Kunlun Yan

Chemical environment of rare earth ions in Ge28.125Ga6.25S65.625 glass-ceramics doped with Dy3+

We have annealed Ge28.125Ga6.25S65.625 glasses doped with 0.5% Dy to create glass-ceramics in order to examine the local chemical environment of the rare earth ions (REI). More than 12 times enhancement of the emission at 2.9 and 3.5 μm was achieved in glass-ceramics produced using prolonged annealing time. Elemental mapping showed clear evidence that Ga2S3 crystalline grains with a size of 50 nm were dispersed in a Ge-S glass matrix in the glass-ceramics, and the REI could only be found near the Ga2S3 crystalline grains. From the unchanged lineshape of the emissions at 2.9 and 3.5 μm and lack of splitting of the absorption peaks, we concluded that the REI were bonded to Ga on the surface of the Ga2S3 crystals.

Photoluminescence in Er-doped Ge-As-Se chalcogenide thin films

We report ion-implanted Er ions into Ge<inf>11.5</inf>As<inf>24</inf>Se<inf>64.5</inf> thin films with different doses, and subsequently thermal-annealed the films with different times. The characterization results indicated that the thickness, refractive index and optical bandgap of the films can be stabilized with 3 hour thermal annealing. The 1.5 μm emission arising from the ⁴I<inf>13/2</inf>→⁴I<inf>15/2</inf> transition was observed and a lifetime of 1.35 ms was obtained in films annealed at 180°C.

Emission properties of erbium-doped Ge-Ga-Se glasses, thin films and waveguides for laser amplifiers

We report, for the first time, Er-doped Ge-Ga-Se films and waveguides deposited using co-thermal evaporation and patterned with plasma etching. The emission properties of the bulk glasses were studied as a function of Erbium doping, showing for the first time that there is a clear concentration quenching effect in the Ge-Ga-Se glasses with a linear radiative lifetime degradation slope of −0.48 ms/mol% Er from a low concentration lifetime of 1.7 ms, even when sufficient Gallium is present to ensure homogeneous distribution of the Erbium. A region between approximately 0.5 and 0.75 mol% Erbium however is shown to provide sufficient doping, good photoluminescence and adequate lifetime to envisage practical planar waveguide amplifier devices. Film emission properties at 0.7 mol% doping were studied and compared with the bulk counterpart showing adequate lifetimes and photoluminescence. Erbium doped films with ~0.8 dB/cm propagation loss at 1550 nm limited by Mie scattering off small particles ejected from the evaporation crucible were fabricated. Planar hybrid Er-Ge-Ga-Se/As2S3 rib waveguides fabricated through photolithography and plasma etching demonstrated propagation losses of ~2 dB/cm at 1650 nm limited by particulate scattering.

Internal gain in Er-doped As₂S₃ chalcogenide planar waveguides.

Low-loss erbium-doped As₂S₃ planar waveguides are fabricated by cothermal evaporation and plasma etching. Internal gain in the telecommunications band is demonstrated for the first time in any chalcogenide glass and additionally in a thin film planar waveguide amplifier configuration.

Hybrid waveguide from As 2 S 3 and Er-doped TeO 2 for lossless nonlinear optics

The fabrication and characterization of loss-compensated dispersion-engineered nonlinear As(2)S(3) on Er:TeO2 waveguides is reported for the first time, to the best of our knowledge. The hybrid waveguide is a strip loaded structure made from an Er-doped TeO2 slab and an etched As(2)S(3) strip. Almost complete loss compensation is demonstrated with 1480 nm pumping and a fully lossless waveguide with high nonlinear coefficient can be achieved with higher 1480 nm pump power.

Greater than 50% inversion in Erbium doped Chalcogenide waveguides.

We report Er-doped Ge-Ga-Se films and waveguides deposited using co-thermal evaporation and patterned with plasma etching. Strong photoluminescence at 1.54 µm with intrinsic lifetime of 1 ms was obtained from deposited films with 1490 nm excitation. Erbium population inversion up to 50% was achieved, with a maximum of ~55% possible at saturation for the first time to the authors knowledge, approaching the theoretical maximum of 65%. Whilst gain was not achieved due to the presence of upconversion pumped photoinduced absorption, this nonetheless represents a further important step towards the realization of future chalcogenide Erbium doped waveguide amplifiers at 1550 nm and in the Mid-infrared.

Intense Photoluminescence from Er Doped Chalcogenide Thin Films Fabricated by Cothermal Evaporation

Erbium doped chalcogenide films were fabricated by cothermal evaporation and demonstrated propagation losses and lifetimes suitable for waveguide amplifiers. The 1490nm pumped Photoluminescence yield is up to ~10x higher than the prior best film material, Er:TeO2.

Hybrid As2S3:Er-TeO2 Loss Compensated Nonlinear Waveguides

Single mode anomalous dispersion As₂S₃ on Er doped TeO₂ waveguides with near zero propagation loss under 1475nm pumping are demonstrated. Fully lossless waveguides with high nonlinear coefficient can be achieved with higher 1480nm pump power.

Hybrid waveguide from As₂S₃ and Er-doped TeO₂ for lossless nonlinear optics

The fabrication and characterization of loss-compensated dispersion-engineered nonlinear As(2)S(3) on Er:TeO2 waveguides is reported for the first time, to the best of our knowledge. The hybrid waveguide is a strip loaded structure made from an Er-doped TeO2 slab and an etched As(2)S(3) strip. Almost complete loss compensation is demonstrated with 1480 nm pumping and a fully lossless waveguide with high nonlinear coefficient can be achieved with higher 1480 nm pump power.

Hybrid waveguide from As_2S_3 and Er-doped TeO_2 for lossless nonlinear optics

The fabrication and characterization of loss-compensated dispersion-engineered nonlinear As(2)S(3) on Er:TeO2 waveguides is reported for the first time, to the best of our knowledge. The hybrid waveguide is a strip loaded structure made from an Er-doped TeO2 slab and an etched As(2)S(3) strip. Almost complete loss compensation is demonstrated with 1480 nm pumping and a fully lossless waveguide with high nonlinear coefficient can be achieved with higher 1480 nm pump power.