Hong-Ji Ma

Optical properties of stoichiometric LiNbO3 waveguides formed by low-dose oxygen ion implantation

The planar waveguides in z-cut stoichiometric LiNbO3 crystal have been fabricated by 3.0 MeV oxygen ion implantation with the dose of 6×1014ions∕cm2 at room temperature. The modes of the waveguides were measured by the prism-coupling method with the wavelength 633 and 1539 nm, respectively. The refractive index profiles of the waveguides were reconstructed using reflectivity calculation method. The Rutherford backscattering/channeling technique was used to investigate the damage produced by the ion implantation, the minimum yield of the spectra was 4.52%. The propagation loss of waveguide was 0.61 dB/cm obtained by fiber probe technique. It was found that positive changes of extraordinary refractive indices happened in the guiding regions, and such change increased after the annealing treatment at 260u2009°C for 60 min.

Ion-implanted optical-stripe waveguides in neodymium-doped calcium barium niobate crystals.

We report on the fabrication and characterization of optical-stripe waveguides in neodymium-doped calcium barium niobate (Nd:CBN) crystals by using He ion implantation assisted with a mask. The guided-mode profiles are successfully modeled through numerical simulations. After annealing at 200 degrees C for 30 min, the waveguide propagation loss could be reduced down to ~3 dB/cm. Room-temperature microluminescence and micro-Raman investigations reveal that the crystal bulk features are well preserved in the active volume of the waveguide, suggesting possible applications as integrated photonic devices.

Formation of waveguides by implantation of 3.0MeV Ni2

3.0MeV Ni2+ in the beam doses from 1×1013to9×1014ions∕cm2 are implanted into LiNbO3 single crystals at room temperature. After 300°C annealing for 30min in air ambient, dark mode measurement is done by the prism-coupling technique. Waveguides from both raised extraordinary index layer and barrier-confined are formed by low and high beam dose implantation, respectively. In the samples implanted by mediate beam doses, a phenomenon of “missing mode” is observed. The experimental results are analyzed and compared with the simulated results from a theoretical model, which is based on the assumption that the change of index induced by implantation is mainly governed by degradation of polarization and reduction of material density. With a fiber probe, the waveguide loss from single transverse magnetic mode is measured, which is about 3dB∕cm.

Optical channel waveguide in Nd/Ce codoped YAG laser crystal produced by carbon ion implantation

Optical channel waveguides in Nd/Ce codoped YAG laser crystal have been fabricated by using mask-assisted carbon ion implantation. The measured waveguide mode distributions were in good agreement with the calculated modal profiles, which implies the feasibility of designable devices. After thermal annealing treatment at 260 degrees C for 30 min in air, the propagation loss of the waveguide was reduced down to approximately 2 dB/cm at a wavelength of 632.8 nm. The microluminescence spectra of the waveguides show that the fluorescence properties of both Ce and Nd ions (including the energy transfer between them) are not significantly affected by the waveguide formation processing, which indicates a fairly good potential for further laser actions in a compact device.

Lithium niobate channel waveguide at optical communication wavelength formed by multienergy implantation

Channel waveguides at 1540 nm in X- and Z-cut LiNbO3 are formed by one-step multienergy MeV O2+ implantation. Single perpendicular mode in both planar and channel waveguides is demonstrated. In the ne channel waveguide, double transverse modes are observed because of the large index difference and broad width of the channel. A single transverse mode is obtained in the no channel waveguide. The thickness of the waveguide is less than 2 mum, and the compactness of the waveguide is attributed to the large index difference between the guiding region and the low-index barrier. The mode patterns and the waveguide loss are measured and analyzed. The loss of 0.9 and 0.7 dB/cm are obtained from the no and ne channel waveguides, respectively.

Property studies of optical waveguide formed by 6.0 MeV carbon ion implantation into Nd:silicate glass

Nd:silicate glass was implanted at room temperature by 6.0 MeV C3+ ions with a dose of 2.0 x 10(15) ions cm(-2). A waveguide with thickness of about 6.3 mu m was formed. The prism-coupling method was used to observe the dark modes of the waveguide at 633 nm and 1539 nm, respectively. There are three dark modes at 633 nm, of which one is the enhanced-index mode. The propagation loss of the enhanced-index mode in the waveguide measured at 633 nm is 0.42 dB cm(-1) after annealing at 217 degrees C for 35 min. The reflectivity calculation method was applied to simulate the refractive index profiles in the waveguide. The mode optical near-field output at 633 nm was presented.

Double optical waveguide in Cu-doped KNSBN crystal formed by MeV boron ion implantation

Abstract We reported for what is to be believed the first time a double optical waveguide in a Cu-doped potassium sodium strontium barium niobate (KNSBN) crystal formed by double boron ion implantation. The energy and dose of B + and B 3+ ions were (3+6) MeV and (2+2)×10 14 ions/cm 2 , respectively. The refractive index profile of the waveguide showed a double-barrier confined shape, which suggested the formation of a two-layer waveguide structure. The two waveguide layers were with thickness of 2.6 and 2xa0μm, respectively, which was in a good agreement with the parameters obtained from transport and range of ions in matter 98 (TRIM) code simulation. The nuclear energy loss distribution of the MeV B ions implanted into this crystal had a similar shape to that of the waveguide index profile, which means an inherent relationship between the waveguide formation and the energetic energy deposition.