Structure and properties of silica containing aluminum and phosphorus near the AlPO4 join

DiGiovanni, D. J.; MacChesney, J. B.; Kometani, T. Y.

doi:10.1016/0022-3093(89)90318-9

Cited by 91 publications

(65 citation statements)

References 14 publications

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“…In 1989, DiGiovanni et al have found, that the refractive index of glasses in the system SiO 2 -Al 2 O 3 -P 2 O 5 drops below that of pure silica near the AlPO 4 join (at the ratio Al:P = 1). 26 To our knowledge, this phenomenon was not further investigated in detail or used in the fiber technology. Our experiments show, that in fact an important index drop is produced in the rare earth doped fiber preform.…”

Section: Decrease Of the Core Refractive Index By Co-dopingmentioning

confidence: 95%

Materials and technologies for microstructured high power laser fibers

et al. 2005

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In the last years rare earth doped double-clad fibers have been developed to high-power laser sources. Important progress was possible by increasing numerical aperture of the pump cladding and decreasing numerical aperture of the laser core. The high NA of the pump cladding enables the acceptance of large pump intensities whereas the low NA of the laser core makes possible to increase the core diameter and to decrease the laser power density retaining high beam quality. Here, actual challanges are discussed and possibilities are demonstrated to use microstructures for improved fiber designs which are realized by stacking and drawing of capillaries and rods. The rare earth doped parts are prepared by modified chemical vapor deposition and solution doping, but other routes of powder technology are also studied. Concerning the currently most important laser and amplifier types -Yb doped at 1.1 : m wavelength and Er/Yb doped at 1.55 : m wavelength -, the question of a high pump aperture is similar, but the limitations concerning a low core aperture are fairly different, because an efficient Er/Yb laser demands high phosphorus co-doping which naturally increases the core NA. The applied microstructures comprise "holey" fiber cross sections in form of "air clads" for the pump light and multiple hole ring structures for laser core and inner cladding. Moreover, microstructured cores made from solid parts yield new possibilities and parameters to compensate the high refractive index of the active material and to optimize the large mode area design. key words: fiber laser, rare-earth doping, microstructured fiber

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Section: Decrease Of the Core Refractive Index By Co-dopingmentioning

confidence: 95%

Materials and technologies for microstructured high power laser fibers

et al. 2005

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“…A case in point is that of alumina in an aluminosilicate glass where properties as a general function of alumina content, [Al 2 O 3 ], are deduced even though the aluminum in Al 2 O 3 is known to exist in multiple coordination environments . Further, reactive species, such as Al 2 O 3 and P 2 O 5 , which can form AlPO 4 , an index‐lowering compound relative to SiO 2 , are treated as the single final reactant.…”

Section: Materials Property Additivitymentioning

confidence: 99%

A unified materials approach to mitigating optical nonlinearities in optical fiber. II. A. Material additivity models and basic glass properties

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et al. 2017

Int J of Appl Glass Sci

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The purpose of this paper, Part IIA in the trilogy (Int J Appl Glass Sci. 2018;9:263-277; Int J Appl Glass Sci. 2018 (in press); Int J Appl Glass Sci. 2018 (in press)), is to describe the continuum models employed to deduce the physical, acoustic, and optical properties of optical fibers that exhibit intrinsically low optical nonlinearities. The continuum models described herein are based on the additivity approaches of Winklemann and Schott (W-S). Initially developed over 120 years ago, W-S additivity works well for predicting the basic properties of bulk silicate glasses. While high-silica-content glasses are still the gold-standard for telecommunication and high energy laser fibers, the models have been systematically expanded to include deduction of the physical, thermophysical, and acoustic constants and coefficients that bear on parasitic nonlinearities. The stateof-the-art in W-S-based continuum materials models is reviewed here with specific examples provided based on canonical material systems suggested from the findings of Part I and treated in detail in Part III. K E Y W O R D Slasers, optical fibers, optical glasses, optical properties 1 | INTRODUCTION Without today's understanding of atomistic and quantum physics and chemistry and the benefits of modern high performance computing, our scientific ancestors developed continuum models for predicting the behavior of a range of materials. Amongst the original approaches was that of Adolph Winkelmann, who introduced an additivity approach for calculating the specific heat of (oxide) glasses of arbitrary composition based on the physical properties of the individual components. That said, one does today have the benefit of high performance computing and numerous atomistic and quantum chemical models and codes with which to simulate the performance of glasses.2-4 As a matter of fact, the simulation of glass properties and processing has become so effective, that glasses have been brought to commercial markets entirely designed and optimized based on modeling.5 Accordingly, the Readers are then within their rights to wonder why continuum-level additivity models as described herein are employed. The simple answer is simplicity . . . and speed and versatility. In the work described in Companion Paper III, 6 there are entire binary, ternary, and quaternary glass systems whose properties need to be estimated in order to predict their physical, acoustic, and optical behavior as relates to the nonlinearities described in Paper I. 7 A macroscale continuum approach offers a rapid yet sufficiently accurate method for screening large computational spaces.--

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“…ytterbium) content with the possibility to tailor the refractive index by means of co-dopant concentration (e.g. aluminum and phosphorous, where the phosphorous can compensate the refractive index change arising from the aluminum [11]) and therefore to control the refractive index contrast. By using this material for the powder in-tube-preform production technique we have full freedom to fabricate fibers with any geometry including microstructured fibers such as LCF (Leakage Channel Fibers) and LMA fibers (Large Mode Area) with no limitations to the core diameter due to inhomogeneity.…”

Section: Introductionmentioning

confidence: 99%

Progress in the fabrication of optical fibers by the sol-gel-based granulated silica method

et al. 2016

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Novel special optical fibers nowadays can take advantage of several new preform production techniques. During the last years we have devoted our attention to the granulated silica method. It is one of the variants of the powder-in-tube technique and potentially offers a high degree of freedom regarding the usable dopants, the maximum possible dopant concentration, the homogeneity of the dopants, the geometry and minimal refractive index contrast. We developed and refined an approach for the production of doped granulated silica material based on the sol-gel process.Here, we present material analysis results of an ytterbium (Yb) doped, aluminum (Al) and phosphorous (P) co-doped glass on the basis of our sol-gel glass based granulated silica method as well as first measurements of two LMA fibers obtained from this material. For the material analysis we used advanced analysis techniques, such as HAADF-STEM and STEM-EDX spectroscopy to determine the composition of the material and the distribution of the dopants and the codopants. The chemical mapping of the STEM-EDX shows an extremely homogeneous distribution of the dopants and co-dopants in nano-scale. Based on self-made LMA fibers, we measured the refractive index contrast of the sol-gelbased granulated silica derived core compared to the pure silica cladding. In addition we quantified optical characteristics such as the emission and absorption spectrum. The measured upper state lifetime of the optical active dopant ytterbium was 0.99ms, which in turn confirms the homogeneous distribution of the Yb atoms. The propagation losses were determined to be 0.2dB/m at 633nm and 0.02414dB/m at1550nm.

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Structure and properties of silica containing aluminum and phosphorus near the AlPO4 join

Cited by 91 publications

References 14 publications

Materials and technologies for microstructured high power laser fibers

Materials and technologies for microstructured high power laser fibers

A unified materials approach to mitigating optical nonlinearities in optical fiber. II. A. Material additivity models and basic glass properties

Progress in the fabrication of optical fibers by the sol-gel-based granulated silica method

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