Investigating orbital angular momentum modes in multimode interference (MMI) waveguides and revealing their mode conversion property.

In this work, the propagation of OAM modes in multimode interference (MMI) waveguides, as the basic elements in many integrated optical devices, is studied to utilize their benefits in integrated OAM applications. OAM modes shape the OAM-maintaining image at the specific length of an MMI waveguide. As the most effective parameters on the properties of the generated image, waveguide's width (W), topological charge ( ) and waist radius (WR) of the input OAM modes are investigated.

Ultra-broadband and high extinction ratio polarization splitter based on triple-tapered directional couplers.

The design and numerically investigation of a silicon polarization splitter (PS) is proposed using triple-tapered directional couplers (DCs).The proposed device consists of a triple-tapered DC, a triple-bent DC at through port, and a tapered waveguide at cross port. The coupling length of the device is 20.

Computational analysis of non-invasive deep brain stimulation based on interfering electric fields.

Neuromodulation modalities are used as effective treatments for some brain disorders. Non-invasive deep brain stimulation (NDBS) via temporally interfering electric fields has emerged recently as a non-invasive strategy for electrically stimulating deep regions in the brain. The objective of this study is to provide insight into the fundamental mechanisms of this strategy and assess the potential uses of this method through computational analysis.

Ultra-deep sub-wavelength mode confinement in nano-scale graphene resonator-coupled waveguides.

Graphene is capable of supporting very slow waves due to sustaining surface plasmon polaritons (SPPs) at THz frequencies, whereas the metal counterpart can support such modes only at optical frequencies. In this paper, a graphene-based resonator-coupled waveguide supporting transverse-magnetic-polarized SPP modes is rigorously studied, which is capable of providing ultra-deep sub-wavelength mode confinement at the working frequency of 40 THz. First, graphene is described both electronically and electromagnetically, as in these regards, graphene's quantum capacitance plays an important role, which is calculated via its DC characteristic.

Limiting factors for optical switching using nano-structured graphene-based field effect transistors.

Thanks to the particular band diagram of graphene, it is recognized as a promising material for developing optoelectronic devices at the nano-scale. In this paper, a functional stack comprised of graphene and other materials is numerically investigated to extract the related capacitance-voltage curve by taking into account practical considerations regarding the nano-structured electronic devices. Polycrystalline silicon gates are used as electrical contacts in this stack, which are considered as semiconductor materials rather than metal contacts owing to the nano-scale dimensions of the constitutive materials.