Non-chemical Vapor Deposition Research Articles

Experiment research on optical properties of all microstructure optical fiber laser

We demonstrate a new all-fiber laser with Yb-doped double-cladding microstructure optical fiber (MOF) that is fabricated through non-chemical vapor deposition (Non-CVD) technology. In our experiments, both of the seed laser and amplifier are made of the same kind of Yb-doped MOF by spatial light coupling method. The amplifier output power is 5.03W with a one-stage amplifier when the seed laser power is 1.07W. The signal power is amplified about five times. These results can provide motivation for the application of Yb-doped MOF. It indicates that all microstructure optical fiber laser has the great potential to provide enormous output power scaling.

Transfer-Free Fabrication of Graphene Scaffolds on High-k Dielectrics from Metal–Organic Oligomers

In situ fabrication of graphene scaffold-ZrO2 nanofilms is achieved by thermal annealing of Zr-based metal-organic oligomers on SiO2 substrates. The structural similarities of the aromatic moieties in the ligand (phenyl-, naphthyl-, anthryl-, and pyrenyl-) compared to graphene play a major role in the ordering of the graphene scaffolds obtained. The depth profiling analysis reveals ultrathin carbon-pure or carbon-rich surfaces of the graphene scaffold-ZrO2 nanofilms. The graphene scaffolds with ∼96.0% transmittance in the visible region and 4.8 nm in thickness can be grown with this non-chemical vapor deposition method. Furthermore, the heterogeneous graphene scaffold-ZrO2 nanofilms show a low sheet resistance of 17.0 kΩ per square, corresponding to electrical conductivity of 3197 S m(-1). The strategy provides a facile method to fabricate graphene scaffolds directly on high-k dielectrics without transferring process, paving the way for its application in fabricating electronic devices.

Investigation on Yb3+-doped silica glass using sol-gel method and laser melting technology

Rare earth doped silica glass can be used as the central material of optical fiber, which can be applied to the fiber laser. It becomes a focus in the field of laser materials. Compared with different kinds of rare earth elements, ytterbium is regarded as a promising laser nuclear fusion material due to its simple level structure, strong energy conversion efficiency, long fluorescent lifetime, etc. Nowadays, the usual fabrication method of optical fiber preform is the chemical vapor deposition (CVD). However, the preform made by CVD has low doping concentration, few kinds of doping elements, low homogeneity and hard-to-make into optical fiber of large core diameter. To solve these problems, a noble method, which is called non-chemical vapor deposition (Non-CVD), is developed. Sol-Gel method is a kind of Non-CVD, which can perfectly solve the inhomogeneity in material. The glass has harmonious component since the whole process is at a liquid level.Sol-Gel method is a liquid phase synthesis method. The raw materials, including TEOS, absolute ethyl alcohol, ammonium hydroxide and deionized water, are uniformly mixed and become gel from sol through the hydrolysis and condensation. AlCl3 and YbCl36H2O are also added as the dopants. After that, heat the gel and let the hydroxyl and organic release, then we will be able to obtain the SiO2-doped powder. Combining with the laser melting technology, the ytterbium doped silica glass is made. It is known from the DSC-TG curve of xerogel that during the heating process, water and organic are expelled from the system. It needs a holding period at 500 ℃ to ensure that the water and organic are expelled adequately. Moreover, the FTIR spectrum shows that after high temperature treatment the OH- concentration in the xerogel decreases dramatically. The physical and spectrum properties of ytterbium doped silica glass are also tested. The Yb-doped silica glass which shows the amorphous state has good optical properties. The absorption spectrum and fluorescence spectrum demonstrate the typical absorption peak and emission peak of Yb3+, respectively. The density and refractive index of the glass are 2.409 g/cm3 and 1.462, respectively. The fluorescence lifetime () of the silica glass is 0.88 ms, the corresponding emission cross-section (emi) is 0.54 pm2, and the gain coefficient (emi) is 0.48 pm2m. In conclusion, the Yb-doped silica glass is successfully prepared by the Sol-Gel method combined with laser melting technology, which possesses good physical and optical properties. This work is meaningful for preparing high-performance Yb-doped fiber, and even for developing the high power laser.

Optical and laser properties of Tm3+-doped air-cladding fiber fabricated by plasma non-chemical vapor deposition

Tm3+/Al3+ co-doped silica glass with the composition of 0.08 Tm2O3–0.8 Al2O3–99.12 SiO2 (mol%) is prepared by combining the high-temperature plasma furnace sintering technology and the dried RE-doped granulates. Using the prepared Tm3+/Al3+ co-doped silica glass as the fiber core, the Tm3+/Al3+ co-doped air-cladding fiber is fabricated by the stack-and-draw technology. Optical and laser properties of Tm3+/Al3+ co-doped air-cladding fiber are studied. The experimental results show that the Tm3+/Al3+ co-doped air-cladding fiber can be used as the potential material for the high-power fiber laser operating at 2 μm.

Fabrication and laser performance of Yb3+/Al3+ co-doped photonic crystal fiber synthesized by plasma nonchemical vapor deposition method

In this paper, the bulk Yb3+/Al3+ co-doped silica glass with 1.3 Yb2O3–2.5Al2O3–96.2SiO2(wt%) are synthesized by plasma nonchemical vapor deposition method combining solution doping technology, where the inductively coupled plasma is used as the heat source. The influence of different O2/N2 ratios on the fluorescence properties of Yb3+/Al3+ co-doped silica glass are investigated. The large mode area photonic crystal fiber (PCF) is fabricated by using the bulk Yb3+/Al3+ co-doped silica glass as fiber core. The laser performance of Yb3+/Al3+ co-doped photonic crystal fiber is studied.

Influence of Yb2 + ions on the optical properties of Yb3 +/Ho3 + co-doped silica glass synthesized by non-chemical vapor deposition method

Yb3+/Ho3+ co-doped silica glasses are synthesized by the non-chemical vapor deposition method. The influence of Yb2+ ions on the optical properties of Yb3+/Ho3+ co-doped silica glass is investigated for the first time. The experimental results show that the formation of Yb2+ ions can improve the intensity of UV and visible light. However, Yb2+ ions have a determined effect on the energy transfer from Yb3+ ions to Ho3+ ions. To our knowledge, this is the first demonstrated on the influence of Yb2+ ions on the emission properties around 2μm of Ho3+ through Yb3+ sensitization in Yb3+/Ho3+ co-doped silica glass when it is excited at 980nm.

Optical properties of Yb3+/Ho3+ co-doped air cladding silica-based fiber fabricated with plasma non-chemical vapor deposition method

In this paper, the fibers with Yb3+/Ho3+ co-doped air cladding are fabricated by the plasma non-chemical vapor deposition method with the stack-capillary-draw technique for the first time to our knowledge. By the excitation at 975 nm, the fluorescence and up-conversion emission properties of these fibers are experimentally investigated. The mechanism of up-conversion emission is analyzed. The results show that such a fiber fabricated by using the plasma non-chemical vapor deposition method can be used as the potential material for the fiber laser at the visible and infrared spectral regions.

Ytterbium-doped silica photonic crystal fiber laser fabricated by the nanoporous glass sintering technique

Based on the sintering of ytterbium-doped nanoporous glass, a nonchemical vapor deposition process aimed at fabricating a large-mode area of photonic crystal fibers has been proposed for the preparation of active silica glass. With the relatively low doping concentration and boron in the silica glass as benefits, a close refractive index between the core and the cladding was obtained. The refractive index variation indicated good homogeneity of the doped fiber core. Up to 34.8 W laser output was demonstrated with the PCF laser and the slope efficiency was 71.3%. The output laser beam quality had slightly multimode behavior, with a mean M2 of 2.42.

Manufacture Technology Research of Large Mode Area and Yb<sup>3+</sup> Doped Photonic Crystal Fiber

The traditional technology in production of doped fiber has disadvantage of low doping concentration, uneven distribution of refractive index, being difficult to produce large core diameter etc. This paper according to the demand of high-power ytterbium doped photonic crystal fiber laser, makes a research of producing methods to large mode area, Yb3+ doped photonic crystal fiber. Anhydrous doping nanometer particles are obtained by solution doping method, using plasma non-chemical vapor deposition method produce fiber core material, large mode area, ytterbium doped fiber sample is made and laser properties experiments has been done. By experiments it is found that at 2cm pre-end of the sample has violet light, Yb3+ doped fiber has laser operation.

Spectral evolution of NIR luminescence in a Yb3+-doped photonic crystal fiber prepared by non-chemical vapor deposition

Silica-based Yb3+-doped glass is prepared by non-chemical vapor deposition. The drawn photonic crystal fiber (PCF) has a strong absorption at 976 nm and emission wavelength of approximately 1 037 nm. The intensity and spectral lineshape of the near infrared (NIR) luminescence of the Yb3+-doped PCF are recorded and discussed in terms of excitation power, excitation wavelength, fiber length, and Yb3+ ion concentration. The emission intensifies as the excitation power and Yb3+ ion concentration increase. The intensity of the shorter wavelength side of the luminescence spectrum decreases as the length of the PCF increases.

Fabrication of Graphene Directly on SiO2without Transfer Processes by Annealing Sputtered Amorphous Carbon

We fabricated multilayer graphene directly on SiO2 by annealing sputtered amorphous carbon with a catalyst – a simple non-chemical vapor deposition method – without the use of complicated transfer processes. Structural analysis revealed that the graphene sheets formed an epitaxial structure aligned to the Co(111) surface between the Co catalyst and SiO2 dielectric. In the multilayer graphene, a resistivity of approximately 500 µΩ cm was obtained, which is one order of magnitude higher than that of highly oriented pyrolytic graphite.

Fabrication of Graphene Directly on SiO2 without Transfer Processes by Annealing Sputtered Amorphous Carbon

We fabricated multilayer graphene directly on SiO2 by annealing sputtered amorphous carbon with a catalyst – a simple non-chemical vapor deposition method – without the use of complicated transfer processes. Structural analysis revealed that the graphene sheets formed an epitaxial structure aligned to the Co(111) surface between the Co catalyst and SiO2 dielectric. In the multilayer graphene, a resistivity of approximately 500 µΩ cm was obtained, which is one order of magnitude higher than that of highly oriented pyrolytic graphite.

Investigation on the fabrication and luminescence characteristics of Yb3+ and Al3+ Co-doped silicate glasses

We demonstrate a new method for fabrication of rare-doped silica-based glass, which is liquid doped with non-chemical vapor deposition (non-CVD) melting process. The Ytterbium doped silica-based glass with the ratio of 98SiO2-0.5Yb2O3-1.5Al2O3wt% is achieved by using this method. The refractive index (nD) and the density(ρ) of the glass are 1.519 and 2.62g/cm3 respectively. In measurement experiment, it shows that it has strong absorption in the wavelength range from 850nm to 1050nm, and the main absorption peak is at 978nm and the secondary absorption peak is at 919nm. Using the laser with wavelength of 978nm as pumping source, the emission peak is at 1018nm in the fluorescence spectrum with a 71.8nm fluorescence half-line width. Meanwhile, the integrated absorption cross section, stimulated emission cross section, fluorescence time, saturated pump intensity, minimum pump intensity and other parameters are calculated. Test results indicate that the doped silica-based glass has good thermal stability and large power threshold, which is an ideal gain medium for large power photonic crystal fiber lasers.