Sua Sponte Appellate Rulings: When Courts Deprive Litigants of an Opportunity to Be Heard

But the Supreme Court and other appellate courts have failed to follow any consistent practice about sua sponte holdings. The difficulty courts have is illustrated by the fact that even the most prominent appellate judges sometimes say they want procedural regularity, but in other cases exercise the freedom to do what they like

The grand opening of the Narrabri Zoo in 2004 July

The zoo system is installed in Narrabri. The relay box is rewired so that it can handle the new blind motor

Four-Wave Mixing in Semiconductor Traveling-wave Amplifiers for Efficient, Broadband, Wavelength Conversion up to 65 nm

Wavelength conversion is recognized as an important function in future fiber networks employing wavelength division multiplexing. The authors have recently demonstrated broad-band wavelength conversion over spans as large as 27 nm. Their approach uses ultra-fast four-wave mixing dynamics associated with intraband relaxation mechanisms in semiconductor traveling-wave amplifiers (TWA's). In the paper the authors present new results showing conversion over wavelength spans as large as 65 nm. This surpasses the previous record by over a factor of two. Of equal importance, they also verify experimentally their previous theoretical prediction that wavelength conversion efficiency varies as the cube of TWA single pass gain. In the course of our previous work, we have shown that the theoretical efficiency, η, of this process can be expressed by the simple relation: η = 3G + 2P + R(Δ⋋) where η is the ratio in dB of the converted signal output power to the signal input power and G is the single pass TWA optical gain. A crucial point is the presence of 3G in this expression - essentially, the wavelength converter uses the available TWA optimal gain three times. We verified this expression using an experimental setup similar to that described in. Tunable, single-frequency, erbium fiber ring lasers were used as pump and signal sources and TWA devices used contained tensile-strained mutli-quantum well active layers described in. Figure 1 shows conversion efficiency data plotted versus single-pass saturated optical gain. The pump power was -5.2 dBm and the signal power was -11.3 dBm. The measured slope of 3.18 confirms the cubic dependence of efficiency on single pass gain

Four-wave mixing wavelength conversion efficiency in semiconductor traveling-wave amplifiers measured to 65 nm of wavelength shift

The efficiency of broadband optical wavelength conversion by four-wave mixing in semiconductor traveling-wave amplifiers is measured for wavelength shifts up to 65 nm using a tandem amplifier geometry. A quantity we call the relative conversion efficiency function, which determines the strength of the four-wave mixing nonlinearity, was extracted from the data. Using this quantity, gain requirements for lossless four-wave mixing wavelength conversion are calculated and discussed. Signal to background noise ratio is also measured and discussed in this study

Study of interwell carrier transport by terahertz four-wave mixing in an optical amplifier with tensile and compressively strained quantum wells

Interwell carrier transport in a semiconductor optical amplifier having a structure of alternating tensile and compressively strained quantum wells was studied by four-wave mixing at detuning frequencies up to 1 THz. A calculation of transbarrier transport efficiency is also presented to qualitatively explain the measured signal spectra

BeebSub #56C -- an improved BBC computer substitute

The improved BBC Computer Substitute in Izaña is described

BeebSub #56A and BeebSub #56B BBC Computer Substitutes

The BBC Computer Substitutes in Izaña are described

The removal of Jabba from Carnarvon in 2006 November

Ian Barnes, Brek Miller, and Barry Jackson visited Carnarvon late in 2006. Jabba was removed from the mount, the weather cabling was replaced, all the dome roolers were replaced, the cloud detector LDR was replaced, some mount limit switches were replaced, the computer was replaced, the temperature onitor was reconfigured to monitor different things, the PMTEB was replaced, and the autoguider was realigned

Efficiency of broadband four-wave mixing wavelength conversion using semiconductor traveling-wave amplifiers

We present a theoretical analysis and experimental measurements of broadband optical wavelength conversion by four-wave mixing in semiconductor traveling-wave amplifiers. In the theoretical analysis, we obtain an analytical expression for the conversion efficiency. In the experiments, both up and down-conversion efficiencies are measured as a function of wavelength shift for shifts up to 27 nm. The experimental data are well explained by the theoretical calculation. The observed higher conversion efficiency for wavelength down-conversion is believed to be caused by phase interferences that exist between various mechanisms contributing to the four-wave mixing process

Terahertz four-wave mixing spectroscopy for study of ultrafast dynamics in a semiconductor optical amplifier

Ultrafast dynamics in a 1.5-µm tensile-strained quantum-well optical amplifier has been studied by highly nondegenerate four-wave mixing at detuning frequencies up to 1.7 THz. Frequency response data indicate the presence of two ultrafast physical processes with characteristic relaxation lifetimes of 650 fs and <100 fs. The longer time constant is believed to be associated with the dynamic carrier heating effect. This is in agreement with previous time-domain pump-probe measurements using ultrashort optical pulses