Active optical properties of Er-containing crystallites in sol–gel derived glass films

Low optical loss planar waveguides prepared in an organic–inorganic hybrid system

“…[1][2][3][4][5] One of the important reasons for that relies on the particle size control of the precursor material. In general, it is possible to produce particle sizes sufficiently small to keep Rayleigh scattering losses to an acceptable low level even for important volume fraction of nanoparticles.…”

Sol-gel Er-doped SiO2–HfO2 planar waveguides: A viable system for 1.5 μm application

“…[1][2][3] In particular, SiO 2 based planar waveguides produced by sol-gel route, could be promising materials for Erdoped waveguide amplifiers ͑EDWA͒ to be used in metropolitan area networks. [1][2][3][4][5] The key requirements for developing EDWAs by the sol-gel route are: ͑i͒ refractive index and thickness of the film have to be tailored, in order to satisfy both single-mode condition at 1.5 m and efficient coupling to fibers; ͑ii͒ the structural and optical homogeneity have to be optimized, in order to reduce losses and rare-earth clustering; 1,5 and ͑iii͒ the OH groups must be effectively removed, because the 4 I 13/2 luminescence of OH Ϫ -coordinated Er 3ϩ ions is completely quenched by two phonon-OH mechanism. 6,7 Among the silica-based systems, binary SiO 2 -TiO 2 has been widely used to produce Er-activated planar waveguides by sol-gel route.…”

“…12 Moreover, the precipitation of passive titania crystalline phases drastically shortens the lifetime of the 4 I 13/2 level. 4 Hafnium, like Ti, belongs to group 4 in the periodic table. Its oxide is transparent over a wide range of wavelengths and exhibits high refractive index.…”

“…sharp defect band, assigned to the (SiO) 4 -ring vibration; ͑iv͒ the absence of the bands at 1060 and 1190 cm Ϫ1 proper of the silica network; ͑v͒ the strong intensity of the boson peak, at about 55 cm Ϫ1 , which dominates the Raman spectrum; and ͑vi͒ the presence of the band centered at 970 cm Ϫ1 , attributed to the Si-O-Hf stretching. 15 The appearance of the 970 cm Ϫ1 Raman band suggests the effective molecular mingling of SiO 2 and HfO 2 components of the films.…”

Investigation of a New Class of Disordered Inorganic Materials

“…Recent work in France suggests that nanocrystalline inclusions in amorphous matrix may provide much better gain properties than dissolved erbium for fiber and waveguide amplifiers [58]. Both approaches may be suitable with Cerablak.…”