Design and analysis of a diffractive optical filter for use in an optoelectronic error-diffusion neural network.

The design, fabrication, experimental characterization, and system-performance analysis of a diffractive optical implementation of an error-diffusion filter for use in digital image halftoning is reported. A diffractive optical filter was fabricated as an eight-level phase element that diffuses the quantization error nonuniformly in both the weighting and the spatial dimensions, according to a prescribed algorithm. Ten identical diffractive elements were fabricated on ten different wafers and subsequently characterized experimentally.

Holographic interferometers with photorefractive recording media.

We discuss two types of holographic interferometer that contain photorefractive recording media. The first type contains two beams interacting in a photorefractive medium. The second type utilizes a single beam and relies on self-pumped phase conjugation from a photorefractive crystal to make phase changes appear as intensity changes.

Performance of GaAs smart pixel components before and after monolithic integration of InGaP LEDs using Epitaxy-on-Electronics technology.

Smart pixel technology provides the ability to integrate complex electronic circuitry with optoelectronic devices to produce signal processing capabilities previously unattainable with a single technology. Epitaxy-on-Electronics (EoE) is a process by which optoelectronic devices are monolithically integrated with electronic circuitry in a common semiconductor material. Here, InGaP LEDs are integrated with GaAs electronic circuitry to produce smart pixel arrays.

Optical oversampled analog-to-digital conversion.

A new approach to optical analog-to-digital (A/D) conversion based on oversampling and interpolative coding techniques is described, and both interferometric and noninterferometric architectures based on this method are presented. This new approach combines the high resolution of classical oversampled A/D conversion with the high speed of optical processing technology to extend the resolution and conversion rates beyond that currently possible with other electronic or optical converters. The proposed optical converters are simple, consisting of multiple quantum well self-electro-optic effect devices, photodetectors, and common optical components that are capable of operating at sampling rates of up to 15 Gbits/s and that can provide scalable resolutions of 16 and 8 bits at a conversion rate of 117 and 938 MHz, respectively.

Noninterferometric optical subtraction using reflection-electroabsorption modulators.

A noninterferometric technique for optical subtraction is demonstrated that employs a multiple-quantum-well reflection-electroabsorption modulator and provides lower insertion loss, larger contrast ratio, and linearity over a larger dynamic range than similar techniques previously reported.