Error diffusion is a popular halftoning algorithm that in its most widely used form, is inherently serial. As a serial algorithm, error diffusion offers limited opportunity for large-scale parallelism. In some implementations, it may also result in excessive bus traffic between the on-chip processor and the off-chip memory used to store the modified continuous-tone image and the halftone image. We introduce a new error diffusion algorithm in which the image is processed in two groups of interlaced blocks. Within each group, the blocks may be processed entirely independently. In the first group, the error diffusion proceeds along an outward spiral from the center of the block. Errors along the boundaries of blocks in the first group are diffused into neighboring blocks in the second group, within which the error diffusion spirals inward. A tone-dependent error diffusion training framework is used to eliminate artifacts associated with the spiral scan paths. We demonstrate image quality that is close to that achieved by conventional line-by-line error diffusion.

Block Interlaced Pinwheel Error Diffusion.

Block interlaced pinwheel error diffusion

A fast convolution-based time-domain approach to global photonic-circuit simulation is presented that incorporates a physical device model in the complete detector or mixer circuit. The device used in the demonstration of this technique is a GaAs metal-semiconductor-metal (MSM) photodetector that offers a high response speed for the detection and generation of millimeter waves. Global simulation greatly increases the accuracy in evaluating the complete circuit performance because it accounts for the effects of the millimeter-wave embedding circuit. Device and circuit performance are assessed by calculating optical responsivity and bandwidth. Device-only simulations using GaAs MSMs are compared with global simulations that illustrate the strong interdependence between device and external circuit.

Convolution-based global simulation technique for millimeter-wave photodetector and photomixer circuits

The University of Arizona's Collaboration to Advance Teaching Technology and Science (CATTS) program sponsored by the National Science Foundation has found a successful way to unite public and charter school students and teachers, university science outreach programs, graduate and undergraduate students, and university faculty for the betterment of science education. A key aspect of this success has been the ability of the project to assist stakeholders in understanding the different cultural perspectives of all of the participants. The success of this program has led us to create a template for a professional development and support program emphasizing the degree of cross-cultural understanding appropriate for today's multinational photonics industry. This template is designed to give future photonics technical, managerial, and manufacturing leaders training in a variety of areas that can enhance their productivity and ability to lead teams. The design would be appropriate for photonics research and development teams, sales and marketing teams, teams with diverse members new college hires, and newly emplaced managers. This education template would also be appropriate for students in photonics industry technician and graduate- level programs. This type of program is not a substitute for other forms of professional managerial training, but rather augments such programs with material that can aid in a more global perspective.

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/4588/0000/Design-of-a-professional-development-and-support-program-for-future/10.1117/12.468746.pdf

Design of a professional development and support program for future photonics industry team leaders

/pdf/design-of-high-speed-laser-driver-using-a-standard-cmos-4o9lbj2jbv.pdf

Design of High-Speed Laser Driver Using a Standard CMOS Technology for Optical Data Transmission

In this letter, we report the design, fabrication, parametric testing, and analysis of a intermediate growth temperature (IGT) GaAs MSM photodetectors. The broad-area, ultrafast photodetector displays linear and nonlinear photocurrent generation characteristics as a function of applied bias and optical power. The photocurrent/dark current ratio 7/spl times/10/sup 3/ is significantly larger than normal growth temperature or low growth temperature 200/spl deg/C based GaAs MSM's. The optical responsivity of 130 mV/pJ Is the highest ever reported for similar ultrafast MSM photodetectors. This device is uniquely suited for high-speed, high-photocurrent applications, such as optoelectronic trigger sources for phased-array antenna systems.

Broad-bandwidth, high-responsivity intermediate growth temperature GaAs MSM photodetectors

Smart pixel technology and an application to two-dimensional analog-to-digital conversion

Recently, there has been a great deal of interest in the application of wavelet transforms to signal processing applications. As an example, to obtain the source density function for a wideband radar or sonar signal from the measurement of scattered signals it is desirable to first perform the wavelet transform of the received signal before processing it. The use of the wavelet transform allows the selection of basis functions which are matched to the transmitted signal. Fundamentally, the wavelet transform of a signal is the correlation of the signal with a basis function derived from a mother wavelet and its scaled versions called daughter wavelets. Thus any real-time correlator can be used for the implementation of the wavelet transform. Since a one-dimensional input signal produces a two-dimensional wavelet transform, optical correlators provide a natural advantage over conventional electronic implementations. The VanderLugt correlator, the joint transform correlator and its derivative, the quasi-Fourier transform joint transform correlator can all be used to implement the wavelet transform, provided a spatial light modulator is used to convert the electrical input signal into an appropriate optical signal. The concept of the smart pixel is to integrate both electronic processing and individual optical devices on a common device to take advantage of the complexity of electronic processing circuits and the speed of optical devices. Arrays of these smart pixels would then bring with them the advantage of parallelism that optics could provide. Smart pixels can function as spatial light modulators providing additional electronic processing features. They are naturally well-suited to realizing wavelet transforms.

Smart pixel-based wavelet transformation for wideband radar and sonar signal processing

Since the first edition of this chapter, the field of smart pixel technology has continued to make significant progress. This progress includes improvements to individual device performance, improvements to circuit performance, extensions to larger arrays, as well as applications to new areas. Over this period, a focus on vertical-cavity surface-emitting laser (VCSEL) technology has produced significant improvements in both individual device performance and array uniformity and performance. Furthermore, during this period, others outside of the smart pixel community have recognized the importance and potential of integrating electronic circuits with optoelectronic devices for a variety of application areas. The smart pixel community has also worked to expand to other non-traditional smart pixel applications including smart imaging systems, and applications based on digital signal processing. As a result of these two mutually supporting trends, the fields of Smart Photonics, Optoelectronic-VLSI, and Electronic-Enhanced Optics all have emerged, with support for progress in smart pixel technology.

Chapter 10 – New Devices for Optoelectronics: Smart Pixels

In meeting the growing demand for graduates who have background in optical engineering,the Department of Electrical Engineering and Computer Science and the Photonics Research Center at the U.S. Military Academy have jointly developed an instructional program that familiarizes every student with principles of laser operation and provides undergraduate research opportunities in optics for electrical engineering majors and others. The program includes a series of laboratory demonstrations in the Photonics Research Center for students in all majors during their sophomore year. For electrical engineering majors, the program also offers a senior level photonics engineering course, advanced individual study in laser applications, and a variety of capstone design projects. Advanced individual study may include up to three semesters of experimental research similar to masters degree thesis work in a graduate program, while the capstone project is accomplished in one semester by design teams based on the design-build- test methodology. Both types of projects address real-world requirements specified by faculty advisors or external mentors. Our integrated approach to optics education supports ongoing state-of-the-art research in the Photonics Research Center and provides technically qualified graduates to meet the demands of the field Army of the 21st century.

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/2525/0000/Integrated-undergraduate-optical-engineering-education-at-West-Point/10.1117/12.224006.pdf

Andre H. Sayles

Papers

Broad-bandwidth, high-responsivity intermediate growth temperature GaAs MSM photodetectors

Smart pixel technology and an application to two-dimensional analog-to-digital conversion

Smart pixel-based wavelet transformation for wideband radar and sonar signal processing

Chapter 10 – New Devices for Optoelectronics: Smart Pixels

Integrated undergraduate optical engineering education at West Point