Untitled

Abstract

Passing across an abrupt junction from a thick vertically bimodal waveguide to a thinner single mode segment, guided light can undergo complete destructive interference, provided that the geometry and the phases of the modes in the initial segment are properly adjusted. We propose to employ this eect to realize a simple polarizer con®guration, using a strip that is etched from a planar waveguide. A beam of light is made to pass the strip perpendicularly. The light enters from the single mode waveguide outside the strip into the strip segment, which is con®gured to support two modes. At the end of the strip, apart from re¯ections, the amount of power that is guided in the following lower segment depends on the local phases of the two modes. These phases are dierent for TE and TM light, hence we may expect a polarization dependent power transfer, resulting in polarizer performance for a properly selected geometry. The paper describes in detail the modeling of the device in terms of rigorous mode expansion. Design guidelines and tolerance requirements for geometric and material parameters are discussed. For typical Si 3 N 4 /SiO 2 materials, our calculations predict a peak performance of 34 dB polarization discrimination and 0.3 dB insertion loss for a device with a total length of about 12 lm that selects TE polarization at a wavelength of 1:3 lm.

Resonant coupling of dielectric optical waveguides via rectangular microcavities: the coupled guided mode perspective

“…The rectangular, segmented structures can be simulated quite accurately and efficiently by mode expansion methods (bidirectional eigenmode propagation techniques) [22,25], where we refer to Refs. [26,16] for details of the present implementation. These simulations are rigorous up to convergence with respect to the extension of the computational window and with respect to the density of the spectral discretization, where forward and backward traveling, radiated and guided parts of the optical fields are taken fully into account.…”

Modeling of grating assisted standing wave, microresonators for filter applications in integrated optics

“…Besides the approximate CMT procedures, the devices were simulated by means of the mode expansion techniques as formulated in Refs. [31,17]. The 2D-TE computations for the resonator devices use uniformly 100 expansion terms on a computational window x ∈ [−20 , 20] µm that is confined by Dirichlet boundary conditions.…”

“…In the next Section 2.1, we outline a simple, somewhat heuristic strategy how to select the many For the simulations we can on the one hand rely on rigorous mode expansion or bidirectional eigenmode propagation simulations [29,30], specifically on the algorithms as described in Refs. [31,17] and on the commercial tool [32]. On the other hand, we apply an ab-initio coupled mode theory model [18], briefly outlined in Section 2.2, that can be regarded as a direct implementation of the abstract design heuristics.…”

Near-field probing of photonic crystals

“…The optical fields inside the photonic crystal structure have been calculated with a 2D simulation, based on solving Maxwell's equations in the frequency domain [18,19]. Fig.…”