The characteristics of whispering-gallery-like modes in the equilateral triangle and square microresonators are introduced,including directional emission triangle and square microlasers connected to an output waveguide.We propose a photonic interconnect scheme by connecting two directional emission microlasers with an optical waveguide on silicon integrated circuit chip.The measurement indicates that the triangle microlasers can work as a resonance enhanced photodetector for optical interconnect.
Mode characteristics of hexagonal resonators are numerically simulated by the two-dimensional(2-D) finite-difference time-domain(FDTD) technique.For the hexagonal resonator with the side length of 3 μm and the refractive index of 3.2,the mode quality(Q) factors decrease from 104 to 102 as the resonant wavelength increases from 1.1 to 3.2 μm.The modes have a relatively high Q factor as their even and odd states have different mode wavelengths and different Q factors,i.e.,they are accidentally degenerate modes.The azimuthal mode numbers obtained from mode field distribution for the accidentally degenerate modes satisfy the mode number relation derived from the symmetry characteristics for the split of double-degenerate modes.Furthermore,the numerical results indicate that an output waveguide parallel to one of the sides is the better scheme for directional emission.For the hexagonal resonator with 3 μm side length and 0.3 μm wide output waveguide,the Q factor of 5.05×103 and output efficiency of 33% are obtained at the mode wavelength of 1.29 μm.
We propose a polarization-insensitive and broadband subwavelength grating reflector based on a multilayer structure.The reflector has an overlapped high reflectivity(>99.5%) bandwidth of 248 nm between the TE and the TM polarizations,which is much higher than the previously reported results.We believe this subwavelength grating reflector can be applied to unpolarized devices.
Mode radiation loss for microdisk resonators with pedestals is investigated by three-dimensional(3D) finite-difference time-domain(FDTD) technique.For the microdisk with a radius of 1μm,a thickness of 0.2μm,and a refractive index of 3.4,on a pedestal with a refractive index of 3.17,the mode quality(Q) factor of the whispering-gallery mode(WGM) quasi-TE_(7.1) first increases with the increase of the radius of the pedestal,and then quickly decreases as the radius is larger than 0.75μm.The mode radiation loss is mainly the vertical radiation loss induced by the mode coupling between the WGM and vertical radiation mode in the pedestal,instead of the scattering loss around the perimeter of the round pedestal.The WG M can keep the high Q factor when the mode coupling is forbidden.
The magnetic plasmon (MP) modes in the metal-dielectric-metal nanosandwich structure are investigated nu-merically,and the principle of energy resonance in such a resonator is proposed.An equivalent inductance capacitance circuit analysis method is proposed and the results are in agreement with the numerical simulations.Based on the MP resonance in such a structure,a nanosandwich chain waveguide is designed.Gold and silver are chosen as the metal materials.The power transmission efficiency of the nanosandwich waveguide can be as high as 0.546 in a specific nanosandwich unit cell,even when the metal absorption loss is large,which is the perspective of the new waveguides and lasers based on MP modes.
