D. M. H. Leung

Numerical analysis of bent waveguides: bending loss, transmission loss, mode coupling, and polarization coupling

A rigorous, full-vectorial and computationally efficient finite-element-based modal solution, together with junction analysis and beam propagation approaches have been used to study bending loss, transition loss, mode coupling, and polarization coupling in bent optical waveguides. The waveguide offset and their widths have been optimized to reduce the transition loss and the mode beating.

Numerical Analysis of Asymmetric Silicon Nanowire Waveguide as Compact Polarization Rotator

In this paper, an ultracompact design of a low-loss silicon (Si) polarization rotator based on a silicon-on-insulator platform, which contains an asymmetric strip Si nanowire waveguide core, is presented. A full-vectorial finite element method and the least squares boundary residual method are used to study the effects of the device parameters, the results of which indicate that a very high polarization conversion with a very low polarization crosstalk is possible.

Rigorous modal analysis of silicon strip nanoscale waveguides.

A full-vectorial H-field Finite Element Method has been used for the rigorous modal analysis of silicon strip waveguides. The spatial variation of the full-vectorial H and E-fields are also discussed in details and further, the Poynting vector is also presented. The modal area, hybridness, single mode operation and birefringence are also described for such silicon strip waveguides.

Rigorous characterization of acoustic-optical interactions in silicon slot waveguides by full-vectorial finite element method

For the first time detailed interactions between optical and acoustic modes in a silicon slot waveguide are presented. A new computer code has been developed by using a full-vectorial formulation to study the acoustic modes in optical waveguides. The results have shown that the acoustic modes in an optical slot waveguide are not purely longitudinal or transverse but fully hybrid in nature. The model allows the effects of Stimulated Brillouin Scattering and the associated frequency shift due to the interaction of these hybrid acoustic modes with the fully hybrid optical mode also to be presented.

RIGOROUS NUMERICAL ANALYSIS AND CHARACTERIZATION OF A SILICON VERTICAL-SLOT NANO-WAVEGUIDE

In this paper, the optical properties of a nanoscale silicon slot-waveguide has been rigorously studied by using a full vectorial H-field finite element method (VFEM) based approach. The variations of effective indices, effective areas, power densities in the slot-region and the confinement factors of the slot waveguide are thoroughly investigated. The full vectorial magnetic and electric field profiles and Poynting vector (Sz) are also presented.

Full-Vectorial Finite-Element Analysis of Acoustic Modes in Silica Waveguides

A finite-element code has been developed to study the vector acoustic modes in high index contrast silica optical waveguides. Detailed spatial variations of the transverse and longitudinal displacement vectors are shown for the bending, radial, and torsional modes. The variation of the frequency shift due to the stimulated Brillouin scattering and the overlaps seen between the acoustic and optical waveguides also are presented, together with the modal hybridness and modal dispersion.

Optimizing the power confinement in silicon slot waveguides by use of Finite Element Method

In this paper, the power confinement and the power density in the slot region of a vertical and horizontal slot waveguide are optimized; full-vectorial H and E-field profiles along with Poynting vector are also shown for both of these silicon waveguides. Bending loss of such slot waveguides is also presented.

Rigorous characterization of silicon nanowire for compact nanophotonic devices

The high index contrast of silicon waveguide allows light confinement in submicron size waveguides along with very compact bends, to allow increased functionality of photonic integrated circuits. A rigorous H-field based full-vectorial modal analysis has been carried out, which is used more accurately to characterize the abrupt dielectric discontinuity of a silicon optical waveguide with a high refractive index contrast. Full-vectorial H and E-field profiles are also illustrated in detail. It is shown here that the mode profile of a circular silicon nanowire is itself not circular and has a strong axial field component. The single mode operation and modal ellipticity of this silicon nanowire are presented here. The modal hybridness and birefringence of rectangular silicon nanowires are also presented.

Bending loss, transition loss, mode coupling, and polarization coupling in bent waveguides

A rigorous, full-vectorial and computationally efficient finite element-based modal solution, together with junction analysis and beam propagation approaches have been used to study bending loss, transition loss, mode coupling and polarization coupling in bent optical waveguides with vertical or slanted side walls. The waveguide offset and their widths have been optimized to reduce the transition loss and the mode beating.

Light-sound interactions in Tellurite Microstructured Fiber

Interactions of acoustic modes with optical modes are presented by using full-vectorial finite element based approaches for a Tellurite microstructured fiber. Results on the SBS frequency shift and the overlap between acoustic and optical modes are also shown.