The highly nonequilibrium conditions under which optical fibers conventionally are drawn afford considerable, yet underappreciated, opportunities to realize fibers comprised of novel materials or materials that themselves cannot be directly fabricated into fiber form using commercial scalable methods. Presented here is an in-depth analysis of the physical, compositional, and selected optical properties of silica-clad erbium-doped yttrium aluminosilicate glass optical fibers derived from undoped, 0.25, and 50 wt % Er3+-doped yttrium aluminum garnet (YAG) crystals. The YAG-derived fibers were found to be noncrystalline as evidenced by x-ray diffraction and corroborated by spectroscopic measurements. Elemental analysis across the core/clad interface strongly suggests that diffusion plays a large role in this amorphization. Despite the noncrystalline nature of the fibers, they do exhibit acceptable low losses (∼0.15–0.2 dB/m) for many applications, broad-band emissions in the near-infrared, and enhanced thermal conductivity along their length while maintaining equivalent mechanical strength with respect to conventional silica optical fibers. Further, considerably higher rare-earth doping levels are realized than can be achieved by conventional solution or vapor-phase doping schemes. A discussion of opportunities for such approaches to nontraditional fiber materials is presented.

We report diode-pumped Er3+:Y2O3 ceramic laser with ~14 W of true CW output at ~2.7 μm. This presents nearly ten-fold power increase with respect to previous best result with this laser material. We also believe this to be the highest power ever reported from Er3+ -doped bulk crystalline laser operating in a ~3-μm wavelength range. Power-scaled performance of 974-nm pumped Er3+:Y2O3 laser was achieved with the slope efficiency of ~26%.

Reported here is the first cryogenically-cooled performance of Er 3+ -doped Y2O3 laser based on 4 I 11/2 → 4 I 13/2 transitions. Laser material was diode-pumped directly into an upper laser manifold 4 I 11/2 in order to minimize quantum defect of this Mid-IR laser. CW output power of over 1.6 W at ∼ 2.7 μm was achieved with the 27.5% slope efficiency, which is approaching the quantum defect-limited efficiency value despite the marginal optical quality of the available laser sample.

We report relevant spectroscopy and efficient diodepumped ∼2.7‐μ m laser operation of Er3+:Y2O3 ceramic resonantly pumped into upper laser level 4I11/2. This is believed to be the first laser demonstration based on 4I11/2 → 4I13/2 transitions of Er3+ in Y2O3. (© 2010 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA)

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