Optimised Chirped Fibre Bragg Gratings for Detonation Velocity Measurements

Abstract

Over the last decade, the use of chirped fibre Bragg gratings (CFBGs) in detonation velocity experiments has been steadily increasing. In this paper, we show how CFBG design parameters—chirp-rate, reflectivity and apodisation—affect linearity in detonation velocity tests. It is found that the optimal CFBG detonation velocity probe should have a high chirp-rate, a low reflectivity and no apodisation. As a further demonstration of these findings, we measure detonation velocity with a 24 cm optimised CFBG; the longest CFBG test of this kind so far.

Keywords

• fibre sensing
• fibre Bragg gratings
• chirped gratings
• detonation
• velocity sensing