High-gain optical amplification of europium-aluminum (Eu3+-Al)-nanocluster-doped planar polymer waveguides

We have fabricated a planar poly(methyl methacrylate) (PMMA) optical waveguide doped with 10 wt % Eu-Al nanoclusters, and have successfully demonstrated optical amplification at 610 nm excited by a N-2 laser (lambda = 337nm). The gain of the optical amplification was found to be as high as 5.57 dB/mm, which, to the best of our knowledge, is the highest observed for various rare-earth (RE)-doped planar optical waveguides. An Er-Al-nanocluster-doped PMMA optical waveguide has also been successfully fabricated, and guided emission at around 1.55 mu m has been observed in spite of the large absorption loss induced by PNIMA. The RE-metal nanoclusters can therefore be regarded as promising candidates as the active materials for polymer-based waveguide-type optical amplification devices.