008, IEEE Journal of Selected Topics in Quantum Electronics.

[19]  David J. Richardson,et al.  High power fiber lasers: current status and future perspectives [Invited] , 2010 .

[20]  Markus B. Raschke,et al.  Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies , 2006 .

[21]  D N Payne,et al.  Er(3+):Yb(3+)-codoped fiber distributed-feedback laser. , 1994, Optics letters.

[22]  F. Laurell,et al.  Improved photodarkening resistivity in ytterbium-doped fiber lasers by cerium codoping. , 2009, Optics letters.

[23]  Y Sheng,et al.  Ytterbium fiber laser based on first-order fiber Bragg gratings written with 400 nm femtosecond pulses and a phase-mask. , 2009, Optics express.

[24]  G. Meltz,et al.  Formation of Bragg gratings in optical fibers by a transverse holographic method. , 1989, Optics letters.