scholarly journals Large-scale and structure-tunable laser spectral compression in an optical dispersion-increasing fiber

2017 ◽  
Vol 25 (15) ◽  
pp. 18024 ◽  
Author(s):  
Yi-Song Lin ◽  
Chen-Bin Huang
2008 ◽  
Vol 47-50 ◽  
pp. 793-796 ◽  
Author(s):  
C.H. Wang ◽  
C.H. Yeh ◽  
F.Y. Shih ◽  
C.W. Chow ◽  
K.C. Hsu ◽  
...  

In this investigation, we propose and experimentally investigate a simply self-restored ring-based fiber Bragg grating (FBG) based sensor system. This proposed multi-ring passive sensing architecture is without any active components in the entire network. In this experiment, the network survivability and capacity for the multi-point sensor systems are also enhanced. Besides, the tunable laser source (TLS) is adopted in central office (CO) for FBG sensing. The survivability of a eight-point FBG sensor is examined and analyzed. Due to the passive sensor network, the cost-effective and intelligent sensing system is entirely centralized by CO. As a result, the experimental results show that the proposed system can assist the reliable FBG sensing network for a large-scale and multi-point architecture.


1987 ◽  
Vol 65 (8) ◽  
pp. 821-830 ◽  
Author(s):  
A. C. de Wilton ◽  
M. Simard-Normandin ◽  
P. T. T. Wong

A new Raman technique for monitoring low-dose ion implants is described. The capability for detection of implants of 20– 50 keV B+ (or equivalent [Formula: see text] energies) at doses as low as ~1010 cm−2 is of particular interest. Currently, there are few other noncontact, nondestructive methods of evaluating implant doses below 1013 cm−2 (e.g., Vt-adjust, field, and p-well implants) in patterened production wafers. The feasibility of using the technique for monitoring Vt-adjust implants is demonstrated.Low-energy B+ and [Formula: see text] ion implants in silicon were studied to determine the detection limits of the technique. Samples were analyzed immediately after implantation, without annealing. Implant doses in the range from 3 × 1016 cm−2 to the detection limit of 3 × 1010 cm−2 were characterized in this way. The presence of a surface layer of SiO2 (≤ 100 nm thick) did not interfere with the measurements. A tunable laser was used to optimize the sensitivity to implants of different energies.Since the frequency spectrum of Raman scattering can also provide information on the structure of the damaged region or on the distribution of activated boron and residual ion damage after annealing, Raman spectroscopy shows promise in several applications for in situ process monitoring of ion implantation for very large scale integration technology.


Author(s):  
Jianglai Wu ◽  
Yiqing Xu ◽  
Xiaoming Wei ◽  
Jingjiang Xu ◽  
Antony C. S. Chan ◽  
...  

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.


1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.


2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.


Author(s):  
Simon Thomas

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.


Author(s):  
V. C. Kannan ◽  
A. K. Singh ◽  
R. B. Irwin ◽  
S. Chittipeddi ◽  
F. D. Nkansah ◽  
...  

Titanium nitride (TiN) films have historically been used as diffusion barrier between silicon and aluminum, as an adhesion layer for tungsten deposition and as an interconnect material etc. Recently, the role of TiN films as contact barriers in very large scale silicon integrated circuits (VLSI) has been extensively studied. TiN films have resistivities on the order of 20μ Ω-cm which is much lower than that of titanium (nearly 66μ Ω-cm). Deposited TiN films show resistivities which vary from 20 to 100μ Ω-cm depending upon the type of deposition and process conditions. TiNx is known to have a NaCl type crystal structure for a wide range of compositions. Change in color from metallic luster to gold reflects the stabilization of the TiNx (FCC) phase over the close packed Ti(N) hexagonal phase. It was found that TiN (1:1) ideal composition with the FCC (NaCl-type) structure gives the best electrical property.


Author(s):  
J. Liu ◽  
N. D. Theodore ◽  
D. Adams ◽  
S. Russell ◽  
T. L. Alford ◽  
...  

Copper-based metallization has recently attracted extensive research because of its potential application in ultra-large-scale integration (ULSI) of semiconductor devices. The feasibility of copper metallization is, however, limited due to its thermal stability issues. In order to utilize copper in metallization systems diffusion barriers such as titanium nitride and other refractory materials, have been employed to enhance the thermal stability of copper. Titanium nitride layers can be formed by annealing Cu(Ti) alloy film evaporated on thermally grown SiO2 substrates in an ammonia ambient. We report here the microstructural evolution of Cu(Ti)/SiO2 layers during annealing in NH3 flowing ambient.The Cu(Ti) films used in this experiment were prepared by electron beam evaporation onto thermally grown SiO2 substrates. The nominal composition of the Cu(Ti) alloy was Cu73Ti27. Thermal treatments were conducted in NH3 flowing ambient for 30 minutes at temperatures ranging from 450°C to 650°C. Cross-section TEM specimens were prepared by the standard procedure.


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