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We propose a unidirectional emission silicon/III-V laser, which comprises an III-V quantum wells microdisk connected to an output waveguide and a silicon-on-insulator (SOI) waveguide. Characteristics of the III-V microdisk with an output waveguide and mode coupling between the III-V output waveguide and the SOI waveguide are investigated by three-dimensional (3D) finite-difference time-domain (FDTD) method. Simulation results show that the Q factor of a coupled mode for a 7.5 μm diameter microdisk connected to a 0.5 μm wide output waveguide is about 8.5×10. And the coupling efficiency between the III-V output waveguide and the SOI waveguide is over 96% when the III-V waveguide width is 0.5 μm, the SOI waveguide width is 0.565 μm and the vertical gap between those two waveguides is 0.1 μm. The proposed hybrid laser would be of valuable applications for on-chip interconnects. [ABSTRACT FROM AUTHOR]

Broadband optical absorption structures in the near infrared by coupling monolayer-graphene with periodical metal structures are proposed and demonstrated numerically. Optical absorption of graphene with over-50%-absorption bandwidth up to hundreds of nanometer caused by magnetic dipole resonances and magnetic coupling effect are investigated in detail, and the demonstrated bandwidths are one order higher than those caused by dielectric guiding mode resonances. In addition, the influences of geometrical parameters of structures are fully analyzed and these demonstrated structures show angular-insensitive absorption for oblique incidence in a large angular range. The demonstrated absorption structures in this work provide new design ideas in the realization of advanced graphene-based optoelectronic devices. [ABSTRACT FROM AUTHOR]