Ultraviolet absorption and excitation spectroscopy of rare-earth-doped glass fibers derived from glassy and crystalline preforms

Ultraviolet absorption and laser excitation spectroscopy (LES) measurements are presented for rare-earth-doped optical fibers produced from both glassy and crystalline preforms. Absorption spectra are obtained via broad-spectrum UV LEDs emitting in the 250nm region. LES measurements are obtained utilizing a tunable UV laser source. The tunable laser employed is a frequency-doubled titanium:sapphire laser-pumped optical parametric amplifier (OPA) operating down to a minimum wavelength of about 225nm. Our results indicate a roughly linear relationship between the concentration of oxygen deficiency centers (ODC) and rare-earth content, regardless of the preform type, and the slope of the line is found to vary significantly with the rare earth. Additionally, LES measurements are used to elucidate the energy transfer mechanism from pumping in the UV to emission by the rare-earth. In all cases the fibers are Al codoped and those produced from glassy preforms are manufactured via standard methods. Fibers produced from crystalline preforms start with a pure silica-sleeved rare-earth doped YAG crystal rod that becomes glassy (amorphous) post-draw.

[1]  Arai,et al.  Two types of oxygen-deficient centers in synthetic silica glass. , 1988, Physical review. B, Condensed matter.

[2]  D. Payne,et al.  Photodarkening in Yb-doped aluminosilicate fibers induced by 488 nm irradiation , 2007 .

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

[4]  H. Imai,et al.  Generation of E' centers and oxygen hole centers in synthetic silica glasses by γ irradiation , 1993 .

[5]  André Croteau,et al.  Characterization of defect luminescence in Yb doped silica fibers: part I NBOHC. , 2008, Optics express.

[6]  M. Söderlund,et al.  Measuring photodarkening from single-mode ytterbium doped silica fibers. , 2006, Optics express.

[7]  L. Norin,et al.  Comment on "Photodarkening in Yb-doped aluminosilicate fibers induced by 488 nm irradiation". , 2008, Optics letters.

[8]  T. Cardinal,et al.  Temporal evolution of photodarkening and successive photobleaching of an Ytterbium-doped silica double-clad LMA fiber , 2007, 2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference.

[9]  George H. Sigel,et al.  Processing-induced defects in optical waveguide materials , 1998, Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides: Applications and Fundamentals.

[10]  L. Skuja.  Optically active oxygen-deficiency-related centers in amorphous silicon dioxide , 1998 .

[11]  L. Norin,et al.  Preventing photodarkening in ytterbium-doped high power fiber lasers; correlation to the UV-transparency of the core glass. , 2008, Optics express.