Performance analysis of self-electro-optic-effect-device-based (SEED-based) smart-pixel arrays used in data sorting.

The performance factors associated with self-electro-optic-effect-device-(SEED-) based smart-pixel arrays are analyzed in terms of semiconductor technology and pixel complexity. The sorting task is chosen as a practical example. Complementary metal-oxide semiconductor (CMOS)-SEED 2 × 2 self-routing nodes operated with quasi-cw-mode lasers are shown to provide the maximum processing power and on- or off-chip communication rate. The need for new front-end amplifiers for the smart-pixel technology is emphasized.

Observation of electro-optic and electroabsorption modulation in a Langmuir-Blodgett film Fabry-Perotétalon.

Electro-optic and electroabsorption modulation by use of a Langmuir-Blodgett (LB) film-based Fabry-Perot étalon is reported. The modulation was found to be dominated by linear effects in the film. The percentage change in transmission was 15% for electro-optic and 30% for electroabsorption modulation at an rms drive voltage of 53 V. The effective linear electro-optic coefficient of the LB film was 13 pm V(-1) at 633 nm for s-polarized light. We believe that this is the highest value reported to date for thick LB films.

Perfect-shuffle interconnected bitonic sorter: optoelectronic design.

The algorithmic, electronic, and optical aspects of the implementation of a perfect-shuffle interconnected bitonic sorter are analyzed. The performance metrics such as the bit output data rate and the power consumption of the system are quantified. The sorting module is designed to demonstrate the parallel nonlocal interconnection of smart-pixel arrays and the use of optical-image control masks in a functioning information processor.

Tolerance analysis of cascaded self-electro-optic-effect-device arrays.

In constructing symmetric self-electro-optic-effect-device-based, two-dimensional information processing circuits, it is necessary to know the nonuniformity that can be tolerated of the reflectivity responses of the arrays of devices. It is also necessary to know the allowable nonuniformity of the passive optical components used to direct beam arrays onto and between the active symmetric self-electro-optic-effect devices. A method for determining the mutual tolerances is presented with examples of the volumes of acceptable operation in the parameter space of the circuits. Leakage between devices is considered, which leads to acceptable regimes for those parameters that can be adjusted once the circuit has been constructed and to narrower regimes in which high clock and cycle rates can be achieved.

Optical cellular logic image processor: implementation and programming of a single channel digital optical circuit.

A diode-laser driven all-optical iterative processor has been constructed and tested. Results are presented showing operation equivalent to a single channel of the cellular logic image processor architecture. Functional features of the circuit include optically programmable logic, thresholding, and data synchronization. Essential elements such as cascadability, logic-level restoration, and data feedback have been demonstrated with the optical processor controlled by a conventional electronic computer. Serial processing algorithms for word recognition, comparison, full addition, and subtraction have been implemented. Comments on the reliability of operation and future plans for expansion are made.

Theory of elliptical defocusing in anisotropic nonlinear-optical media.

We have determined the far-field beam profiles of an initially Gaussian laser beam that traverses a thin slab of nonlinear-optical material in which the spatial distribution of the refractive nonlinearity is anisotropic by an expansion in terms of elliptical Gaussian functions. In marked contrast to the annular structures observed with isotropic media, it is shown that the transmitted beam breaks into two beams in the far field. This nonlinear beam-splitting behavior has been confirmed experimentally.

All-optical programmable logic gate.

Experimental results are presented showing all-optical programmability and operation of a multifunction Boolean logic gate. All eight symmetric two-input logic functions have been demonstrated. Comments on the practical implementation and usage of this gate within an optical circuit are made.

Home nebulizers in childhood asthma. Parental perceptions and practices.

Seventy five percent of 91 parents of asthmatic children (aged 6 months to 15.4 years) with home nebulizers, responded to a questionnaire that sought to document parental experience with this form of therapy. The most common indications for acquiring a nebulizer were inability to use metered dose inhalers and poor response or intolerance to oral medications. When the children were classified into those who used the nebulizer daily (27/69) and those who used it less than daily (42/69), we found that the daily users were more likely to be in the severest category of asthma, by parental assessment, prior to the home nebulization program (p = 0.0035). Retrospective, uncontrolled comparison before and after the acquisition of a home nebulizer showed significant decreases both in hospital admissions (1.7 vs 0.7; p less than 0.001) and total in-patient days (4.1 vs 1.7; p less than 0.0001). Home nebulizers are well tolerated by parents and children alike and may be associated with decreased morbidity.

Effect of low-power nonlinear refraction on laser-beam propagation in InSb.

By use of an expansion in Gaussian functions we solve the problem of the propagation of a laser beam that has been passed through a thin slab of nonlinearly refracting material. We compare the theoretical results for beam profile with experimental measurements for the semiconductor InSb and confirm that self-defocusing has been observed by D. A. B. Miller, M. H. Mozolowski, A. Miller, and S. D. Smith [Opt. Commun. 27, 133 (1978)]. The deduced value for the nonlinear refractive index at ~5 K is -6 x 10(-5) cm(2) W(-1) at 1886 cm(-1). This implies a third-order optical nonlinearity chi((3)) ~ 10(-2) esu, much larger than any previously reported for a solid.

Oscillation characteristics of an external-cavity system as used with the spin-flip Raman laser.

A model external-cavity system is investigated to describe the tuning characteristics appropriate to the various experimental procedures used in the operation of the spin-flip Raman laser. In particular a calculation is made of the amount by which internal subcavities pull the oscillation frequency away from the Raman frequency under the servocontrolled conditions used to achieve continuous tuning.