Bo-Rong Shi

Monomode optical waveguide in lithium niobate formed by MeV Si+ ion implantation

The monomode enhanced-index LiNbO3 waveguide fabricated by low-dose ion implantation is reported. LiNbO3 crystals were implanted with 3 MeV Si+ ions to doses around 1014 ions/cm2. After annealing, the waveguides were formed by the extraordinary refractive index enhancement in the waveguide regions. The effective extraordinary refractive index of the waveguide increased with ion implantation dose. The loss was 0.64 dB/cm in the X-cut sample with an implantation dose of 3.3×1014 ions/cm2. The scattering loss in the Z-cut samples was even lower than that in the X-cut samples.The monomode enhanced-index LiNbO3 waveguide fabricated by low-dose ion implantation is reported. LiNbO3 crystals were implanted with 3 MeV Si+ ions to doses around 1014 ions/cm2. After annealing, the waveguides were formed by the extraordinary refractive index enhancement in the waveguide regions. The effective extraordinary refractive index of the waveguide increased with ion implantation dose. The loss was 0.64 dB/cm in the X-cut sample with an implantation dose of 3.3×1014 ions/cm2. The scattering loss in the Z-cut samples was even lower than that in the X-cut samples.

Waveguide laser film in erbium-doped KTiOPO4 by pulsed laser deposition

Erbium doping into potassium titanyl phosphate (KTiOPO4 or KTP) was performed by pulsed laser deposition. Waveguide laser film in Er-doped KTiOPO4 was formed using both KTiOPO4 and erbium as targets and optically polished KTiOPO4 as a substrate. Rutherford backscattering, photoluminescence spectrometry, x-ray diffraction, and prism coupling method are used to investigate the properties of Er-doped KTiOPO4. The results show that (1) Er-doped KTiOPO4 emits the characteristic photoluminescence of Er3+ around 1.54 μm corresponding to transition between the 4I13/2 and 4I15/2 manifolds of the Er3+ ions in KTiOPO4 host. (2) two bright modes in Er-doped KTiOPO4 were observed. This approach may be useful for direct fabrication of thin film waveguide laser for other optoelectrical materials.

Ion-implanted waveguides in Nd3+-doped silicate glass and Er3+/Yb3+ co-doped phosphate glass

The data are presented on the waveguides formation in the Nd 3þ -doped silicate glass and Er 3þ /Yb 3þ co-doped phosphate glass by the implantations of He þ or Si þ ions, respectively. The prism-coupling method is used to measure the effective refractive indices of the waveguide dark modes. The refractive index profiles of the waveguides are reconstructed by using the reflectivity calculation method (RCM) and a comparison of such profiles among the different waveguides has been made. The reasons for the formation of the present waveguides are analyzed in a primary way. # 2002 Elsevier Science B.V. All rights reserved.

Mean projected range and range straggling of 50‐ to 400‐keV Hg+ in glass

The range profile of Hg+ implanted at energies from 50 to 400 keV in glass was measured by 4He+ Rutherford backscattering. The measured projected ranges are in good agreement with those predicted by the Biersack model. A marked improvement in the range straggling fit is obtained after considering the second‐order energy loss.

Optical waveguide formation by MeV H+ implanted into LiNbO3 crystal

Abstract A MeV H+ ion-implanted waveguide was formed on an LiNbO3 substrate. The dose of implanted H+ ions was 2×1016 ions/cm2 with an energy of 1.0 MeV at room temperature. The dark modes were measured using the prism coupling technique. The refractive index profile was analyzed using the reflectivity calculation method. The fiber probe technique was used to measure the attenuation of the waveguide. The lattice damage in the guide region caused by H+ ion implantation was investigated using the RBS/channeling technique.

Calculation of mean projected range and range straggling of heavy ions in polyatomic targets

Based on Biersacks angular diffusion model for the slowing down of ions in matter, an efficient method has been developed for calculating the mean projected range and range straggling of heavy ions in polyatomic targets. The method differs from both the LSS procedure and Monte Carlo simulation. Heavy ions such as Br+, Au+, Hg+ and Bi+ have been chosen. The target ranged from diatomic to heptatomic, and included amorphous SiO2, quartz, polymers, Li0.16Na0.84NbO3 crystals, tungsten bronze crystals and seven-component glasses. In each case, calculated values are compared with experimental data at energies from 50 to 400 keV. Good agreement between calculated and experimental values of the mean projected range is found for the first-order treatment in Biersacks model; for the range straggling, the calculated values are much lower than experimental values in the first-order treatment. However, after considering the second-order energy loss, marked improvements are obtained.

Optical Waveguide in X-Cut LiNbO3 Crystals by MeV P+ Ion Implantation with Low Dose

The X-cut, Y-propagation LiNbO 3 crystals were implanted by 2.8 MeV P + ions with doses of ∼1 x 10 14 ions/cm 2 at room temperature. Planar optical waveguides were formed by P + implantation at doses of 1 × 10 14 , 2 × 10 14 . 3 × 10 14 and 4 x 10 14 ions/cm 2 . Contrary to high-dose ion-implanted waveguides, the extraordinary refractive index was found to increase in the guide region for implantation with low doses by the dark mode. When the light beam was coupled to the LiNbO 3 waveguide which was formed by MeV P + implantation at a dose of 1 x 10 14 ions/cm 2 and a following annealing at 200 °C for 30 min in air, obvious light was found propagating through the entire length of the waveguide, and Rutherford Backscattering (RBS)/channeling technique was used to characterize the lattice reconstruction of LiNbO 3 crystals after the annealing treatment.

Waveguide formation in LiTaO3 and LiB3O5 by keV hydrogen ion implantation

Abstract Lithium tantalate (LiTaO 3 ) samples were implanted with H + ions at different energies from 250 to 350 keV using different doses. Lithium triborate (LiB 3 O 5 ) samples were implanted at 350 keV H + ions with doses from 1×10 16 to 5×10 16 ions/cm 2 in increment of 1×10 16 ions/cm 2 at room temperature. The modes in LiTaO 3 and LiB 3 O 5 samples were measured by a model 2010 prism coupler. Two or three modes were observed in most cases. The change of the refractive index depends on the energy, dose and annealing temperature. Multi-energy implantation was used to broaden the optical barrier. There is a threshold dose of around 4×10 16 ions/cm 2 for LiB 3 O 5 which is different from the case of LiTaO 3 . The preliminary results show that the waveguide formation in LiTaO 3 and LiB 3 O 5 crystals is possible by using keV H + ion implantation.

Optical Waveguide of MeV Hydrogen Ion Implanted KTiOPO4.

The first MeV hydrogen ion implanted waveguide in KTiOPO4 is reported. The planar optical waveguide in KTiOPO4 was fabricated by 1.0 MeV hydrogen ions to a dose of 2×1016 ions/cm2 at room temperature. The dark modes were observed by prism coupling. Both refractive index profiles before and after annealing show a typical barrier waveguide in KTiOPO4 formed by 1.0 MeV hydrogen ion implantation. After annealing at 200°C for 30 min, a 0.4% decrease in the refractive index was observed. Loss is estimated to be less than 2.2 dB/cm.

The mean projected range and range straggling of Xe ions implanted in Si and Si1N1.375H0.603

Abstract Xe ions at energies from 50 to 400 keV as well as from 600, 800 and 1000 keV were implanted into Si and Si1N1.375H0.603, respectively. The mean projected ranges and range stragglings are measured by Rutherford backscattering of MeV He ions. The values obtained are compared with different calculation procedures. The results show that the maximum differences between experimental and calculated values are 11%, 14% and 7% by transport of ions in matter (TRIM), projected range algorithm (PRAL) and Wang and Shi (WS) calculation procedure based on Biersacks model, respectively. The experimental range stragglings are higher than the calculated ones for the case of 50–400 keV Xe ions implanted into amorphous Si. As for the case of 600, 800 and 1000 keV Xe implanted into Si1N1.375H0.603, the maximum differences between experimental and calculated values of the mean projected range are 25%, 26% and 15% by TRIM, PRAL and WS, respectively. Also it is observed that there are significant deviations of the experimental values from the calculated values for the range straggling.