Engineering lattice matching, doping level, and optical properties of KY(WO4)2:Gd,Lu,Yb layers for a cladding-side-pumped channel waveguide laser

S. Aravazhi, D. Geskus, Koop van Dalfsen, Sergio Andrés Vázquez-Córdova, C. Grivas, U. Griebner, Sonia Maria García Blanco, Markus Pollnau

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Abstract

Single-crystalline KY1-x-y-zGdxLuyYbz(WO4)2 layers are grown onto undoped KY(WO4)2 substrates by liquid-phase epitaxy. The purpose of co-doping the KY(WO4)2 layer with suitable fractions of Gd3+ and Lu3+ is to achieve lattice-matched layers that allow us to engineer a high refractive-index contrast between waveguiding layer and substrate for obtaining tight optical mode confinement and simultaneously accommodate a large range of Yb3+ doping concentrations by replacing Lu3+ ions of similar ionic radius for a variety of optical amplifier or laser applications. Crack-free layers, up to a maximum lattice mismatch of ~0.08 %, are grown with systematic variations of Y3+, Gd3+, Lu3+, and Yb3+ concentrations, their refractive indices are measured at several wavelengths, and Sellmeier dispersion curves are derived. The influence of co-doping on the spectroscopy of Yb3+ is investigated. As evidenced by the experimental results, the lattice constants, refractive indices, and transition cross-sections of Yb3+ in these co-doped layers can be approximated with good accuracy by weighted averages of data from the pure compounds. The obtained information is exploited to fabricate a twofold refractive-index-engineered sample consisting of a highly Yb3+-doped tapered channel waveguide embedded in a passive planar waveguide, and a cladding-side-pumped channel waveguide laser is demonstrated.
Original languageUndefined
Pages (from-to)433-446
Number of pages14
JournalApplied physics B: Lasers and optics
Volume111
Issue number3
DOIs
Publication statusPublished - May 2013

Keywords

  • IOMS-APD: Active Photonic Devices
  • IR-86216
  • METIS-297681
  • EWI-23407

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