Y.E. Romanyuk

Yb-doped KY(WO4)2 planar waveguide laser

High-quality monoclinic KY(WO4)2 optical waveguides were grown by liquid-phase epitaxy, and laser operation of an Yb-doped KY(WO4)2 waveguide was demonstrated for the first time to our knowledge. Continuous-wave laser emission near 1 microm was achieved with both surface and buried planar waveguides. An output power of 290 mW was obtained in the fundamental mode and the slope efficiency was above 80%.

Double Tungstate Lasers: From Bulk Toward On-Chip Integrated Waveguide Devices

It has been recognized that the monoclinic double tungstates KY(WO4)2, KGd(WO4)2, and KLu(WO4)2 possess a high potential as rare-earth-ion-doped solid-state laser materials, partly due to the high absorption and emission cross sections of rare-earth ions when doped into these materials. Besides, their high refractive indexes make these materials potentially suitable for applications that require optical gain and high power in integrated optics, with rather high integration density. We review the recent advances in the field of bulk lasers in these materials and present our work toward the demonstration of waveguide lasers and their integration with other optical structures on a chip.

Lu, Gd codoped KY(WO4)(2): Yb epitaxial layers: towards integrated optics based on KY(WO4)(2)

Codoping KY(WO(4))(2):Yb layers with optically inert Lu and Gd ions allows a large increase of the refractive index contrast with respect to KY(WO(4))(2) substrates. This paves the way for the realization of integrated optical circuits based on this very promising material. First riblike waveguide structures have been fabricated and propagation losses below 1 dB/cm have been evaluated. A Y-junction with a splitting ratio close to 1:1 and additional losses of 1.4 dB has also been demonstrated.

Tm:KY(WO4)2 waveguide laser

High-quality monoclinic planar waveguide crystals of Tm-doped KY(WO(4))(2) were grown by liquid-phase epitaxy with several dopant concentrations and thicknesses. Waveguide lasing in the 2 mum spectral range was demonstrated in the fundamental mode. The maximum continuous-wave output power achieved was 32 mW using a Ti:sapphire laser pump near 800 nm.

Tm:KY{(WO_4)}_2 waveguide laser

High-quality monoclinic planar waveguide crystals of Tm-doped KY(WO(4))(2) were grown by liquid-phase epitaxy with several dopant concentrations and thicknesses. Waveguide lasing in the 2 mum spectral range was demonstrated in the fundamental mode. The maximum continuous-wave output power achieved was 32 mW using a Ti:sapphire laser pump near 800 nm.

KY(WO 4 ) 2 :Tm 3+ planar waveguide laser

Waveguide lasing of monoclinic KY(WO₄)₂:Tm³⁺ grown by liquid-phase epitaxy is demonstrated in the 2 mum spectral range. The maximum continuous-wave output power achieved was 32 mW in the fundamental mode.

Optical Rib Waveguide Structures Based on (Lu, Gd) Co-doped KY(WO 4 ) 2 : Yb Epitaxial Layers

Co-doping KY(WO<inf>4</inf>)<inf>2</inf>: Yb layers with Lu and Gd increases 10x the refractive-index-contrast with respect to KY(WO<inf>4</inf>)<inf>2</inf> substrates. These results pave the way for integrated optical circuits in this promising material.

KY(WO/sub 4/)/sub 2/:Yb/sup 3+/ planar waveguide laser

Continuous-wave waveguide lasing in a thin layer of monoclinic KY(WO/sub 4/)/sub 2/:Yb/sup 3+/ grown by liquid-phase epitaxy is demonstrated at 1024 nm in the fundamental mode with 50% slope efficiency and 290 mW of output power.

Flux growth and liquid-phase epitaxy of Mn/sup 6+/ -doped molybdates and tungstates

We performed a systematic investigation of Mn/sup 6+/ in (Ca/Sr/Ba)(Mo/W)O/sub 4/ compounds which can be divided into three parts. Crystal-growth experiments in order to estimate the best conditions for liquid-phase epitaxy (LPE) of thin films doped with Mn/sup 6+/, whose spectroscopic properties are then studied. Since Mn/sup 6+/ tends to be reduced to Mn/sup 5+/ at temperatures T>600/spl deg/C, we used NaCl-KCl-CsCl as a solvent for the flux and LPE experiments. Due to the low solidification temperature of the solvent (480/spl deg/C), the maximum growth temperature could be kept below 600/spl deg/C. The dependencies of the crystal dimensions versus solute concentration for all six (Ca/Sr/Ba)(Mo/W)O/sub 4/ compounds were constructed from the results of the flux experiments.