A novel wavelength-selective photonic time-delay filter is proposed and demonstrated. The device consists of an optical phased-array waveguide grating in a recirculating feedback configuration. It can function as a true-time-delay generator for squint-free beam steering in optically controlled phased-array antennas and as an encoding-decoding filter for wavelength code-division multiple access.

This paper presents a novel third-order cross-coupled rectangular cavity filter by using standard low-temperature cofired ceramic (LTCC) technology, in which the multilayer substrate integrated waveguide (SIW) is implemented. Particularly, the desired filter has a single finite frequency attenuation pole at j4.0 with asymmetrical frequency selectivity. An experimental band pass filter (BPF) has...

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 ...

Passive nonlinear filters provide a rich source of evolving spectra for sound synthesis. This paper describes a nonlinear allpass filter of arbitrary order based on the normalized ladder filter. It is expressed in FAUST recursively in only two statements. Toward the synthesis of cymbals and gongs, it was used to make nonlinear waveguide meshes and feedback-delay-network reverberators.

Two “one-filter” scattering junctions are derived which provide very accurate models of woodwind toneholes in the context of a digital waveguide model. Because toneholes in the clarinet possess only one resonance and/or anti-resonance within the audio band, a second-order digital filter suffices.

We introduce a mechanism that provides an on/off switching capability in channel add-drop filter structures. These filters consist of two waveguides, a bus and a drop, coupled through a frequency-selective element. The switching functionality is achieved by incorporating materials with variable absorbing characteristics into the coupling element. When the variable material displays minimum abso...

The design of grating-assisted, channel waveguide, codirectional couplers is demonstrated using the Gel’fand-Levitan-Marchenko inverse scattering method. Weighted coupling coefficients are computed from rational function expressions for the desired wavelength response. Approximate formulas are derived which relate the waveguide and grating geometries to the computed coupling coefficients. The t...

In this work, a first report on fabricating an asymmetric Bragg coupler-based filter on polymeric waveguides without input-waveguide grating was revealed. The fabrication process we developed was using holographic interference techniques, capillary effect, soft lithography, and micro molding process. The transmission dip of about -9.2 dB and the 3 dB transmission bandwidth of about 0.125 nm wer...

We apply wavelet-based numerical homogenization to the simulation of an optical waveguide filter. We use the method to derive approximate one-dimensional models and subgrid models of the filter. Numerical examples of the technique are presented, and the computational gains are investigated. c © 2001 Academic Press