Abstract: The invention relates to a waveguide laser or amplifier material comprising a silica glass host material, one or more rare earth elements in total concentration CRE at. %, one or more network modifier elements selected from the group of tri- or penta-valent atoms of the periodic table of the elements in total concentration CNME at. %, wherein the ratio of atomic concentrations of the modifier elements to that of the rare earth elements CNWCRE is larger than or equal to 1, and wherein the total atomic concentration of rare earth and the tri-valent network modifiers, such as aluminium and/or boron, is substantially equal to the atomic concentration of the penta-valent network modifier, such as phosphorous. Such materials exhibit reduced risk of photo darkening.

Abstract: An integrated photonic crystal (IPC) structure and method of producing the same in which the IPC structure includes a first layered sub-structure with a surface and a one-dimensional periodic refractive index variation along the direction perpendicular to the surface, and a second sub-structure with a plurality of essentially straight identical passages arranged in a two-dimensional periodic pattern cutting through the layered structure at an angle ?. First and second defects in the first and second sub-structures, respectively, enable electromagnetic modes to be localized in the vicinity of the defects and allow photonic crystal waveguide to be constructed that can control and filter light very efficiently and minimize radiation losses.

Abstract: An integrated photonic crystal (IPC) structure and method of producing same is disclosed. The (IPC) structure includes a first layered sub-structure (610, 620) with a surface and a one-dimensional periodic refractive index variation along the direction perpendicular to the surface. This first layered sub-structure enables a photonic band gap or high omnidirectional reflectivity for propagation of radiation having a spectrum of electromagnetic modes incident from a direction perpendicular to the plane of the surface. The PC-structure further includes a first defect (630) in the first layered sub-structure that enables an electromagnetic mode to be localised in the vicinity of the first defect. The electromagnetic radiation is hereby vertically confined. Furthermore, the IPC-structure consists of a second sub-structure with a plurality of essentially straight identical passages (635) arranged in a two-dimensional periodic pattern cutting through the layered structure at an angle &agr;.

Abstract: An integrated silicon mesa structure integrated in a glass-on-silicon waveguide, and a method of manufacturing it. The silicon mesa waveguide is integrated in a glass-on-silicon waveguide composed of a wave-guiding core between lower and upper sheath layers having a refractive index lower than the index of the wave-guiding core. The silicon mesa structure is preferably made of the silicon substrate, and a low loss silicon mesa waveguide is formed by removing excess material below the mesa structure. Further, transitions between the glass-on-silicon waveguide the the silicon mesa waveguide section are preferably formed such that transmission of light passing the transitions is adiabatic.