[Show abstract][Hide abstract] ABSTRACT: We present a novel technique for the calibration of a high speed FBG interrogation system which incorporates an Arrayed Waveguide Grating (AWG). It uses temperature tuning to wavelength sweep the AWG to generate calibration data and to determine the optimum temperature of AWG for the actual test. For ideal operation the FBG wavelengths under zero stimulus would lie midway between the International Telecommunications Union (ITU) grid wavelengths of the AWG. The attached FBG wavelengths cannot always be accurately prescribed since they vary during attachment, and with temperature. This technique reduces this constraint and enables different detector gains to be used on different channels for system optimisation.
Proceedings of SPIE - The International Society for Optical Engineering 10/2009; DOI:10.1117/12.835967 · 0.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ultra fast X-ray imaging has been undertaken upon AWE's and Sandia National Laboratories' radiation effects x-ray simulators. These simulators typically yield a single very short (<20ns) pulse of high-energy (MeV endpoint energy bremsstrahlung) x-ray radiation with doses in the kilorad (krad (Si)) region. X-ray source targets vary in size from 2 to 25cm diameter, dependent upon the particular simulator. Electronic imaging of the source x-ray emission under dynamic conditions yields valuable information upon how the simulator is performing. The resultant images are of interest to the simulator designer who may configure new x-ray source converter targets and diode designs. The images can provide quantitative information about machine performance during radiation effects testing of components under active conditions. The paper highlights the new ULTRA fast framing camera, developed by Photek Ltd. in-conjunction with AWE, which is capable of imaging up to 500 Million frames per second. Unique sequences of time resolved high spatial resolution images, have been captured in the nanosecond timeframe with zero interframe time, of the source x-rays, utilising our novel configurations. Further, a dedicated diagnostic experiment capturing time resolved x-ray phenomenon, utilising a customised streak tomographic technique, with a multi-billion frames per second recording and 2048 frames capture sequence capability, is described. The fundamental principles of our imaging systems can be applied to other visible and x-ray imaging scenarios.
Proceedings of SPIE - The International Society for Optical Engineering 11/2008; DOI:10.1117/12.819937 · 0.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We report a compact two-dimensional accelerometer based upon a simple fiber cantilever constructed from a short length of multicore optical fiber. Two-axis measurement is demonstrated up to 3 kHz. Differential measurement between fiber Bragg gratings written in the multicore fiber provides temperature-insensitive measurements.
[Show abstract][Hide abstract] ABSTRACT: We report an accelerometer based upon a simple fibre cantilever constructed from a short length of multicore fibre (MCF) containing fibre Bragg gratings (FBGs). Two-axis measurement is demonstrated up to 3 kHz.
Proceedings of SPIE - The International Society for Optical Engineering 01/2007; DOI:10.1117/12.738411 · 0.20 Impact Factor