Time-resolved spectra of a self-pulsing quantum dot laser

Self-sustained pulsations in the output of an InAs quantum dot laser diode in the MHz range are reported for the first time. The characteristics (shape, range and frequency) are presented for the free running laser and when optical feedback in the Littrow configuration is applied. The frequency resolved optical spectra reveal different envelope shifts between the two cases. This might be related to a change of phase-amplitude coupling across the gain maximum in agreement with the expectation for a two level system. The time scale and bifurcation scenario suggest that these are opto-thermal pulsation like those reported in quantum well amplifiers.(1

A 100-MIPS GaAs asynchronous microprocessor

The authors describe how they ported an asynchronous microprocessor previously implemented in CMOS to gallium arsenide, using a technology-independent asynchronous design technique. They introduce new circuits including a sense-amplifier, a completion detection circuit, and a general circuit structure for operators specified by production rules. The authors used and tested these circuits in a variety of designs

Low-Energy Asynchronous Memory Design

We introduce the concept of energy per operation as a measure of performance of an asynchronous circuit. We show how to model energy consumption based on the high-level language specification. This model is independent of voltage and timing considerations. We apply this model to memory design. We show first how to dimension a memory array, and how to break up this memory array into smaller arrays to minimize the energy per access. We then show how to use cache memory and pre-fetch mechanisms to further reduce energy per access

Integrated Transversal Equalizers in High-Speed Fiber-Optic Systems

Intersymbol interference (ISI) caused by intermodal dispersion in multimode fibers is the major limiting factor in the achievable data rate or transmission distance in high-speed multimode fiber-optic links for local area networks applications. Compared with optical-domain and other electrical-domain dispersion compensation methods, equalization with transversal filters based on distributed circuit techniques presents a cost-effective and low-power solution. The design of integrated distributed transversal equalizers is described in detail with focus on delay lines and gain stages. This seven-tap distributed transversal equalizer prototype has been implemented in a commercial 0.18-µm SiGe BiCMOS process for 10-Gb/s multimode fiber-optic links. A seven-tap distributed transversal equalizer reduces the ISI of a 10-Gb/s signal after 800 m of 50-µm multimode fiber from 5 to 1.38 dB, and improves the bit-error rate from about 10^-5 to less than 10^-12

Propensity of Tampons and Barrier Contraceptives to Amplify Staphylococcus aureusToxic Shock Syndrome Toxin-I

Objective: Although the incidence of reported cases of toxic shock syndrome (TSS) has declined in recent years, the disease continues to occur in menstruating women using the newer, less-absorbent tampons or barrier contraceptives. Extant tampons and other vaginal devices were tested for the ability to induce TSS toxin-1 (TSST-1) by a TSS strain of Staphylococcus aureus MN8, a known high-toxin producer. Tested for the first time were 20 varieties of tampons, including 2 all-cotton brands newly introduced in the United States, a polyurethane contraceptive sponge, a latex diaphragm, and a polymer menstrual collection cup

High density InAlAs/GaAlAs quantum dots for non-linear optics in microcavities

Structural and optical properties of InAlAs/GaAlAs quantum dots grown by molecular beam epitaxy are studied using transmission electron microscopy, temperature- and time resolvedphotoluminescence. The control of the recombination lifetime (50 ps – 1.25 ns), and of the dot density (5.10−8 – 2.1011 cm−3) strongly suggest that these material systems can find wide applications in opto-electronic devices as focusing non linear dispersive materials as well as fast saturable absorbers

Designing Asynchronous Circuits in Gallium Arsenide

[No abstract

Fin del Estado de Alarma y nuevas realidades laborales: Una especial atención a los mayores

Once it is considered to put an end to the State of Alarm, doubts arise about the issues linked to the employment situations arising from the health crisis by COVID 19. In this context, some normative provisions are gaining strength, such as those that affect the enhancement of telework or the maintenance of an temporary employment regulation Dossier. Issues that deserve minimal attention. Even more so when these measures affect to elderly.Una vez que se plantea poner fin al Estado de Alarma surgen dudas en torno a las cuestiones vinculadas a las situaciones laborales derivadas de la crisis sanitaria por COVID 19. En este contexto recobran fuerza algunas previsiones normativas, como, por ejemplo, aquellas que afectan a la potenciación del teletrabajo o el mantenimiento de un Expediente de regulación temporal de empleo. Cuestiones que merecen una mínima reflexión. Más aún cuando estas medidas afectan a mayores