Characterisation of a fibre Raman oscillator using fibre grating reflectors

We have constructed a completely integrated fibre Raman oscillator using two fibre grating reflectors. This was synchronously mode-locked using a CW mode-locked Nd:YAG laser operating at 1.06?m. Spectral and temporal characteristics of the Raman oscillator are presented.     

Performance evaluation of waveguide phase modulators for coherent systems at 1.3 and 1.5 µm

This article describes the fabrication and performance evaluation ofX-cut andZ-cut Ti:LiNbO3traveling wave waveguide phase modulators designed for coherent systems applications at 1.3 and 1.5 μm. Details of device fabrication and measurements of phase shift as a function of optical wavelength, input polarization, modulation voltage, and modulation frequency are reported. Phase modulator performance in a 40-Mbit/s self-heterodyne coherent DPSK experiment is also discussed.     

Bush u-turn on renewables?

Despite early indications from the Bush Administration that renewable energy was neither a top priority nor to be funded at levels seen in the Clinton Administration, there appears to be a slow back peddling on this issue. President George W. Bush's proposed energy programme has been encountering mounting hostility on Capitol Hill in Washington as well as significantly growing opposition among many Americans. Don Smith, US correspondent for Refocus magazine reports.     

Device for Controlling and Programming a Pneumatic Amplifier Pump in a Supercritical Fluid Chromatograph

ABSTRACT

Feedback from a pressure transducer at the pump output is used to activate a stepper motor to adjust an air regulator that controls the pump pressure. Control within 2.4% at 615 psig was obtained. In addition, linear pressure programs at flow rates between 0.2 and 2 cc/min were performed. Control or programming was limited only by the inherent range of the pressure transducer.     

The effect of solder paste residues on RF signal integrity

Wireless devices such as pagers and cellular phones are becoming common consumer items. These products require low loss RF signal propagation which is affected by material choices and processing conditions. This paper examines the effect of a series of no-clean solder pastes on signal integrity using an RF test circuit which sends a broadband signal through a gallium arsenide antenna switch and measures its transmission using a network analyzer. The test circuit also measures signal leakage. This paper reports on two different test vehicles, one that uses a 900 MHz antenna switch, and the other that uses a 2.0 GHz antenna switch. The transmission and leakage readings were taken daily for 16–21 days while the test vehicles were under accelerated aging conditions of 85°C and 85% RH. Average values for the readings for each solder paste were plotted to provide comparison among the pastes. The comparison data clearly distinguish solder pastes that provide consistency throughout the test period from those which do not.