Duncan L. MacFarlane

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An optical coupler for integrated photonic circuits is presented and analyzed. The coupler is based on frustrated total internal reflection (FTIR) and offers high efficiency in a compact footprint. Analytic expressions for the transmission and reflection coefficients of the coupler are obtained using a plane-wave theory and experimentally verified.(More)
Novel lattice-filter structures consisting of four-directional couplers are introduced, analyzed, and discussed. Four-directional couplers are discussed, and energy-conservation relations in a field-wave application are derived. A thick linear lattice filter is presented and studied as a simple extension to the traditional lattice. A two-dimensional lattice(More)
A novel brush optode was designed and demonstrated to overcome poor optical contact with the scalp that can occur during functional near infrared spectroscopy (fNIRS) and imaging due to light obstruction by hair. The brush optodes were implemented as an attachment to existing commercial flat-faced (conventional) fiber bundle optodes. The goal was that the(More)
A true three-dimensional monitor is being developed for the direct display of three- (or higher-) dimensional information. The device is constructed of a three-dimensional array of pixels, actually voxels or volume elements, which in their quiescent state are transparent. When these elements are excited optically through a fiber-optic pigtail, they(More)
We designed, fabricated, and characterized a thermo-optically tunable compact (10 μm × 10 μm) silicon photonic crystal (PhC) light modulator that operates at around 1.55 µm for TE polarization. The operational principle of the device is the modulation of the cutoff frequency in a silicon-based line defect PhC. The cutoff frequency is shifted because of the(More)
The detection of electric field by monitoring the optical whispering gallery mode shifts of polymeric microspheres is demonstrated. Two types of spheres are considered; (i) a polydimethylsiloxane (PDMS) sphere with 60 parts base silicon elastomer-to-1 part polymer curing agent by volume and; (ii) a silica sphere coated with a PDMS (uncured) base. The(More)
A system theoretic model of a unit cell of a two-dimensional tunable lattice filter architecture consisting of four 4-port couplers and four waveguides containing semiconductor optical amplifiers is provided. It is shown that such multiple input-multiple output devices can be modeled in state space and by transfer function matrices. This modeling can also(More)
We present the design, fabrication, and characterization of a sensor capable of detecting minute changes in pressure within a polydimethylsiloxane (PDMS) microchannel. The device consists of a guided-mode resonance (GMR) grating with a resonant wavelength of 731 nm embedded in an 85 µm thick PDMS membrane which acts as one wall of the microchannel.(More)
Planar photonic integrated circuits based on four-port couplers offer enhanced sophistication and functionality. Each four-port coupler is characterized by sixteen signal coupling coefficients governed by ten energy constraints. The ability to generate the constrained sixteen coupling coefficients is needed in the analysis of the four-port coupler. However,(More)