IPG Photonics

About: IPG Photonics is a based out in . It is known for research contribution in the topics: Laser & Fiber laser. The organization has 903 authors who have published 1241 publications receiving 63339 citations.

Decomposition of the elastic tensor and geophysical applications

Abstract: SUMMARY Elasticity is described in general by a fourth-order tensor with 21 independent coefficients, which corresponds to the triclinic symmetry class. However seismological observations are usually explained with a higher order of symmetry using fewer parameters. We propose an analytical method to decompose the elastic tensor into a sum of orthogonal tensors belonging to the different symmetry classes. The method relies on a vectorial description of the elastic tensor. Any symmetry class constitutes a subspace of a class of lower symmetry and an orthogonal projection on this subspace removes the lower symmetry part. Orthogonal projectors on each higher symmetry class are given explicitly. In addition, the method provides optimal higher symmetry approximations, which allow us to decrease the number of independent parameters. Consequences of the symmetry approximation of the elastic tensor on shear wave splitting (SWS) are investigated for upper-mantle minerals (olivine and enstatite), natural samples and numerically deformed olivine aggregates. The orthorhombic part of the elastic tensor as well as the presence of enstatite are important second-order effects.

Amorphous materials: Properties, structure, and durability: Structure of Mg- and Mg/Ca aluminosilicate glasses: 27Al NMR and Raman spectroscopy investigations

Abstract: The structure and properties of glasses and melts in the MgO-Al2O3-SiO2 (MAS) and CaO-MgO-Al2O3-SiO2 (CMAS) systems play an important role in Earth and material sciences. Aluminum has a crucial influence in these systems, and its environment is still questioned. In this paper, we present new results using Raman spectroscopy and 27Al nuclear magnetic resonance on MAS and CMAS glasses. We propose an Al/Si tetrahedral distribution in the glass network in different Qn species for silicon and essentially in Q4 and VAl for aluminum. For the CMAS glasses, an increase of VAl and VIAl is clearly visible as a function of the increase of Mg/Ca ratio in the (Ca,Mg)3Al2Si3O12 (garnet) and (Ca,Mg)AlSi2O8 (anorthite) glass compositions. In the MAS system, the proportion of VAl and VIAl increases with decreasing SiO2 and, similarly with calcium aluminosilicate glasses, the maximum of VAl is located in the center of the ternary system.

DWDM 40 G transmission over trans-Pacific distance (10,000 km) casing CSRZ-DPSK, enhanced FEC and all-Raman amplified 100 km UltraWave/spl trade/ fiber spans

Abstract: We demonstrate error-free dense-wavelength-division multiplexing (DWDM) transmission of 40 40-Gb/s channels with 100-GHz spacing over 10 000 km dispersion-managed fiber using carrier-suppressed return-to-zero differential-phase-shift keying (CSRZ-DPSK), enhanced foward-error correction, and all-Raman-amplified spans with 100-km terrestrial length.

Methods and systems for coherent imaging and feedback control for modification of materials

Abstract: Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser or welding applications. An imaging optical source that produces imaging light. A feedback controller controls at least one processing parameter of the material modification process based on an interferometry output generated using the imaging light. A method of processing interferograms is provided based on homodyne filtering. A method of generating a record of a material modification process using an interferometry output is provided.