Abstract: Disclosed is an optical device with enhanced pumping efficiency where light from a pumping light source is efficiently absorbed in a gain medium structure placed under the pumping light. The major characteristic of the optical device of the present invention is that it is top-pumped and a portion in the gain medium structure, which is included in a beam spot of the light source, has a larger area than other portions in the gain medium structure. According to the present invention, a top-pumped optical device with higher pumping efficiency can be provided.

Abstract: The present invention relates to a input light signal waveguide amplifier which is comprised of silica or silica-related material co-doped with silicon nanoclusters and rare earth elements, and more particularly, to a pumping light h 100 waveguide amplifier with higher efficiency enhanced by top-pumping method and focusing means for pumping light. The waveguide amplifier of the present invention comprises of: (a) a substrate; (b) an optical waveguide including: a lower cladding layer formed on the substrate; a core layer which is made of silica or silica-related material co-doped with silicon nanoclusters and rare earth elements on the lower cladding layer and has a refractive index higher than that of the lower cladding; and an upper cladding layer formed on the core layer; and (c) a light source, spaced apart from the waveguide, for optically pumping the waveguide, wherein the waveguide amplifier operates by exciting the rare earth elements through electron-hole combinations in the silicon nanoclusters.

Abstract: Thin film for optical applications, light-emitting structure using the same and the fabrication method thereof are disclosed. The present invention provides a silica or silica-related thin film for optical applications in which silicon nanoclusters and rare earth elements are co-doped. The average size of the silicon nanoclusters is less than 3 nm and the concentration of the rare earth elements is less than 0.1 atomic %. The ratio of the rare earth element concentration to that of silicon nanoclusters is controlled to range from 1 to 10 in the thin film. The thin film emits light by exciting the rare earth elements through electron-hole recombinations in the silicon nanoclusters. According to the present invention, the conditions such as the size and concentration of the silicon nanoclusters, the concentration of the rare earth element, and their concentration ratio are specifically optimized to fabricate optical devices with better performance.