Polarization-Insensitive Silica on Silicon Arrayed Waveguide Grating Design

A new technology for fabrication of silica on silicon arrayed waveguide grating (AWG) based on deep etching and thermal oxidation is presented.Using this method,a silicon layer is remained at the side of waveguide.The stress distribution and effective refractive index of waveguide fabricated by this approach are calculated using finite element and finite difference beam propagation method,respectively.The results of these studies indicate that the stress of silica on silicon optical waveguide can be matched in parallel and vertical direction and AWG polarization dependent wavelength (PDλ) can be reduced effectively due to side-silicon layer.

Stress analysis of silica-based arrayed waveguide grating by a finite element method

The stress distribution in silica optical waveguides on silicon is calculated by using finite element method (FEM). The waveguides are mainly subjected to compressive stress along the x direction and the z direction, and it is accumulated near the interfaces between the core and cladding layers. The shift of central wavelength of silica arrayed waveguide grating (AWG) on silicon-substrate with the designed wavelength and the polarization dependence are caused by the stress in the silica waveguides.

Preparation and characterization of erbium doped sol-gel silica glasses

Erbium-doped silica glasses were made by sol-gel process. Intensive photoluminescence (PL) spectra from the Er-doped silica glasses at room temperature were measured. A broadband peak at 1535 ma, corresponding to the I-4(13/2)-I-4(15/2) transition, its full width at half-maximum (FWHM) of 10 nm, and a shoulder at 1546 nm in the PL spectra were observed. At lower temperatures, main line of 1535 nm and another line of 1552 Mn instead of 1546 nm appear. So two types of luminescence centers must exist in the samples at different temperature. The intensity of main line does not decrease obviously with increasing temperature. By varying the Er ion concentration in the range of 0.2 wt% - 5wt%, the highest photoluminescence intensity was obtained at 0.2wt% erbium doped concentration. Luminescence intensity decreases with increasing erbium concentration. Cooperative upconversion was used to explain the concentration quenching of luminescence from silica glass with high erbium concentration. Extended X-ray absorption fine structure measurements were carried out. It was found that the majority of the erbium impurities in the glasses have a local structure of eight first neighbor oxygen atoms at a mean distance of 0.255 nm, which is consistent with the typical coordination structure of rare earth ion.

Generation of 10 GHz, 1.9 ps optical pulse train using semiconductor optical amplifier and silica-based highly nonlinear fiber

We propose a simple approach to generate a high quality 10 GHz 1.9 ps optical pulse train using a semiconductor optical amplifier and silica-based highly nonlinear fiber. An optical pulse generator based on our proposed scheme is easy to set up with commercially available optical components. A 10 GHz, 1.9 ps optical pulse train is obtained with timing jitter as low as 60 fs over the frequency range 10 Hz-1 MHz. With a wavelength tunable CW laser, a wide wavelength tunable span can be achieved over the entire C band. The proposed optical pulse generator also can operate at different repetition rates from 3 to 10 GHz.

Linear and nonlinear optical properties of the PbSe quantum dots doped germane-silica glass optical fiber

We report development of a new fiber doped with PbSe quantum dots for nonlinear optical applications. PbSe quantum dots related absorption peaks were obtained at 1021, 1093 and 1351 nm. The resonant optical nonlinearity and attenuation at 1500 nm were measured to be 9.4 × 10−16 m2/W and 0.01 dB/m, respectively. The emission around 1540 nm was observed upon near resonant pumping at 1064 nm.