Photon Design (United Kingdom)

In this paper, we propose a novel numerical method for modeling\nnanostructures containing dispersive and nonlinear two-dimensional (2D)\nmaterials, by incorporating a nonlinear generalized source (GS) into the\nfinite-difference time-domain (FDTD) method. Starting from the expressions of\nnonlinear currents characterizing nonlinear processes in 2D materials, such as\nsecond- and third-harmonic generation, we prove that the nonlinear response of\nsuch nanostructures can be rigorously determined using two linear simulations.\nIn the first simulation, one computes the linear response of the system upon\nits excitation by a pulsed incoming wave, whereas in the second one the system\nis excited by a nonlinear generalized source, which is determined by the linear\nnear-field calculated in the first linear simulation. This new method is\nparticularly suitable for the analysis of dispersive and nonlinear 2D\nmaterials, such as graphene and transition-metal dichalcogenides, chiefly\nbecause, unlike the case of most alternative approaches, it does not require\nthe thickness of the 2D material. In order to investigate the accuracy of the\nproposed GS-FDTD method and illustrate its versatility, the linear and\nnonlinear response of graphene gratings have been calculated and compared to\nresults obtained using alternative methods. Importantly, the proposed GS-FDTD\ncan be extended to 3D bulk nonlinearities, rendering it a powerful tool for the\ndesign and analysis of more complicated nanodevices.\n

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text D. F. G. Gallagher, "Modelling Photonic Integrated Circuits using TDTW," in Asia Optical Fiber Communication and Optoelectronic Exposition and Conference, OSA Technical Digest (CD) (Optica Publishing Group, 2008), paper SuQ4. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Abstract A novel approach for the interpolation of dispersive materials for use in the finite‐difference time‐domain (FDTD) method is presented. The method allows for the simulation of geometrical structures that cannot be aligned to the discretized grid. Materials overlapping multiple cells are described by averaging flux densities in the cells concerned. This method provides an efficient way to simulate structures that are smaller than the minimum grid size. A formulation for an absorbing boundary condition using the uniform perfectly matched layer approach is given for the complex dispersive material model. The approach is validated by analysing reflection from metal sheets extending into multiple grid cells and two‐dimensional photonic crystals. Excellent agreement between analytical calculations and FDTD simulations is obtained for the simulation of real metal structures. Copyright © 2007 John Wiley & Sons, Ltd.

The FUNFOX European IST-project exploits photonic crystals and nanophotonic concepts to elaborate functional applications of InP-based devices for metropolitan-area-network applications, among which a polarization rotator, a linear amplifier, and a wavelength monitoring device.

This paper reviews the time-domain travelling wave (TDTW) model for the simulation of active semiconductor waveguides. We outline the theory, present a discussion of its advantages and limitations and show how it can be applied to the design and simulation of a tunable 4-section sampled-grating DBR laser.