Papers by Keyword: Photonic Integrated Circuits

Abstract: We demonstrate self-collimation phenomena based on a new type of photonic crystals made of square lattice with ring shaped holes. The plane wave expansion (PWE) method is used to get the three dimensional band diagram and equi-frequency of the second band which displays the self-collimation phenomena for the structure we proposed in this paper. The collimation angle is mainly depending on the maximum flatness half width (MFHW) of the equi-frequency. The FDTD method is employed to demonstrate the electric field amplitude distributions for the collimation phenomena. Partly, in order to achieve high efficient coupling of the input and output port, we modify both surface structures to modulate the wave-front to obtain desired effect. The parameter of the input surface is modified which will prevent the production of surface modes which takes away the EM power and enhance the transmittance. For a square lattice with the modified parameters at each side of the input surface, the surface modes are suppressed to couple with the continuum of the dielectric waveguide modes. More importantly, they might have potential application in integrated optical circuits.

Abstract: We investigate the influence of sputtered silica as annealing cap on the enhancement of intermixing rate of semiconductor quantum nanostructures. After sputtered silica application and subsequent rapid thermal annealing, we observed bandgap shift of over 200 meV with respect to the bandgap of as-grown material from various GaAs-based quantum well (QW) heterostructures such as GaAs/AlGaAs, InAlGaP/GaAs, and GaAs/AlGaAs systems at significantly lower temperature than the conventional dielectric cap process with plasma enhanced chemical vapor deposition (PECVD). The results suggest that the sputtered silica process is a promising intermixing technique for the monolithic integration of multiple active/passive photonic components on GaAs-based material systems.