Dispersion Trimming in a Reconfigurable Wavelength Selective Switch

We experimentally demonstrate dispersion compensation in a wavelength selective switch, and characterize the bandwidth-dispersion product. At a channel bit-rate of 80 Gbit/s, we compensate for various amounts of dispersion (up to plusmn60 ps/nm), tunable for each wavelength division multiplexed channel, solely by adjusting the phase front of the optical signal inside the wavelength selective switch. Error-free operation is obtained for all of the channels, and for each output port after propagation over various lengths of dispersive fiber.     

The effects of defects on the early failure of metal interconnects

A method that predicts the effect of particular defects on the failure rate of metal interconnections in semiconductor integrated circuits due to electromigration is presented. The defects of interest are missing material that reduces the effective cross section of the conductor at the point of the defect. Reliability measures for the conductor are computed from a given defect distribution. These defects appreciably increase conductor failure rate during early life but have little effect on median life for linewidths above 1 μm. However, for defect densities typically encountered in current semiconductor manufacturing environments a rapid decrease in median life is predicted for conductors less than 0.30 μm wide. This result extends the practical data for submicron conductors. Poorer median life as well as poorer yield due to these defects will ultimately limit the trend toward narrower linewidths unless a way is found to overcome this problem     

1.6-μ m Multiwavelength Emission of an InAs–InGaAsP Quantum-Dot Laser

A multiwavelength laser with maximum signal-to-noise ratio up to 62 dB was demonstrated on the basis of a 461-m-long InAs-InGaAsP quantum-dot waveguide Fabry-Perot cavity chip. It has 24 channels with 0.8-nm channel spacing and 8.0-dB maximum channel intensity nonuniformity over a wavelength range from 1612 to 1632 nm. Its channel spacing irregularity due to linear intracavity waveguide dispersion was also investigated.     

A model for predicting the effect of deformation after solution treatment on the subsequent artificial aging behavior of AA7030 and AA7108 alloys

The effect of deformation after solution treatment on the two-step artificial aging response has been examined for AA7030 and AA7108 alloys. Aging experiments were conducted where the prestrain level was varied between 0 and 1.2. It was observed that the kinetics of aging were accelerated and the magnitude of the peak strength decreased in the presence of prestrain. This was attributed to the increased growth/coarsening rate of precipitates on dislocations and the widening of the precipitate-size distribution, respectively. A model was developed based on the internal state variable approach to predict yield stress as a function of the heat treatment and the level of prestrain. The increase in the kinetics of aging was accounted for in an average sense by the use of an effective diffusion coefficient that combines bulk and short-circuit diffusion. The precipitation model was based on two variables; the average spacing between precipitates and the average strength of precipitates. The variation of the average strength of precipitates with precipitate radius was varied to account for the change in the width of the precipitate-size distribution. Static recovery of the deformed structure during artificial aging was also accounted for in a first-order approximation. Good agreement was found between the model predictions and experimental results. Additional experimental data were obtained after the model was developed, and it was observed that the model made excellent predictions.     

Ultrastructural localization of the C-propeptide released from type II procollagen in fetal bovine growth plate cartilage

We used immunochemical and immunoelectron gold techniques to determine whether the C-propeptide previously identified in the matrix of endochondral cartilage (CPII) was still a part of the Type 11 procollagen molecule or had been released from it. Guanidinium hydrochloride extraction, followed by SDS-PAGE and Western blotting techniques and immunoelectron localization, revealed that predominantly only the released form (hereafter referred to as released CPII) was detected. The ultrastructural distribution of this CPII was examined with affinity-purified antibodies and with immunogold or immunoperoxidase localization techniques in the presence or absence of embedding resins. These methods yielded similar results. Although no significant amount of this CPII was retained in the matrix after guanidinium hydrochloride extraction, it was present in two recognizable sites under normal conditions, i.e., locally concentrated in a random association with collagen fibrils in the nonmineralized matrix and mainly concentrated in interfibrillar mineralizing sites in the mineralized matrix. These results suggest that the C-propeptide that has been released from Type II procollagen associates with collagen fibrils and then preferentially associates with mineralizing sites when these form in the endochondral cartilage. The significance of this preference for mineral is not known but may have something to do with its high affinity for hydroxyapatite.     

Cocaine Exposure Is Associated With Subtle Compromises of Infants' and Mothers' Social-Emotional Behavior and Dyadic Features of Their Interaction in the Face-to-Face Still-Face Paradigm.

Prenatal cocaine and opiate exposure are thought to subtly compromise social and emotional development. The authors observed a large sample of 236 cocaine-exposed and 459 nonexposed infants (49 were opiate exposed and 646 nonexposed) with their mothers in the face-to-face still-face paradigm. Infant and maternal behaviors were microanalytically coded. No opiate-exposure effects were detected. However, mothers of cocaine-exposed infants showed more negative engagement than other mothers. The cocaine-exposed dyads also showed higher overall levels of mismatched engagement states than other dyads, including more negative engagement when the infants were in states of neutral engagement. Infants exposed to heavier levels of cocaine showed more passive-withdrawn negative engagement and engaged in more negative affective matching with their mothers than other infants. Although effect sizes were small, cocaine exposure, especially heavy cocaine exposure, was associated with subtly negative interchanges, which may have a cumulative impact on infants' later development and their relationships with their mothers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of UV/VUV enhanced RTP on process variation and device performance of metal gate/high-/spl kappa/ gate stacks for the sub-90-nm CMOS regime

We show that UV/VUV-enhanced rapid thermal processing (RTP) in combination with single-wafer processing using a single tool for the fabrication of metal gate/high-/spl kappa/ dielectric gate stacks not only improves overall device performance, but also leads to a significant reduction in process variation at the front end of the CMOS process flow for the sub-90-nm technology node. The gate stacks were fabricated under various UV/VUV conditions. Gate stacks processed under UV/VUV radiation during all processing steps displayed low leakage currents of the order of 10/sup -11/ A/cm/sup 2/. It is shown that the Al-Al/sub 2/O/sub 3/-Si gate stacks processed under UV/VUV conditions also display the lowest variations both in mean leakage current and mean capacitance, as compared to devices where UV/VUV was not used for all the processing steps. Therefore, it can be see that reliance on successive corrective iterations common to automatic process control or standard design simulation can be reduced significantly. As a result, UV/VUV-enhanced RTP has the potential to reduce the effect of process variations on overall device performance, thereby making the overall process more cost effective and time efficient and therefore improving yield and device reliability.     

Wide-band Fabry-Perot-like filters in optical fiber

We report the fabrication and characterization of wide-band Fabry-Perot-like resonators in optical fiber. Using Bragg gratings with variable detuning, resonators that operate ever a wavelength span in excess of 140 nm have been produced, with free spectral ranges between 0.09 nm and 11.27 nm. Numerical and experimental results for two typical resonators are presented, showing good agreement between the two