In this paper, we present the simulation results on the absorption modification in photonic crystal (PC) structures. For one-dimensional (1D) PC, using transfer matrix method (TMM), we obtained enhanced absorption in both defectfree and defect based PC structures. High absorption (>60%) and small bandwidth (< 0.1 λ0) at defect level were observed with optimal absorption layers of 10-15 for stru...

We present a systematic design of coupled-resonator optical waveguides (CROWs) based on high-Q tapered grating-defect resonators. The formalism is based on coupled-mode theory where forward and backward waveguide modes are coupled by the grating. Although applied to strong gratings (periodic air holes in single-mode silicon-on-insulator waveguides), coupled-mode theory is shown to be valid, sin...

We express the quality factor of a mode in terms of the Fourier transforms of its field components and prove that the reduction in radiation loss can be achieved by suppressing the mode’s wavevector components within the light cone. Although this is intuitively clear, our analytical proof gives us insight into how to achieve the factor optimization, without the mode delocalization. We focus on ...

We investigate the characterization of defect modes in one-dimensional ternary symmetric metallo-dielectric photonic crystal (1DTSMDPC) band-gap structures. We consider the defect modes for symmetric model with respect to the defect layer. We demonstrate reflectance with respect to the wavelength and its dependence on different thicknesses and indices of refraction of dielectric defect layer, a...

We report on a channel drop filter with a mode gap in the propagating mode of a photonic crystal slab that was fabricated on silicon on an insulator wafer. The results, simulated with the 3-dimensional finite-difference time-domain and plane-wave methods, demonstrated that an index-guiding mode for the line defect waveguide of a photonic crystal slab has a band gap at wave vector k = 0.5 for a ...

patients and methods previously recorded data of 231 patients who underwent surgical closure of vsd between january 2009 and january 2012 at the rajaie cardiovascular medical and research center were retrospectively reviewed. vsd surgical repair was performed using continues suturing technique in group a patients (n = 163, 70.6%) and interrupted suturing technique in group b patients (n = 68, 2...

We demonstrate that twisting one part of a chiral photonic structure about its helical axis produces a single circularly polarized localized mode that gives rise to an anomalous crossover in propagation. Up to a crossover thickness, this defect results in a peak in transmission and exponential scaling of the linewidth for a circularly polarized wave with the same handedness as structure. Above ...

This article analyzes compact laterally coupled distributed feedback DFB lasers with three defect regions. These devices are more flexible and smaller than conventional DFB lasers, having typical lengths between 20 and 50 m and a width less than 1 m lateral gratings are inserted in a single-mode waveguide . We optimize the defect regions to achieve an improved performance. In other words, an ad...